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1e0e535b02
libvirt/src/util/virfile.c
Michal Privoznik b7d4e6b67e lib: Replace VIR_AUTOSTRINGLIST with GStrv 
Glib provides g_auto(GStrv) which is in-place replacement of our
VIR_AUTOSTRINGLIST.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-12-02 15:43:07 +01:00

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116 KiB
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/*
* virfile.c: safer file handling
*
* Copyright (C) 2010-2014 Red Hat, Inc.
* Copyright (C) 2010 IBM Corporation
* Copyright (C) 2010 Stefan Berger
* Copyright (C) 2010 Eric Blake
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include "internal.h"
#include <fcntl.h>
#ifndef WIN32
# include <termios.h>
#endif
#ifdef WITH_PTY_H
/* Linux openpty */
# include <pty.h>
#endif
#ifdef WITH_UTIL_H
/* macOS openpty */
# include <util.h>
#endif
#ifdef WITH_LIBUTIL_H
/* FreeBSD openpty */
# include <libutil.h>
#endif
#include <sys/stat.h>
#if defined(WITH_SYS_MOUNT_H)
# include <sys/mount.h>
#endif
#include <unistd.h>
#include <dirent.h>
#if defined WITH_MNTENT_H && defined WITH_GETMNTENT_R
# include <mntent.h>
#endif
#if WITH_MMAP
# include <sys/mman.h>
#endif
#if WITH_SYS_SYSCALL_H
# include <sys/syscall.h>
#endif
#if WITH_SYS_ACL_H
# include <sys/acl.h>
#endif
#include <sys/file.h>
#ifdef __linux__
# if WITH_LINUX_MAGIC_H
# include <linux/magic.h>
# endif
# include <sys/statfs.h>
# if WITH_DECL_LO_FLAGS_AUTOCLEAR
# include <linux/loop.h>
# endif
# include <sys/ioctl.h>
# include <linux/cdrom.h>
# include <linux/fs.h>
#endif
#if WITH_LIBATTR
# include <sys/xattr.h>
#endif
#include "configmake.h"
#include "viralloc.h"
#include "vircommand.h"
#include "virerror.h"
#include "virfile.h"
#include "virkmod.h"
#include "virlog.h"
#include "virprocess.h"
#include "virstring.h"
#include "virutil.h"
#include "virsocket.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.file");
#ifndef S_ISUID
# define S_ISUID 04000
#endif
#ifndef S_ISGID
# define S_ISGID 02000
#endif
#ifndef S_ISVTX
# define S_ISVTX 01000
#endif
#ifndef O_DIRECT
# define O_DIRECT 0
#endif
int virFileClose(int *fdptr, virFileCloseFlags flags)
{
int saved_errno = 0;
int rc = 0;
if (*fdptr < 0)
return 0;
if (flags & VIR_FILE_CLOSE_PRESERVE_ERRNO)
saved_errno = errno;
rc = close(*fdptr);
if (!(flags & VIR_FILE_CLOSE_DONT_LOG)) {
if (rc < 0) {
if (errno == EBADF) {
if (!(flags & VIR_FILE_CLOSE_IGNORE_EBADF))
VIR_WARN("Tried to close invalid fd %d", *fdptr);
} else {
VIR_DEBUG("Failed to close fd %d: %s",
*fdptr, g_strerror(errno));
}
}
}
*fdptr = -1;
if (flags & VIR_FILE_CLOSE_PRESERVE_ERRNO)
errno = saved_errno;
return rc;
}
int virFileFclose(FILE **file, bool preserve_errno)
{
int saved_errno = 0;
int rc = 0;
if (*file) {
if (preserve_errno)
saved_errno = errno;
rc = fclose(*file);
*file = NULL;
if (preserve_errno)
errno = saved_errno;
}
return rc;
}
FILE *virFileFdopen(int *fdptr, const char *mode)
{
FILE *file = NULL;
if (*fdptr >= 0) {
file = fdopen(*fdptr, mode);
if (file)
*fdptr = -1;
} else {
errno = EBADF;
}
return file;
}
/**
* virFileDirectFdFlag:
*
* Returns 0 if the kernel can avoid file system cache pollution
* without any additional flags, O_DIRECT if the original fd must be
* opened in direct mode, or -1 if there is no support for bypassing
* the file system cache.
*/
int
virFileDirectFdFlag(void)
{
/* XXX For now, Linux posix_fadvise is not powerful enough to
* avoid O_DIRECT. */
return O_DIRECT ? O_DIRECT : -1;
}
/* Opaque type for managing a wrapper around a fd. For now,
* read-write is not supported, just a single direction. */
struct _virFileWrapperFd {
bool closed; /* Whether virFileWrapperFdClose() has been already called */
virCommandPtr cmd; /* Child iohelper process to do the I/O. */
char *err_msg; /* stderr of @cmd */
};
#ifndef WIN32
/**
* virFileWrapperFdNew:
* @fd: pointer to fd to wrap
* @name: name of fd, for diagnostics
* @flags: bitwise-OR of virFileWrapperFdFlags
*
* Update @fd so that it meets parameters requested by @flags.
*
* If VIR_FILE_WRAPPER_BYPASS_CACHE bit is set in @flags, @fd will be updated
* in a way that all I/O to that file will bypass the system cache. The
* original fd must have been created with virFileDirectFdFlag() among the
* flags to open().
*
* If VIR_FILE_WRAPPER_NON_BLOCKING bit is set in @flags, @fd will be updated
* to ensure it properly supports non-blocking I/O, i.e., it will report
* EAGAIN.
*
* This must be called after open() and optional fchown() or fchmod(), but
* before any seek or I/O, and only on seekable fd. The file must be O_RDONLY
* (to read the entire existing file) or O_WRONLY (to write to an empty file).
* In some cases, @fd is changed to a non-seekable pipe; in this case, the
* caller must not do anything further with the original fd.
*
* On success, the new wrapper object is returned, which must be later
* freed with virFileWrapperFdFree(). On failure, @fd is unchanged, an
* error message is output, and NULL is returned.
*/
virFileWrapperFdPtr
virFileWrapperFdNew(int *fd, const char *name, unsigned int flags)
{
virFileWrapperFdPtr ret = NULL;
bool output = false;
int pipefd[2] = { -1, -1 };
int mode = -1;
g_autofree char *iohelper_path = NULL;
if (!flags) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use with no flags"));
return NULL;
}
/* XXX support posix_fadvise rather than O_DIRECT, if the kernel support
* for that is decent enough. In that case, we will also need to
* explicitly support VIR_FILE_WRAPPER_NON_BLOCKING since
* VIR_FILE_WRAPPER_BYPASS_CACHE alone will no longer require spawning
* iohelper.
*/
if ((flags & VIR_FILE_WRAPPER_BYPASS_CACHE) && !O_DIRECT) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("O_DIRECT unsupported on this platform"));
return NULL;
}
ret = g_new0(virFileWrapperFd, 1);
mode = fcntl(*fd, F_GETFL);
if (mode < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, _("invalid fd %d for %s"),
*fd, name);
goto error;
} else if ((mode & O_ACCMODE) == O_WRONLY) {
output = true;
} else if ((mode & O_ACCMODE) != O_RDONLY) {
virReportError(VIR_ERR_INTERNAL_ERROR, _("unexpected mode 0x%x for %s"),
mode & O_ACCMODE, name);
goto error;
}
if (virPipe(pipefd) < 0)
goto error;
if (!(iohelper_path = virFileFindResource("libvirt_iohelper",
abs_top_builddir "/src",
LIBEXECDIR)))
goto error;
ret->cmd = virCommandNewArgList(iohelper_path, name, NULL);
if (output) {
virCommandSetInputFD(ret->cmd, pipefd[0]);
virCommandSetOutputFD(ret->cmd, fd);
virCommandAddArg(ret->cmd, "1");
} else {
virCommandSetInputFD(ret->cmd, *fd);
virCommandSetOutputFD(ret->cmd, &pipefd[1]);
virCommandAddArg(ret->cmd, "0");
}
/* In order to catch iohelper stderr, we must change
* iohelper's env so virLog functions print to stderr
*/
virCommandAddEnvPair(ret->cmd, "LIBVIRT_LOG_OUTPUTS", "1:stderr");
virCommandSetErrorBuffer(ret->cmd, &ret->err_msg);
virCommandDoAsyncIO(ret->cmd);
if (virCommandRunAsync(ret->cmd, NULL) < 0)
goto error;
if (VIR_CLOSE(pipefd[!output]) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("unable to close pipe"));
goto error;
}
VIR_FORCE_CLOSE(*fd);
*fd = pipefd[output];
return ret;
error:
VIR_FORCE_CLOSE(pipefd[0]);
VIR_FORCE_CLOSE(pipefd[1]);
virFileWrapperFdFree(ret);
return NULL;
}
#else /* WIN32 */
virFileWrapperFdPtr
virFileWrapperFdNew(int *fd G_GNUC_UNUSED,
const char *name G_GNUC_UNUSED,
unsigned int fdflags G_GNUC_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("virFileWrapperFd unsupported on this platform"));
return NULL;
}
#endif /* WIN32 */
/**
* virFileWrapperFdClose:
* @wfd: fd wrapper, or NULL
*
* If @wfd is valid, then ensure that I/O has completed, which may
* include reaping a child process. Return 0 if all data for the
* wrapped fd is complete, or -1 on failure with an error emitted.
* This function intentionally returns 0 when @wfd is NULL, so that
* callers can conditionally create a virFileWrapperFd wrapper but
* unconditionally call the cleanup code. To avoid deadlock, only
* call this after closing the fd resulting from virFileWrapperFdNew().
*
* This function can be safely called multiple times on the same @wfd.
*/
int
virFileWrapperFdClose(virFileWrapperFdPtr wfd)
{
int ret;
if (!wfd || wfd->closed)
return 0;
ret = virCommandWait(wfd->cmd, NULL);
/* If the command used to process I/O has failed and produced some
* messages on stderr, it's fair to assume those will be more
* relevant to the user than whatever eg. QEMU can figure out on its
* own having no knowledge of the fact a command is handling its I/O
* in the first place, so it's okay if we end up discarding an
* existing error here */
if (ret < 0 && wfd->err_msg && *wfd->err_msg)
virReportError(VIR_ERR_OPERATION_FAILED, "%s", wfd->err_msg);
wfd->closed = true;
return ret;
}
/**
* virFileWrapperFdFree:
* @wfd: fd wrapper, or NULL
*
* Free all remaining resources associated with @wfd. If
* virFileWrapperFdClose() was not previously called, then this may
* discard some previous I/O. To avoid deadlock, only call this after
* closing the fd resulting from virFileWrapperFdNew().
*/
void
virFileWrapperFdFree(virFileWrapperFdPtr wfd)
{
if (!wfd)
return;
VIR_FREE(wfd->err_msg);
virCommandFree(wfd->cmd);
VIR_FREE(wfd);
}
#ifndef WIN32
/**
* virFileLock:
* @fd: file descriptor to acquire the lock on
* @shared: type of lock to acquire
* @start: byte offset to start lock
* @len: length of lock (0 to acquire entire remaining file from @start)
* @waitForLock: wait for previously held lock or not
*
* Attempt to acquire a lock on the file @fd. If @shared
* is true, then a shared lock will be acquired,
* otherwise an exclusive lock will be acquired. If
* the lock cannot be acquired, an error will be
* returned. If @waitForLock is true, this will wait
* for the lock if another process has already acquired it.
*
* The lock will be released when @fd is closed. The lock
* will also be released if *any* other open file descriptor
* pointing to the same underlying file is closed. As such
* this function should not be relied on in multi-threaded
* apps where other threads can be opening/closing arbitrary
* files.
*
* Returns 0 on success, or -errno otherwise
*/
int virFileLock(int fd, bool shared, off_t start, off_t len, bool waitForLock)
{
struct flock fl = {
.l_type = shared ? F_RDLCK : F_WRLCK,
.l_whence = SEEK_SET,
.l_start = start,
.l_len = len,
};
int cmd = waitForLock ? F_SETLKW : F_SETLK;
if (fcntl(fd, cmd, &fl) < 0)
return -errno;
return 0;
}
/**
* virFileUnlock:
* @fd: file descriptor to release the lock on
* @start: byte offset to start unlock
* @len: length of lock (0 to release entire remaining file from @start)
*
* Release a lock previously acquired with virFileUnlock().
