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glib/glib/gfileutils.c
Will Thompson c1a8e93dc4
gfileutils: document non-atomicity of g_file_set_contents() 
This function only calls fsync() if @target exists and is non-empty. If
not, it doesn't provide the "old contents or new contents" guarantee
that one might expect. This has been the case since
d20a188b12, and is justified either as a
performance optimization or by asserting that this function only
guarantees to not destroy existing data (implicitly defining
non-existence or emptiness as not data).

In addition, explicitly spell out that whether it's atomic in the
non-empty case is system-dependent. If the system administrator has
configured some funky filesystem options, they may be out of luck on the
atomicity front.

https://gitlab.gnome.org/GNOME/glib/issues/1302
2018-06-15 14:47:47 +01:00

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/* gfileutils.c - File utility functions
*
* Copyright 2000 Red Hat, Inc.
*
* 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 "glibconfig.h"
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#ifdef G_OS_UNIX
#include <unistd.h>
#endif
#ifdef G_OS_WIN32
#include <windows.h>
#include <io.h>
#endif /* G_OS_WIN32 */
#ifndef S_ISLNK
#define S_ISLNK(x) 0
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
#include "gfileutils.h"
#include "gstdio.h"
#include "gstdioprivate.h"
#include "glibintl.h"
#ifdef HAVE_LINUX_MAGIC_H /* for btrfs check */
#include <linux/magic.h>
#include <sys/vfs.h>
#endif
/**
* SECTION:fileutils
* @title: File Utilities
* @short_description: various file-related functions
*
* Do not use these APIs unless you are porting a POSIX application to Windows.
* A more high-level file access API is provided as GIO — see the documentation
* for #GFile.
*
* There is a group of functions which wrap the common POSIX functions
* dealing with filenames (g_open(), g_rename(), g_mkdir(), g_stat(),
* g_unlink(), g_remove(), g_fopen(), g_freopen()). The point of these
* wrappers is to make it possible to handle file names with any Unicode
* characters in them on Windows without having to use ifdefs and the
* wide character API in the application code.
*
* On some Unix systems, these APIs may be defined as identical to their POSIX
* counterparts. For this reason, you must check for and include the necessary
* header files (such as `fcntl.h`) before using functions like g_creat(). You
* must also define the relevant feature test macros.
*
* The pathname argument should be in the GLib file name encoding.
* On POSIX this is the actual on-disk encoding which might correspond
* to the locale settings of the process (or the `G_FILENAME_ENCODING`
* environment variable), or not.
*
* On Windows the GLib file name encoding is UTF-8. Note that the
* Microsoft C library does not use UTF-8, but has separate APIs for
* current system code page and wide characters (UTF-16). The GLib
* wrappers call the wide character API if present (on modern Windows
* systems), otherwise convert to/from the system code page.
*
* Another group of functions allows to open and read directories
* in the GLib file name encoding. These are g_dir_open(),
* g_dir_read_name(), g_dir_rewind(), g_dir_close().
*/
/**
* GFileError:
* @G_FILE_ERROR_EXIST: Operation not permitted; only the owner of
* the file (or other resource) or processes with special privileges
* can perform the operation.
* @G_FILE_ERROR_ISDIR: File is a directory; you cannot open a directory
* for writing, or create or remove hard links to it.
* @G_FILE_ERROR_ACCES: Permission denied; the file permissions do not
* allow the attempted operation.
* @G_FILE_ERROR_NAMETOOLONG: Filename too long.
* @G_FILE_ERROR_NOENT: No such file or directory. This is a "file
* doesn't exist" error for ordinary files that are referenced in
* contexts where they are expected to already exist.
* @G_FILE_ERROR_NOTDIR: A file that isn't a directory was specified when
* a directory is required.
* @G_FILE_ERROR_NXIO: No such device or address. The system tried to
* use the device represented by a file you specified, and it
* couldn't find the device. This can mean that the device file was
* installed incorrectly, or that the physical device is missing or
* not correctly attached to the computer.
* @G_FILE_ERROR_NODEV: The underlying file system of the specified file
* does not support memory mapping.
* @G_FILE_ERROR_ROFS: The directory containing the new link can't be
* modified because it's on a read-only file system.
* @G_FILE_ERROR_TXTBSY: Text file busy.
* @G_FILE_ERROR_FAULT: You passed in a pointer to bad memory.
* (GLib won't reliably return this, don't pass in pointers to bad
* memory.)
* @G_FILE_ERROR_LOOP: Too many levels of symbolic links were encountered
* in looking up a file name. This often indicates a cycle of symbolic
* links.
* @G_FILE_ERROR_NOSPC: No space left on device; write operation on a
* file failed because the disk is full.
* @G_FILE_ERROR_NOMEM: No memory available. The system cannot allocate
* more virtual memory because its capacity is full.
* @G_FILE_ERROR_MFILE: The current process has too many files open and
* can't open any more. Duplicate descriptors do count toward this
* limit.
* @G_FILE_ERROR_NFILE: There are too many distinct file openings in the
* entire system.
* @G_FILE_ERROR_BADF: Bad file descriptor; for example, I/O on a
* descriptor that has been closed or reading from a descriptor open
* only for writing (or vice versa).
* @G_FILE_ERROR_INVAL: Invalid argument. This is used to indicate
* various kinds of problems with passing the wrong argument to a
* library function.
* @G_FILE_ERROR_PIPE: Broken pipe; there is no process reading from the
* other end of a pipe. Every library function that returns this
* error code also generates a 'SIGPIPE' signal; this signal
* terminates the program if not handled or blocked. Thus, your
* program will never actually see this code unless it has handled
* or blocked 'SIGPIPE'.
* @G_FILE_ERROR_AGAIN: Resource temporarily unavailable; the call might
* work if you try again later.
* @G_FILE_ERROR_INTR: Interrupted function call; an asynchronous signal
* occurred and prevented completion of the call. When this
* happens, you should try the call again.
* @G_FILE_ERROR_IO: Input/output error; usually used for physical read
* or write errors. i.e. the disk or other physical device hardware
* is returning errors.
* @G_FILE_ERROR_PERM: Operation not permitted; only the owner of the
* file (or other resource) or processes with special privileges can
* perform the operation.
* @G_FILE_ERROR_NOSYS: Function not implemented; this indicates that
* the system is missing some functionality.
* @G_FILE_ERROR_FAILED: Does not correspond to a UNIX error code; this
* is the standard "failed for unspecified reason" error code present
* in all #GError error code enumerations. Returned if no specific
* code applies.
*
* Values corresponding to @errno codes returned from file operations
* on UNIX. Unlike @errno codes, GFileError values are available on
* all systems, even Windows. The exact meaning of each code depends
* on what sort of file operation you were performing; the UNIX
* documentation gives more details. The following error code descriptions
* come from the GNU C Library manual, and are under the copyright
* of that manual.
*
* It's not very portable to make detailed assumptions about exactly
* which errors will be returned from a given operation. Some errors
* don't occur on some systems, etc., sometimes there are subtle
* differences in when a system will report a given error, etc.
*/
/**
* G_FILE_ERROR:
*
* Error domain for file operations. Errors in this domain will
* be from the #GFileError enumeration. See #GError for information
* on error domains.
*/
/**
* GFileTest:
* @G_FILE_TEST_IS_REGULAR: %TRUE if the file is a regular file
* (not a directory). Note that this test will also return %TRUE
* if the tested file is a symlink to a regular file.
* @G_FILE_TEST_IS_SYMLINK: %TRUE if the file is a symlink.
* @G_FILE_TEST_IS_DIR: %TRUE if the file is a directory.
* @G_FILE_TEST_IS_EXECUTABLE: %TRUE if the file is executable.
* @G_FILE_TEST_EXISTS: %TRUE if the file exists. It may or may not
* be a regular file.
*
* A test to perform on a file using g_file_test().
*/
/**
* g_mkdir_with_parents:
* @pathname: (type filename): a pathname in the GLib file name encoding
* @mode: permissions to use for newly created directories
*
* Create a directory if it doesn't already exist. Create intermediate
* parent directories as needed, too.
*
* Returns: 0 if the directory already exists, or was successfully
* created. Returns -1 if an error occurred, with errno set.
