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/* vi:set et sw=2 sts=2 cin cino=t0,f0,(0,{s,>2s,n-s,^-s,e-s:
* Copyright © 2019-2021 Collabora Ltd.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This program 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 <glib.h>
#include <glib/gstdio.h>
#include <fcntl.h>
#include <fcntl.h>
#include <sysexits.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "libglnx.h"
static GArray *global_locks = NULL;
static gboolean opt_wait = FALSE;
static gboolean opt_write = FALSE;
static gboolean
opt_fd_cb (const char *name,
const char *value,
gpointer data,
GError **error)
{
char *endptr;
gint64 i64 = g_ascii_strtoll (value, &endptr, 10);
int fd;
int fd_flags;
g_return_val_if_fail (global_locks != NULL, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
g_return_val_if_fail (value != NULL, FALSE);
if (i64 < 0 || i64 > G_MAXINT || endptr == value || *endptr != '\0')
{
g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
"Integer out of range or invalid: %s", value);
return FALSE;
}
fd = (int) i64;
fd_flags = fcntl (fd, F_GETFD);
if (fd_flags < 0)
return glnx_throw_errno_prefix (error, "Unable to receive --fd %d", fd);
if ((fd_flags & FD_CLOEXEC) == 0
&& fcntl (fd, F_SETFD, fd_flags | FD_CLOEXEC) != 0)
return glnx_throw_errno_prefix (error,
"Unable to configure --fd %d for "
"close-on-exec",
fd);
g_array_append_val (global_locks, fd);
return TRUE;
}
static gboolean
opt_lock_file_cb (const char *name,
const char *value,
gpointer data,
GError **error)
{
int open_flags = O_CLOEXEC | O_CREAT | O_NOCTTY | O_RDWR;
int fd;
int cmd;
struct flock l =
{
.l_type = F_RDLCK,
.l_whence = SEEK_SET,
.l_start = 0,
.l_len = 0,
};
g_return_val_if_fail (global_locks != NULL, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
g_return_val_if_fail (value != NULL, FALSE);
fd = TEMP_FAILURE_RETRY (open (value, open_flags, 0644));
if (fd < 0)
return glnx_throw_errno_prefix (error, "open %s", value);
if (opt_write)
l.l_type = F_WRLCK;
if (opt_wait)
cmd = F_SETLKW;
else
cmd = F_SETLK;
if (TEMP_FAILURE_RETRY (fcntl (fd, cmd, &l)) < 0)
{
if (errno == EACCES || errno == EAGAIN)
g_set_error (error, G_IO_ERROR, G_IO_ERROR_BUSY,
"Unable to lock %s: file is busy", value);
else
glnx_throw_errno_prefix (error, "lock %s", value);
close (fd);
return FALSE;
}
g_array_append_val (global_locks, fd);
return TRUE;
}
static GOptionEntry options[] =
{
{ "fd", '\0',
G_OPTION_FLAG_NONE, G_OPTION_ARG_CALLBACK, opt_fd_cb,
"Take a file descriptor, already locked if desired, and keep it "
"open. May be repeated.",
NULL },
{ "wait", '\0',
G_OPTION_FLAG_NONE, G_OPTION_ARG_NONE, &opt_wait,
"Wait for each subsequent lock file.",
NULL },
{ "no-wait", '\0',
G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &opt_wait,
"Exit unsuccessfully if a lock-file is busy [default].",
NULL },
{ "write", '\0',
G_OPTION_FLAG_NONE, G_OPTION_ARG_NONE, &opt_write,
"Lock each subsequent lock file for write access.",
NULL },
{ "no-write", '\0',
G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &opt_write,
"Lock each subsequent lock file for read-only access [default].",
NULL },
{ "lock-file", '\0',
G_OPTION_FLAG_NONE, G_OPTION_ARG_CALLBACK, opt_lock_file_cb,
"Open the given file and lock it, affected by options appearing "
"earlier on the command-line. May be repeated.",
NULL },
{ NULL }
};
int
main (int argc,
char *argv[])
{
g_autoptr(GArray) locks = NULL;
g_autoptr(GOptionContext) context = NULL;
g_autoptr(GError) local_error = NULL;
GError **error = &local_error;
int ret = EX_USAGE;
locks = g_array_new (FALSE, FALSE, sizeof (int));
global_locks = locks;
context = g_option_context_new (NULL);
g_option_context_add_main_entries (context, options, NULL);
if (!g_option_context_parse (context, &argc, &argv, error))
{
if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_BUSY))
ret = EX_TEMPFAIL;
else if (local_error->domain == G_OPTION_ERROR)
ret = EX_USAGE;
else
ret = EX_UNAVAILABLE;
goto out;
}
ret = EX_UNAVAILABLE;
/* Self-destruct when parent exits */
if (prctl (PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0) != 0)
{
glnx_throw_errno_prefix (error,
"Unable to set parent death signal");
goto out;
}
/* Signal to caller that we are ready */
fclose (stdout);
while (TRUE)
pause ();
g_assert_not_reached ();
out:
global_locks = NULL;
if (local_error != NULL)
g_warning ("%s", local_error->message);
return ret;
}
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