* NB the lock will also be released if any open file descriptor
* pointing to the same file as @fd is closed
*
* Returns 0 on success, or -errno on error
*/
int virFileUnlock(int fd, off_t start, off_t len)
{
struct flock fl = {
.l_type = F_UNLCK,
.l_whence = SEEK_SET,
.l_start = start,
.l_len = len,
};
if (fcntl(fd, F_SETLK, &fl) < 0)
return -errno;
return 0;
}
#else /* WIN32 */
int virFileLock(int fd G_GNUC_UNUSED,
bool shared G_GNUC_UNUSED,
off_t start G_GNUC_UNUSED,
off_t len G_GNUC_UNUSED,
bool waitForLock G_GNUC_UNUSED)
{
return -ENOSYS;
}
int virFileUnlock(int fd G_GNUC_UNUSED,
off_t start G_GNUC_UNUSED,
off_t len G_GNUC_UNUSED)
{
return -ENOSYS;
}
#endif /* WIN32 */
int
virFileRewrite(const char *path,
mode_t mode,
virFileRewriteFunc rewrite,
const void *opaque)
{
g_autofree char *newfile = NULL;
int fd = -1;
int ret = -1;
newfile = g_strdup_printf("%s.new", path);
if ((fd = open(newfile, O_WRONLY | O_CREAT | O_TRUNC, mode)) < 0) {
virReportSystemError(errno, _("cannot create file '%s'"),
newfile);
goto cleanup;
}
if (rewrite(fd, opaque) < 0) {
virReportSystemError(errno, _("cannot write data to file '%s'"),
newfile);
goto cleanup;
}
if (g_fsync(fd) < 0) {
virReportSystemError(errno, _("cannot sync file '%s'"),
newfile);
goto cleanup;
}
if (VIR_CLOSE(fd) < 0) {
virReportSystemError(errno, _("cannot save file '%s'"),
newfile);
goto cleanup;
}
if (rename(newfile, path) < 0) {
virReportSystemError(errno, _("cannot rename file '%s' as '%s'"),
newfile, path);
goto cleanup;
}
ret = 0;
cleanup:
VIR_FORCE_CLOSE(fd);
unlink(newfile);
return ret;
}
static int
virFileRewriteStrHelper(int fd, const void *opaque)
{
const char *data = opaque;
if (safewrite(fd, data, strlen(data)) < 0)
return -1;
return 0;
}
int
virFileRewriteStr(const char *path,
mode_t mode,
const char *str)
{
return virFileRewrite(path, mode,
virFileRewriteStrHelper, str);
}
int virFileTouch(const char *path, mode_t mode)
{
int fd = -1;
if ((fd = open(path, O_WRONLY | O_CREAT, mode)) < 0) {
virReportSystemError(errno, _("cannot create file '%s'"),
path);
return -1;
}
if (VIR_CLOSE(fd) < 0) {
virReportSystemError(errno, _("cannot save file '%s'"),
path);
VIR_FORCE_CLOSE(fd);
return -1;
}
return 0;
}
#define MODE_BITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
int virFileUpdatePerm(const char *path,
mode_t mode_remove,
mode_t mode_add)
{
struct stat sb;
mode_t mode;
if (mode_remove & ~MODE_BITS || mode_add & ~MODE_BITS) {
virReportError(VIR_ERR_INVALID_ARG, "%s", _("invalid mode"));
return -1;
}
if (stat(path, &sb) < 0) {
virReportSystemError(errno, _("cannot stat '%s'"), path);
return -1;
}
mode = sb.st_mode & MODE_BITS;
if ((mode & mode_remove) == 0 && (mode & mode_add) == mode_add)
return 0;
mode &= MODE_BITS ^ mode_remove;
mode |= mode_add;
if (chmod(path, mode) < 0) {
virReportSystemError(errno, _("cannot change permission of '%s'"),
path);
return -1;
}
return 0;
}
#if defined(__linux__) && WITH_DECL_LO_FLAGS_AUTOCLEAR
# if WITH_DECL_LOOP_CTL_GET_FREE
/* virFileLoopDeviceOpenLoopCtl() returns -1 when a real failure has occurred
* while in the process of allocating or opening the loop device. On success
* we return 0 and modify the fd to the appropriate file descriptor.
* If /dev/loop-control does not exist, we return 0 and do not set fd. */
static int virFileLoopDeviceOpenLoopCtl(char **dev_name, int *fd)
{
int devnr;
int ctl_fd;
char *looppath = NULL;
VIR_DEBUG("Opening loop-control device");
if ((ctl_fd = open("/dev/loop-control", O_RDWR)) < 0) {
if (errno == ENOENT)
return 0;
virReportSystemError(errno, "%s",
_("Unable to open /dev/loop-control"));
return -1;
}
if ((devnr = ioctl(ctl_fd, LOOP_CTL_GET_FREE)) < 0) {
virReportSystemError(errno, "%s",
_("Unable to get free loop device via ioctl"));
close(ctl_fd);
return -1;
}
close(ctl_fd);
VIR_DEBUG("Found free loop device number %i", devnr);
looppath = g_strdup_printf("/dev/loop%i", devnr);
if ((*fd = open(looppath, O_RDWR)) < 0) {
virReportSystemError(errno,
_("Unable to open %s"), looppath);
VIR_FREE(looppath);
return -1;
}
*dev_name = looppath;
return 0;
}
# endif /* WITH_DECL_LOOP_CTL_GET_FREE */
static int virFileLoopDeviceOpenSearch(char **dev_name)
{
int fd = -1;
g_autoptr(DIR) dh = NULL;
struct dirent *de;
char *looppath = NULL;
struct loop_info64 lo;
int direrr;
VIR_DEBUG("Looking for loop devices in /dev");
if (virDirOpen(&dh, "/dev") < 0)
goto cleanup;
while ((direrr = virDirRead(dh, &de, "/dev")) > 0) {
/* Checking 'loop' prefix is insufficient, since
* new kernels have a dev named 'loop-control'
*/
if (!STRPREFIX(de->d_name, "loop") ||
!g_ascii_isdigit(de->d_name[4]))
continue;
looppath = g_strdup_printf("/dev/%s", de->d_name);
VIR_DEBUG("Checking up on device %s", looppath);
if ((fd = open(looppath, O_RDWR)) < 0) {
virReportSystemError(errno,
_("Unable to open %s"), looppath);
goto cleanup;
}
if (ioctl(fd, LOOP_GET_STATUS64, &lo) < 0) {
/* Got a free device, return the fd */
if (errno == ENXIO)
goto cleanup;
VIR_FORCE_CLOSE(fd);
virReportSystemError(errno,
_("Unable to get loop status on %s"),
looppath);
goto cleanup;
}
/* Oh well, try the next device */
VIR_FORCE_CLOSE(fd);
VIR_FREE(looppath);
}
if (direrr < 0)
goto cleanup;
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Unable to find a free loop device in /dev"));
cleanup:
if (fd != -1) {
VIR_DEBUG("Got free loop device %s %d", looppath, fd);
*dev_name = looppath;
} else {
VIR_DEBUG("No free loop devices available");
VIR_FREE(looppath);
}
return fd;
}
static int virFileLoopDeviceOpen(char **dev_name)
{
int loop_fd = -1;
# if WITH_DECL_LOOP_CTL_GET_FREE
if (virFileLoopDeviceOpenLoopCtl(dev_name, &loop_fd) < 0)
return -1;
VIR_DEBUG("Return from loop-control got fd %d", loop_fd);
if (loop_fd >= 0)
return loop_fd;
# endif /* WITH_DECL_LOOP_CTL_GET_FREE */
/* Without the loop control device we just use the old technique. */
loop_fd = virFileLoopDeviceOpenSearch(dev_name);
return loop_fd;
}
int virFileLoopDeviceAssociate(const char *file,
char **dev)
{
int lofd = -1;
int fsfd = -1;
struct loop_info64 lo;
g_autofree char *loname = NULL;
int ret = -1;
if ((lofd = virFileLoopDeviceOpen(&loname)) < 0)
return -1;
memset(&lo, 0, sizeof(lo));
lo.lo_flags = LO_FLAGS_AUTOCLEAR;
/* Set backing file name for LOOP_GET_STATUS64 queries */
if (virStrncpy((char *) lo.lo_file_name, file,
strlen(file), LO_NAME_SIZE) < 0) {
virReportSystemError(errno,
_("Unable to set backing file %s"), file);
goto cleanup;
}
if ((fsfd = open(file, O_RDWR)) < 0) {
virReportSystemError(errno,
_("Unable to open %s"), file);
goto cleanup;
}
if (ioctl(lofd, LOOP_SET_FD, fsfd) < 0) {
virReportSystemError(errno,
_("Unable to attach %s to loop device"),
file);
goto cleanup;
}
if (ioctl(lofd, LOOP_SET_STATUS64, &lo) < 0) {
virReportSystemError(errno, "%s",
_("Unable to mark loop device as autoclear"));
if (ioctl(lofd, LOOP_CLR_FD, 0) < 0)
VIR_WARN("Unable to detach %s from loop device", file);
goto cleanup;
}
VIR_DEBUG("Attached loop device %s %d to %s", file, lofd, loname);
*dev = loname;
loname = NULL;
ret = 0;
cleanup:
VIR_FORCE_CLOSE(fsfd);
if (ret == -1)
VIR_FORCE_CLOSE(lofd);
return lofd;
}
# define SYSFS_BLOCK_DIR "/sys/block"
# define NBD_DRIVER "nbd"
static int
virFileNBDDeviceIsBusy(const char *dev_name)
{
g_autofree char *path = NULL;
path = g_strdup_printf(SYSFS_BLOCK_DIR "/%s/pid", dev_name);
if (!virFileExists(path)) {
if (errno == ENOENT)
return 0;
else
virReportSystemError(errno,
_("Cannot check NBD device %s pid"),
dev_name);
return -1;
}
return 1;
}
static char *
virFileNBDDeviceFindUnused(void)
{
g_autoptr(DIR) dh = NULL;
struct dirent *de;
int direrr;
if (virDirOpen(&dh, SYSFS_BLOCK_DIR) < 0)
return NULL;
while ((direrr = virDirRead(dh, &de, SYSFS_BLOCK_DIR)) > 0) {
if (STRPREFIX(de->d_name, "nbd")) {
int rv = virFileNBDDeviceIsBusy(de->d_name);
if (rv < 0)
return NULL;
if (rv == 0)
return g_strdup_printf("/dev/%s", de->d_name);
}
}
if (direrr < 0)
return NULL;
virReportSystemError(EBUSY, "%s", _("No free NBD devices"));
return NULL;
}
static bool
virFileNBDLoadDriver(void)
{
if (virKModIsProhibited(NBD_DRIVER)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Failed to load nbd module: "
"administratively prohibited"));
return false;
} else {
g_autofree char *errbuf = NULL;
if ((errbuf = virKModLoad(NBD_DRIVER))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Failed to load nbd module"));
return false;
}
}
return true;
}
int virFileNBDDeviceAssociate(const char *file,
virStorageFileFormat fmt,
bool readonly,
char **dev)
{
g_autofree char *nbddev = NULL;
g_autofree char *qemunbd = NULL;
g_autoptr(virCommand) cmd = NULL;
const char *fmtstr = NULL;
if (!virFileNBDLoadDriver())
return -1;
if (!(nbddev = virFileNBDDeviceFindUnused()))
return -1;
if (!(qemunbd = virFindFileInPath("qemu-nbd"))) {
virReportSystemError(ENOENT, "%s",
_("Unable to find 'qemu-nbd' binary in $PATH"));
return -1;
}
if (fmt > 0)
fmtstr = virStorageFileFormatTypeToString(fmt);
cmd = virCommandNew(qemunbd);
/* Explicitly not trying to cope with old qemu-nbd which
* lacked --format. We want to see a fatal error in that
* case since it would be security flaw to continue */
if (fmtstr)
virCommandAddArgList(cmd, "--format", fmtstr, NULL);
if (readonly)
virCommandAddArg(cmd, "-r");
virCommandAddArgList(cmd,
"-n", /* Don't cache in qemu-nbd layer */
"-c", nbddev,
file, NULL);
/* qemu-nbd will daemonize itself */
if (virCommandRun(cmd, NULL) < 0)
return -1;
VIR_DEBUG("Associated NBD device %s with file %s and format %s",
nbddev, file, fmtstr);
*dev = nbddev;
nbddev = NULL;
return 0;
}
#else /* __linux__ */
int virFileLoopDeviceAssociate(const char *file,
char **dev G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS,
_("Unable to associate file %s with loop device"),
file);
*dev = NULL;
return -1;
}
int virFileNBDDeviceAssociate(const char *file,
virStorageFileFormat fmt G_GNUC_UNUSED,
bool readonly G_GNUC_UNUSED,
char **dev G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS,
_("Unable to associate file %s with NBD device"),
file);
return -1;
}
#endif /* __linux__ */
/**
* virFileDeleteTree:
*
* Recursively deletes all files / directories
* starting from the directory @dir. Does not
* follow symlinks
*
* NB the algorithm is not efficient, and is subject to
* race conditions which can be exploited by malicious
* code. It should not be used in any scenarios where
* performance is important, or security is critical.
