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c8fa7e8c55
libvirt/src/util/virfile.c
Eric Blake d34ef01779 build: fix use of mmap 
Commit bfe7721d introduced a regression, but only on platforms
like FreeBSD that lack posix_fallocate and where mmap serves as
a nice fallback for safezero.

util/virfile.c: In function 'safezero':
util/virfile.c:837: error: 'PROT_READ' undeclared (first use in this function)

* src/util/virutil.c (includes): Move use of <sys/mman.h>...
* src/util/virfile.c (includes): ...to the file that uses mmap.

Signed-off-by: Eric Blake <eblake@redhat.com>
2013-05-10 20:52:57 -06:00

2174 lines
56 KiB
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/*
* virfile.c: safer file handling
*
* Copyright (C) 2010-2013 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 <passfd.h>
#include <fcntl.h>
#include <pty.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <dirent.h>
#include <dirname.h>
#if defined HAVE_MNTENT_H && defined HAVE_GETMNTENT_R
# include <mntent.h>
#endif
#include <stdlib.h>
#if HAVE_MMAP
# include <sys/mman.h>
#endif
#if defined(__linux__) && HAVE_DECL_LO_FLAGS_AUTOCLEAR
# include <linux/loop.h>
# include <sys/ioctl.h>
#endif
#include "configmake.h"
#include "viralloc.h"
#include "vircommand.h"
#include "virerror.h"
#include "virfile.h"
#include "virlog.h"
#include "virprocess.h"
#include "virstring.h"
#include "virstoragefile.h"
#include "virutil.h"
#define VIR_FROM_THIS VIR_FROM_NONE
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 {
char ebuf[1024] ATTRIBUTE_UNUSED;
VIR_DEBUG("Failed to close fd %d: %s",
*fdptr, virStrerror(errno, ebuf, sizeof(ebuf)));
}
} else {
VIR_DEBUG("Closed fd %d", *fdptr);
}
}
*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 {
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;
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;
}
if (VIR_ALLOC(ret) < 0) {
virReportOOMError();
return NULL;
}
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 %x for %s"),
mode & O_ACCMODE, name);
goto error;
}
if (pipe2(pipefd, O_CLOEXEC) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("unable to create pipe for %s"), name);
goto error;
}
ret->cmd = virCommandNewArgList(LIBEXECDIR "/libvirt_iohelper",
name, "0", 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
virFileWrapperFdPtr
virFileWrapperFdNew(int *fd ATTRIBUTE_UNUSED,
const char *name ATTRIBUTE_UNUSED,
unsigned int fdflags ATTRIBUTE_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("virFileWrapperFd unsupported on this platform"));
return NULL;
}
#endif
/**
* 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().
*/
int
virFileWrapperFdClose(virFileWrapperFdPtr wfd)
{
int ret;
if (!wfd)
return 0;
ret = virCommandWait(wfd->cmd, NULL);
if (wfd->err_msg)
VIR_WARN("iohelper reports: %s", wfd->err_msg);
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)
*
* 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. This will not wait to acquire the lock if
* another process already holds 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)
{
struct flock fl = {
.l_type = shared ? F_RDLCK : F_WRLCK,
.l_whence = SEEK_SET,
.l_start = start,
.l_len = len,
};
if (fcntl(fd, F_SETLK, &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 succcess, 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
int virFileLock(int fd ATTRIBUTE_UNUSED,
bool shared ATTRIBUTE_UNUSED,
off_t start ATTRIBUTE_UNUSED,
off_t len ATTRIBUTE_UNUSED)
{
return -ENOSYS;
}
int virFileUnlock(int fd ATTRIBUTE_UNUSED,
off_t start ATTRIBUTE_UNUSED,
off_t len ATTRIBUTE_UNUSED)
{
return -ENOSYS;
}
#endif
int
virFileRewrite(const char *path,
mode_t mode,
virFileRewriteFunc rewrite,
void *opaque)
{
char *newfile = NULL;
int fd = -1;
int ret = -1;
if (virAsprintf(&newfile, "%s.new", path) < 0) {
virReportOOMError();
goto cleanup;
}
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 (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);
if (newfile) {
unlink(newfile);
VIR_FREE(newfile);
}
return ret;
}