*
* Since: 2.8
*/
int
g_mkdir_with_parents (const gchar *pathname,
int mode)
{
gchar *fn, *p;
if (pathname == NULL || *pathname == '\0')
{
errno = EINVAL;
return -1;
}
fn = g_strdup (pathname);
if (g_path_is_absolute (fn))
p = (gchar *) g_path_skip_root (fn);
else
p = fn;
do
{
while (*p && !G_IS_DIR_SEPARATOR (*p))
p++;
if (!*p)
p = NULL;
else
*p = '\0';
if (!g_file_test (fn, G_FILE_TEST_EXISTS))
{
if (g_mkdir (fn, mode) == -1 && errno != EEXIST)
{
int errno_save = errno;
g_free (fn);
errno = errno_save;
return -1;
}
}
else if (!g_file_test (fn, G_FILE_TEST_IS_DIR))
{
g_free (fn);
errno = ENOTDIR;
return -1;
}
if (p)
{
*p++ = G_DIR_SEPARATOR;
while (*p && G_IS_DIR_SEPARATOR (*p))
p++;
}
}
while (p);
g_free (fn);
return 0;
}
/**
* g_file_test:
* @filename: (type filename): a filename to test in the
* GLib file name encoding
* @test: bitfield of #GFileTest flags
*
* Returns %TRUE if any of the tests in the bitfield @test are
* %TRUE. For example, `(G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR)`
* will return %TRUE if the file exists; the check whether it's a
* directory doesn't matter since the existence test is %TRUE. With
* the current set of available tests, there's no point passing in
* more than one test at a time.
*
* Apart from %G_FILE_TEST_IS_SYMLINK all tests follow symbolic links,
* so for a symbolic link to a regular file g_file_test() will return
* %TRUE for both %G_FILE_TEST_IS_SYMLINK and %G_FILE_TEST_IS_REGULAR.
*
* Note, that for a dangling symbolic link g_file_test() will return
* %TRUE for %G_FILE_TEST_IS_SYMLINK and %FALSE for all other flags.
*
* You should never use g_file_test() to test whether it is safe
* to perform an operation, because there is always the possibility
* of the condition changing before you actually perform the operation.
* For example, you might think you could use %G_FILE_TEST_IS_SYMLINK
* to know whether it is safe to write to a file without being
* tricked into writing into a different location. It doesn't work!
* |[<!-- language="C" -->
* // DON'T DO THIS
* if (!g_file_test (filename, G_FILE_TEST_IS_SYMLINK))
* {
* fd = g_open (filename, O_WRONLY);
* // write to fd
* }
* ]|
*
* Another thing to note is that %G_FILE_TEST_EXISTS and
* %G_FILE_TEST_IS_EXECUTABLE are implemented using the access()
* system call. This usually doesn't matter, but if your program
* is setuid or setgid it means that these tests will give you
* the answer for the real user ID and group ID, rather than the
* effective user ID and group ID.
*
* On Windows, there are no symlinks, so testing for
* %G_FILE_TEST_IS_SYMLINK will always return %FALSE. Testing for
* %G_FILE_TEST_IS_EXECUTABLE will just check that the file exists and
* its name indicates that it is executable, checking for well-known
* extensions and those listed in the `PATHEXT` environment variable.
*
* Returns: whether a test was %TRUE
**/
gboolean
g_file_test (const gchar *filename,
GFileTest test)
{
#ifdef G_OS_WIN32
int attributes;
wchar_t *wfilename;
#endif
g_return_val_if_fail (filename != NULL, FALSE);
#ifdef G_OS_WIN32
/* stuff missing in std vc6 api */
# ifndef INVALID_FILE_ATTRIBUTES
# define INVALID_FILE_ATTRIBUTES -1
# endif
# ifndef FILE_ATTRIBUTE_DEVICE
# define FILE_ATTRIBUTE_DEVICE 64
# endif
wfilename = g_utf8_to_utf16 (filename, -1, NULL, NULL, NULL);
if (wfilename == NULL)
return FALSE;
attributes = GetFileAttributesW (wfilename);
g_free (wfilename);
if (attributes == INVALID_FILE_ATTRIBUTES)
return FALSE;
if (test & G_FILE_TEST_EXISTS)
return TRUE;
if (test & G_FILE_TEST_IS_REGULAR)
{
if ((attributes & (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_DEVICE)) == 0)
return TRUE;
}
if (test & G_FILE_TEST_IS_DIR)
{
if ((attributes & FILE_ATTRIBUTE_DIRECTORY) != 0)
return TRUE;
}
/* "while" so that we can exit this "loop" with a simple "break" */
while (test & G_FILE_TEST_IS_EXECUTABLE)
{
const gchar *lastdot = strrchr (filename, '.');
const gchar *pathext = NULL, *p;
int extlen;
if (lastdot == NULL)
break;
if (_stricmp (lastdot, ".exe") == 0 ||
_stricmp (lastdot, ".cmd") == 0 ||
_stricmp (lastdot, ".bat") == 0 ||
_stricmp (lastdot, ".com") == 0)
return TRUE;
/* Check if it is one of the types listed in %PATHEXT% */
pathext = g_getenv ("PATHEXT");
if (pathext == NULL)
break;
pathext = g_utf8_casefold (pathext, -1);
lastdot = g_utf8_casefold (lastdot, -1);
extlen = strlen (lastdot);
p = pathext;
while (TRUE)
{
const gchar *q = strchr (p, ';');
if (q == NULL)
q = p + strlen (p);
if (extlen == q - p &&
memcmp (lastdot, p, extlen) == 0)
{
g_free ((gchar *) pathext);
g_free ((gchar *) lastdot);
return TRUE;
}
if (*q)
p = q + 1;
else
break;
}
g_free ((gchar *) pathext);
g_free ((gchar *) lastdot);
break;
}
return FALSE;
#else
if ((test & G_FILE_TEST_EXISTS) && (access (filename, F_OK) == 0))
return TRUE;
if ((test & G_FILE_TEST_IS_EXECUTABLE) && (access (filename, X_OK) == 0))
{
if (getuid () != 0)
return TRUE;
/* For root, on some POSIX systems, access (filename, X_OK)
* will succeed even if no executable bits are set on the
* file. We fall through to a stat test to avoid that.
*/
}
else
test &= ~G_FILE_TEST_IS_EXECUTABLE;
if (test & G_FILE_TEST_IS_SYMLINK)
{
struct stat s;
if ((lstat (filename, &s) == 0) && S_ISLNK (s.st_mode))
return TRUE;
}
if (test & (G_FILE_TEST_IS_REGULAR |
G_FILE_TEST_IS_DIR |
G_FILE_TEST_IS_EXECUTABLE))
{
struct stat s;
if (stat (filename, &s) == 0)
{
if ((test & G_FILE_TEST_IS_REGULAR) && S_ISREG (s.st_mode))
return TRUE;
if ((test & G_FILE_TEST_IS_DIR) && S_ISDIR (s.st_mode))
return TRUE;
/* The extra test for root when access (file, X_OK) succeeds.
*/
if ((test & G_FILE_TEST_IS_EXECUTABLE) &&
((s.st_mode & S_IXOTH) ||
(s.st_mode & S_IXUSR) ||
(s.st_mode & S_IXGRP)))
return TRUE;
}
}
return FALSE;
#endif
}
G_DEFINE_QUARK (g-file-error-quark, g_file_error)
/**
* g_file_error_from_errno:
* @err_no: an "errno" value
*
* Gets a #GFileError constant based on the passed-in @err_no.
* For example, if you pass in `EEXIST` this function returns
* #G_FILE_ERROR_EXIST. Unlike `errno` values, you can portably
* assume that all #GFileError values will exist.
*
* Normally a #GFileError value goes into a #GError returned
* from a function that manipulates files. So you would use
* g_file_error_from_errno() when constructing a #GError.