*/
int virFileDeleteTree(const char *dir)
{
g_autoptr(DIR) dh = NULL;
struct dirent *de;
int direrr;
/* Silently return 0 if passed NULL or directory doesn't exist */
if (!dir || !virFileExists(dir))
return 0;
if (virDirOpen(&dh, dir) < 0)
return -1;
while ((direrr = virDirRead(dh, &de, dir)) > 0) {
g_autofree char *filepath = NULL;
GStatBuf sb;
filepath = g_strdup_printf("%s/%s", dir, de->d_name);
if (g_lstat(filepath, &sb) < 0) {
virReportSystemError(errno, _("Cannot access '%s'"),
filepath);
return -1;
}
if (S_ISDIR(sb.st_mode)) {
if (virFileDeleteTree(filepath) < 0)
return -1;
} else {
if (unlink(filepath) < 0 && errno != ENOENT) {
virReportSystemError(errno,
_("Cannot delete file '%s'"),
filepath);
return -1;
}
}
}
if (direrr < 0)
return -1;
if (rmdir(dir) < 0 && errno != ENOENT) {
virReportSystemError(errno,
_("Cannot delete directory '%s'"),
dir);
return -1;
}
return 0;
}
/* Like read(), but restarts after EINTR. Doesn't play
* nicely with nonblocking FD and EAGAIN, in which case
* you want to use bare read(). Or even use virSocket()
* if the FD is related to a socket rather than a plain
* file or pipe. */
ssize_t
saferead(int fd, void *buf, size_t count)
{
size_t nread = 0;
while (count > 0) {
ssize_t r = read(fd, buf, count);
if (r < 0 && errno == EINTR)
continue;
if (r < 0)
return r;
if (r == 0)
return nread;
buf = (char *)buf + r;
count -= r;
nread += r;
}
return nread;
}
/* Like write(), but restarts after EINTR. Doesn't play
* nicely with nonblocking FD and EAGAIN, in which case
* you want to use bare write(). Or even use virSocket()
* if the FD is related to a socket rather than a plain
* file or pipe. */
ssize_t
safewrite(int fd, const void *buf, size_t count)
{
size_t nwritten = 0;
while (count > 0) {
ssize_t r = write(fd, buf, count);
if (r < 0 && errno == EINTR)
continue;
if (r < 0)
return r;
if (r == 0)
return nwritten;
buf = (const char *)buf + r;
count -= r;
nwritten += r;
}
return nwritten;
}
#ifdef WITH_POSIX_FALLOCATE
static int
safezero_posix_fallocate(int fd, off_t offset, off_t len)
{
int ret = posix_fallocate(fd, offset, len);
if (ret == 0)
return 0;
errno = ret;
return -1;
}
#else /* !WITH_POSIX_FALLOCATE */
static int
safezero_posix_fallocate(int fd G_GNUC_UNUSED,
off_t offset G_GNUC_UNUSED,
off_t len G_GNUC_UNUSED)
{
return -2;
}
#endif /* !WITH_POSIX_FALLOCATE */
#if WITH_SYS_SYSCALL_H && defined(SYS_fallocate)
static int
safezero_sys_fallocate(int fd,
off_t offset,
off_t len)
{
return syscall(SYS_fallocate, fd, 0, offset, len);
}
#else /* !WITH_SYS_SYSCALL_H || !defined(SYS_fallocate) */
static int
safezero_sys_fallocate(int fd G_GNUC_UNUSED,
off_t offset G_GNUC_UNUSED,
off_t len G_GNUC_UNUSED)
{
return -2;
}
#endif /* !WITH_SYS_SYSCALL_H || !defined(SYS_fallocate) */
#ifdef WITH_MMAP
static int
safezero_mmap(int fd, off_t offset, off_t len)
{
int r;
char *buf;
static long pagemask;
off_t map_skip;
/* align offset and length, rounding offset down and length up */
if (pagemask == 0)
pagemask = ~(virGetSystemPageSize() - 1);
map_skip = offset - (offset & pagemask);
/* memset wants the mmap'ed file to be present on disk so create a
* sparse file
*/
r = ftruncate(fd, offset + len);
if (r < 0)
return -1;
buf = mmap(NULL, len + map_skip, PROT_READ | PROT_WRITE, MAP_SHARED,
fd, offset - map_skip);
if (buf != MAP_FAILED) {
memset(buf + map_skip, 0, len);
munmap(buf, len + map_skip);
return 0;
}
/* fall back to writing zeroes using safewrite if mmap fails (for
* example because of virtual memory limits) */
return -2;
}
#else /* !WITH_MMAP */
static int
safezero_mmap(int fd G_GNUC_UNUSED,
off_t offset G_GNUC_UNUSED,
off_t len G_GNUC_UNUSED)
{
return -2;
}
#endif /* !WITH_MMAP */
static int
safezero_slow(int fd, off_t offset, off_t len)
{
int r;
g_autofree char *buf = NULL;
unsigned long long remain, bytes;
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;
/* Split up the write in small chunks so as not to allocate lots of RAM */
remain = len;
bytes = MIN(1024 * 1024, len);
buf = g_new0(char, bytes);
while (remain) {
if (bytes > remain)
bytes = remain;
r = safewrite(fd, buf, bytes);
if (r < 0)
return -1;
/* safewrite() guarantees all data will be written */
remain -= bytes;
}
return 0;
}
int safezero(int fd, off_t offset, off_t len)
{
int ret;
ret = safezero_posix_fallocate(fd, offset, len);
if (ret != -2)
return ret;
if (safezero_sys_fallocate(fd, offset, len) == 0)
return 0;
ret = safezero_mmap(fd, offset, len);
if (ret != -2)
return ret;
return safezero_slow(fd, offset, len);
}
int virFileAllocate(int fd, off_t offset, off_t len)
{
int ret;
ret = safezero_posix_fallocate(fd, offset, len);
if (ret != -2)
return ret;
return safezero_sys_fallocate(fd, offset, len);
}
#if defined WITH_MNTENT_H && defined WITH_GETMNTENT_R
/* search /proc/mounts for mount point of *type; return pointer to
* malloc'ed string of the path if found, otherwise return NULL
* with errno set to an appropriate value.
*/
char *
virFileFindMountPoint(const char *type)
{
FILE *f;
struct mntent mb;
char mntbuf[1024];
char *ret = NULL;
f = setmntent("/proc/mounts", "r");
if (!f)
return NULL;
while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) {
if (STREQ(mb.mnt_type, type)) {
ret = g_strdup(mb.mnt_dir);
goto cleanup;
}
}
if (!ret)
errno = ENOENT;
cleanup:
endmntent(f);
return ret;
}
#else /* defined WITH_MNTENT_H && defined WITH_GETMNTENT_R */
char *
virFileFindMountPoint(const char *type G_GNUC_UNUSED)
{
errno = ENOSYS;
return NULL;
}
#endif /* defined WITH_MNTENT_H && defined WITH_GETMNTENT_R */
int
virBuildPathInternal(char **path, ...)
{
char *path_component = NULL;
g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
va_list ap;
int ret = 0;
va_start(ap, path);
path_component = va_arg(ap, char *);
virBufferAdd(&buf, path_component, -1);
while ((path_component = va_arg(ap, char *)) != NULL) {
virBufferAddChar(&buf, '/');
virBufferAdd(&buf, path_component, -1);
}
va_end(ap);
*path = virBufferContentAndReset(&buf);
if (*path == NULL)
ret = -1;
return ret;
}
/* Read no more than the specified maximum number of bytes. */
static char *
saferead_lim(int fd, size_t max_len, size_t *length)
{
char *buf = NULL;
size_t alloc = 0;
size_t size = 0;
int save_errno;
for (;;) {
int count;
int requested;
if (size + BUFSIZ + 1 > alloc) {
alloc += alloc / 2;
if (alloc < size + BUFSIZ + 1)
alloc = size + BUFSIZ + 1;
if (VIR_REALLOC_N(buf, alloc) < 0) {
save_errno = errno;
break;
}
}
/* Ensure that (size + requested <= max_len); */
requested = MIN(size < max_len ? max_len - size : 0,
alloc - size - 1);
count = saferead(fd, buf + size, requested);
size += count;
if (count != requested || requested == 0) {
save_errno = errno;
if (count < 0)
break;
buf[size] = '\0';
*length = size;
return buf;
}
}
VIR_FREE(buf);
errno = save_errno;
return NULL;
}
/* A wrapper around saferead_lim that merely stops reading at the
* specified maximum size. */
int
virFileReadHeaderFD(int fd, int maxlen, char **buf)
{
size_t len;
char *s;
if (maxlen <= 0) {
errno = EINVAL;
return -1;
}
s = saferead_lim(fd, maxlen, &len);
if (s == NULL)
return -1;
*buf = s;
return len;
}
int
virFileReadHeaderQuiet(const char *path,
int maxlen,
char **buf)
{
int fd;
int len;
fd = open(path, O_RDONLY);
if (fd < 0)
return -1;
len = virFileReadHeaderFD(fd, maxlen, buf);
VIR_FORCE_CLOSE(fd);
return len;
}
/* A wrapper around saferead_lim that maps a failure due to
exceeding the maximum size limitation to EOVERFLOW. */
int
virFileReadLimFD(int fd, int maxlen, char **buf)
{
size_t len;
char *s;
if (maxlen <= 0) {
errno = EINVAL;
return -1;
}
s = saferead_lim(fd, maxlen+1, &len);
if (s == NULL)
return -1;
if (len > maxlen || (int)len != len) {
VIR_FREE(s);
/* There was at least one byte more than MAXLEN.
Set errno accordingly. */
errno = EOVERFLOW;
return -1;
}
*buf = s;
return len;
}
int
virFileReadAll(const char *path, int maxlen, char **buf)
{
int fd;
int len;
fd = open(path, O_RDONLY);
if (fd < 0) {
virReportSystemError(errno, _("Failed to open file '%s'"), path);
return -1;
}
len = virFileReadLimFD(fd, maxlen, buf);
VIR_FORCE_CLOSE(fd);
if (len < 0) {
virReportSystemError(errno, _("Failed to read file '%s'"), path);
return -1;
}
return len;
}
int
virFileReadAllQuiet(const char *path, int maxlen, char **buf)
{
int fd;
int len;
fd = open(path, O_RDONLY);
if (fd < 0)
return -errno;
len = virFileReadLimFD(fd, maxlen, buf);
VIR_FORCE_CLOSE(fd);
if (len < 0)
return -errno;
return len;
}
/* Read @file into preallocated buffer @buf of size @len.
* Return value is -errno in case of errors and size
* of data read (no trailing zero) in case of success.
* If there is more data then @len - 1 then data will be
* truncated. */
int
virFileReadBufQuiet(const char *file, char *buf, int len)
{
int fd;
ssize_t sz;
fd = open(file, O_RDONLY);
if (fd < 0)
return -errno;
sz = saferead(fd, buf, len - 1);
VIR_FORCE_CLOSE(fd);
if (sz < 0)
return -errno;
buf[sz] = '\0';
return sz;
}
/* Truncate @path and write @str to it. If @mode is 0, ensure that
@path exists; otherwise, use @mode if @path must be created.
Return 0 for success, nonzero for failure.
Be careful to preserve any errno value upon failure. */
int
virFileWriteStr(const char *path, const char *str, mode_t mode)
{
int fd;
if (mode)
fd = open(path, O_WRONLY|O_TRUNC|O_CREAT, mode);
else
fd = open(path, O_WRONLY|O_TRUNC);
if (fd == -1)
return -1;
if (safewrite(fd, str, strlen(str)) < 0) {
VIR_FORCE_CLOSE(fd);
return -1;
}
/* Use errno from failed close only if there was no write error. */
if (VIR_CLOSE(fd) != 0)
return -1;
return 0;
}
#define SAME_INODE(Stat_buf_1, Stat_buf_2) \
((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
&& (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
/* Return nonzero if checkLink and checkDest
* refer to the same file. Otherwise, return 0.
*/
int
virFileLinkPointsTo(const char *checkLink,
const char *checkDest)
{
struct stat src_sb;
struct stat dest_sb;
return (stat(checkLink, &src_sb) == 0
&& stat(checkDest, &dest_sb) == 0
&& SAME_INODE(src_sb, dest_sb));
}
/* Return positive if checkLink (residing within directory if not
* absolute) and checkDest refer to the same file. Otherwise, return
* -1 on allocation failure (error reported), or 0 if not the same
* (silent).
*/
int
virFileRelLinkPointsTo(const char *directory,
const char *checkLink,
const char *checkDest)
{
g_autofree char *candidate = NULL;
if (*checkLink == '/')
return virFileLinkPointsTo(checkLink, checkDest);
if (!directory) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("cannot resolve '%s' without starting directory"),
checkLink);
return -1;
}
candidate = g_strdup_printf("%s/%s", directory, checkLink);
return virFileLinkPointsTo(candidate, checkDest);
}
static int
virFileResolveLinkHelper(const char *linkpath,
bool intermediatePaths,
char **resultpath)
{
GStatBuf st;
*resultpath = NULL;
/* We don't need the full canonicalization of intermediate
* directories, if linkpath is absolute and the basename is
* already a non-symlink. */
if (g_path_is_absolute(linkpath) && !intermediatePaths) {
if (g_lstat(linkpath, &st) < 0)
return -1;
#ifndef WIN32
if (!S_ISLNK(st.st_mode)) {
*resultpath = g_strdup(linkpath);
return 0;
}
#endif /* WIN32 */
}
*resultpath = virFileCanonicalizePath(linkpath);
return *resultpath == NULL ? -1 : 0;
}
/*
* Attempt to resolve a symbolic link, returning an
* absolute path where only the last component is guaranteed
* not to be a symlink.
*
* Return 0 if path was not a symbolic, or the link was
* resolved. Return -1 with errno set upon error
*/
int
virFileResolveLink(const char *linkpath, char **resultpath)
{
return virFileResolveLinkHelper(linkpath, false, resultpath);
}
/*
* Attempt to resolve a symbolic link, returning an
* absolute path where every component is guaranteed
* not to be a symlink.
*
* Return 0 if path was not a symbolic, or the link was
* resolved. Return -1 with errno set upon error
*/
int
virFileResolveAllLinks(const char *linkpath, char **resultpath)
{
return virFileResolveLinkHelper(linkpath, true, resultpath);
}
/*
* Check whether the given file is a link.
* Returns 1 in case of the file being a link, 0 in case it is not
* a link and the negative errno in all other cases.
*/
int
virFileIsLink(const char *linkpath)
{
GStatBuf st;
/* Still do this on Windows so we report
* errors like ENOENT, etc
*/
if (g_lstat(linkpath, &st) < 0)
return -errno;
#ifndef WIN32
return S_ISLNK(st.st_mode) != 0;
#else /* WIN32 */
return 0;
#endif /* WIN32 */
}
/*
* Finds a requested executable file in the PATH env. e.g.:
* "qemu-img" will return "/usr/bin/qemu-img"
*
* You must free the result
*/
char *
virFindFileInPath(const char *file)
{
const char *origpath = NULL;
g_auto(GStrv) paths = NULL;
char **pathiter;
if (file == NULL)
return NULL;
/* if we are passed an absolute path (starting with /), return a
* copy of that path, after validating that it is executable
*/
if (g_path_is_absolute(file)) {
if (!virFileIsExecutable(file))
return NULL;
return g_strdup(file);
}
/* If we are passed an anchored path (containing a /), then there
* is no path search - it must exist in the current directory
*/
if (strchr(file, '/')) {
char *abspath = NULL;
if (!virFileIsExecutable(file))
return NULL;
ignore_value(virFileAbsPath(file, &abspath));
return abspath;
}
/* copy PATH env so we can tweak it */
origpath = getenv("PATH");
if (!origpath)
origpath = "/bin:/usr/bin";
/* for each path segment, append the file to search for and test for
* it. return it if found.
*/
if (!(paths = virStringSplit(origpath, ":", 0)))
return NULL;
for (pathiter = paths; *pathiter; pathiter++) {
g_autofree char *fullpath = g_strdup_printf("%s/%s", *pathiter, file);
if (virFileIsExecutable(fullpath))
return g_steal_pointer(&fullpath);
}
return NULL;
}
static bool useDirOverride;
/**
* virFileFindResourceFull:
* @filename: libvirt distributed filename without any path
* @prefix: optional string to prepend to filename
* @suffix: optional string to append to filename
* @builddir: location of the filename in the build tree including
* abs_top_srcdir or abs_top_builddir prefix
* @installdir: location of the installed binary
* @envname: environment variable used to override all dirs
*
* A helper which will return a path to @filename within
* the current build tree, if the calling binary is being
* run from the source tree. Otherwise it will return the
* path in the installed location.