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__) && HAVE_DECL_LO_FLAGS_AUTOCLEAR
static int virFileLoopDeviceOpen(char **dev_name)
{
int fd = -1;
DIR *dh = NULL;
struct dirent *de;
char *looppath = NULL;
struct loop_info64 lo;
VIR_DEBUG("Looking for loop devices in /dev");
if (!(dh = opendir("/dev"))) {
virReportSystemError(errno, "%s",
_("Unable to read /dev"));
goto cleanup;
}
while ((de = readdir(dh)) != NULL) {
if (!STRPREFIX(de->d_name, "loop"))
continue;
if (virAsprintf(&looppath, "/dev/%s", de->d_name) < 0) {
virReportOOMError();
goto cleanup;
}
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);
}
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);
}
if (dh)
closedir(dh);
return fd;
}
int virFileLoopDeviceAssociate(const char *file,
char **dev)
{
int lofd = -1;
int fsfd = -1;
struct loop_info64 lo;
char *loname = NULL;
int ret = -1;
if ((lofd = virFileLoopDeviceOpen(&loname)) < 0)
return -1;
memset(&lo, 0, sizeof(lo));
lo.lo_flags = LO_FLAGS_AUTOCLEAR;
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_FREE(loname);
VIR_FORCE_CLOSE(fsfd);
if (ret == -1)
VIR_FORCE_CLOSE(lofd);
return lofd;
}
#else /* __linux__ */
int virFileLoopDeviceAssociate(const char *file,
char **dev ATTRIBUTE_UNUSED)
{
virReportSystemError(ENOSYS,
_("Unable to associate file %s with loop device"),
file);
*dev = NULL;
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)
{
DIR *dh = opendir(dir);
struct dirent *de;
char *filepath = NULL;
int ret = -1;
if (!dh) {
virReportSystemError(errno, _("Cannot open dir '%s'"),
dir);
return -1;
}
errno = 0;
while ((de = readdir(dh)) != NULL) {
struct stat sb;
if (STREQ(de->d_name, ".") ||
STREQ(de->d_name, ".."))
continue;
if (virAsprintf(&filepath, "%s/%s",
dir, de->d_name) < 0) {
virReportOOMError();
goto cleanup;
}
if (lstat(filepath, &sb) < 0) {
virReportSystemError(errno, _("Cannot access '%s'"),
filepath);
goto cleanup;
}
if (S_ISDIR(sb.st_mode)) {
if (virFileDeleteTree(filepath) < 0)
goto cleanup;
} else {
if (unlink(filepath) < 0 && errno != ENOENT) {
virReportSystemError(errno,
_("Cannot delete file '%s'"),
filepath);
goto cleanup;
}
}
VIR_FREE(filepath);
errno = 0;
}
if (errno) {
virReportSystemError(errno, _("Cannot read dir '%s'"),
dir);
goto cleanup;
}
if (rmdir(dir) < 0 && errno != ENOENT) {
virReportSystemError(errno,
_("Cannot delete directory '%s'"),
dir);
goto cleanup;
}
ret = 0;
cleanup:
VIR_FREE(filepath);
closedir(dh);
return ret;
}
int
virFileStripSuffix(char *str, const char *suffix)
{
int len = strlen(str);
int suffixlen = strlen(suffix);
if (len < suffixlen)
return 0;
if (!STREQ(str + len - suffixlen, suffix))
return 0;
str[len-suffixlen] = '\0';
return 1;
}
/* 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 HAVE_POSIX_FALLOCATE
int
safezero(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
# ifdef HAVE_MMAP
int
safezero(int fd, off_t offset, off_t len)
{
int r;
char *buf;
/* 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, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
if (buf == MAP_FAILED)
return -1;
memset(buf, 0, len);
munmap(buf, len);
return 0;
}
# else /* HAVE_MMAP */
int
safezero(int fd, off_t offset, off_t len)
{
int r;
char *buf;
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 = 1024 * 1024;
r = VIR_ALLOC_N(buf, bytes);
if (r < 0) {
errno = ENOMEM;
return -1;
}
while (remain) {
if (bytes > remain)
bytes = remain;
r = safewrite(fd, buf, bytes);
if (r < 0) {
VIR_FREE(buf);
return -1;
}
/* safewrite() guarantees all data will be written */
remain -= bytes;
}
VIR_FREE(buf);
return 0;
}
# endif /* HAVE_MMAP */
#endif /* HAVE_POSIX_FALLOCATE */
#if defined HAVE_MNTENT_H && defined HAVE_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 = strdup(mb.mnt_dir);
goto cleanup;
}
}
if (!ret)
errno = ENOENT;
cleanup:
endmntent(f);
return ret;
}
#else /* defined HAVE_MNTENT_H && defined HAVE_GETMNTENT_R */
char *
virFileFindMountPoint(const char *type ATTRIBUTE_UNUSED)
{
errno = ENOSYS;
return NULL;
}
#endif /* defined HAVE_MNTENT_H && defined HAVE_GETMNTENT_R */
int
virBuildPathInternal(char **path, ...)
