libvirt/src/util/util.h

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/*
* utils.h: common, generic utility functions
*
* Copyright (C) 2010-2012 Red Hat, Inc.
* Copyright (C) 2006, 2007 Binary Karma
* Copyright (C) 2006 Shuveb Hussain
*
* 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/>.
*
* File created Jul 18, 2007 - Shuveb Hussain <shuveb@binarykarma.com>
*/
#ifndef __VIR_UTIL_H__
# define __VIR_UTIL_H__
# include "verify.h"
# include "internal.h"
# include <unistd.h>
# include <sys/select.h>
# include <sys/types.h>
# include <stdarg.h>
# ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
# endif
# ifndef MAX
# define MAX(a, b) ((a) > (b) ? (a) : (b))
# endif
ssize_t saferead(int fd, void *buf, size_t count) ATTRIBUTE_RETURN_CHECK;
ssize_t safewrite(int fd, const void *buf, size_t count)
ATTRIBUTE_RETURN_CHECK;
int safezero(int fd, off_t offset, off_t len)
ATTRIBUTE_RETURN_CHECK;
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int virSetBlocking(int fd, bool blocking) ATTRIBUTE_RETURN_CHECK;
int virSetNonBlock(int fd) ATTRIBUTE_RETURN_CHECK;
int virSetInherit(int fd, bool inherit) ATTRIBUTE_RETURN_CHECK;
int virSetCloseExec(int fd) ATTRIBUTE_RETURN_CHECK;
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int virPipeReadUntilEOF(int outfd, int errfd,
char **outbuf, char **errbuf);
int virSetUIDGID(uid_t uid, gid_t gid);
int virFileReadLimFD(int fd, int maxlen, char **buf) ATTRIBUTE_RETURN_CHECK;
int virFileReadAll(const char *path, int maxlen, char **buf) ATTRIBUTE_RETURN_CHECK;
int virFileWriteStr(const char *path, const char *str, mode_t mode)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
int virFileMatchesNameSuffix(const char *file,
const char *name,
const char *suffix);
int virFileHasSuffix(const char *str,
const char *suffix);
int virFileStripSuffix(char *str,
const char *suffix) ATTRIBUTE_RETURN_CHECK;
int virFileLinkPointsTo(const char *checkLink,
const char *checkDest);
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int virFileResolveLink(const char *linkpath,
char **resultpath) ATTRIBUTE_RETURN_CHECK;
int virFileResolveAllLinks(const char *linkpath,
char **resultpath) ATTRIBUTE_RETURN_CHECK;
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int virFileIsLink(const char *linkpath)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
char *virFindFileInPath(const char *file);
bool virFileIsDir (const char *file) ATTRIBUTE_NONNULL(1);
bool virFileExists(const char *file) ATTRIBUTE_NONNULL(1);
bool virFileIsExecutable(const char *file) ATTRIBUTE_NONNULL(1);
char *virFileSanitizePath(const char *path);
enum {
VIR_FILE_OPEN_NONE = 0,
util: refactor virFileOpenAs virFileOpenAs previously would only try opening a file as the current user, or as a different user, but wouldn't try both methods in a single call. This made it cumbersome to use as a replacement for open(2). Additionally, it had a lot of historical baggage that led to it being difficult to understand. This patch refactors virFileOpenAs in the following ways: * reorganize the code so that everything dealing with both the parent and child sides of the "fork+setuid+setgid+open" method are in a separate function. This makes the public function easier to understand. * Allow a single call to virFileOpenAs() to first attempt the open as the current user, and if that fails to automatically re-try after doing fork+setuid (if deemed appropriate, i.e. errno indicates it would now be successful, and the file is on a networkFS). This makes it possible (in many, but possibly not all, cases) to drop-in virFileOpenAs() as a replacement for open(2). (NB: currently qemuOpenFile() calls virFileOpenAs() twice, once without forking, then again with forking. That unfortunately can't be changed without at least some discussion of the ramifications, because the requested file permissions are different in each case, which is something that a single call to virFileOpenAs() can't deal with.) * Add a flag so that any fchown() of the file to a different uid:gid is explicitly requested when the function is called, rather than it being implied by the presence of the O_CREAT flag. This just makes for less subtle surprises to consumers. (Commit b1643dc15c5de886fefe56ad18608d65f1325a2c added the check for O_CREAT before forcing ownership. This patch just makes that restriction more explicit.) * If either the uid or gid is specified as "-1", virFileOpenAs will interpret this to mean "the current [gu]id". All current consumers of virFileOpenAs should retain their present behavior (after a few minor changes to their setup code and arguments).