*
* Note that this function does not actually check whether
* the file exists on disk, it merely builds the fully
* qualified path where it is supposed to exist.
*
* If @envname is non-NULL it will override all other
* directory lookup.
*
* Only use this with @filename files that are part of
* the libvirt tree, not 3rd party binaries/files.
*
* Returns the resolved path (caller frees) or NULL on error
*/
char *
virFileFindResourceFull(const char *filename,
const char *prefix,
const char *suffix,
const char *builddir,
const char *installdir,
const char *envname)
{
char *ret = NULL;
const char *envval = envname ? getenv(envname) : NULL;
const char *path;
if (!prefix)
prefix = "";
if (!suffix)
suffix = "";
if (envval)
path = envval;
else if (useDirOverride)
path = builddir;
else
path = installdir;
ret = g_strdup_printf("%s/%s%s%s", path, prefix, filename, suffix);
VIR_DEBUG("Resolved '%s' to '%s'", filename, ret);
return ret;
}
char *
virFileFindResource(const char *filename,
const char *builddir,
const char *installdir)
{
return virFileFindResourceFull(filename, NULL, NULL, builddir, installdir, NULL);
}
/**
* virFileActivateDirOverrideForProg:
* @argv0: argv[0] of the calling program
*
* Canonicalize current process path from argv0 and check if abs_top_builddir
* matches as prefix in the path.
*/
void
virFileActivateDirOverrideForProg(const char *argv0)
{
g_autofree char *path = virFileCanonicalizePath(argv0);
if (!path) {
VIR_DEBUG("Failed to get canonicalized path errno=%d", errno);
return;
}
if (STRPREFIX(path, abs_top_builddir)) {
useDirOverride = true;
VIR_DEBUG("Activating build dir override for %s", path);
}
}
/**
* virFileActivateDirOverrideForLib:
*
* Look for LIBVIRT_DIR_OVERRIDE env var to see if we should find files from
* the build/src tree instead of install tree.
*/
void
virFileActivateDirOverrideForLib(void)
{
if (getenv("LIBVIRT_DIR_OVERRIDE") != NULL)
useDirOverride = true;
}
/**
* virFileLength:
* @path: full path of the file
* @fd: open file descriptor for file (or -1 to use @path)
*
* If fd >= 0, return the length of the open file indicated by @fd.
* If fd < 0 (i.e. -1) return the length of the file indicated by
* @path.
*
* Returns the length, or -1 if the file doesn't
* exist or its info was inaccessible. No error is logged.
*/
off_t
virFileLength(const char *path, int fd)
{
struct stat s;
if (fd >= 0) {
if (fstat(fd, &s) < 0)
return -1;
} else {
if (stat(path, &s) < 0)
return -1;
}
if (!S_ISREG(s.st_mode))
return -1;
return s.st_size;
}
bool
virFileIsDir(const char *path)
{
struct stat s;
return (stat(path, &s) == 0) && S_ISDIR(s.st_mode);
}
bool
virFileIsRegular(const char *path)
{
struct stat s;
return (stat(path, &s) == 0) && S_ISREG(s.st_mode);
}
/**
* virFileExists: Check for presence of file
* @path: Path of file to check
*
* Returns true if the file exists, false if it doesn't, setting errno
* appropriately.
*/
bool
virFileExists(const char *path)
{
return access(path, F_OK) == 0;
}
/* Check that a file is regular and has executable bits. If false is
* returned, errno is valid.
*
* Note: In the presence of ACLs, this may return true for a file that
* would actually fail with EACCES for a given user, or false for a
* file that the user could actually execute, but setups with ACLs
* that weird are unusual. */
bool
virFileIsExecutable(const char *file)
{
struct stat sb;
/* We would also want to check faccessat if we cared about ACLs,
* but we don't. */
if (stat(file, &sb) < 0)
return false;
if (S_ISREG(sb.st_mode) && (sb.st_mode & 0111) != 0)
return true;
errno = S_ISDIR(sb.st_mode) ? EISDIR : EACCES;
return false;
}
/*
* Check that a file refers to a mount point. Trick is that for
* a mount point, the st_dev field will differ from the parent
* directory.
*
* Note that this will not detect bind mounts of dirs/files,
* only true filesystem mounts.
*/
int virFileIsMountPoint(const char *file)
{
g_autofree char *parent = NULL;
int ret;
struct stat sb1, sb2;
parent = g_path_get_dirname(file);
VIR_DEBUG("Comparing '%s' to '%s'", file, parent);
if (stat(file, &sb1) < 0) {
if (errno == ENOENT)
return 0;
else
virReportSystemError(errno,
_("Cannot stat '%s'"),
file);
return -1;
}
if (stat(parent, &sb2) < 0) {
virReportSystemError(errno,
_("Cannot stat '%s'"),
parent);
return -1;
}
if (!S_ISDIR(sb1.st_mode))
return 0;
ret = sb1.st_dev != sb2.st_dev;
VIR_DEBUG("Is mount %d", ret);
return ret;
}
#if defined(__linux__)
/**
* virFileIsCDROM:
* @path: File to check
*
* Returns 1 if @path is a cdrom device 0 if it is not a cdrom and -1 on
* error. 'errno' of the failure is preserved and no libvirt errors are
* reported.
*/
int
virFileIsCDROM(const char *path)
{
struct stat st;
VIR_AUTOCLOSE fd = -1;
if ((fd = open(path, O_RDONLY | O_NONBLOCK)) < 0)
return -1;
if (fstat(fd, &st) < 0)
return -1;
if (!S_ISBLK(st.st_mode))
return 0;
/* Attempt to detect via a CDROM specific ioctl */
if (ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT) >= 0)
return 1;
return 0;
}
#else
int
virFileIsCDROM(const char *path)
{
if (STRPREFIX(path, "/dev/cd") ||
STRPREFIX(path, "/dev/acd"))
return 1;
return 0;
}
#endif /* defined(__linux__) */
#if defined WITH_MNTENT_H && defined WITH_GETMNTENT_R
static int
virFileGetMountSubtreeImpl(const char *mtabpath,
const char *prefix,
char ***mountsret,
size_t *nmountsret,
bool reverse)
{
FILE *procmnt;
struct mntent mntent;
char mntbuf[1024];
int ret = -1;
char **mounts = NULL;
size_t nmounts = 0;
VIR_DEBUG("prefix=%s", prefix);
*mountsret = NULL;
*nmountsret = 0;
if (!(procmnt = setmntent(mtabpath, "r"))) {
virReportSystemError(errno,
_("Failed to read %s"), mtabpath);
return -1;
}
while (getmntent_r(procmnt, &mntent, mntbuf, sizeof(mntbuf)) != NULL) {
if (!(STREQ(mntent.mnt_dir, prefix) ||
(STRPREFIX(mntent.mnt_dir, prefix) &&
mntent.mnt_dir[strlen(prefix)] == '/')))
continue;
if (VIR_EXPAND_N(mounts, nmounts, nmounts ? 1 : 2) < 0)
goto cleanup;
mounts[nmounts - 2] = g_strdup(mntent.mnt_dir);
}
if (mounts)
qsort(mounts, nmounts - 1, sizeof(mounts[0]),
reverse ? virStringSortRevCompare : virStringSortCompare);
*mountsret = mounts;
*nmountsret = nmounts ? nmounts - 1 : 0;
ret = 0;
cleanup:
if (ret < 0)
g_strfreev(mounts);
endmntent(procmnt);
return ret;
}
#else /* ! defined WITH_MNTENT_H && defined WITH_GETMNTENT_R */
static int
virFileGetMountSubtreeImpl(const char *mtabpath G_GNUC_UNUSED,
const char *prefix G_GNUC_UNUSED,
char ***mountsret G_GNUC_UNUSED,
size_t *nmountsret G_GNUC_UNUSED,
bool reverse G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS, "%s",
_("Unable to determine mount table on this platform"));
return -1;
}
#endif /* ! defined WITH_MNTENT_H && defined WITH_GETMNTENT_R */
/**
* virFileGetMountSubtree:
* @mtabpath: mount file to parser (eg /proc/mounts)
* @prefix: mount path prefix to match
* @mountsret: allocated and filled with matching mounts
* @nmountsret: filled with number of matching mounts, not counting NULL terminator
*
* Return the list of mounts from @mtabpath which contain
* the path @prefix, sorted alphabetically.
*
* The @mountsret array will be NULL terminated and should
* be freed with g_strfreev
*
* Returns 0 on success, -1 on error
*/
int virFileGetMountSubtree(const char *mtabpath,
const char *prefix,
char ***mountsret,
size_t *nmountsret)
{
return virFileGetMountSubtreeImpl(mtabpath, prefix, mountsret, nmountsret, false);
}
/**
* virFileGetMountReverseSubtree:
* @mtabpath: mount file to parser (eg /proc/mounts)
* @prefix: mount path prefix to match
* @mountsret: allocated and filled with matching mounts
* @nmountsret: filled with number of matching mounts, not counting NULL terminator
*
* Return the list of mounts from @mtabpath which contain
* the path @prefix, reverse-sorted alphabetically.
*
* The @mountsret array will be NULL terminated and should
* be freed with g_strfreev
*
* Returns 0 on success, -1 on error
*/
int virFileGetMountReverseSubtree(const char *mtabpath,
const char *prefix,
char ***mountsret,
size_t *nmountsret)
{
return virFileGetMountSubtreeImpl(mtabpath, prefix, mountsret, nmountsret, true);
}
#ifndef WIN32
/* Check that a file is accessible under certain
* user & gid.
* @mode can be F_OK, or a bitwise combination of R_OK, W_OK, and X_OK.
* see 'man access' for more details.
* Returns 0 on success, -1 on fail with errno set.
*/
int
virFileAccessibleAs(const char *path, int mode,
uid_t uid, gid_t gid)
{
pid_t pid = 0;
int status, ret = 0;
g_autofree gid_t *groups = NULL;
int ngroups;
if (uid == geteuid() &&
gid == getegid())
return access(path, mode);
ngroups = virGetGroupList(uid, gid, &groups);
if (ngroups < 0)
return -1;
pid = virFork();
if (pid < 0)
return -1;
if (pid) { /* parent */
if (virProcessWait(pid, &status, false) < 0) {
/* virProcessWait() already reported error */
errno = EINTR;
return -1;
}
if (status) {
errno = status;
return -1;
}
return 0;
}
if (virSetUIDGID(uid, gid, groups, ngroups) < 0) {
ret = errno;
goto childerror;
}
if (access(path, mode) < 0)
ret = errno;
childerror:
if ((ret & 0xFF) != ret) {
VIR_WARN("unable to pass desired return value %d", ret);
ret = 0xFF;
}
_exit(ret);
}
/* virFileOpenForceOwnerMode() - an internal utility function called
* only by virFileOpenAs(). Sets the owner and mode of the file
* opened as "fd" if it's not correct AND the flags say it should be
* forced. */
static int
virFileOpenForceOwnerMode(const char *path, int fd, mode_t mode,
uid_t uid, gid_t gid, unsigned int flags)
{
int ret = 0;
struct stat st;
if (!(flags & (VIR_FILE_OPEN_FORCE_OWNER | VIR_FILE_OPEN_FORCE_MODE)))
return 0;
if (fstat(fd, &st) == -1) {
ret = -errno;
virReportSystemError(errno, _("stat of '%s' failed"), path);
return ret;
}
/* NB: uid:gid are never "-1" (default) at this point - the caller
* has always changed -1 to the value of get[gu]id().
*/
if ((flags & VIR_FILE_OPEN_FORCE_OWNER) &&
((st.st_uid != uid) || (st.st_gid != gid)) &&
(fchown(fd, uid, gid) < 0)) {
ret = -errno;
virReportSystemError(errno,
_("cannot chown '%s' to (%u, %u)"),
path, (unsigned int) uid,
(unsigned int) gid);
return ret;
}
if ((flags & VIR_FILE_OPEN_FORCE_MODE) &&
((mode & (S_IRWXU|S_IRWXG|S_IRWXO)) !=
(st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO))) &&
(fchmod(fd, mode) < 0)) {
ret = -errno;
virReportSystemError(errno,
_("cannot set mode of '%s' to %04o"),
path, mode);
return ret;
}
return ret;
}
/* virFileOpenForked() - an internal utility function called only by
* virFileOpenAs(). It forks, then the child does setuid+setgid to
* given uid:gid and attempts to open the file, while the parent just
* calls recvfd to get the open fd back from the child. returns the
* fd, or -errno if there is an error. Additionally, to avoid another
* round-trip to unlink the file in a forked process; on error if this
* function created the file, but failed to perform some action after
* creation, then perform the unlink of the file. The storage driver
* buildVol backend function expects the file to be deleted on error.
*/
static int
virFileOpenForked(const char *path, int openflags, mode_t mode,
uid_t uid, gid_t gid, unsigned int flags)
{
pid_t pid;
int status = 0, ret = 0;
int recvfd_errno = 0;
int fd = -1;
int pair[2] = { -1, -1 };
g_autofree gid_t *groups = NULL;
int ngroups;
bool created = false;
/* parent is running as root, but caller requested that the
* file be opened as some other user and/or group). The
* following dance avoids problems caused by root-squashing
* NFS servers. */
ngroups = virGetGroupList(uid, gid, &groups);
if (ngroups < 0)
return -errno;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) {
ret = -errno;
virReportSystemError(errno,
_("failed to create socket needed for '%s'"),
path);
return ret;
}
pid = virFork();
if (pid < 0)
return -errno;
if (pid == 0) {
/* child */
/* set desired uid/gid, then attempt to create the file */
VIR_FORCE_CLOSE(pair[0]);
if (virSetUIDGID(uid, gid, groups, ngroups) < 0) {
ret = -errno;
goto childerror;
}
if ((fd = open(path, openflags, mode)) < 0) {
ret = -errno;
virReportSystemError(errno,
_("child process failed to create file '%s'"),
path);
goto childerror;
}
if (openflags & O_CREAT)
created = true;
/* File is successfully open. Set permissions if requested. */
ret = virFileOpenForceOwnerMode(path, fd, mode, uid, gid, flags);
if (ret < 0) {
ret = -errno;
virReportSystemError(errno,
_("child process failed to force owner mode file '%s'"),
path);
goto childerror;
}
do {
ret = virSocketSendFD(pair[1], fd);
} while (ret < 0 && errno == EINTR);
if (ret < 0) {
ret = -errno;
virReportSystemError(errno, "%s",
_("child process failed to send fd to parent"));
goto childerror;
}
childerror:
/* ret tracks -errno on failure, but exit value must be positive.
