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Adding upstream version 9.7.

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Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
This commit is contained in:
Daniel Baumann 2025-06-21 07:57:52 +02:00
parent 4b8dc12adb
commit c08a8f7410
Signed by: daniel.baumann
GPG key ID: BCC918A2ABD66424
3561 changed files with 1457043 additions and 0 deletions
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lib/savewd.c Normal file
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/* Save and restore the working directory, possibly using a child process.
Copyright (C) 2006-2007, 2009-2025 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#include <config.h>
#define SAVEWD_INLINE _GL_EXTERN_INLINE
#include "savewd.h"
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "assure.h"
#include "attribute.h"
#include "filename.h"
#if GNULIB_FCNTL_SAFER
# include "fcntl--.h"
#endif
#if defined _WIN32 && !defined __CYGWIN__
# define fork() (assure (false), -1)
#endif
/* Save the working directory into *WD, if it hasn't been saved
already. Return true if a child has been forked to do the real
work. */
static bool
savewd_save (struct savewd *wd)
{
switch (wd->state)
{
case INITIAL_STATE:
/* Save the working directory, or prepare to fall back if possible. */
{
int fd = open (".", O_SEARCH);
if (0 <= fd)
{
wd->state = FD_STATE;
wd->val.fd = fd;
break;
}
/* There is no point to forking on native MS-Windows which lacks 'fork'.
Although there is also no point on systems that support O_SEARCH,
macOS 12.6 APFS open (".", O_SEARCH) incorrectly fails if "." is
mode 311, so do not attempt to optimize for O_SEARCH != O_RDONLY. */
# if defined _WIN32 && !defined __CYGWIN__
bool try_fork = false;
# else
bool try_fork = errno == EACCES || errno == ESTALE;
# endif
if (!try_fork)
{
wd->state = ERROR_STATE;
wd->val.errnum = errno;
break;
}
}
wd->state = FORKING_STATE;
wd->val.child = -1;
FALLTHROUGH;
case FORKING_STATE:
if (wd->val.child < 0)
{
/* "Save" the initial working directory by forking a new
subprocess that will attempt all the work from the chdir
until the next savewd_restore. */
wd->val.child = fork ();
if (wd->val.child != 0)
{
if (0 < wd->val.child)
return true;
wd->state = ERROR_STATE;
wd->val.errnum = errno;
}
}
break;
case FD_STATE:
case FD_POST_CHDIR_STATE:
case ERROR_STATE:
case FINAL_STATE:
break;
default:
assure (false);
}
return false;
}
int
savewd_chdir (struct savewd *wd, char const *dir, int options,
int open_result[2])
{
int fd = -1;
int result = 0;
/* Open the directory if requested, or if avoiding a race condition
is requested and possible. */
if (open_result
|| (options & (HAVE_WORKING_O_NOFOLLOW ? SAVEWD_CHDIR_NOFOLLOW : 0)))
{
fd = open (dir,
(O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK
| (options & SAVEWD_CHDIR_NOFOLLOW ? O_NOFOLLOW : 0)));
if (open_result)
{
open_result[0] = fd;
open_result[1] = errno;
}
if (fd < 0 && errno != EACCES)
result = -1;
}
if (result == 0 && ! (0 <= fd && options & SAVEWD_CHDIR_SKIP_READABLE))
{
if (savewd_save (wd))
{
open_result = NULL;
result = -2;
}
else
{
result = (fd < 0 ? chdir (dir) : fchdir (fd));
if (result == 0)
switch (wd->state)
{
case FD_STATE:
wd->state = FD_POST_CHDIR_STATE;
break;
case ERROR_STATE:
case FD_POST_CHDIR_STATE:
case FINAL_STATE:
break;
case FORKING_STATE:
assure (wd->val.child == 0);
break;
case INITIAL_STATE: default:
assure (false);
}
}
}
if (0 <= fd && ! open_result)
{
int e = errno;
close (fd);
errno = e;
}
return result;
}
int
savewd_restore (struct savewd *wd, int status)
{
switch (wd->state)
{
case INITIAL_STATE:
case FD_STATE:
/* The working directory is the desired directory, so there's no
work to do. */
break;
case FD_POST_CHDIR_STATE:
/* Restore the working directory using fchdir. */
if (fchdir (wd->val.fd) == 0)
{
wd->state = FD_STATE;
break;
}
else
{
int chdir_errno = errno;
close (wd->val.fd);
wd->state = ERROR_STATE;
wd->val.errnum = chdir_errno;
}
FALLTHROUGH;
case ERROR_STATE:
/* Report an error if asked to restore the working directory. */
errno = wd->val.errnum;
return -1;
case FORKING_STATE:
/* "Restore" the working directory by waiting for the subprocess
to finish. */
{
pid_t child = wd->val.child;
if (child == 0)
_exit (status);
if (0 < child)
{
int child_status;
while (waitpid (child, &child_status, 0) < 0)
assure (errno == EINTR);
wd->val.child = -1;
if (! WIFEXITED (child_status))
raise (WTERMSIG (child_status));
return WEXITSTATUS (child_status);
}
}
break;
case FINAL_STATE: default:
assure (false);
}
return 0;
}
void
savewd_finish (struct savewd *wd)
{
switch (wd->state)
{
case ERROR_STATE:
break;
case FD_STATE:
case FD_POST_CHDIR_STATE:
close (wd->val.fd);
FALLTHROUGH;
case INITIAL_STATE:
wd->val.errnum = 0;
break;
case FORKING_STATE:
assure (wd->val.child < 0);
wd->val.errnum = 0;
break;
case FINAL_STATE: default:
assure (false);
}
wd->state = FINAL_STATE;
}
/* Return true if the actual work is currently being done by a
subprocess.
A true return means that the caller and the subprocess should
resynchronize later with savewd_restore, using only their own
memory to decide when to resynchronize; they should not consult the
file system to decide, because that might lead to race conditions.
This is why savewd_chdir is broken out into another function;
savewd_chdir's callers _can_ inspect the file system to decide
whether to call savewd_chdir. */
static bool
savewd_delegating (struct savewd const *wd)
{
return wd->state == FORKING_STATE && 0 < wd->val.child;
}
int
savewd_process_files (int n_files, char **file,
int (*act) (char *, struct savewd *, void *),
void *options)
{
int i = 0;
int last_relative;
int exit_status = EXIT_SUCCESS;
struct savewd wd;
savewd_init (&wd);
for (last_relative = n_files - 1; 0 <= last_relative; last_relative--)
if (! IS_ABSOLUTE_FILE_NAME (file[last_relative]))
break;
for (; i < last_relative; i++)
{
if (! savewd_delegating (&wd))
{
int s = act (file[i], &wd, options);
if (exit_status < s)
exit_status = s;
}
if (! IS_ABSOLUTE_FILE_NAME (file[i + 1]))
{
int r = savewd_restore (&wd, exit_status);
if (exit_status < r)
exit_status = r;
}
}
savewd_finish (&wd);
for (; i < n_files; i++)
{
int s = act (file[i], &wd, options);
if (exit_status < s)
exit_status = s;
}
return exit_status;
}