*
* Returns: #GFileError corresponding to the given @errno
**/
GFileError
g_file_error_from_errno (gint err_no)
{
switch (err_no)
{
#ifdef EEXIST
case EEXIST:
return G_FILE_ERROR_EXIST;
#endif
#ifdef EISDIR
case EISDIR:
return G_FILE_ERROR_ISDIR;
#endif
#ifdef EACCES
case EACCES:
return G_FILE_ERROR_ACCES;
#endif
#ifdef ENAMETOOLONG
case ENAMETOOLONG:
return G_FILE_ERROR_NAMETOOLONG;
#endif
#ifdef ENOENT
case ENOENT:
return G_FILE_ERROR_NOENT;
#endif
#ifdef ENOTDIR
case ENOTDIR:
return G_FILE_ERROR_NOTDIR;
#endif
#ifdef ENXIO
case ENXIO:
return G_FILE_ERROR_NXIO;
#endif
#ifdef ENODEV
case ENODEV:
return G_FILE_ERROR_NODEV;
#endif
#ifdef EROFS
case EROFS:
return G_FILE_ERROR_ROFS;
#endif
#ifdef ETXTBSY
case ETXTBSY:
return G_FILE_ERROR_TXTBSY;
#endif
#ifdef EFAULT
case EFAULT:
return G_FILE_ERROR_FAULT;
#endif
#ifdef ELOOP
case ELOOP:
return G_FILE_ERROR_LOOP;
#endif
#ifdef ENOSPC
case ENOSPC:
return G_FILE_ERROR_NOSPC;
#endif
#ifdef ENOMEM
case ENOMEM:
return G_FILE_ERROR_NOMEM;
#endif
#ifdef EMFILE
case EMFILE:
return G_FILE_ERROR_MFILE;
#endif
#ifdef ENFILE
case ENFILE:
return G_FILE_ERROR_NFILE;
#endif
#ifdef EBADF
case EBADF:
return G_FILE_ERROR_BADF;
#endif
#ifdef EINVAL
case EINVAL:
return G_FILE_ERROR_INVAL;
#endif
#ifdef EPIPE
case EPIPE:
return G_FILE_ERROR_PIPE;
#endif
#ifdef EAGAIN
case EAGAIN:
return G_FILE_ERROR_AGAIN;
#endif
#ifdef EINTR
case EINTR:
return G_FILE_ERROR_INTR;
#endif
#ifdef EIO
case EIO:
return G_FILE_ERROR_IO;
#endif
#ifdef EPERM
case EPERM:
return G_FILE_ERROR_PERM;
#endif
#ifdef ENOSYS
case ENOSYS:
return G_FILE_ERROR_NOSYS;
#endif
default:
return G_FILE_ERROR_FAILED;
}
}
static char *
format_error_message (const gchar *filename,
const gchar *format_string,
int saved_errno) G_GNUC_FORMAT(2);
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
static char *
format_error_message (const gchar *filename,
const gchar *format_string,
int saved_errno)
{
gchar *display_name;
gchar *msg;
display_name = g_filename_display_name (filename);
msg = g_strdup_printf (format_string, display_name, g_strerror (saved_errno));
g_free (display_name);
return msg;
}
#pragma GCC diagnostic pop
/* format string must have two '%s':
*
* - the place for the filename
* - the place for the strerror
*/
static void
set_file_error (GError **error,
const gchar *filename,
const gchar *format_string,
int saved_errno)
{
char *msg = format_error_message (filename, format_string, saved_errno);
g_set_error_literal (error, G_FILE_ERROR, g_file_error_from_errno (saved_errno),
msg);
g_free (msg);
}
static gboolean
get_contents_stdio (const gchar *filename,
FILE *f,
gchar **contents,
gsize *length,
GError **error)
{
gchar buf[4096];
gsize bytes; /* always <= sizeof(buf) */
gchar *str = NULL;
gsize total_bytes = 0;
gsize total_allocated = 0;
gchar *tmp;
gchar *display_filename;
g_assert (f != NULL);
while (!feof (f))
{
gint save_errno;
bytes = fread (buf, 1, sizeof (buf), f);
save_errno = errno;
if (total_bytes > G_MAXSIZE - bytes)
goto file_too_large;
/* Possibility of overflow eliminated above. */
while (total_bytes + bytes >= total_allocated)
{
if (str)
{
if (total_allocated > G_MAXSIZE / 2)
goto file_too_large;
total_allocated *= 2;
}
else
{
total_allocated = MIN (bytes + 1, sizeof (buf));
}
tmp = g_try_realloc (str, total_allocated);
if (tmp == NULL)
{
display_filename = g_filename_display_name (filename);
g_set_error (error,
G_FILE_ERROR,
G_FILE_ERROR_NOMEM,
g_dngettext (GETTEXT_PACKAGE, "Could not allocate %lu byte to read file “%s”", "Could not allocate %lu bytes to read file “%s”", (gulong)total_allocated),
(gulong) total_allocated,
display_filename);
g_free (display_filename);
goto error;
}
str = tmp;
}
if (ferror (f))
{
display_filename = g_filename_display_name (filename);
g_set_error (error,
G_FILE_ERROR,
g_file_error_from_errno (save_errno),
_("Error reading file “%s”: %s"),
display_filename,
g_strerror (save_errno));
g_free (display_filename);
goto error;
}
g_assert (str != NULL);
memcpy (str + total_bytes, buf, bytes);
total_bytes += bytes;
}
fclose (f);
if (total_allocated == 0)
{
str = g_new (gchar, 1);
total_bytes = 0;
}
str[total_bytes] = '\0';
if (length)
*length = total_bytes;
*contents = str;
return TRUE;
file_too_large:
display_filename = g_filename_display_name (filename);
g_set_error (error,
G_FILE_ERROR,
G_FILE_ERROR_FAILED,
_("File “%s” is too large"),
display_filename);
g_free (display_filename);
error:
g_free (str);
fclose (f);
return FALSE;
}
#ifndef G_OS_WIN32
static gboolean
get_contents_regfile (const gchar *filename,
struct stat *stat_buf,
gint fd,
gchar **contents,
gsize *length,
GError **error)
{
gchar *buf;
gsize bytes_read;
gsize size;
gsize alloc_size;
gchar *display_filename;
size = stat_buf->st_size;
alloc_size = size + 1;
buf = g_try_malloc (alloc_size);
if (buf == NULL)
{
display_filename = g_filename_display_name (filename);
g_set_error (error,
G_FILE_ERROR,
G_FILE_ERROR_NOMEM,
g_dngettext (GETTEXT_PACKAGE, "Could not allocate %lu byte to read file “%s”", "Could not allocate %lu bytes to read file “%s”", (gulong)alloc_size),
(gulong) alloc_size,
display_filename);
g_free (display_filename);
goto error;
}
bytes_read = 0;
while (bytes_read < size)
{
gssize rc;
rc = read (fd, buf + bytes_read, size - bytes_read);
if (rc < 0)
{
if (errno != EINTR)
{
int save_errno = errno;
g_free (buf);
display_filename = g_filename_display_name (filename);
g_set_error (error,
G_FILE_ERROR,
g_file_error_from_errno (save_errno),
_("Failed to read from file “%s”: %s"),
display_filename,
g_strerror (save_errno));
g_free (display_filename);
goto error;
}
}
else if (rc == 0)
break;
else
bytes_read += rc;
}
buf[bytes_read] = '\0';
if (length)
*length = bytes_read;
*contents = buf;
close (fd);
return TRUE;
error:
close (fd);
return FALSE;
}
static gboolean
get_contents_posix (const gchar *filename,
gchar **contents,
gsize *length,
GError **error)
{
struct stat stat_buf;
gint fd;
/* O_BINARY useful on Cygwin */
fd = open (filename, O_RDONLY|O_BINARY);
if (fd < 0)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Failed to open file “%s”: %s"),
saved_errno);
return FALSE;
}
/* I don't think this will ever fail, aside from ENOMEM, but. */
if (fstat (fd, &stat_buf) < 0)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Failed to get attributes of file “%s”: fstat() failed: %s"),
saved_errno);
close (fd);
return FALSE;
}
if (stat_buf.st_size > 0 && S_ISREG (stat_buf.st_mode))
{
gboolean retval = get_contents_regfile (filename,
&stat_buf,
fd,
contents,
length,
error);
return retval;
}
else
{
FILE *f;
gboolean retval;
f = fdopen (fd, "r");
if (f == NULL)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Failed to open file “%s”: fdopen() failed: %s"),
saved_errno);
return FALSE;
}
retval = get_contents_stdio (filename, f, contents, length, error);
return retval;
}
}
#else /* G_OS_WIN32 */
static gboolean
get_contents_win32 (const gchar *filename,
gchar **contents,
gsize *length,
GError **error)
{
FILE *f;
gboolean retval;
f = g_fopen (filename, "rb");
if (f == NULL)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Failed to open file “%s”: %s"),
saved_errno);
return FALSE;
}
retval = get_contents_stdio (filename, f, contents, length, error);
return retval;
}
#endif
/**
* g_file_get_contents:
* @filename: (type filename): name of a file to read contents from, in the GLib file name encoding
* @contents: (out) (array length=length) (element-type guint8): location to store an allocated string, use g_free() to free
* the returned string
* @length: (nullable): location to store length in bytes of the contents, or %NULL
* @error: return location for a #GError, or %NULL
*
* Reads an entire file into allocated memory, with good error
* checking.
*
* If the call was successful, it returns %TRUE and sets @contents to the file
* contents and @length to the length of the file contents in bytes. The string
* stored in @contents will be nul-terminated, so for text files you can pass
* %NULL for the @length argument. If the call was not successful, it returns
* %FALSE and sets @error. The error domain is #G_FILE_ERROR. Possible error
* codes are those in the #GFileError enumeration. In the error case,
* @contents is set to %NULL and @length is set to zero.
*
* Returns: %TRUE on success, %FALSE if an error occurred
**/
gboolean
g_file_get_contents (const gchar *filename,
gchar **contents,
gsize *length,
GError **error)
{
g_return_val_if_fail (filename != NULL, FALSE);
g_return_val_if_fail (contents != NULL, FALSE);
*contents = NULL;
if (length)
*length = 0;
#ifdef G_OS_WIN32
return get_contents_win32 (filename, contents, length, error);
#else
return get_contents_posix (filename, contents, length, error);
#endif
}
static gboolean
rename_file (const char *old_name,
const char *new_name,
GError **err)
{
errno = 0;
if (g_rename (old_name, new_name) == -1)
{
int save_errno = errno;
gchar *display_old_name = g_filename_display_name (old_name);
gchar *display_new_name = g_filename_display_name (new_name);
g_set_error (err,
G_FILE_ERROR,
g_file_error_from_errno (save_errno),
_("Failed to rename file “%s” to “%s”: g_rename() failed: %s"),
display_old_name,
display_new_name,
g_strerror (save_errno));
g_free (display_old_name);
g_free (display_new_name);
return FALSE;
}
return TRUE;
}
static gchar *
write_to_temp_file (const gchar *contents,
gssize length,
const gchar *dest_file,
GError **err)
{
gchar *tmp_name;
gchar *retval;
gint fd;
retval = NULL;
tmp_name = g_strdup_printf ("%s.XXXXXX", dest_file);
errno = 0;
fd = g_mkstemp_full (tmp_name, O_RDWR | O_BINARY, 0666);
if (fd == -1)
{
int saved_errno = errno;
set_file_error (err,
tmp_name, _("Failed to create file “%s”: %s"),
saved_errno);
goto out;
}
#ifdef HAVE_FALLOCATE
if (length > 0)
{
/* We do this on a 'best effort' basis... It may not be supported
* on the underlying filesystem.