* If the child exits with EACCES, then the parent tries again. */
/* XXX This makes assumptions about errno being < 255, which is
* not true on Hurd. */
VIR_FORCE_CLOSE(pair[1]);
if (ret < 0) {
VIR_FORCE_CLOSE(fd);
if (created)
unlink(path);
}
ret = -ret;
if ((ret & 0xff) != ret) {
VIR_WARN("unable to pass desired return value %d", ret);
ret = 0xff;
}
_exit(ret);
}
/* parent */
VIR_FORCE_CLOSE(pair[1]);
do {
fd = virSocketRecvFD(pair[0], 0);
} while (fd < 0 && errno == EINTR);
VIR_FORCE_CLOSE(pair[0]); /* NB: this preserves errno */
if (fd < 0)
recvfd_errno = errno;
if (virProcessWait(pid, &status, 0) < 0) {
/* virProcessWait() reports errno on waitpid failure, so we'll just
* set our return status to EINTR; otherwise, set status to EACCES
* since the original failure for the fork+setuid path would have
* been EACCES or EPERM by definition.
*/
if (virLastErrorIsSystemErrno(0))
status = EINTR;
else if (!status)
status = EACCES;
}
if (status) {
VIR_FORCE_CLOSE(fd);
return -status;
}
/* if waitpid succeeded, but recvfd failed, report recvfd_errno */
if (recvfd_errno != 0) {
virReportSystemError(recvfd_errno,
_("failed recvfd for child creating '%s'"),
path);
return -recvfd_errno;
}
/* otherwise, waitpid and recvfd succeeded, return the fd */
return fd;
}
/**
* virFileOpenAs:
* @path: file to open or create
* @openflags: flags to pass to open
* @mode: mode to use on creation or when forcing permissions
* @uid: uid that should own file on creation
* @gid: gid that should own file
* @flags: bit-wise or of VIR_FILE_OPEN_* flags
*
* Open @path, and return an fd to the open file. @openflags contains
* the flags normally passed to open(2), while those in @flags are
* used internally. If @flags includes VIR_FILE_OPEN_NOFORK, then try
* opening the file while executing with the current uid:gid
* (i.e. don't fork+setuid+setgid before the call to open()). If
* @flags includes VIR_FILE_OPEN_FORK, then try opening the file while
* the effective user id is @uid (by forking a child process); this
* allows one to bypass root-squashing NFS issues; NOFORK is always
* tried before FORK (the absence of both flags is treated identically
* to (VIR_FILE_OPEN_NOFORK | VIR_FILE_OPEN_FORK)). If @flags includes
* VIR_FILE_OPEN_FORCE_OWNER, then ensure that @path is owned by
* uid:gid before returning (even if it already existed with a
* different owner). If @flags includes VIR_FILE_OPEN_FORCE_MODE,
* ensure it has those permissions before returning (again, even if
* the file already existed with different permissions).
*
* The return value (if non-negative) is the file descriptor, left
* open. Returns -errno on failure. Additionally, to avoid another
* round-trip to unlink the file; on error if this function created the
* file, but failed to perform some action after creation, then perform
* the unlink of the file. The storage driver buildVol backend function
* expects the file to be deleted on error.
*/
int
virFileOpenAs(const char *path, int openflags, mode_t mode,
uid_t uid, gid_t gid, unsigned int flags)
{
int ret = 0, fd = -1;
bool created = false;
/* allow using -1 to mean "current value" */
if (uid == (uid_t) -1)
uid = geteuid();
if (gid == (gid_t) -1)
gid = getegid();
/* treat absence of both flags as presence of both for simpler
* calling. */
if (!(flags & (VIR_FILE_OPEN_NOFORK|VIR_FILE_OPEN_FORK)))
flags |= VIR_FILE_OPEN_NOFORK|VIR_FILE_OPEN_FORK;
if ((flags & VIR_FILE_OPEN_NOFORK)
|| (geteuid() != 0)
|| ((uid == 0) && (gid == 0))) {
if ((fd = open(path, openflags, mode)) < 0) {
ret = -errno;
if (!(flags & VIR_FILE_OPEN_FORK))
goto error;
} else {
if (openflags & O_CREAT)
created = true;
ret = virFileOpenForceOwnerMode(path, fd, mode, uid, gid, flags);
if (ret < 0)
goto error;
}
}
/* If we either 1) didn't try opening as current user at all, or
* 2) failed, and errno/virStorageFileIsSharedFS indicate we might
* be successful if we try as a different uid, then try doing
* fork+setuid+setgid before opening.
*/
if ((fd < 0) && (flags & VIR_FILE_OPEN_FORK)) {
if (ret < 0) {
/* An open(2) that failed due to insufficient permissions
* could return one or the other of these depending on OS
* version and circumstances. Any other errno indicates a
* problem that couldn't be remedied by fork+setuid
* anyway. */
if (ret != -EACCES && ret != -EPERM)
goto error;
/* On Linux we can also verify the FS-type of the
* directory. (this is a NOP on other platforms). */
if (virFileIsSharedFS(path) <= 0)
goto error;
}
/* passed all prerequisites - retry the open w/fork+setuid */
if ((fd = virFileOpenForked(path, openflags, mode, uid, gid, flags)) < 0) {
ret = fd;
goto error;
}
}
/* File is successfully opened */
return fd;
error:
if (fd >= 0) {
/* some other failure after the open succeeded */
VIR_FORCE_CLOSE(fd);
if (created)
unlink(path);
}
/* whoever failed the open last has already set ret = -errno */
return ret;
}
/* virFileRemoveNeedsSetuid:
* @path: file we plan to remove
* @uid: file uid to check
* @gid: file gid to check
*
* Return true if we should use setuid/setgid before deleting a file
* owned by the passed uid/gid pair. Needed for NFS with root-squash
*/
static bool
virFileRemoveNeedsSetuid(const char *path, uid_t uid, gid_t gid)
{
/* If running unprivileged, setuid isn't going to work */
if (geteuid() != 0)
return false;
/* uid/gid weren't specified */
if ((uid == (uid_t) -1) && (gid == (gid_t) -1))
return false;
/* already running as proper uid/gid */
if (uid == geteuid() && gid == getegid())
return false;
/* Only perform the setuid stuff for NFS, which is the only case
that may actually need it. This can error, but just be safe and
only check for a clear negative result. */
if (virFileIsSharedFSType(path, VIR_FILE_SHFS_NFS) == 0)
return false;
return true;
}
/* virFileRemove:
* @path: file to unlink or directory to remove
* @uid: uid that was used to create the file (not required)
* @gid: gid that was used to create the file (not required)
*
* If a file/volume was created in an NFS root-squash environment,
* then we must 'unlink' the file in the same environment. Unlike
* the virFileOpenAs[Forked] and virDirCreate[NoFork], this code
* takes no extra flags and does not bother with EACCES failures
* from the child.
*/
int
virFileRemove(const char *path,
uid_t uid,
gid_t gid)
{
pid_t pid;
int status = 0, ret = 0;
g_autofree gid_t *groups = NULL;
int ngroups;
if (!virFileRemoveNeedsSetuid(path, uid, gid)) {
if (virFileIsDir(path))
return rmdir(path);
else
return unlink(path);
}
/* Otherwise, we have to deal with the NFS root-squash craziness
* to run under the uid/gid that created the volume in order to
* perform the unlink of the volume.
*/
if (uid == (uid_t) -1)
uid = geteuid();
if (gid == (gid_t) -1)
gid = getegid();
ngroups = virGetGroupList(uid, gid, &groups);
if (ngroups < 0)
return -errno;
pid = virFork();
if (pid < 0)
return -errno;
if (pid) { /* parent */
/* wait for child to complete, and retrieve its exit code */
if (virProcessWait(pid, &status, 0) < 0) {
/* virProcessWait() reports errno on waitpid failure, so we'll just
* set our return status to EINTR; otherwise, set status to EACCES
* since the original failure for the fork+setuid path would have
* been EACCES or EPERM by definition.
*/
if (virLastErrorIsSystemErrno(0))
status = EINTR;
else if (!status)
status = EACCES;
}
if (status) {
errno = status;
ret = -1;
}
return ret;
}
/* child */
/* set desired uid/gid, then attempt to unlink the file */
if (virSetUIDGID(uid, gid, groups, ngroups) < 0) {
ret = errno;
goto childerror;
}
if (virFileIsDir(path)) {
if (rmdir(path) < 0) {
ret = errno;
goto childerror;
}
} else {
if (unlink(path) < 0) {
ret = errno;
goto childerror;
}
}
childerror:
if ((ret & 0xff) != ret) {
VIR_WARN("unable to pass desired return value %d", ret);
ret = 0xff;
}
_exit(ret);
}
/* Attempt to create a directory and possibly adjust its owner/group and
* permissions.
*
* return 0 on success or -errno on failure. Additionally to avoid another
* round-trip to remove the directory on failure, perform the rmdir when
* a mkdir was successful, but some other failure would cause a -1 return.
* The storage driver buildVol backend function expects the directory to
* be deleted on error.
*/
static int
virDirCreateNoFork(const char *path,
mode_t mode, uid_t uid, gid_t gid,
unsigned int flags)
{
int ret = 0;
struct stat st;
bool created = false;
if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
if (mkdir(path, mode) < 0) {
ret = -errno;
virReportSystemError(errno, _("failed to create directory '%s'"),
path);
goto error;
}
created = true;
}
if (stat(path, &st) == -1) {
ret = -errno;
virReportSystemError(errno, _("stat of '%s' failed"), path);
goto error;
}
# ifndef WIN32
if (((uid != (uid_t) -1 && st.st_uid != uid) ||
(gid != (gid_t) -1 && st.st_gid != gid))
&& (chown(path, uid, gid) < 0)) {
ret = -errno;
virReportSystemError(errno, _("cannot chown '%s' to (%u, %u)"),
path, (unsigned int) uid, (unsigned int) gid);
goto error;
}
# endif /* !WIN32 */
if (mode != (mode_t) -1 && chmod(path, mode) < 0) {
ret = -errno;
virReportSystemError(errno,
_("cannot set mode of '%s' to %04o"),
path, mode);
goto error;
}
error:
if (ret < 0 && created)
rmdir(path);
return ret;
}
/*
* virDirCreate:
* @path: directory to create
* @mode: mode to use on creation or when forcing permissions
* @uid: uid that should own directory
* @gid: gid that should own directory
* @flags: bit-wise or of VIR_DIR_CREATE_* flags
*
* Attempt to create a directory and possibly adjust its owner/group and
* permissions. If conditions allow, use the *NoFork code in order to create
* the directory under current owner/group rather than via a forked process.
*
* return 0 on success or -errno on failure. Additionally to avoid another
* round-trip to remove the directory on failure, perform the rmdir if a
* mkdir was successful, but some other failure would cause a -1 return.
* The storage driver buildVol backend function expects the directory to
* be deleted on error.
*
*/
int
virDirCreate(const char *path,
mode_t mode, uid_t uid, gid_t gid,
unsigned int flags)
{
struct stat st;
pid_t pid;
int status = 0, ret = 0;
g_autofree gid_t *groups = NULL;
int ngroups;
bool created = false;
/* Everything after this check is crazyness to allow setting uid/gid
* on directories that are on root-squash NFS shares. We only want
* to go that route if the follow conditions are true:
*
* 1) VIR_DIR_CREATE_AS_UID was passed, currently only used when
* directory is being created for a NETFS pool
* 2) We are running as root, since that's when the root-squash
* workaround is required.
* 3) An explicit uid/gid was requested
* 4) The directory doesn't already exist and the ALLOW_EXIST flag
* wasn't passed.
*
* If any of those conditions are _not_ met, ignore the fork crazyness
*/
if ((!(flags & VIR_DIR_CREATE_AS_UID))
|| (geteuid() != 0)
|| ((uid == (uid_t) -1) && (gid == (gid_t) -1))
|| ((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
return virDirCreateNoFork(path, mode, uid, gid, flags);
}
if (uid == (uid_t) -1)
uid = geteuid();
if (gid == (gid_t) -1)
gid = getegid();
ngroups = virGetGroupList(uid, gid, &groups);
if (ngroups < 0)
return -errno;
pid = virFork();
if (pid < 0)
return -errno;
if (pid) { /* parent */
/* wait for child to complete, and retrieve its exit code */
if (virProcessWait(pid, &status, 0) < 0) {
/* virProcessWait() reports errno on waitpid failure, so we'll just
* set our return status to EINTR; otherwise, set status to EACCES
* since the original failure for the fork+setuid path would have
* been EACCES or EPERM by definition.
*/
if (virLastErrorIsSystemErrno(0))
status = EINTR;
else if (!status)
status = EACCES;
}
/*
* If the child exited with EACCES, then fall back to non-fork method
* as in the original logic introduced and explained by commit 98f6f381.