{
char *path_component = NULL;
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;
}
/* Like gnulib's fread_file, but read no more than the specified maximum
number of bytes. If the length of the input is <= max_len, and
upon error while reading that data, it works just like fread_file. */
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 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 = open(path, O_RDONLY);
if (fd < 0) {
virReportSystemError(errno, _("Failed to open file '%s'"), path);
return -1;
}
int len = virFileReadLimFD(fd, maxlen, buf);
VIR_FORCE_CLOSE(fd);
if (len < 0) {
virReportSystemError(errno, _("Failed to read file '%s'"), path);
return -1;
}
return len;
}
/* 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;
}
int
virFileMatchesNameSuffix(const char *file,
const char *name,
const char *suffix)
{
int filelen = strlen(file);
int namelen = strlen(name);
int suffixlen = strlen(suffix);
if (filelen == (namelen + suffixlen) &&
STREQLEN(file, name, namelen) &&
STREQLEN(file + namelen, suffix, suffixlen))
return 1;
else
return 0;
}
int
virFileHasSuffix(const char *str,
const char *suffix)
{
int len = strlen(str);
int suffixlen = strlen(suffix);
if (len < suffixlen)
return 0;
return STRCASEEQ(str + len - suffixlen, suffix);
}
#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));
}
static int
virFileResolveLinkHelper(const char *linkpath,
bool intermediatePaths,
char **resultpath)
{
struct stat 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 (IS_ABSOLUTE_FILE_NAME(linkpath) && !intermediatePaths) {
if (lstat(linkpath, &st) < 0)
return -1;
if (!S_ISLNK(st.st_mode)) {
if (!(*resultpath = strdup(linkpath)))
return -1;
return 0;
}
}
*resultpath = canonicalize_file_name(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)
{
struct stat st;
if (lstat(linkpath, &st) < 0)
return -errno;
return S_ISLNK(st.st_mode) != 0;
}
/*
* Finds a requested executable file in the PATH env. e.g.:
* "kvm-img" will return "/usr/bin/kvm-img"
*
* You must free the result
*/
char *
virFindFileInPath(const char *file)
{
char *path = NULL;
char *pathiter;
char *pathseg;
char *fullpath = NULL;
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 (IS_ABSOLUTE_FILE_NAME(file)) {
if (virFileIsExecutable(file))
return strdup(file);
else
return NULL;
}
/* 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, '/')) {
if (virFileIsExecutable(file))
ignore_value(virFileAbsPath(file, &path));
return path;
}
/* copy PATH env so we can tweak it */
path = getenv("PATH");
if (path == NULL || (path = strdup(path)) == NULL)
return NULL;
/* for each path segment, append the file to search for and test for
* it. return it if found.
*/
pathiter = path;
while ((pathseg = strsep(&pathiter, ":")) != NULL) {
if (virAsprintf(&fullpath, "%s/%s", pathseg, file) < 0 ||
virFileIsExecutable(fullpath))
break;
VIR_FREE(fullpath);
}
VIR_FREE(path);
return fullpath;
}
bool
virFileIsDir(const char *path)
{
struct stat s;
return (stat(path, &s) == 0) && S_ISDIR(s.st_mode);
}
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;
}
#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;
int forkRet = 0;
if (uid == getuid() &&
gid == getgid())
return access(path, mode);
forkRet = virFork(&pid);
if (pid < 0) {
return -1;
}
if (pid) { /* parent */
if (virProcessWait(pid, &status) < 0) {
/* virProcessWait() already
* reported error */
return -1;
}
if (!WIFEXITED(status)) {
errno = EINTR;
return -1;
}
if (status) {
errno = WEXITSTATUS(status);
return -1;
}
return 0;
}
/* child.