*/
(void) fallocate (fd, 0, 0, length);
}
#endif
while (length > 0)
{
gssize s;
s = write (fd, contents, length);
if (s < 0)
{
int saved_errno = errno;
if (saved_errno == EINTR)
continue;
set_file_error (err,
tmp_name, _("Failed to write file “%s”: write() failed: %s"),
saved_errno);
close (fd);
g_unlink (tmp_name);
goto out;
}
g_assert (s <= length);
contents += s;
length -= s;
}
#ifdef BTRFS_SUPER_MAGIC
{
struct statfs buf;
/* On Linux, on btrfs, skip the fsync since rename-over-existing is
* guaranteed to be atomic and this is the only case in which we
* would fsync() anyway.
*/
if (fstatfs (fd, &buf) == 0 && buf.f_type == BTRFS_SUPER_MAGIC)
goto no_fsync;
}
#endif
#ifdef HAVE_FSYNC
{
struct stat statbuf;
errno = 0;
/* If the final destination exists and is > 0 bytes, we want to sync the
* newly written file to ensure the data is on disk when we rename over
* the destination. Otherwise if we get a system crash we can lose both
* the new and the old file on some filesystems. (I.E. those that don't
* guarantee the data is written to the disk before the metadata.)
*/
if (g_lstat (dest_file, &statbuf) == 0 && statbuf.st_size > 0 && fsync (fd) != 0)
{
int saved_errno = errno;
set_file_error (err,
tmp_name, _("Failed to write file “%s”: fsync() failed: %s"),
saved_errno);
close (fd);
g_unlink (tmp_name);
goto out;
}
}
#endif
#ifdef BTRFS_SUPER_MAGIC
no_fsync:
#endif
errno = 0;
if (!g_close (fd, err))
{
g_unlink (tmp_name);
goto out;
}
retval = g_strdup (tmp_name);
out:
g_free (tmp_name);
return retval;
}
/**
* g_file_set_contents:
* @filename: (type filename): name of a file to write @contents to, in the GLib file name
* encoding
* @contents: (array length=length) (element-type guint8): string to write to the file
* @length: length of @contents, or -1 if @contents is a nul-terminated string
* @error: return location for a #GError, or %NULL
*
* Writes all of @contents to a file named @filename, with good error checking.
* If a file called @filename already exists it will be overwritten.
*
* This write is atomic in the sense that it is first written to a temporary
* file which is then renamed to the final name. Notes:
*
* - On UNIX, if @filename already exists hard links to @filename will break.
* Also since the file is recreated, existing permissions, access control
* lists, metadata etc. may be lost. If @filename is a symbolic link,
* the link itself will be replaced, not the linked file.
*
* - On UNIX, if @filename already exists and is non-empty, and if the system
* supports it (via a journalling filesystem or equivalent), the fsync()
* call (or equivalent) will be used to ensure atomic replacement: @filename
* will contain either its old contents or @contents, even in the face of
* system power loss, the disk being unsafely removed, etc.
*
* - On UNIX, if @filename does not already exist or is empty, there is a
* possibility that system power loss etc. after calling this function will
* leave @filename empty or full of NUL bytes, depending on the underlying
* filesystem.
*
* - On Windows renaming a file will not remove an existing file with the
* new name, so on Windows there is a race condition between the existing
* file being removed and the temporary file being renamed.
*
* - On Windows there is no way to remove a file that is open to some
* process, or mapped into memory. Thus, this function will fail if
* @filename already exists and is open.
*
* If the call was successful, it returns %TRUE. If the call was not successful,
* it returns %FALSE and sets @error. The error domain is #G_FILE_ERROR.
* Possible error codes are those in the #GFileError enumeration.
*
* Note that the name for the temporary file is constructed by appending up
* to 7 characters to @filename.
*
* Returns: %TRUE on success, %FALSE if an error occurred
*
* Since: 2.8
*/
gboolean
g_file_set_contents (const gchar *filename,
const gchar *contents,
gssize length,
GError **error)
{
gchar *tmp_filename;
gboolean retval;
GError *rename_error = NULL;
g_return_val_if_fail (filename != NULL, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
g_return_val_if_fail (contents != NULL || length == 0, FALSE);
g_return_val_if_fail (length >= -1, FALSE);
if (length == -1)
length = strlen (contents);
tmp_filename = write_to_temp_file (contents, length, filename, error);
if (!tmp_filename)
{
retval = FALSE;
goto out;
}
if (!rename_file (tmp_filename, filename, &rename_error))
{
#ifndef G_OS_WIN32
g_unlink (tmp_filename);
g_propagate_error (error, rename_error);
retval = FALSE;
goto out;
#else /* G_OS_WIN32 */
/* Renaming failed, but on Windows this may just mean
* the file already exists. So if the target file
* exists, try deleting it and do the rename again.
*/
if (!g_file_test (filename, G_FILE_TEST_EXISTS))
{
g_unlink (tmp_filename);
g_propagate_error (error, rename_error);
retval = FALSE;
goto out;
}
g_error_free (rename_error);
if (g_unlink (filename) == -1)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Existing file “%s” could not be removed: g_unlink() failed: %s"),
saved_errno);
g_unlink (tmp_filename);
retval = FALSE;
goto out;
}
if (!rename_file (tmp_filename, filename, error))
{
g_unlink (tmp_filename);
retval = FALSE;
goto out;
}
#endif
}
retval = TRUE;
out:
g_free (tmp_filename);
return retval;
}
/*
* get_tmp_file based on the mkstemp implementation from the GNU C library.
* Copyright (C) 1991,92,93,94,95,96,97,98,99 Free Software Foundation, Inc.
*/
typedef gint (*GTmpFileCallback) (const gchar *, gint, gint);
static gint
get_tmp_file (gchar *tmpl,
GTmpFileCallback f,
int flags,
int mode)
{
char *XXXXXX;
int count, fd;
static const char letters[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
static const int NLETTERS = sizeof (letters) - 1;
glong value;
GTimeVal tv;
static int counter = 0;
g_return_val_if_fail (tmpl != NULL, -1);
/* find the last occurrence of "XXXXXX" */
XXXXXX = g_strrstr (tmpl, "XXXXXX");
if (!XXXXXX || strncmp (XXXXXX, "XXXXXX", 6))
{
errno = EINVAL;
return -1;
}
/* Get some more or less random data. */
g_get_current_time (&tv);
value = (tv.tv_usec ^ tv.tv_sec) + counter++;
for (count = 0; count < 100; value += 7777, ++count)
{
glong v = value;
/* Fill in the random bits. */
XXXXXX[0] = letters[v % NLETTERS];
v /= NLETTERS;
XXXXXX[1] = letters[v % NLETTERS];
v /= NLETTERS;
XXXXXX[2] = letters[v % NLETTERS];
v /= NLETTERS;
XXXXXX[3] = letters[v % NLETTERS];
v /= NLETTERS;
XXXXXX[4] = letters[v % NLETTERS];
v /= NLETTERS;
XXXXXX[5] = letters[v % NLETTERS];
fd = f (tmpl, flags, mode);
if (fd >= 0)
return fd;
else if (errno != EEXIST)
/* Any other error will apply also to other names we might
* try, and there are 2^32 or so of them, so give up now.
*/
return -1;
}
/* We got out of the loop because we ran out of combinations to try. */
errno = EEXIST;
return -1;
}
/* Some GTmpFileCallback implementations.
*
* Note: we cannot use open() or g_open() directly because even though
* they appear compatible, they may be vararg functions and calling
* varargs functions through a non-varargs type is undefined.
*/
static gint
wrap_g_mkdir (const gchar *filename,
int flags G_GNUC_UNUSED,
int mode)
{
/* tmpl is in UTF-8 on Windows, thus use g_mkdir() */
return g_mkdir (filename, mode);
}
static gint
wrap_g_open (const gchar *filename,
int flags,
int mode)
{
return g_open (filename, flags, mode);
}
/**
* g_mkdtemp_full: (skip)
* @tmpl: (type filename): template directory name
* @mode: permissions to create the temporary directory with
*
* Creates a temporary directory. See the mkdtemp() documentation
* on most UNIX-like systems.