*/
if (status == EACCES) {
virResetLastError();
return virDirCreateNoFork(path, mode, uid, gid, flags);
}
if (status)
ret = -status;
return ret;
}
/* child */
/* set desired uid/gid, then attempt to create the directory */
if (virSetUIDGID(uid, gid, groups, ngroups) < 0) {
ret = errno;
goto childerror;
}
if (mkdir(path, mode) < 0) {
ret = errno;
if (ret != EACCES) {
/* in case of EACCES, the parent will retry */
virReportSystemError(errno, _("child failed to create directory '%s'"),
path);
}
goto childerror;
}
created = true;
/* check if group was set properly by creating after
* setgid. If not, try doing it with chown */
if (stat(path, &st) == -1) {
ret = errno;
virReportSystemError(errno,
_("stat of '%s' failed"), path);
goto childerror;
}
if ((st.st_gid != gid) && (chown(path, (uid_t) -1, gid) < 0)) {
ret = errno;
virReportSystemError(errno,
_("cannot chown '%s' to group %u"),
path, (unsigned int) gid);
goto childerror;
}
if (mode != (mode_t) -1 && chmod(path, mode) < 0) {
virReportSystemError(errno,
_("cannot set mode of '%s' to %04o"),
path, mode);
goto childerror;
}
childerror:
if (ret != 0 && created)
rmdir(path);
if ((ret & 0xff) != ret) {
VIR_WARN("unable to pass desired return value %d", ret);
ret = 0xff;
}
_exit(ret);
}
#else /* WIN32 */
int
virFileAccessibleAs(const char *path,
int mode,
uid_t uid G_GNUC_UNUSED,
gid_t gid G_GNUC_UNUSED)
{
VIR_WARN("Ignoring uid/gid due to WIN32");
return access(path, mode);
}
/* return -errno on failure, or 0 on success */
int
virFileOpenAs(const char *path G_GNUC_UNUSED,
int openflags G_GNUC_UNUSED,
mode_t mode G_GNUC_UNUSED,
uid_t uid G_GNUC_UNUSED,
gid_t gid G_GNUC_UNUSED,
unsigned int flags_unused G_GNUC_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virFileOpenAs is not implemented for WIN32"));
return -ENOSYS;
}
int
virDirCreate(const char *path G_GNUC_UNUSED,
mode_t mode G_GNUC_UNUSED,
uid_t uid G_GNUC_UNUSED,
gid_t gid G_GNUC_UNUSED,
unsigned int flags_unused G_GNUC_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virDirCreate is not implemented for WIN32"));
return -ENOSYS;
}
int
virFileRemove(const char *path,
uid_t uid G_GNUC_UNUSED,
gid_t gid G_GNUC_UNUSED)
{
if (unlink(path) < 0) {
virReportSystemError(errno, _("Unable to unlink path '%s'"),
path);
return -1;
}
return 0;
}
#endif /* WIN32 */
static int
virDirOpenInternal(DIR **dirp, const char *name, bool ignoreENOENT, bool quiet)
{
*dirp = opendir(name); /* exempt from syntax-check */
if (!*dirp) {
if (quiet)
return -1;
if (ignoreENOENT && errno == ENOENT)
return 0;
virReportSystemError(errno, _("cannot open directory '%s'"), name);
return -1;
}
return 1;
}
/**
* virDirOpen
* @dirp: directory stream
* @name: path of the directory
*
* Returns 1 on success.
* On failure, -1 is returned and an error is reported.
*/
int
virDirOpen(DIR **dirp, const char *name)
{
return virDirOpenInternal(dirp, name, false, false);
}
/**
* virDirOpenIfExists
* @dirp: directory stream
* @name: path of the directory
*
* Returns 1 on success.
* If opendir returns ENOENT, 0 is returned without reporting an error.
* On other errors, -1 is returned and an error is reported.
*/
int
virDirOpenIfExists(DIR **dirp, const char *name)
{
return virDirOpenInternal(dirp, name, true, false);
}
/**
* virDirOpenQuiet
* @dirp: directory stream
* @name: path of the directory
*
* Returns 1 on success.
* -1 on failure.
*
* Does not report any errors and errno is preserved.
*/
int
virDirOpenQuiet(DIR **dirp, const char *name)
{
return virDirOpenInternal(dirp, name, false, true);
}
/**
* virDirRead:
* @dirp: directory to read
* @ent: output one entry
* @name: if non-NULL, the name related to @dirp for use in error reporting
*
* Wrapper around readdir. Typical usage:
* struct dirent *ent;
* int rc;
* DIR *dir;
* if (virDirOpen(&dir, name) < 0)
* goto error;
* while ((rc = virDirRead(dir, &ent, name)) > 0)
* process ent;
* if (rc < 0)
* goto error;
*
* Returns -1 on error, with error already reported if @name was
* supplied. On success, returns 1 for entry read, 0 for end-of-dir.
*/
int virDirRead(DIR *dirp, struct dirent **ent, const char *name)
{
do {
errno = 0;
*ent = readdir(dirp); /* exempt from syntax-check */
if (!*ent && errno) {
if (name)
virReportSystemError(errno, _("Unable to read directory '%s'"),
name);
return -1;
}
} while (*ent && (STREQ((*ent)->d_name, ".") ||
STREQ((*ent)->d_name, "..")));
return !!*ent;
}
void virDirClose(DIR *dirp)
{
if (!dirp)
return;
closedir(dirp); /* exempt from syntax-check */
}
/*
* virFileChownFiles:
* @name: name of the directory
* @uid: uid
* @gid: gid
*
* Change ownership of all regular files in a directory.
*
* Returns -1 on error, with error already reported, 0 on success.
*/
#ifndef WIN32
int virFileChownFiles(const char *name,
uid_t uid,
gid_t gid)
{
struct dirent *ent;
int direrr;
g_autoptr(DIR) dir = NULL;
if (virDirOpen(&dir, name) < 0)
return -1;
while ((direrr = virDirRead(dir, &ent, name)) > 0) {
g_autofree char *path = NULL;
path = g_strdup_printf("%s/%s", name, ent->d_name);
if (!virFileIsRegular(path))
continue;
if (chown(path, uid, gid) < 0) {
virReportSystemError(errno,
_("cannot chown '%s' to (%u, %u)"),
ent->d_name, (unsigned int) uid,
(unsigned int) gid);
return -1;
}
}
if (direrr < 0)
return -1;
return 0;
}
#else /* WIN32 */
int virFileChownFiles(const char *name,
uid_t uid,
gid_t gid)
{
virReportSystemError(ENOSYS,
_("cannot chown '%s' to (%u, %u)"),
name, (unsigned int) uid,
(unsigned int) gid);
return -1;
}
#endif /* WIN32 */
static int
virFileMakePathHelper(char *path, mode_t mode)
{
struct stat st;
char *p;
VIR_DEBUG("path=%s mode=0%o", path, mode);
if (stat(path, &st) >= 0) {
if (S_ISDIR(st.st_mode))
return 0;
errno = ENOTDIR;
return -1;
}
if (errno != ENOENT)
return -1;
if ((p = strrchr(path, '/')) == NULL) {
errno = EINVAL;
return -1;
}
if (p != path) {
*p = '\0';
if (virFileMakePathHelper(path, mode) < 0)
return -1;
*p = '/';
}
if (g_mkdir(path, mode) < 0 && errno != EEXIST)
return -1;
return 0;
}
/**
* Creates the given directory with mode 0777 if it's not already existing.
*
* Returns 0 on success, or -1 if an error occurred (in which case, errno
* is set appropriately).
*/
int
virFileMakePath(const char *path)
{
return virFileMakePathWithMode(path, 0777);
}
int
virFileMakePathWithMode(const char *path,
mode_t mode)
{
g_autofree char *tmp = NULL;
tmp = g_strdup(path);
return virFileMakePathHelper(tmp, mode);
}
int
virFileMakeParentPath(const char *path)
{
char *p;
g_autofree char *tmp = NULL;
VIR_DEBUG("path=%s", path);
tmp = g_strdup(path);
if ((p = strrchr(tmp, '/')) == NULL) {
errno = EINVAL;
return -1;
}
*p = '\0';
return virFileMakePathHelper(tmp, 0777);
}
/* Build up a fully qualified path for a config file to be
* associated with a persistent guest or network */
char *
virFileBuildPath(const char *dir, const char *name, const char *ext)
{
char *path;
if (ext == NULL) {
path = g_strdup_printf("%s/%s", dir, name);
} else {
path = g_strdup_printf("%s/%s%s", dir, name, ext);
}
return path;
}
/* Open a non-blocking primary side of a pty. If ttyName is not NULL,
* then populate it with the name of the secondary peer. If rawmode is
* set, also put the primary side into raw mode before returning. */
#ifndef WIN32
int
virFileOpenTty(int *ttyprimary, char **ttyName, int rawmode)
{
/* XXX A word of caution - on some platforms (Solaris and HP-UX),
* additional ioctl() calls are needs after opening the secondary
* before it will cause isatty() to return true. Should we make
* virFileOpenTty also return the opened secondary fd, so the caller
* doesn't have to worry about that mess? */
int ret = -1;
int secondary = -1;
g_autofree char *name = NULL;
/* Unfortunately, we can't use the name argument of openpty, since
* there is no guarantee on how large the buffer has to be.
* Likewise, we can't use the termios argument: we have to use
* read-modify-write since there is no portable way to initialize
* a struct termios without use of tcgetattr. */
if (openpty(ttyprimary, &secondary, NULL, NULL, NULL) < 0)
return -1;
/* What a shame that openpty cannot atomically set FD_CLOEXEC, but
* that using posix_openpt/grantpt/unlockpt/ptsname is not
* thread-safe, and that ptsname_r is not portable. */
if (virSetNonBlock(*ttyprimary) < 0 ||
virSetCloseExec(*ttyprimary) < 0)
goto cleanup;
/* While Linux supports tcgetattr on either the primary or the
* secondary, Solaris requires it to be on the secondary. */
if (rawmode) {
struct termios ttyAttr;
if (tcgetattr(secondary, &ttyAttr) < 0)
goto cleanup;
cfmakeraw(&ttyAttr);
if (tcsetattr(secondary, TCSADRAIN, &ttyAttr) < 0)
goto cleanup;
}
/* ttyname_r on the secondary is required by POSIX, while ptsname_r on
* the primary is a glibc extension, and the POSIX ptsname is not
* thread-safe. Since openpty gave us both descriptors, guess
* which way we will determine the name? :) */
if (ttyName) {
/* Initial guess of 64 is generally sufficient; rely on ERANGE
* to tell us if we need to grow. */
size_t len = 64;
int rc;
name = g_new0(char, len);
while ((rc = ttyname_r(secondary, name, len)) == ERANGE) {
if (VIR_RESIZE_N(name, len, len, len) < 0)
goto cleanup;
}
if (rc != 0) {
errno = rc;
goto cleanup;
}
*ttyName = name;
name = NULL;
}
ret = 0;
cleanup:
if (ret != 0)
VIR_FORCE_CLOSE(*ttyprimary);
VIR_FORCE_CLOSE(secondary);
return ret;
}
#else /* WIN32 */
int
virFileOpenTty(int *ttyprimary G_GNUC_UNUSED,
char **ttyName G_GNUC_UNUSED,
int rawmode G_GNUC_UNUSED)
{
/* mingw completely lacks pseudo-terminals */
errno = ENOSYS;
return -1;
}
#endif /* WIN32 */
/*
* Creates an absolute path for a potentially relative path.
* Return 0 if the path was not relative, or on success.
* Return -1 on error.
*
* You must free the result.
*/
int
virFileAbsPath(const char *path, char **abspath)
{
if (path[0] == '/') {
*abspath = g_strdup(path);
} else {
g_autofree char *buf = g_get_current_dir();
*abspath = g_strdup_printf("%s/%s", buf, path);
}
return 0;
}
/* Remove spurious / characters from a path. The result must be freed */
char *
virFileSanitizePath(const char *path)
{
const char *cur = path;
char *uri;
char *cleanpath;
int idx = 0;
cleanpath = g_strdup(path);
/* don't sanitize URIs - rfc3986 states that two slashes may lead to a
* different resource, thus removing them would possibly change the path */
if ((uri = strstr(path, "://")) && strchr(path, '/') > uri)
return cleanpath;
/* Need to sanitize:
* // -> //
* /// -> /
* /../foo -> /../foo
* /foo///bar/ -> /foo/bar
*/
/* Starting with // is valid posix, but ///foo == /foo */
if (cur[0] == '/' && cur[1] == '/' && cur[2] != '/') {
idx = 2;
cur += 2;
}
/* Sanitize path in place */
while (*cur != '\0') {
if (*cur != '/') {
cleanpath[idx++] = *cur++;
continue;
}
/* Skip all extra / */
while (*++cur == '/')
continue;
/* Don't add a trailing / */
if (idx != 0 && *cur == '\0')
break;
cleanpath[idx++] = '/';
}
cleanpath[idx] = '\0';
return cleanpath;
}
/**
* virFileCanonicalizePath:
*
* Returns the canonical representation of @path.
*
* The returned string must be freed after use.
*/
char *
virFileCanonicalizePath(const char *path)
{
#ifdef WIN32
/* Does not resolve symlinks, only expands . & .. & repeated /.
* It will never fail, so sanitize errno to indicate success */
errno = 0;
return g_canonicalize_filename(path, NULL);
#else
return realpath(path, NULL); /* exempt from syntax-check */
#endif
}
/**
* virFileRemoveLastComponent:
*
* For given path cut off the last component. If there's no dir
* separator (whole path is one file name), @path is turned into
* an empty string.