* Return positive value here. Parent
* will change it to negative one. */
if (forkRet < 0) {
ret = errno;
goto childerror;
}
if (virSetUIDGID(uid, gid) < 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. */
static int
virFileOpenForked(const char *path, int openflags, mode_t mode,
uid_t uid, gid_t gid, unsigned int flags)
{
pid_t pid;
int waitret, status, ret = 0;
int fd = -1;
int pair[2] = { -1, -1 };
int forkRet;
/* 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. */
if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) {
ret = -errno;
virReportSystemError(errno,
_("failed to create socket needed for '%s'"),
path);
return ret;
}
forkRet = virFork(&pid);
if (pid < 0)
return -errno;
if (pid == 0) {
/* child */
VIR_FORCE_CLOSE(pair[0]); /* preserves errno */
if (forkRet < 0) {
/* error encountered and logged in virFork() after the fork. */
ret = -errno;
goto childerror;
}
/* set desired uid/gid, then attempt to create the file */
if (virSetUIDGID(uid, gid) < 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;
}
/* File is successfully open. Set permissions if requested. */
ret = virFileOpenForceOwnerMode(path, fd, mode, uid, gid, flags);
if (ret < 0)
goto childerror;
do {
ret = sendfd(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);
}
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 = recvfd(pair[0], 0);
} while (fd < 0 && errno == EINTR);
VIR_FORCE_CLOSE(pair[0]); /* NB: this preserves errno */
if (fd < 0 && errno != EACCES) {
ret = -errno;
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR);
return ret;
}
/* wait for child to complete, and retrieve its exit code */
while ((waitret = waitpid(pid, &status, 0) == -1)
&& (errno == EINTR));
if (waitret == -1) {
ret = -errno;
virReportSystemError(errno,
_("failed to wait for child creating '%s'"),
path);
VIR_FORCE_CLOSE(fd);
return ret;
}
if (!WIFEXITED(status) || (ret = -WEXITSTATUS(status)) == -EACCES ||
fd == -1) {
/* fall back to the simpler method, which works better in
* some cases */
VIR_FORCE_CLOSE(fd);
if (flags & VIR_FILE_OPEN_NOFORK) {
/* If we had already tried opening w/o fork+setuid and
* failed, no sense trying again. Just set return the
* original errno that we got at that time (by
* definition, always either EACCES or EPERM - EACCES
* is close enough).
*/
return -EACCES;
}
if ((fd = open(path, openflags, mode)) < 0)
return -errno;
ret = virFileOpenForceOwnerMode(path, fd, mode, uid, gid, flags);
if (ret < 0) {
VIR_FORCE_CLOSE(fd);
return ret;
}
}
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.