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VIR_FILE_OPEN_NOFORK = (1 << 0),
VIR_FILE_OPEN_FORK = (1 << 1),
VIR_FILE_OPEN_FORCE_MODE = (1 << 2),
VIR_FILE_OPEN_FORCE_OWNER = (1 << 3),
};
int virFileAccessibleAs(const char *path, int mode,
uid_t uid, gid_t gid)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virFileOpenAs(const char *path, int openflags, mode_t mode,
uid_t uid, gid_t gid,
unsigned int flags)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
Rename virFileCreate to virFileOperation, add hook function It turns out it is also useful to be able to perform other operations on a file created while running as a different uid (eg, write things to that file), and possibly to do this to a file that already exists. This patch adds an optional hook function to the renamed (for more accuracy of purpose) virFileOperation; the hook will be called after the file has been opened (possibly created) and gid/mode checked/set, before closing it. As with the other operations on the file, if the VIR_FILE_OP_AS_UID flag is set, this hook function will be called in the context of a child process forked from the process that called virFileOperation. The implication here is that, while all data in memory is available to this hook function, any modification to that data will not be seen by the caller - the only indication in memory of what happened in the hook will be the return value (which the hook should set to 0 on success, or one of the standard errno values on failure). Another piece of making the function more flexible was to add an "openflags" argument. This arg should contain exactly the flags to be passed to open(2), eg O_RDWR | O_EXCL, etc. In the process of adding the hook to virFileOperation, I also realized that the bits to fix up file owner/group/mode settings after creation were being done in the parent process, which could fail, so I moved them to the child process where they should be. * src/util/util.[ch]: rename and rework virFileCreate-->virFileOperation, and redo flags in virDirCreate * storage/storage_backend.c, storage/storage_backend_fs.c: update the calls to virFileOperation/virDirCreate to reflect changes in the API, but don't yet take advantage of the hook.
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enum {
VIR_DIR_CREATE_NONE = 0,
VIR_DIR_CREATE_AS_UID = (1 << 0),
VIR_DIR_CREATE_FORCE_PERMS = (1 << 1),
VIR_DIR_CREATE_ALLOW_EXIST = (1 << 2),
};
int virDirCreate(const char *path, mode_t mode, uid_t uid, gid_t gid,
unsigned int flags) ATTRIBUTE_RETURN_CHECK;
int virFileMakePath(const char *path) ATTRIBUTE_RETURN_CHECK;
int virFileMakePathWithMode(const char *path,
mode_t mode) ATTRIBUTE_RETURN_CHECK;
char *virFileBuildPath(const char *dir,
const char *name,
const char *ext) ATTRIBUTE_RETURN_CHECK;
# ifdef WIN32
/* On Win32, the canonical directory separator is the backslash, and
* the search path separator is the semicolon. Note that also the
* (forward) slash works as directory separator.