*/
void
virFileRemoveLastComponent(char *path)
{
char *tmp;
if ((tmp = strrchr(path, G_DIR_SEPARATOR)))
tmp[1] = '\0';
else
path[0] = '\0';
}
#ifdef __linux__
# ifndef NFS_SUPER_MAGIC
# define NFS_SUPER_MAGIC 0x6969
# endif
# ifndef OCFS2_SUPER_MAGIC
# define OCFS2_SUPER_MAGIC 0x7461636f
# endif
# ifndef GFS2_MAGIC
# define GFS2_MAGIC 0x01161970
# endif
# ifndef AFS_FS_MAGIC
# define AFS_FS_MAGIC 0x6B414653
# endif
# ifndef SMB_SUPER_MAGIC
# define SMB_SUPER_MAGIC 0x517B
# endif
# ifndef CIFS_SUPER_MAGIC
# define CIFS_SUPER_MAGIC 0xFF534D42
# endif
# ifndef HUGETLBFS_MAGIC
# define HUGETLBFS_MAGIC 0x958458f6
# endif
# ifndef FUSE_SUPER_MAGIC
# define FUSE_SUPER_MAGIC 0x65735546
# endif
# ifndef CEPH_SUPER_MAGIC
# define CEPH_SUPER_MAGIC 0x00C36400
# endif
# ifndef GPFS_SUPER_MAGIC
# define GPFS_SUPER_MAGIC 0x47504653
# endif
# ifndef QB_MAGIC
# define QB_MAGIC 0x51626d6e
# endif
# define VIR_ACFS_MAGIC 0x61636673
# define PROC_MOUNTS "/proc/mounts"
static int
virFileIsSharedFixFUSE(const char *path,
long long *f_type)
{
FILE *f = NULL;
struct mntent mb;
char mntbuf[1024];
char *mntDir = NULL;
char *mntType = NULL;
char *canonPath = NULL;
size_t maxMatching = 0;
int ret = -1;
if (!(canonPath = virFileCanonicalizePath(path))) {
virReportSystemError(errno,
_("unable to canonicalize %s"),
path);
return -1;
}
VIR_DEBUG("Path canonicalization: %s->%s", path, canonPath);
if (!(f = setmntent(PROC_MOUNTS, "r"))) {
virReportSystemError(errno,
_("Unable to open %s"),
PROC_MOUNTS);
goto cleanup;
}
while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) {
const char *p;
size_t len = strlen(mb.mnt_dir);
if (!(p = STRSKIP(canonPath, mb.mnt_dir)))
continue;
if (*(p - 1) != '/' && *p != '/' && *p != '\0')
continue;
if (len > maxMatching) {
maxMatching = len;
VIR_FREE(mntType);
VIR_FREE(mntDir);
mntDir = g_strdup(mb.mnt_dir);
mntType = g_strdup(mb.mnt_type);
}
}
if (STREQ_NULLABLE(mntType, "fuse.glusterfs")) {
VIR_DEBUG("Found gluster FUSE mountpoint=%s for path=%s. "
"Fixing shared FS type", mntDir, canonPath);
*f_type = GFS2_MAGIC;
} else if (STREQ_NULLABLE(mntType, "fuse.quobyte")) {
VIR_DEBUG("Found Quobyte FUSE mountpoint=%s for path=%s. "
"Fixing shared FS type", mntDir, canonPath);
*f_type = QB_MAGIC;
}
ret = 0;
cleanup:
VIR_FREE(canonPath);
VIR_FREE(mntType);
VIR_FREE(mntDir);
endmntent(f);
return ret;
}
int
virFileIsSharedFSType(const char *path,
int fstypes)
{
g_autofree char *dirpath = NULL;
char *p = NULL;
struct statfs sb;
int statfs_ret;
long long f_type = 0;
dirpath = g_strdup(path);
statfs_ret = statfs(dirpath, &sb);
while ((statfs_ret < 0) && (p != dirpath)) {
/* Try less and less of the path until we get to a
* directory we can stat. Even if we don't have 'x'
* permission on any directory in the path on the NFS
* server (assuming it's NFS), we will be able to stat the
* mount point, and that will properly tell us if the
* fstype is NFS.
*/
if ((p = strrchr(dirpath, '/')) == NULL) {
virReportSystemError(EINVAL,
_("Invalid relative path '%s'"), path);
return -1;
}
if (p == dirpath)
*(p+1) = '\0';
else
*p = '\0';
statfs_ret = statfs(dirpath, &sb);
}
if (statfs_ret < 0) {
virReportSystemError(errno,
_("cannot determine filesystem for '%s'"),
path);
return -1;
}
f_type = sb.f_type;
if (f_type == FUSE_SUPER_MAGIC) {
VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path);
virFileIsSharedFixFUSE(path, &f_type);
}
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
path, f_type);
if ((fstypes & VIR_FILE_SHFS_NFS) &&
(f_type == NFS_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_GFS2) &&
(f_type == GFS2_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_OCFS) &&
(f_type == OCFS2_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_AFS) &&
(f_type == AFS_FS_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_SMB) &&
(f_type == SMB_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_CIFS) &&
(f_type == CIFS_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_CEPH) &&
(f_type == CEPH_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_GPFS) &&
(f_type == GPFS_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_QB) &&
(f_type == QB_MAGIC))
return 1;
if ((fstypes & VIR_FILE_SHFS_ACFS) &&
(f_type == VIR_ACFS_MAGIC))
return 1;
return 0;
}
int
virFileGetHugepageSize(const char *path,
unsigned long long *size)
{
struct statfs fs;
if (statfs(path, &fs) < 0) {
virReportSystemError(errno,
_("cannot determine filesystem for '%s'"),
path);
return -1;
}
if (fs.f_type != HUGETLBFS_MAGIC) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("not a hugetlbfs mount: '%s'"),
path);
return -1;
}
*size = fs.f_bsize / 1024; /* we are storing size in KiB */
return 0;
}
# define PROC_MEMINFO "/proc/meminfo"
# define HUGEPAGESIZE_STR "Hugepagesize:"
static int
virFileGetDefaultHugepageSize(unsigned long long *size)
{
g_autofree char *meminfo = NULL;
char *c;
char *n;
char *unit;
if (virFileReadAll(PROC_MEMINFO, 4096, &meminfo) < 0)
return -1;
if (!(c = strstr(meminfo, HUGEPAGESIZE_STR))) {
virReportError(VIR_ERR_NO_SUPPORT,
_("%s not found in %s"),
HUGEPAGESIZE_STR,
PROC_MEMINFO);
return -1;
}
c += strlen(HUGEPAGESIZE_STR);
if ((n = strchr(c, '\n'))) {
/* Cut off the rest of the meminfo file */
*n = '\0';
}
if (virStrToLong_ull(c, &unit, 10, size) < 0 || STRNEQ(unit, " kB")) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unable to parse %s %s"),
HUGEPAGESIZE_STR, c);
return -1;
}
return 0;
}
int
virFileFindHugeTLBFS(virHugeTLBFSPtr *ret_fs,
size_t *ret_nfs)
{
int ret = -1;
FILE *f = NULL;
struct mntent mb;
char mntbuf[1024];
virHugeTLBFSPtr fs = NULL;
size_t nfs = 0;
unsigned long long default_hugepagesz = 0;
if (!(f = setmntent(PROC_MOUNTS, "r"))) {
virReportSystemError(errno,
_("Unable to open %s"),
PROC_MOUNTS);
goto cleanup;
}
while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) {
virHugeTLBFSPtr tmp;
if (STRNEQ(mb.mnt_type, "hugetlbfs"))
continue;
if (VIR_EXPAND_N(fs, nfs, 1) < 0)
goto cleanup;
tmp = &fs[nfs - 1];
tmp->mnt_dir = g_strdup(mb.mnt_dir);
if (virFileGetHugepageSize(tmp->mnt_dir, &tmp->size) < 0)
goto cleanup;
if (!default_hugepagesz &&
virFileGetDefaultHugepageSize(&default_hugepagesz) < 0)
goto cleanup;
tmp->deflt = tmp->size == default_hugepagesz;
}
*ret_fs = fs;
*ret_nfs = nfs;
fs = NULL;
nfs = 0;
ret = 0;
cleanup:
endmntent(f);
while (nfs)
VIR_FREE(fs[--nfs].mnt_dir);
VIR_FREE(fs);
return ret;
}
#else /* defined __linux__ */
int virFileIsSharedFSType(const char *path G_GNUC_UNUSED,
int fstypes G_GNUC_UNUSED)
{
/* XXX implement me :-) */
return 0;
}
int
virFileGetHugepageSize(const char *path G_GNUC_UNUSED,
unsigned long long *size G_GNUC_UNUSED)
{
/* XXX implement me :-) */
virReportUnsupportedError();
return -1;
}
int
virFileFindHugeTLBFS(virHugeTLBFSPtr *ret_fs G_GNUC_UNUSED,
size_t *ret_nfs G_GNUC_UNUSED)
{
/* XXX implement me :-) */
virReportUnsupportedError();
return -1;
}
#endif /* defined __linux__ */
/**
* virFileGetDefaultHugepage:
* @fs: array of hugetlbfs mount points
* @nfs: number of items in @fs
*
* In the passed array of hugetlbfs mount points @fs find the
* default one. It's the one which has no '-o pagesize'.
*
* Returns: default hugepage, or
* NULL if none found
*/
virHugeTLBFSPtr
virFileGetDefaultHugepage(virHugeTLBFSPtr fs,
size_t nfs)
{
size_t i;
for (i = 0; i < nfs; i++) {
if (fs[i].deflt)
return &fs[i];
}
return NULL;
}
int virFileIsSharedFS(const char *path)
{
return virFileIsSharedFSType(path,
VIR_FILE_SHFS_NFS |
VIR_FILE_SHFS_GFS2 |
VIR_FILE_SHFS_OCFS |
VIR_FILE_SHFS_AFS |
VIR_FILE_SHFS_SMB |
VIR_FILE_SHFS_CIFS |
VIR_FILE_SHFS_CEPH |
VIR_FILE_SHFS_GPFS|
VIR_FILE_SHFS_QB |
VIR_FILE_SHFS_ACFS);
}
#if defined(__linux__) && defined(WITH_SYS_MOUNT_H)
int
virFileSetupDev(const char *path,
const char *mount_options)
{
const unsigned long mount_flags = MS_NOSUID;
const char *mount_fs = "tmpfs";
if (virFileMakePath(path) < 0) {
virReportSystemError(errno,
_("Failed to make path %s"), path);
return -1;
}
VIR_DEBUG("Mount devfs on %s type=tmpfs flags=0x%lx, opts=%s",
path, mount_flags, mount_options);
if (mount("devfs", path, mount_fs, mount_flags, mount_options) < 0) {
virReportSystemError(errno,
_("Failed to mount devfs on %s type %s (%s)"),
path, mount_fs, mount_options);
return -1;
}
return 0;
}
int
virFileBindMountDevice(const char *src,
const char *dst)
{
if (!virFileExists(dst)) {
if (virFileIsDir(src)) {
if (virFileMakePath(dst) < 0) {
virReportSystemError(errno, _("Unable to make dir %s"), dst);
return -1;
}
} else {
if (virFileTouch(dst, 0666) < 0)
return -1;
}
}
if (mount(src, dst, "none", MS_BIND, NULL) < 0) {
virReportSystemError(errno, _("Failed to bind %s on to %s"), src,
dst);
return -1;
}
return 0;
}
int
virFileMoveMount(const char *src,
const char *dst)
{
const unsigned long mount_flags = MS_MOVE;
if (mount(src, dst, "none", mount_flags, NULL) < 0) {
virReportSystemError(errno,
_("Unable to move %s mount to %s"),
src, dst);
return -1;
}
return 0;
}
#else /* !defined(__linux__) || !defined(WITH_SYS_MOUNT_H) */
int
virFileSetupDev(const char *path G_GNUC_UNUSED,
const char *mount_options G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS, "%s",
_("mount is not supported on this platform."));
return -1;
}
int
virFileBindMountDevice(const char *src G_GNUC_UNUSED,
const char *dst G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS, "%s",
_("mount is not supported on this platform."));
return -1;
}
int
virFileMoveMount(const char *src G_GNUC_UNUSED,
const char *dst G_GNUC_UNUSED)
{
virReportSystemError(ENOSYS, "%s",
_("mount move is not supported on this platform."));
return -1;
}
#endif /* !defined(__linux__) || !defined(WITH_SYS_MOUNT_H) */
#if defined(WITH_SYS_ACL_H)
int
virFileGetACLs(const char *file,
void **acl)
{
if (!(*acl = acl_get_file(file, ACL_TYPE_ACCESS)))
return -1;
return 0;
}
int
virFileSetACLs(const char *file,
void *acl)
{
if (acl_set_file(file, ACL_TYPE_ACCESS, acl) < 0)
return -1;
return 0;
}
void
virFileFreeACLs(void **acl)
{
acl_free(*acl);
*acl = NULL;
}
#else /* !defined(WITH_SYS_ACL_H) */
int
virFileGetACLs(const char *file G_GNUC_UNUSED,
void **acl G_GNUC_UNUSED)
{
errno = ENOTSUP;
return -1;
}
int
virFileSetACLs(const char *file G_GNUC_UNUSED,
void *acl G_GNUC_UNUSED)
{
errno = ENOTSUP;
return -1;
}
void
virFileFreeACLs(void **acl)
{
*acl = NULL;
}
#endif /* !defined(WITH_SYS_ACL_H) */
int
virFileCopyACLs(const char *src,
const char *dst)
{
void *acl = NULL;
int ret = -1;
if (virFileGetACLs(src, &acl) < 0)
return ret;
if (virFileSetACLs(dst, acl) < 0)
goto cleanup;
ret = 0;
cleanup:
virFileFreeACLs(&acl);
return ret;
}
/*
* virFileComparePaths:
* @p1: source path 1
* @p2: source path 2
*
* Compares two paths for equality. To do so, it first canonicalizes both paths
* to resolve all symlinks and discard relative path components. If symlinks
* resolution or path canonicalization fails, plain string equality of @p1
* and @p2 is performed.
*
* Returns:
* 1 : Equal
* 0 : Non-Equal
*/
int
virFileComparePaths(const char *p1, const char *p2)
{
g_autofree char *res1 = NULL;
g_autofree char *res2 = NULL;
/* Assume p1 and p2 are symlinks, so try to resolve and canonicalize them.
* Canonicalization fails for example on file systems names like 'proc' or
* 'sysfs', since they're no real paths so fallback to plain string
* comparison.
*/
ignore_value(virFileResolveLink(p1, &res1));
if (!res1)
res1 = g_strdup(p1);
ignore_value(virFileResolveLink(p2, &res2));
if (!res2)
res2 = g_strdup(p2);
return STREQ_NULLABLE(res1, res2);
}
#if WITH_DECL_SEEK_HOLE
/**
* virFileInData:
* @fd: file to check
* @inData: true if current position in the @fd is in data section
* @length: amount of bytes until the end of the current section
*
* With sparse files not every extent has to be physically stored on
* the disk. This results in so called data or hole sections. This
* function checks whether the current position in the file @fd is
* in a data section (@inData = 1) or in a hole (@inData = 0). Also,
* it sets @length to match the number of bytes remaining until the
* end of the current section.
*
* As a special case, there is an implicit hole at the end of any
* file. In this case, the function sets @inData = 0, @length = 0.