*/
int
virFileOpenAs(const char *path, int openflags, mode_t mode,
uid_t uid, gid_t gid, unsigned int flags)
{
int ret = 0, fd = -1;
/* allow using -1 to mean "current value" */
if (uid == (uid_t) -1)
uid = getuid();
if (gid == (gid_t) -1)
gid = getgid();
/* 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)
|| (getuid() != 0)
|| ((uid == 0) && (gid == 0))) {
if ((fd = open(path, openflags, mode)) < 0) {
ret = -errno;
if (!(flags & VIR_FILE_OPEN_FORK))
goto error;
} else {
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 (virStorageFileIsSharedFS(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);
}
/* whoever failed the open last has already set ret = -errno */
return ret;
}
/* return -errno on failure, or 0 on success */
static int
virDirCreateNoFork(const char *path,
mode_t mode, uid_t uid, gid_t gid,
unsigned int flags)
{
int ret = 0;
struct stat st;
if ((mkdir(path, mode) < 0)
&& !((errno == EEXIST) && (flags & VIR_DIR_CREATE_ALLOW_EXIST))) {
ret = -errno;
virReportSystemError(errno, _("failed to create directory '%s'"),
path);
goto error;
}
if (stat(path, &st) == -1) {
ret = -errno;
virReportSystemError(errno, _("stat of '%s' failed"), path);
goto error;
}
if (((st.st_uid != uid) || (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;
}
if ((flags & VIR_DIR_CREATE_FORCE_PERMS)
&& (chmod(path, mode) < 0)) {
ret = -errno;
virReportSystemError(errno,
_("cannot set mode of '%s' to %04o"),
path, mode);
goto error;
}
error:
return ret;
}
/* return -errno on failure, or 0 on success */
int
virDirCreate(const char *path,
mode_t mode, uid_t uid, gid_t gid,
unsigned int flags)
{
struct stat st;
pid_t pid;
int waitret;
int status, ret = 0;
/* allow using -1 to mean "current value" */
if (uid == (uid_t) -1)
uid = getuid();
if (gid == (gid_t) -1)
gid = getgid();
if ((!(flags & VIR_DIR_CREATE_AS_UID))
|| (getuid() != 0)
|| ((uid == 0) && (gid == 0))
|| ((flags & VIR_DIR_CREATE_ALLOW_EXIST) && (stat(path, &st) >= 0))) {
return virDirCreateNoFork(path, mode, uid, gid, flags);
}
int forkRet = virFork(&pid);
if (pid < 0) {
ret = -errno;
return ret;
}
if (pid) { /* parent */
/* wait for child to complete, and retrieve its exit code */
while ((waitret = waitpid(pid, &status, 0) == -1) && (errno == EINTR));
if (waitret == -1) {
ret = -errno;
virReportSystemError(errno,
_("failed to wait for child creating '%s'"),
path);
goto parenterror;
}
if (!WIFEXITED(status) || (ret = -WEXITSTATUS(status)) == -EACCES) {
/* fall back to the simpler method, which works better in
* some cases */
return virDirCreateNoFork(path, mode, uid, gid, flags);
}
parenterror:
return ret;
}
/* child */
if (forkRet < 0) {
/* error encountered and logged in virFork() after the fork. */
goto childerror;
}
/* set desired uid/gid, then attempt to create the directory */
if (virSetUIDGID(uid, gid) < 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;
}
/* 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 ((flags & VIR_DIR_CREATE_FORCE_PERMS)
&& chmod(path, mode) < 0) {
virReportSystemError(errno,
_("cannot set mode of '%s' to %04o"),
path, mode);
goto childerror;
}
childerror:
_exit(ret);
}
#else /* WIN32 */
int
virFileAccessibleAs(const char *path,
int mode,
uid_t uid ATTRIBUTE_UNUSED,
gid_t gid ATTRIBUTE_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 ATTRIBUTE_UNUSED,
int openflags ATTRIBUTE_UNUSED,
mode_t mode ATTRIBUTE_UNUSED,
uid_t uid ATTRIBUTE_UNUSED,
gid_t gid ATTRIBUTE_UNUSED,
unsigned int flags_unused ATTRIBUTE_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virFileOpenAs is not implemented for WIN32"));
return -ENOSYS;
}
int
virDirCreate(const char *path ATTRIBUTE_UNUSED,
mode_t mode ATTRIBUTE_UNUSED,
uid_t uid ATTRIBUTE_UNUSED,
gid_t gid ATTRIBUTE_UNUSED,
unsigned int flags_unused ATTRIBUTE_UNUSED)
{
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virDirCreate is not implemented for WIN32"));
return -ENOSYS;
}
#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 (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)