*
* The parameter is a string that should follow the rules for
* mkdtemp() templates, i.e. contain the string "XXXXXX".
* g_mkdtemp_full() is slightly more flexible than mkdtemp() in that the
* sequence does not have to occur at the very end of the template
* and you can pass a @mode. The X string will be modified to form
* the name of a directory that didn't exist. The string should be
* in the GLib file name encoding. Most importantly, on Windows it
* should be in UTF-8.
*
* If you are going to be creating a temporary directory inside the
* directory returned by g_get_tmp_dir(), you might want to use
* g_dir_make_tmp() instead.
*
* Returns: (nullable) (type filename): A pointer to @tmpl, which has been
* modified to hold the directory name. In case of errors, %NULL is
* returned, and %errno will be set.
*
* Since: 2.30
*/
gchar *
g_mkdtemp_full (gchar *tmpl,
gint mode)
{
if (get_tmp_file (tmpl, wrap_g_mkdir, 0, mode) == -1)
return NULL;
else
return tmpl;
}
/**
* g_mkdtemp: (skip)
* @tmpl: (type filename): template directory name
*
* Creates a temporary directory. See the mkdtemp() documentation
* on most UNIX-like systems.
*
* The parameter is a string that should follow the rules for
* mkdtemp() templates, i.e. contain the string "XXXXXX".
* g_mkdtemp() is slightly more flexible than mkdtemp() in that the
* sequence does not have to occur at the very end of the template.
* The X string will be modified to form the name of a directory that
* didn't exist.
* The string should be in the GLib file name encoding. Most importantly,
* on Windows it should be in UTF-8.
*
* If you are going to be creating a temporary directory inside the
* directory returned by g_get_tmp_dir(), you might want to use
* g_dir_make_tmp() instead.
*
* Returns: (nullable) (type filename): A pointer to @tmpl, which has been
* modified to hold the directory name. In case of errors, %NULL is
* returned and %errno will be set.
*
* Since: 2.30
*/
gchar *
g_mkdtemp (gchar *tmpl)
{
return g_mkdtemp_full (tmpl, 0700);
}
/**
* g_mkstemp_full: (skip)
* @tmpl: (type filename): template filename
* @flags: flags to pass to an open() call in addition to O_EXCL
* and O_CREAT, which are passed automatically
* @mode: permissions to create the temporary file with
*
* Opens a temporary file. See the mkstemp() documentation
* on most UNIX-like systems.
*
* The parameter is a string that should follow the rules for
* mkstemp() templates, i.e. contain the string "XXXXXX".
* g_mkstemp_full() is slightly more flexible than mkstemp()
* in that the sequence does not have to occur at the very end of the
* template and you can pass a @mode and additional @flags. The X
* string will be modified to form the name of a file that didn't exist.
* The string should be in the GLib file name encoding. Most importantly,
* on Windows it should be in UTF-8.
*
* Returns: A file handle (as from open()) to the file
* opened for reading and writing. The file handle should be
* closed with close(). In case of errors, -1 is returned
* and %errno will be set.
*
* Since: 2.22
*/
gint
g_mkstemp_full (gchar *tmpl,
gint flags,
gint mode)
{
/* tmpl is in UTF-8 on Windows, thus use g_open() */
return get_tmp_file (tmpl, wrap_g_open,
flags | O_CREAT | O_EXCL, mode);
}
/**
* g_mkstemp: (skip)
* @tmpl: (type filename): template filename
*
* Opens a temporary file. See the mkstemp() documentation
* on most UNIX-like systems.
*
* The parameter is a string that should follow the rules for
* mkstemp() templates, i.e. contain the string "XXXXXX".
* g_mkstemp() is slightly more flexible than mkstemp() in that the
* sequence does not have to occur at the very end of the template.
* The X string will be modified to form the name of a file that
* didn't exist. The string should be in the GLib file name encoding.
* Most importantly, on Windows it should be in UTF-8.
*
* Returns: A file handle (as from open()) to the file
* opened for reading and writing. The file is opened in binary
* mode on platforms where there is a difference. The file handle
* should be closed with close(). In case of errors, -1 is
* returned and %errno will be set.
*/
gint
g_mkstemp (gchar *tmpl)
{
return g_mkstemp_full (tmpl, O_RDWR | O_BINARY, 0600);
}
static gint
g_get_tmp_name (const gchar *tmpl,
gchar **name_used,
GTmpFileCallback f,
gint flags,
gint mode,
GError **error)
{
int retval;
const char *tmpdir;
const char *sep;
char *fulltemplate;
const char *slash;
if (tmpl == NULL)
tmpl = ".XXXXXX";
if ((slash = strchr (tmpl, G_DIR_SEPARATOR)) != NULL
#ifdef G_OS_WIN32
|| (strchr (tmpl, '/') != NULL && (slash = "/"))
#endif
)
{
gchar *display_tmpl = g_filename_display_name (tmpl);
char c[2];
c[0] = *slash;
c[1] = '\0';
g_set_error (error,
G_FILE_ERROR,
G_FILE_ERROR_FAILED,
_("Template “%s” invalid, should not contain a “%s”"),
display_tmpl, c);
g_free (display_tmpl);
return -1;
}
if (strstr (tmpl, "XXXXXX") == NULL)
{
gchar *display_tmpl = g_filename_display_name (tmpl);
g_set_error (error,
G_FILE_ERROR,
G_FILE_ERROR_FAILED,
_("Template “%s” doesn’t contain XXXXXX"),
display_tmpl);
g_free (display_tmpl);
return -1;
}
tmpdir = g_get_tmp_dir ();
if (G_IS_DIR_SEPARATOR (tmpdir [strlen (tmpdir) - 1]))
sep = "";
else
sep = G_DIR_SEPARATOR_S;
fulltemplate = g_strconcat (tmpdir, sep, tmpl, NULL);
retval = get_tmp_file (fulltemplate, f, flags, mode);
if (retval == -1)
{
int saved_errno = errno;
set_file_error (error,
fulltemplate,
_("Failed to create file “%s”: %s"),
saved_errno);
g_free (fulltemplate);
return -1;
}
*name_used = fulltemplate;
return retval;
}
/**
* g_file_open_tmp:
* @tmpl: (type filename) (nullable): Template for file name, as in
* g_mkstemp(), basename only, or %NULL for a default template
* @name_used: (out) (type filename): location to store actual name used,
* or %NULL
* @error: return location for a #GError
*
* Opens a file for writing in the preferred directory for temporary
* files (as returned by g_get_tmp_dir()).
*
* @tmpl should be a string in the GLib file name encoding containing
* a sequence of six 'X' characters, as the parameter to g_mkstemp().
* However, unlike these functions, the template should only be a
* basename, no directory components are allowed. If template is
* %NULL, a default template is used.
*
* Note that in contrast to g_mkstemp() (and mkstemp()) @tmpl is not
* modified, and might thus be a read-only literal string.
*
* Upon success, and if @name_used is non-%NULL, the actual name used
* is returned in @name_used. This string should be freed with g_free()
* when not needed any longer. The returned name is in the GLib file
* name encoding.
*
* Returns: A file handle (as from open()) to the file opened for
* reading and writing. The file is opened in binary mode on platforms
* where there is a difference. The file handle should be closed with
* close(). In case of errors, -1 is returned and @error will be set.
*/
gint
g_file_open_tmp (const gchar *tmpl,
gchar **name_used,
GError **error)
{
gchar *fulltemplate;
gint result;
g_return_val_if_fail (error == NULL || *error == NULL, -1);
result = g_get_tmp_name (tmpl, &fulltemplate,
wrap_g_open,
O_CREAT | O_EXCL | O_RDWR | O_BINARY,
0600,
error);
if (result != -1)
{
if (name_used)
*name_used = fulltemplate;
else
g_free (fulltemplate);
}
return result;
}
/**
* g_dir_make_tmp:
* @tmpl: (type filename) (nullable): Template for directory name,
* as in g_mkdtemp(), basename only, or %NULL for a default template
* @error: return location for a #GError
*
* Creates a subdirectory in the preferred directory for temporary
* files (as returned by g_get_tmp_dir()).
*
* @tmpl should be a string in the GLib file name encoding containing
* a sequence of six 'X' characters, as the parameter to g_mkstemp().
* However, unlike these functions, the template should only be a
* basename, no directory components are allowed. If template is
* %NULL, a default template is used.
*
* Note that in contrast to g_mkdtemp() (and mkdtemp()) @tmpl is not
* modified, and might thus be a read-only literal string.
*
* Returns: (type filename): The actual name used. This string
* should be freed with g_free() when not needed any longer and is
* is in the GLib file name encoding. In case of errors, %NULL is
* returned and @error will be set.