*/
# define VIR_FILE_DIR_SEPARATOR '\\'
# define VIR_FILE_DIR_SEPARATOR_S "\\"
# define VIR_FILE_IS_DIR_SEPARATOR(c) ((c) == VIR_FILE_DIR_SEPARATOR || (c) == '/')
# define VIR_FILE_PATH_SEPARATOR ';'
# define VIR_FILE_PATH_SEPARATOR_S ";"
# else /* !WIN32 */
# define VIR_FILE_DIR_SEPARATOR '/'
# define VIR_FILE_DIR_SEPARATOR_S "/"
# define VIR_FILE_IS_DIR_SEPARATOR(c) ((c) == VIR_FILE_DIR_SEPARATOR)
# define VIR_FILE_PATH_SEPARATOR ':'
# define VIR_FILE_PATH_SEPARATOR_S ":"
# endif /* !WIN32 */
bool virFileIsAbsPath(const char *path);
int virFileAbsPath(const char *path,
char **abspath) ATTRIBUTE_RETURN_CHECK;
const char *virFileSkipRoot(const char *path);
int virFileOpenTty(int *ttymaster,
char **ttyName,
int rawmode);
char *virArgvToString(const char *const *argv);
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int virStrToLong_i(char const *s,
char **end_ptr,
int base,
int *result);
int virStrToLong_ui(char const *s,
char **end_ptr,
int base,
unsigned int *result);
int virStrToLong_l(char const *s,
char **end_ptr,
int base,
long *result);
int virStrToLong_ul(char const *s,
char **end_ptr,
int base,
unsigned long *result);
int virStrToLong_ll(char const *s,
char **end_ptr,
int base,
long long *result);
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int virStrToLong_ull(char const *s,
char **end_ptr,
int base,
unsigned long long *result);
int virStrToDouble(char const *s,
char **end_ptr,
double *result);
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int virScaleInteger(unsigned long long *value, const char *suffix,
unsigned long long scale, unsigned long long limit)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virHexToBin(unsigned char c);
void virSkipSpaces(const char **str) ATTRIBUTE_NONNULL(1);
void virSkipSpacesAndBackslash(const char **str) ATTRIBUTE_NONNULL(1);
void virTrimSpaces(char *str, char **endp) ATTRIBUTE_NONNULL(1);
void virSkipSpacesBackwards(const char *str, char **endp)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
int virParseNumber(const char **str);
int virParseVersionString(const char *str, unsigned long *version,
bool allowMissing);
int virAsprintf(char **strp, const char *fmt, ...)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_FMT_PRINTF(2, 3);
int virVasprintf(char **strp, const char *fmt, va_list list)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_FMT_PRINTF(2, 0);
char *virStrncpy(char *dest, const char *src, size_t n, size_t destbytes)
ATTRIBUTE_RETURN_CHECK;
char *virStrcpy(char *dest, const char *src, size_t destbytes)
ATTRIBUTE_RETURN_CHECK;
# define virStrcpyStatic(dest, src) virStrcpy((dest), (src), sizeof(dest))
int virDiskNameToIndex(const char* str);
char *virIndexToDiskName(int idx, const char *prefix);
int virEnumFromString(const char *const*types,
unsigned int ntypes,
const char *type);
const char *virEnumToString(const char *const*types,
unsigned int ntypes,
int type);
# define VIR_ENUM_IMPL(name, lastVal, ...) \
static const char *const name ## TypeList[] = { __VA_ARGS__ }; \
verify(ARRAY_CARDINALITY(name ## TypeList) == lastVal); \
const char *name ## TypeToString(int type) { \
return virEnumToString(name ## TypeList, \
ARRAY_CARDINALITY(name ## TypeList), \
type); \
} \
int name ## TypeFromString(const char *type) { \
return virEnumFromString(name ## TypeList, \
ARRAY_CARDINALITY(name ## TypeList), \
type); \
}
# define VIR_ENUM_DECL(name) \
const char *name ## TypeToString(int type); \
int name ## TypeFromString(const char*type);
# ifndef HAVE_GETUID
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static inline int getuid (void) { return 0; }
# endif
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# ifndef HAVE_GETEUID
static inline int geteuid (void) { return 0; }
# endif
# ifndef HAVE_GETGID
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static inline int getgid (void) { return 0; }
# endif
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char *virGetHostname(virConnectPtr conn);
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int virKillProcess(pid_t pid, int sig);
char *virGetUserDirectory(void);
char *virGetUserConfigDirectory(void);
char *virGetUserCacheDirectory(void);
char *virGetUserRuntimeDirectory(void);
char *virGetUserName(uid_t uid);
char *virGetGroupName(gid_t gid);
int virGetUserID(const char *name,
uid_t *uid) ATTRIBUTE_RETURN_CHECK;
int virGetGroupID(const char *name,
gid_t *gid) ATTRIBUTE_RETURN_CHECK;
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char *virFileFindMountPoint(const char *type);
void virFileWaitForDevices(void);
# define virBuildPath(path, ...) virBuildPathInternal(path, __VA_ARGS__, NULL)
int virBuildPathInternal(char **path, ...) ATTRIBUTE_SENTINEL;
bool virIsDevMapperDevice(const char *dev_name) ATTRIBUTE_NONNULL(1);
#endif /* __VIR_UTIL_H__ */