{
int ret = -1;
char *tmp;
if ((tmp = strdup(path)) == NULL)
goto cleanup;
ret = virFileMakePathHelper(tmp, mode);
cleanup:
VIR_FREE(tmp);
return ret;
}
/* 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) {
if (virAsprintf(&path, "%s/%s", dir, name) < 0) {
virReportOOMError();
return NULL;
}
} else {
if (virAsprintf(&path, "%s/%s%s", dir, name, ext) < 0) {
virReportOOMError();
return NULL;
}
}
return path;
}
/* Open a non-blocking master side of a pty. If ttyName is not NULL,
* then populate it with the name of the slave. If rawmode is set,
* also put the master side into raw mode before returning. */
#ifndef WIN32
int
virFileOpenTty(int *ttymaster, char **ttyName, int rawmode)
{
/* XXX A word of caution - on some platforms (Solaris and HP-UX),
* additional ioctl() calls are needs after opening the slave
* before it will cause isatty() to return true. Should we make
* virFileOpenTty also return the opened slave fd, so the caller
* doesn't have to worry about that mess? */
int ret = -1;
int slave = -1;
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(ttymaster, &slave, 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(*ttymaster) < 0 ||
virSetCloseExec(*ttymaster) < 0)
goto cleanup;
/* While Linux supports tcgetattr on either the master or the
* slave, Solaris requires it to be on the slave. */
if (rawmode) {
struct termios ttyAttr;
if (tcgetattr(slave, &ttyAttr) < 0)
goto cleanup;
cfmakeraw(&ttyAttr);
if (tcsetattr(slave, TCSADRAIN, &ttyAttr) < 0)
goto cleanup;
}
/* ttyname_r on the slave is required by POSIX, while ptsname_r on
* the master 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;
if (VIR_ALLOC_N(name, len) < 0)
goto cleanup;
while ((rc = ttyname_r(slave, 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(*ttymaster);
VIR_FORCE_CLOSE(slave);
VIR_FREE(name);
return ret;
}
#else /* WIN32 */
int
virFileOpenTty(int *ttymaster ATTRIBUTE_UNUSED,
char **ttyName ATTRIBUTE_UNUSED,
int rawmode ATTRIBUTE_UNUSED)
{
/* mingw completely lacks pseudo-terminals, and the gnulib
* replacements are not (yet) license compatible. */
errno = ENOSYS;
return -1;
}
#endif /* WIN32 */
bool
virFileIsAbsPath(const char *path)
{
if (!path)
return false;
if (VIR_FILE_IS_DIR_SEPARATOR(path[0]))
return true;
#ifdef WIN32
if (c_isalpha(path[0]) &&
path[1] == ':' &&
VIR_FILE_IS_DIR_SEPARATOR(path[2]))
return true;
#endif
return false;
}
const char *
virFileSkipRoot(const char *path)
{
#ifdef WIN32
/* Skip \\server\share or //server/share */
if (VIR_FILE_IS_DIR_SEPARATOR(path[0]) &&
VIR_FILE_IS_DIR_SEPARATOR(path[1]) &&
path[2] &&
!VIR_FILE_IS_DIR_SEPARATOR(path[2]))
{
const char *p = strchr(path + 2, VIR_FILE_DIR_SEPARATOR);
const char *q = strchr(path + 2, '/');
if (p == NULL || (q != NULL && q < p))
p = q;
if (p && p > path + 2 && p[1]) {
path = p + 1;
while (path[0] &&
!VIR_FILE_IS_DIR_SEPARATOR(path[0]))
path++;
/* Possibly skip a backslash after the share name */
if (VIR_FILE_IS_DIR_SEPARATOR(path[0]))
path++;
return path;
}
}
#endif
/* Skip initial slashes */
if (VIR_FILE_IS_DIR_SEPARATOR(path[0])) {
while (VIR_FILE_IS_DIR_SEPARATOR(path[0]))
path++;
return path;
}
#ifdef WIN32
/* Skip X:\ */
if (c_isalpha(path[0]) &&
path[1] == ':' &&
VIR_FILE_IS_DIR_SEPARATOR(path[2]))
return path + 3;
#endif
return path;
}
/*
* 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)
{
char *buf;
if (path[0] == '/') {
if (!(*abspath = strdup(path)))
return -1;
} else {
buf = getcwd(NULL, 0);
if (buf == NULL)
return -1;
if (virAsprintf(abspath, "%s/%s", buf, path) < 0) {
VIR_FREE(buf);
return -1;
}
VIR_FREE(buf);
}
return 0;
}
/* Remove spurious / characters from a path. The result must be freed */
char *
virFileSanitizePath(const char *path)
{
const char *cur = path;
char *cleanpath;
int idx = 0;
cleanpath = strdup(path);
if (!cleanpath) {
virReportOOMError();
return NULL;
}
/* 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;
}
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