*
* Since: 2.30
*/
gchar *
g_dir_make_tmp (const gchar *tmpl,
GError **error)
{
gchar *fulltemplate;
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
if (g_get_tmp_name (tmpl, &fulltemplate, wrap_g_mkdir, 0, 0700, error) == -1)
return NULL;
else
return fulltemplate;
}
static gchar *
g_build_path_va (const gchar *separator,
const gchar *first_element,
va_list *args,
gchar **str_array)
{
GString *result;
gint separator_len = strlen (separator);
gboolean is_first = TRUE;
gboolean have_leading = FALSE;
const gchar *single_element = NULL;
const gchar *next_element;
const gchar *last_trailing = NULL;
gint i = 0;
result = g_string_new (NULL);
if (str_array)
next_element = str_array[i++];
else
next_element = first_element;
while (TRUE)
{
const gchar *element;
const gchar *start;
const gchar *end;
if (next_element)
{
element = next_element;
if (str_array)
next_element = str_array[i++];
else
next_element = va_arg (*args, gchar *);
}
else
break;
/* Ignore empty elements */
if (!*element)
continue;
start = element;
if (separator_len)
{
while (strncmp (start, separator, separator_len) == 0)
start += separator_len;
}
end = start + strlen (start);
if (separator_len)
{
while (end >= start + separator_len &&
strncmp (end - separator_len, separator, separator_len) == 0)
end -= separator_len;
last_trailing = end;
while (last_trailing >= element + separator_len &&
strncmp (last_trailing - separator_len, separator, separator_len) == 0)
last_trailing -= separator_len;
if (!have_leading)
{
/* If the leading and trailing separator strings are in the
* same element and overlap, the result is exactly that element
*/
if (last_trailing <= start)
single_element = element;
g_string_append_len (result, element, start - element);
have_leading = TRUE;
}
else
single_element = NULL;
}
if (end == start)
continue;
if (!is_first)
g_string_append (result, separator);
g_string_append_len (result, start, end - start);
is_first = FALSE;
}
if (single_element)
{
g_string_free (result, TRUE);
return g_strdup (single_element);
}
else
{
if (last_trailing)
g_string_append (result, last_trailing);
return g_string_free (result, FALSE);
}
}
/**
* g_build_pathv:
* @separator: a string used to separator the elements of the path.
* @args: (array zero-terminated=1) (element-type filename): %NULL-terminated
* array of strings containing the path elements.
*
* Behaves exactly like g_build_path(), but takes the path elements
* as a string array, instead of varargs. This function is mainly
* meant for language bindings.
*
* Returns: (type filename): a newly-allocated string that must be freed
* with g_free().
*
* Since: 2.8
*/
gchar *
g_build_pathv (const gchar *separator,
gchar **args)
{
if (!args)
return NULL;
return g_build_path_va (separator, NULL, NULL, args);
}
/**
* g_build_path:
* @separator: (type filename): a string used to separator the elements of the path.
* @first_element: (type filename): the first element in the path
* @...: remaining elements in path, terminated by %NULL
*
* Creates a path from a series of elements using @separator as the
* separator between elements. At the boundary between two elements,
* any trailing occurrences of separator in the first element, or
* leading occurrences of separator in the second element are removed
* and exactly one copy of the separator is inserted.
*
* Empty elements are ignored.
*
* The number of leading copies of the separator on the result is
* the same as the number of leading copies of the separator on
* the first non-empty element.
*
* The number of trailing copies of the separator on the result is
* the same as the number of trailing copies of the separator on
* the last non-empty element. (Determination of the number of
* trailing copies is done without stripping leading copies, so
* if the separator is `ABA`, then `ABABA` has 1 trailing copy.)
*
* However, if there is only a single non-empty element, and there
* are no characters in that element not part of the leading or
* trailing separators, then the result is exactly the original value
* of that element.
*
* Other than for determination of the number of leading and trailing
* copies of the separator, elements consisting only of copies
* of the separator are ignored.
*
* Returns: (type filename): a newly-allocated string that must be freed with
* g_free().
**/
gchar *
g_build_path (const gchar *separator,
const gchar *first_element,
...)
{
gchar *str;
va_list args;
g_return_val_if_fail (separator != NULL, NULL);
va_start (args, first_element);
str = g_build_path_va (separator, first_element, &args, NULL);
va_end (args);
return str;
}
#ifdef G_OS_WIN32
static gchar *
g_build_pathname_va (const gchar *first_element,
va_list *args,
gchar **str_array)
{
/* Code copied from g_build_pathv(), and modified to use two
* alternative single-character separators.
*/
GString *result;
gboolean is_first = TRUE;
gboolean have_leading = FALSE;
const gchar *single_element = NULL;
const gchar *next_element;
const gchar *last_trailing = NULL;
gchar current_separator = '\\';
gint i = 0;
result = g_string_new (NULL);
if (str_array)
next_element = str_array[i++];
else
next_element = first_element;
while (TRUE)
{
const gchar *element;
const gchar *start;
const gchar *end;
if (next_element)
{
element = next_element;
if (str_array)
next_element = str_array[i++];
else
next_element = va_arg (*args, gchar *);
}
else
break;
/* Ignore empty elements */
if (!*element)
continue;
start = element;
if (TRUE)
{
while (start &&
(*start == '\\' || *start == '/'))
{
current_separator = *start;
start++;
}
}
end = start + strlen (start);
if (TRUE)
{
while (end >= start + 1 &&
(end[-1] == '\\' || end[-1] == '/'))
{
current_separator = end[-1];
end--;
}
last_trailing = end;
while (last_trailing >= element + 1 &&
(last_trailing[-1] == '\\' || last_trailing[-1] == '/'))
last_trailing--;
if (!have_leading)
{
/* If the leading and trailing separator strings are in the
* same element and overlap, the result is exactly that element
*/
if (last_trailing <= start)
single_element = element;
g_string_append_len (result, element, start - element);
have_leading = TRUE;
}
else
single_element = NULL;
}
if (end == start)
continue;
if (!is_first)
g_string_append_len (result, &current_separator, 1);
g_string_append_len (result, start, end - start);
is_first = FALSE;
}
if (single_element)
{
g_string_free (result, TRUE);
return g_strdup (single_element);
}
else
{
if (last_trailing)
g_string_append (result, last_trailing);
return g_string_free (result, FALSE);
}
}
#endif
static gchar *
g_build_filename_va (const gchar *first_argument,
va_list *args,
gchar **str_array)
{
gchar *str;
#ifndef G_OS_WIN32
str = g_build_path_va (G_DIR_SEPARATOR_S, first_argument, args, str_array);
#else
str = g_build_pathname_va (first_argument, args, str_array);
#endif
return str;
}
/**
* g_build_filename_valist:
* @first_element: (type filename): the first element in the path
* @args: va_list of remaining elements in path
*
* Behaves exactly like g_build_filename(), but takes the path elements
* as a va_list. This function is mainly meant for language bindings.
*
* Returns: (type filename): a newly-allocated string that must be freed
* with g_free().
*
* Since: 2.56
*/
gchar *
g_build_filename_valist (const gchar *first_element,
va_list *args)
{
g_return_val_if_fail (first_element != NULL, NULL);
return g_build_filename_va (first_element, args, NULL);
}
/**
* g_build_filenamev:
* @args: (array zero-terminated=1) (element-type filename): %NULL-terminated
* array of strings containing the path elements.
*
* Behaves exactly like g_build_filename(), but takes the path elements
* as a string array, instead of varargs. This function is mainly
* meant for language bindings.
*
* Returns: (type filename): a newly-allocated string that must be freed
* with g_free().
*
* Since: 2.8
*/
gchar *
g_build_filenamev (gchar **args)
{
return g_build_filename_va (NULL, NULL, args);
}
/**
* g_build_filename:
* @first_element: (type filename): the first element in the path
* @...: remaining elements in path, terminated by %NULL
*
* Creates a filename from a series of elements using the correct
* separator for filenames.
*
* On Unix, this function behaves identically to `g_build_path
* (G_DIR_SEPARATOR_S, first_element, ....)`.
*
* On Windows, it takes into account that either the backslash
* (`\` or slash (`/`) can be used as separator in filenames, but
* otherwise behaves as on UNIX. When file pathname separators need
* to be inserted, the one that last previously occurred in the
* parameters (reading from left to right) is used.
*
* No attempt is made to force the resulting filename to be an absolute
* path. If the first element is a relative path, the result will
* be a relative path.
*
* Returns: (type filename): a newly-allocated string that must be freed with
* g_free().
**/
gchar *
g_build_filename (const gchar *first_element,
...)
{
gchar *str;
va_list args;
va_start (args, first_element);
str = g_build_filename_va (first_element, &args, NULL);
va_end (args);
return str;
}
/**
* g_file_read_link:
* @filename: (type filename): the symbolic link
* @error: return location for a #GError
*
* Reads the contents of the symbolic link @filename like the POSIX
* readlink() function. The returned string is in the encoding used
* for filenames. Use g_filename_to_utf8() to convert it to UTF-8.
*
* Returns: (type filename): A newly-allocated string with the contents of
* the symbolic link, or %NULL if an error occurred.