*
* Upon its return, the position in the @fd is left unchanged, i.e.
* despite this function lseek()-ing back and forth it always
* restores the original position in the file.
*
* NB, @length is type of long long because it corresponds to off_t
* the best.
*
* Returns 0 on success,
* -1 otherwise.
*/
int
virFileInData(int fd,
int *inData,
long long *length)
{
int ret = -1;
off_t cur, data, hole, end;
/* Get current position */
cur = lseek(fd, 0, SEEK_CUR);
if (cur == (off_t) -1) {
virReportSystemError(errno, "%s",
_("Unable to get current position in file"));
goto cleanup;
}
/* Now try to get data and hole offsets */
data = lseek(fd, cur, SEEK_DATA);
/* There are four options:
* 1) data == cur; @cur is in data
* 2) data > cur; @cur is in a hole, next data at @data
* 3) data < 0, errno = ENXIO; either @cur is in trailing hole, or @cur is beyond EOF.
* 4) data < 0, errno != ENXIO; we learned nothing
*/
if (data == (off_t) -1) {
/* cases 3 and 4 */
if (errno != ENXIO) {
virReportSystemError(errno, "%s",
_("Unable to seek to data"));
goto cleanup;
}
*inData = 0;
/* There are two situations now. There is always an
* implicit hole at EOF. However, there might be a
* trailing hole just before EOF too. If that's the case
* report it. */
if ((end = lseek(fd, 0, SEEK_END)) == (off_t) -1) {
virReportSystemError(errno, "%s",
_("Unable to seek to EOF"));
goto cleanup;
}
*length = end - cur;
} else if (data > cur) {
/* case 2 */
*inData = 0;
*length = data - cur;
} else {
/* case 1 */
*inData = 1;
/* We don't know where does the next hole start. Let's
* find out. Here we get the same 4 possibilities as
* described above.*/
hole = lseek(fd, data, SEEK_HOLE);
if (hole == (off_t) -1 || hole == data) {
/* cases 1, 3 and 4 */
/* Wait a second. The reason why we are here is
* because we are in data. But at the same time we
* are in a trailing hole? Wut!? Do the best what we
* can do here. */
virReportSystemError(errno, "%s",
_("unable to seek to hole"));
goto cleanup;
} else {
/* case 2 */
*length = (hole - data);
}
}
ret = 0;
cleanup:
/* At any rate, reposition back to where we started. */
if (cur != (off_t) -1) {
int theerrno = errno;
if (lseek(fd, cur, SEEK_SET) == (off_t) -1) {
virReportSystemError(errno, "%s",
_("unable to restore position in file"));
ret = -1;
if (theerrno == 0)
theerrno = errno;
}
errno = theerrno;
}
return ret;
}
#else /* !WITH_DECL_SEEK_HOLE */
int
virFileInData(int fd G_GNUC_UNUSED,
int *inData G_GNUC_UNUSED,
long long *length G_GNUC_UNUSED)
{
errno = ENOSYS;
virReportSystemError(errno, "%s",
_("sparse files not supported"));
return -1;
}
#endif /* !WITH_DECL_SEEK_HOLE */
/**
* virFileReadValueInt:
* @value: pointer to int to be filled in with the value
* @format, ...: file to read from
*
* Read int from @format and put it into @value.
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueInt(int *value, const char *format, ...)
{
g_autofree char *str = NULL;
g_autofree char *path = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
if (virFileReadAll(path, VIR_INT64_STR_BUFLEN, &str) < 0)
return -1;
virStringTrimOptionalNewline(str);
if (virStrToLong_i(str, NULL, 10, value) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Invalid integer value '%s' in file '%s'"),
str, path);
return -1;
}
return 0;
}
/**
* virFileReadValueUint:
* @value: pointer to int to be filled in with the value
* @format, ...: file to read from
*
* Read unsigned int from @format and put it into @value.
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueUint(unsigned int *value, const char *format, ...)
{
g_autofree char *str = NULL;
g_autofree char *path = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
if (virFileReadAll(path, VIR_INT64_STR_BUFLEN, &str) < 0)
return -1;
virStringTrimOptionalNewline(str);
if (virStrToLong_uip(str, NULL, 10, value) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Invalid unsigned integer value '%s' in file '%s'"),
str, path);
return -1;
}
return 0;
}
/**
* virFileReadValueUllong:
* @value: pointer to unsigned long long to be filled in with the value
* @format, ...: file to read from
*
* Read unsigned int from @format and put it into @value.
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueUllong(unsigned long long *value, const char *format, ...)
{
g_autofree char *str = NULL;
g_autofree char *path = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
if (virFileReadAll(path, VIR_INT64_STR_BUFLEN, &str) < 0)
return -1;
virStringTrimOptionalNewline(str);
if (virStrToLong_ullp(str, NULL, 10, value) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Invalid unsigned long long value '%s' in file '%s'"),
str, path);
return -1;
}
return 0;
}
/**
* virFileReadValueScaledInt:
* @value: pointer to unsigned long long int to be filled in with the value
* @format, ...: file to read from
*
* Read unsigned scaled int from @format and put it into @value.
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueScaledInt(unsigned long long *value, const char *format, ...)
{
g_autofree char *str = NULL;
g_autofree char *path = NULL;
char *endp = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
if (virFileReadAll(path, VIR_INT64_STR_BUFLEN, &str) < 0)
return -1;
virStringTrimOptionalNewline(str);
if (virStrToLong_ullp(str, &endp, 10, value) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Invalid unsigned scaled integer value '%s' in file '%s'"),
str, path);
return -1;
}
return virScaleInteger(value, endp, 1024, ULLONG_MAX);
}
/* Arbitrarily sized number, feel free to change, but the function should be
* used for small, interface-like files, so it should not be huge (subjective) */
#define VIR_FILE_READ_VALUE_STRING_MAX 4096
/**
* virFileReadValueBitmap:
* @value: pointer to virBitmapPtr to be allocated and filled in with the value
* @format, ...: file to read from
*
* Read int from @format and put it into @value.
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueBitmap(virBitmapPtr *value, const char *format, ...)
{
g_autofree char *str = NULL;
g_autofree char *path = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
if (virFileReadAll(path, VIR_FILE_READ_VALUE_STRING_MAX, &str) < 0)
return -1;
virStringTrimOptionalNewline(str);
*value = virBitmapParseUnlimited(str);
if (!*value)
return -1;
return 0;
}
/**
* virFileReadValueString:
* @value: pointer to char * to be allocated and filled in with the value
* @format, ...: file to read from
*
* Read string from @format and put it into @value. Don't get this mixed with
* virFileReadAll(). This function is a wrapper over it with the behaviour
* aligned to other virFileReadValue* functions
*
* Return -2 for non-existing file, -1 on other errors and 0 if everything went
* fine.
*/
int
virFileReadValueString(char **value, const char *format, ...)
{
int ret;
g_autofree char *path = NULL;
va_list ap;
va_start(ap, format);
path = g_strdup_vprintf(format, ap);
va_end(ap);
if (!virFileExists(path))
return -2;
ret = virFileReadAll(path, VIR_FILE_READ_VALUE_STRING_MAX, value);
if (*value)
virStringTrimOptionalNewline(*value);
return ret;
}
/**
* virFileWaitForExists:
* @path: absolute path to a sysfs attribute (can be a symlink)
* @ms: how long to wait (in milliseconds)
* @tries: how many times should we try to wait for @path to become accessible
*
* Checks the existence of @path. In case the file defined by @path
* doesn't exist, we wait for it to appear in @ms milliseconds (for up to
* @tries attempts).
*
* Returns 0 on success, -1 on error, setting errno appropriately.
*/
int
virFileWaitForExists(const char *path,
size_t ms,
size_t tries)
{
errno = 0;
/* wait for @path to be accessible in @ms milliseconds, up to @tries */
while (tries-- > 0 && !virFileExists(path)) {
if (tries == 0 || errno != ENOENT)
return -1;
g_usleep(ms * 1000);
}
return 0;
}
#if WITH_LIBATTR
/**
* virFileGetXAttrQuiet;
* @path: a filename
* @name: name of xattr
* @value: read value
*
* Reads xattr with @name for given @path and stores it into
* @value. Caller is responsible for freeing @value.
*
* Returns: 0 on success,
* -1 otherwise (with errno set).
*/
int
virFileGetXAttrQuiet(const char *path,
const char *name,
char **value)
{
g_autofree char *buf = NULL;
/* We might be racing with somebody who sets the same attribute. */
while (1) {
ssize_t need;
ssize_t got;
/* The first call determines how many bytes we need to allocate. */
if ((need = getxattr(path, name, NULL, 0)) < 0)
return -1;
buf = g_renew(char, buf, need + 1);
if ((got = getxattr(path, name, buf, need)) < 0) {
if (errno == ERANGE)
continue;
return -1;
}
buf[got] = '\0';
break;
}
*value = g_steal_pointer(&buf);
return 0;
}
/**
* virFileSetXAttr:
* @path: a filename
* @name: name of xattr
* @value: value to set
*
* Sets xattr of @name and @value on @path.
*
* Returns: 0 on success,
* -1 otherwise (with errno set AND error reported).
*/
int
virFileSetXAttr(const char *path,
const char *name,
const char *value)
{
if (setxattr(path, name, value, strlen(value), 0) < 0) {
virReportSystemError(errno,
_("Unable to set XATTR %s on %s"),
name, path);
return -1;
}
return 0;
}
/**
* virFileRemoveXAttr:
* @path: a filename
* @name: name of xattr
*
* Remove xattr of @name on @path.
*
* Returns: 0 on success,
* -1 otherwise (with errno set AND error reported).
*/
int
virFileRemoveXAttr(const char *path,
const char *name)
{
if (removexattr(path, name) < 0) {
virReportSystemError(errno,
_("Unable to remove XATTR %s on %s"),
name, path);
return -1;
}
return 0;
}
#else /* !WITH_LIBATTR */
int
virFileGetXAttrQuiet(const char *path G_GNUC_UNUSED,
const char *name G_GNUC_UNUSED,
char **value G_GNUC_UNUSED)
{
errno = ENOSYS;
return -1;
}
int
virFileSetXAttr(const char *path,
const char *name,
const char *value G_GNUC_UNUSED)
{
errno = ENOSYS;
virReportSystemError(errno,
_("Unable to set XATTR %s on %s"),
name, path);
return -1;
}
int
virFileRemoveXAttr(const char *path,
const char *name)
{
errno = ENOSYS;
virReportSystemError(errno,
_("Unable to remove XATTR %s on %s"),
name, path);
return -1;
}
#endif /* WITH_LIBATTR */
/**
* virFileGetXAttr;
* @path: a filename
* @name: name of xattr
* @value: read value
*
* Reads xattr with @name for given @path and stores it into
* @value. Caller is responsible for freeing @value.
*
* Returns: 0 on success,
* -1 otherwise (with errno set AND error reported).
*/
int
virFileGetXAttr(const char *path,
const char *name,
char **value)
{
int ret;
if ((ret = virFileGetXAttrQuiet(path, name, value)) < 0) {
virReportSystemError(errno,
_("Unable to get XATTR %s on %s"),
name, path);
}
return ret;
}
int
virFileDataSync(int fd)
{
#if defined(__APPLE__) || defined(WIN32)
return g_fsync(fd);
#else
return fdatasync(fd);
#endif
}
/**
* virFileSetCow:
* @path: file or directory to control the COW flag on
* @state: the desired state of the COW flag
*
* When @state is VIR_TRISTATE_BOOL_ABSENT, some helpful
* default logic will be used. Specifically if the filesystem
* containing @path is 'btrfs', then it will attempt to
* disable the COW flag, but errors will be ignored. For
* any other filesystem no change will be made.
*
* When @state is VIR_TRISTATE_BOOL_YES or VIR_TRISTATE_BOOL_NO,
* it will attempt to set the COW flag state to that explicit
* value, and always return an error if it fails. Note this
* means it will always return error if the filesystem is not
* 'btrfs'.
*/
int
virFileSetCOW(const char *path,
virTristateBool state)
{
#if __linux__
int val = 0;
struct statfs buf;
VIR_AUTOCLOSE fd = -1;
VIR_DEBUG("Setting COW flag on '%s' to '%s'",
path, virTristateBoolTypeToString(state));
fd = open(path, O_RDONLY|O_NONBLOCK|O_LARGEFILE);
if (fd < 0) {
virReportSystemError(errno, _("unable to open '%s'"),
path);
return -1;
}
if (fstatfs(fd, &buf) < 0) {
virReportSystemError(errno, _("unable query filesystem type on '%s'"),
path);
return -1;
}
if (buf.f_type != BTRFS_SUPER_MAGIC) {
if (state != VIR_TRISTATE_BOOL_ABSENT) {
virReportSystemError(ENOSYS,
_("unable to control COW flag on '%s', not btrfs"),
path);
return -1;
}
return 0;
}
if (ioctl(fd, FS_IOC_GETFLAGS, &val) < 0) {
virReportSystemError(errno, _("unable get directory flags on '%s'"),
path);
return -1;
}
VIR_DEBUG("Current flags on '%s' are 0x%x", path, val);
if (state == VIR_TRISTATE_BOOL_YES) {
val &= ~FS_NOCOW_FL;
} else {
val |= FS_NOCOW_FL;
}
VIR_DEBUG("New flags on '%s' will be 0x%x", path, val);
if (ioctl(fd, FS_IOC_SETFLAGS, &val) < 0) {
int saved_err = errno;
VIR_DEBUG("Failed to set flags on '%s': %s", path, g_strerror(saved_err));
if (state != VIR_TRISTATE_BOOL_ABSENT) {
virReportSystemError(saved_err,
_("unable control COW flag on '%s'"),
path);
return -1;
} else {
VIR_DEBUG("Ignoring failure to set COW");
}
}
return 0;
#else /* ! __linux__ */
if (state != VIR_TRISTATE_BOOL_ABSENT) {
virReportSystemError(ENOSYS,
_("Unable to set copy-on-write state on '%s' to '%s'"),
path, virTristateBoolTypeToString(state));
return -1;
}
return 0;
#endif /* ! __linux__ */
}
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