*
* Since: 2.4
*/
gchar *
g_file_read_link (const gchar *filename,
GError **error)
{
#if defined (HAVE_READLINK) || defined (G_OS_WIN32)
gchar *buffer;
size_t size;
gssize read_size;
g_return_val_if_fail (filename != NULL, NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
size = 256;
buffer = g_malloc (size);
while (TRUE)
{
#ifndef G_OS_WIN32
read_size = readlink (filename, buffer, size);
#else
read_size = g_win32_readlink_utf8 (filename, buffer, size);
#endif
if (read_size < 0)
{
int saved_errno = errno;
set_file_error (error,
filename,
_("Failed to read the symbolic link “%s”: %s"),
saved_errno);
g_free (buffer);
return NULL;
}
if ((size_t) read_size < size)
{
buffer[read_size] = 0;
return buffer;
}
size *= 2;
buffer = g_realloc (buffer, size);
}
#else
g_return_val_if_fail (filename != NULL, NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
g_set_error_literal (error,
G_FILE_ERROR,
G_FILE_ERROR_INVAL,
_("Symbolic links not supported"));
return NULL;
#endif
}
/**
* g_path_is_absolute:
* @file_name: (type filename): a file name
*
* Returns %TRUE if the given @file_name is an absolute file name.
* Note that this is a somewhat vague concept on Windows.
*
* On POSIX systems, an absolute file name is well-defined. It always
* starts from the single root directory. For example "/usr/local".
*
* On Windows, the concepts of current drive and drive-specific
* current directory introduce vagueness. This function interprets as
* an absolute file name one that either begins with a directory
* separator such as "\Users\tml" or begins with the root on a drive,
* for example "C:\Windows". The first case also includes UNC paths
* such as "\\\\myserver\docs\foo". In all cases, either slashes or
* backslashes are accepted.
*
* Note that a file name relative to the current drive root does not
* truly specify a file uniquely over time and across processes, as
* the current drive is a per-process value and can be changed.
*
* File names relative the current directory on some specific drive,
* such as "D:foo/bar", are not interpreted as absolute by this
* function, but they obviously are not relative to the normal current
* directory as returned by getcwd() or g_get_current_dir()
* either. Such paths should be avoided, or need to be handled using
* Windows-specific code.
*
* Returns: %TRUE if @file_name is absolute
*/
gboolean
g_path_is_absolute (const gchar *file_name)
{
g_return_val_if_fail (file_name != NULL, FALSE);
if (G_IS_DIR_SEPARATOR (file_name[0]))
return TRUE;
#ifdef G_OS_WIN32
/* Recognize drive letter on native Windows */
if (g_ascii_isalpha (file_name[0]) &&
file_name[1] == ':' && G_IS_DIR_SEPARATOR (file_name[2]))
return TRUE;
#endif
return FALSE;
}
/**
* g_path_skip_root:
* @file_name: (type filename): a file name
*
* Returns a pointer into @file_name after the root component,
* i.e. after the "/" in UNIX or "C:\" under Windows. If @file_name
* is not an absolute path it returns %NULL.
*
* Returns: (type filename) (nullable): a pointer into @file_name after the
* root component
*/
const gchar *
g_path_skip_root (const gchar *file_name)
{
g_return_val_if_fail (file_name != NULL, NULL);
#ifdef G_PLATFORM_WIN32
/* Skip \\server\share or //server/share */
if (G_IS_DIR_SEPARATOR (file_name[0]) &&
G_IS_DIR_SEPARATOR (file_name[1]) &&
file_name[2] &&
!G_IS_DIR_SEPARATOR (file_name[2]))
{
gchar *p;
p = strchr (file_name + 2, G_DIR_SEPARATOR);
#ifdef G_OS_WIN32
{
gchar *q;
q = strchr (file_name + 2, '/');
if (p == NULL || (q != NULL && q < p))
p = q;
}
#endif
if (p && p > file_name + 2 && p[1])
{
file_name = p + 1;
while (file_name[0] && !G_IS_DIR_SEPARATOR (file_name[0]))
file_name++;
/* Possibly skip a backslash after the share name */
if (G_IS_DIR_SEPARATOR (file_name[0]))
file_name++;
return (gchar *)file_name;
}
}
#endif
/* Skip initial slashes */
if (G_IS_DIR_SEPARATOR (file_name[0]))
{
while (G_IS_DIR_SEPARATOR (file_name[0]))
file_name++;
return (gchar *)file_name;
}
#ifdef G_OS_WIN32
/* Skip X:\ */
if (g_ascii_isalpha (file_name[0]) &&
file_name[1] == ':' &&
G_IS_DIR_SEPARATOR (file_name[2]))
return (gchar *)file_name + 3;
#endif
return NULL;
}
/**
* g_basename:
* @file_name: (type filename): the name of the file
*
* Gets the name of the file without any leading directory
* components. It returns a pointer into the given file name
* string.
*
* Returns: (type filename): the name of the file without any leading
* directory components
*
* Deprecated:2.2: Use g_path_get_basename() instead, but notice
* that g_path_get_basename() allocates new memory for the
* returned string, unlike this function which returns a pointer
* into the argument.
*/
const gchar *
g_basename (const gchar *file_name)
{
gchar *base;
g_return_val_if_fail (file_name != NULL, NULL);
base = strrchr (file_name, G_DIR_SEPARATOR);
#ifdef G_OS_WIN32
{
gchar *q;
q = strrchr (file_name, '/');
if (base == NULL || (q != NULL && q > base))
base = q;
}
#endif
if (base)
return base + 1;
#ifdef G_OS_WIN32
if (g_ascii_isalpha (file_name[0]) && file_name[1] == ':')
return (gchar*) file_name + 2;
#endif
return (gchar*) file_name;
}
/**
* g_path_get_basename:
* @file_name: (type filename): the name of the file
*
* Gets the last component of the filename.
*
* If @file_name ends with a directory separator it gets the component
* before the last slash. If @file_name consists only of directory
* separators (and on Windows, possibly a drive letter), a single
* separator is returned. If @file_name is empty, it gets ".".
*
* Returns: (type filename): a newly allocated string containing the last
* component of the filename
*/
gchar *
g_path_get_basename (const gchar *file_name)
{
gssize base;
gssize last_nonslash;
gsize len;
gchar *retval;
g_return_val_if_fail (file_name != NULL, NULL);
if (file_name[0] == '\0')
return g_strdup (".");
last_nonslash = strlen (file_name) - 1;
while (last_nonslash >= 0 && G_IS_DIR_SEPARATOR (file_name [last_nonslash]))
last_nonslash--;
if (last_nonslash == -1)
/* string only containing slashes */
return g_strdup (G_DIR_SEPARATOR_S);
#ifdef G_OS_WIN32
if (last_nonslash == 1 &&
g_ascii_isalpha (file_name[0]) &&
file_name[1] == ':')
/* string only containing slashes and a drive */
return g_strdup (G_DIR_SEPARATOR_S);
#endif
base = last_nonslash;
while (base >=0 && !G_IS_DIR_SEPARATOR (file_name [base]))
base--;
#ifdef G_OS_WIN32
if (base == -1 &&
g_ascii_isalpha (file_name[0]) &&
file_name[1] == ':')
base = 1;
#endif /* G_OS_WIN32 */
len = last_nonslash - base;
retval = g_malloc (len + 1);
memcpy (retval, file_name + base + 1, len);
retval [len] = '\0';
return retval;
}
/**
* g_dirname:
* @file_name: (type filename): the name of the file
*
* Gets the directory components of a file name.
*
* If the file name has no directory components "." is returned.
* The returned string should be freed when no longer needed.
*
* Returns: (type filename): the directory components of the file
*
* Deprecated: use g_path_get_dirname() instead
*/
/**
* g_path_get_dirname:
* @file_name: (type filename): the name of the file
*
* Gets the directory components of a file name.
*
* If the file name has no directory components "." is returned.
* The returned string should be freed when no longer needed.
*
* Returns: (type filename): the directory components of the file
*/
gchar *
g_path_get_dirname (const gchar *file_name)
{
gchar *base;
gsize len;
g_return_val_if_fail (file_name != NULL, NULL);
base = strrchr (file_name, G_DIR_SEPARATOR);
#ifdef G_OS_WIN32
{
gchar *q;
q = strrchr (file_name, '/');
if (base == NULL || (q != NULL && q > base))
base = q;
}
#endif
if (!base)
{
#ifdef G_OS_WIN32
if (g_ascii_isalpha (file_name[0]) && file_name[1] == ':')
{
gchar drive_colon_dot[4];
drive_colon_dot[0] = file_name[0];
drive_colon_dot[1] = ':';
drive_colon_dot[2] = '.';
drive_colon_dot[3] = '\0';
return g_strdup (drive_colon_dot);
}
#endif
return g_strdup (".");
}
while (base > file_name && G_IS_DIR_SEPARATOR (*base))
base--;
#ifdef G_OS_WIN32
/* base points to the char before the last slash.
*
* In case file_name is the root of a drive (X:\) or a child of the
* root of a drive (X:\foo), include the slash.
*
* In case file_name is the root share of an UNC path
* (\\server\share), add a slash, returning \\server\share\ .
*
* In case file_name is a direct child of a share in an UNC path
* (\\server\share\foo), include the slash after the share name,
* returning \\server\share\ .
*/
if (base == file_name + 1 &&
g_ascii_isalpha (file_name[0]) &&
file_name[1] == ':')
base++;
else if (G_IS_DIR_SEPARATOR (file_name[0]) &&
G_IS_DIR_SEPARATOR (file_name[1]) &&
file_name[2] &&
!G_IS_DIR_SEPARATOR (file_name[2]) &&
base >= file_name + 2)
{
const gchar *p = file_name + 2;
while (*p && !G_IS_DIR_SEPARATOR (*p))
p++;
if (p == base + 1)
{
len = (guint) strlen (file_name) + 1;
base = g_new (gchar, len + 1);
strcpy (base, file_name);
base[len-1] = G_DIR_SEPARATOR;
base[len] = 0;
return base;
}
if (G_IS_DIR_SEPARATOR (*p))
{
p++;
while (*p && !G_IS_DIR_SEPARATOR (*p))
p++;
if (p == base + 1)
base++;
}
}
#endif
len = (guint) 1 + base - file_name;
base = g_new (gchar, len + 1);
memmove (base, file_name, len);
base[len] = 0;
return base;
}
/**
* g_canonicalize_filename:
* @filename: (type filename): the name of the file
* @relative_to: (type filename) (nullable): the relative directory, or %NULL
* to use the current working directory
*
* Gets the canonical file name from @filename. All triple slashes are turned into
* single slashes, and all `..` and `.`s resolved against @relative_to.
*
* Symlinks are not followed, and the returned path is guaranteed to be absolute.
*
* If @filename is an absolute path, @relative_to is ignored. Otherwise,
* @relative_to will be prepended to @filename to make it absolute. @relative_to
* must be an absolute path, or %NULL. If @relative_to is %NULL, it'll fallback
* to g_get_current_dir().
*
* This function never fails, and will canonicalize file paths even if they don't
* exist.
*
* No file system I/O is done.
*
* Returns: (type filename) (transfer full): a newly allocated string with the
* canonical file path
* Since: 2.58
*/
gchar *
g_canonicalize_filename (const gchar *filename,
const gchar *relative_to)
{
gchar *canon, *start, *p, *q;
guint i;
g_return_val_if_fail (relative_to == NULL || g_path_is_absolute (relative_to), NULL);
if (!g_path_is_absolute (filename))
{
gchar *cwd_allocated = NULL;
const gchar *cwd;
if (relative_to != NULL)
cwd = relative_to;
else
cwd = cwd_allocated = g_get_current_dir ();
canon = g_build_filename (cwd, filename, NULL);
g_free (cwd_allocated);
}
else
{
canon = g_strdup (filename);
}
start = (char *)g_path_skip_root (canon);
if (start == NULL)
{
/* This shouldn't really happen, as g_get_current_dir() should
return an absolute pathname, but bug 573843 shows this is
not always happening */
g_free (canon);
return g_build_filename (G_DIR_SEPARATOR_S, filename, NULL);
}
/* POSIX allows double slashes at the start to
* mean something special (as does windows too).
* So, "//" != "/", but more than two slashes
* is treated as "/".
*/
i = 0;
for (p = start - 1;
(p >= canon) &&
G_IS_DIR_SEPARATOR (*p);
p--)
i++;
if (i > 2)
{
i -= 1;
start -= i;
memmove (start, start+i, strlen (start+i) + 1);
}
/* Make sure we're using the canonical dir separator */
p++;
while (p < start && G_IS_DIR_SEPARATOR (*p))
*p++ = G_DIR_SEPARATOR;
p = start;
while (*p != 0)
{
if (p[0] == '.' && (p[1] == 0 || G_IS_DIR_SEPARATOR (p[1])))
{
memmove (p, p+1, strlen (p+1)+1);
}
else if (p[0] == '.' && p[1] == '.' && (p[2] == 0 || G_IS_DIR_SEPARATOR (p[2])))
{
q = p + 2;
/* Skip previous separator */
p = p - 2;
if (p < start)
p = start;
while (p > start && !G_IS_DIR_SEPARATOR (*p))
p--;
if (G_IS_DIR_SEPARATOR (*p))
*p++ = G_DIR_SEPARATOR;
memmove (p, q, strlen (q)+1);
}
else
{
/* Skip until next separator */
while (*p != 0 && !G_IS_DIR_SEPARATOR (*p))
p++;
if (*p != 0)
{
/* Canonicalize one separator */
*p++ = G_DIR_SEPARATOR;
}
}
/* Remove additional separators */
q = p;
while (*q && G_IS_DIR_SEPARATOR (*q))
q++;
if (p != q)
memmove (p, q, strlen (q) + 1);
}
/* Remove trailing slashes */
if (p > start && G_IS_DIR_SEPARATOR (*(p-1)))
*(p-1) = 0;
return canon;
}
#if defined(MAXPATHLEN)
#define G_PATH_LENGTH MAXPATHLEN
#elif defined(PATH_MAX)
#define G_PATH_LENGTH PATH_MAX
#elif defined(_PC_PATH_MAX)
#define G_PATH_LENGTH sysconf(_PC_PATH_MAX)
#else
#define G_PATH_LENGTH 2048
#endif
/**
* g_get_current_dir:
*
* Gets the current directory.
*
* The returned string should be freed when no longer needed.
* The encoding of the returned string is system defined.
* On Windows, it is always UTF-8.
*
* Since GLib 2.40, this function will return the value of the "PWD"
* environment variable if it is set and it happens to be the same as
* the current directory. This can make a difference in the case that
* the current directory is the target of a symbolic link.
*
* Returns: (type filename): the current directory
*/
gchar *
g_get_current_dir (void)
{
#ifdef G_OS_WIN32
gchar *dir = NULL;
wchar_t dummy[2], *wdir;
int len;
len = GetCurrentDirectoryW (2, dummy);
wdir = g_new (wchar_t, len);
if (GetCurrentDirectoryW (len, wdir) == len - 1)
dir = g_utf16_to_utf8 (wdir, -1, NULL, NULL, NULL);
g_free (wdir);
if (dir == NULL)
dir = g_strdup ("\\");
return dir;
#else
const gchar *pwd;
gchar *buffer = NULL;
gchar *dir = NULL;
static gulong max_len = 0;
struct stat pwdbuf, dotbuf;
pwd = g_getenv ("PWD");
if (pwd != NULL &&
g_stat (".", &dotbuf) == 0 && g_stat (pwd, &pwdbuf) == 0 &&
dotbuf.st_dev == pwdbuf.st_dev && dotbuf.st_ino == pwdbuf.st_ino)
return g_strdup (pwd);
if (max_len == 0)
max_len = (G_PATH_LENGTH == -1) ? 2048 : G_PATH_LENGTH;
while (max_len < G_MAXULONG / 2)
{
g_free (buffer);
buffer = g_new (gchar, max_len + 1);
*buffer = 0;
dir = getcwd (buffer, max_len);
if (dir || errno != ERANGE)
break;
max_len *= 2;
}
if (!dir || !*buffer)
{
/* hm, should we g_error() out here?
* this can happen if e.g. "./" has mode \0000
*/
buffer[0] = G_DIR_SEPARATOR;
buffer[1] = 0;
}
dir = g_strdup (buffer);
g_free (buffer);
return dir;
#endif /* !G_OS_WIN32 */
}
#ifdef G_OS_WIN32
/* Binary compatibility versions. Not for newly compiled code. */
_GLIB_EXTERN gboolean g_file_test_utf8 (const gchar *filename,
GFileTest test);
_GLIB_EXTERN gboolean g_file_get_contents_utf8 (const gchar *filename,
gchar **contents,
gsize *length,
GError **error);
_GLIB_EXTERN gint g_mkstemp_utf8 (gchar *tmpl);
_GLIB_EXTERN gint g_file_open_tmp_utf8 (const gchar *tmpl,
gchar **name_used,
GError **error);
_GLIB_EXTERN gchar *g_get_current_dir_utf8 (void);
gboolean
g_file_test_utf8 (const gchar *filename,
GFileTest test)
{
return g_file_test (filename, test);
}
gboolean
g_file_get_contents_utf8 (const gchar *filename,
gchar **contents,
gsize *length,
GError **error)
{
return g_file_get_contents (filename, contents, length, error);
}
gint
g_mkstemp_utf8 (gchar *tmpl)
{
return g_mkstemp (tmpl);
}
gint
g_file_open_tmp_utf8 (const gchar *tmpl,
gchar **name_used,
GError **error)
{
return g_file_open_tmp (tmpl, name_used, error);
}
gchar *
g_get_current_dir_utf8 (void)
{
return g_get_current_dir ();
}
#endif
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