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-rw-r--r--sys-utils/flock.c405
1 files changed, 296 insertions, 109 deletions
diff --git a/sys-utils/flock.c b/sys-utils/flock.c
index 27d78d43c..8ea5fce6c 100644
--- a/sys-utils/flock.c
+++ b/sys-utils/flock.c
@@ -1,116 +1,303 @@
-/*
- flock - acquires a file lock and executes a command with the lock held.
- Usage: flock [--shared | --timeout=seconds] lockfile program [args...]
-
- Written by Adam J. Richter
- Copyright (C) 2004 Yggdrasil Computing, 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 2 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, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-*/
-#include <sys/file.h>
+/* $Id: flock.c,v 1.13 2005/07/11 05:32:56 hpa Exp $ */
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2003-2005 H. Peter Anvin - All Rights Reserved
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <signal.h>
+#include <ctype.h>
+#include <string.h>
+#include <paths.h>
+#include <sysexits.h>
#include <sys/types.h>
+#include <sys/file.h>
+#include <sys/time.h>
#include <sys/wait.h>
-#include <getopt.h>
-#include <unistd.h>
-#include <stdlib.h> /* exit */
-#include <signal.h> /* kill */
-#include <stdio.h>
-#include "nls.h"
-
-static int non_blocking = 0;
-static int shared = LOCK_EX;
-static const struct option options[] = {
- {"shared", no_argument, &shared, LOCK_SH },
- {"timeout", required_argument, NULL, 't' },
- {NULL, 0, NULL, 0 },
+static const struct option long_options[] = {
+ { "shared", 0, NULL, 's' },
+ { "exclusive", 0, NULL, 'x' },
+ { "unlock", 0, NULL, 'u' },
+ { "nonblocking", 0, NULL, 'n' },
+ { "nb", 0, NULL, 'n' },
+ { "timeout", 1, NULL, 'w' },
+ { "wait", 1, NULL, 'w' },
+ { "close", 0, NULL, 'o' },
+ { "help", 0, NULL, 'h' },
+ { "version", 0, NULL, 'V' },
+ { 0, 0, 0, 0 }
};
-int main(int argc, char **argv)
+const char *program;
+
+static void usage(int ex)
+{
+ fprintf(stderr,
+ "flock (%s)\n"
+ "Usage: %s [-seun][-w #] fd#\n"
+ " %s [-seon][-w #] file [-c] command...\n"
+ " -s --shared Get a shared lock\n"
+ " -e --exclusive Get an exclusive lock\n"
+ " -u --unlock Remove a lock\n"
+ " -n --nonblock Fail rather than wait\n"
+ " -w --timeout Wait for a limited amount of time\n"
+ " -o --close Close file descriptor before running command\n"
+ " -c --command Run a single command string through the shell\n"
+ " -h --help Display this text\n"
+ " -V --version Display version\n",
+ PACKAGE_STRING, program, program);
+ exit(ex);
+}
+
+
+static sig_atomic_t timeout_expired = 0;
+
+static void timeout_handler(int sig)
+{
+ (void)sig;
+
+ timeout_expired = 1;
+}
+
+
+static char * strtotimeval(const char *str, struct timeval *tv)
+{
+ char *s;
+ long fs; /* Fractional seconds */
+ int i;
+
+ tv->tv_sec = strtol(str, &s, 10);
+ fs = 0;
+
+ if ( *s == '.' ) {
+ s++;
+
+ for ( i = 0 ; i < 6 ; i++ ) {
+ if ( !isdigit(*s) )
+ break;
+
+ fs *= 10;
+ fs += *s++ - '0';
+ }
+
+ for ( ; i < 6; i++ )
+ fs *= 10;
+
+ while ( isdigit(*s) )
+ s++;
+ }
+
+ tv->tv_usec = fs;
+ return s;
+}
+
+int main(int argc, char *argv[])
{
- int fd;
- int opt;
- int pid;
- int child_status;
- int option_index;
- int timeout = 0;
-
- setlocale(LC_ALL, "");
- bindtextdomain(PACKAGE, LOCALEDIR);
- textdomain(PACKAGE);
-
- do {
- opt = getopt_long(argc, argv, "+", options, &option_index);
- switch(opt) {
- case '?':
- fprintf (stderr,
- _("flock: unknown option, aborting.\n"));
- exit(1);
- break;
- case 't':
- timeout = atoi(optarg);
- if (timeout == 0)
- non_blocking |= LOCK_NB;
- break;
- default:
- break;
- }
- } while (opt != -1);
-
- argc -= optind;
- argv += optind;
-
- if (argc < 2) {
- fprintf(stderr,
- _("Usage flock [--shared] [--timeout=seconds] "
- "filename command {arg arg...}\n"));
- exit(2);
- }
-
- fd = open(argv[0], O_RDONLY);
- if (fd < 0) {
- perror(argv[0]);
- exit(3);
- }
-
- alarm(timeout);
- if (flock(fd, shared | non_blocking) != 0) {
- perror("flock");
- exit(4);
- }
- alarm(0);
-
- pid = fork();
- if (pid < 0) {
- perror("fork");
- exit(5);
- }
- if (pid == 0) {
- execvp(argv[1], argv+1);
- perror(argv[1]);
- exit(6);
- }
- waitpid(pid, &child_status, 0);
-
- /* flock(fd, LOCK_UN); */
- /* No need to explicitly release the flock, since we are just
- going to exit now anyhow. */
-
- /* Lame attempt to simulate child's mode of death. */
- if (WIFSIGNALED(child_status))
- kill(0, WTERMSIG(child_status));
-
- return WEXITSTATUS(child_status);
+ struct itimerval timeout, old_timer;
+ int have_timeout = 0;
+ int type = LOCK_EX;
+ int block = 0;
+ int fd = -1;
+ int opt, ix;
+ int do_close = 0;
+ int err;
+ int status;
+ char *eon;
+ char **cmd_argv = NULL, *sh_c_argv[4];
+ const char *filename = NULL;
+ struct sigaction sa, old_sa;
+
+ program = argv[0];
+
+ if ( argc < 2 )
+ usage(EX_USAGE);
+
+ memset(&timeout, 0, sizeof timeout);
+
+ optopt = 0;
+ while ( (opt = getopt_long(argc, argv, "+sexnouw:hV?", long_options, &ix)) != EOF ) {
+ switch(opt) {
+ case 's':
+ type = LOCK_SH;
+ break;
+ case 'e':
+ case 'x':
+ type = LOCK_EX;
+ break;
+ case 'u':
+ type = LOCK_UN;
+ break;
+ case 'o':
+ do_close = 1;
+ break;
+ case 'n':
+ block = LOCK_NB;
+ break;
+ case 'w':
+ have_timeout = 1;
+ eon = strtotimeval(optarg, &timeout.it_value);
+ if ( *eon )
+ usage(EX_USAGE);
+ break;
+ case 'V':
+ printf("flock (%s)\n", PACKAGE_STRING);
+ exit(0);
+ default:
+ /* optopt will be set if this was an unrecognized option, i.e. *not* 'h' or '?' */
+ usage(optopt ? EX_USAGE : 0);
+ break;
+ }
+ }
+
+ if ( argc > optind+1 ) {
+ /* Run command */
+
+ if ( !strcmp(argv[optind+1], "-c") ||
+ !strcmp(argv[optind+1], "--command") ) {
+
+ if ( argc != optind+3 ) {
+ fprintf(stderr, "%s: %s requires exactly one command argument\n",
+ program, argv[optind+1]);
+ exit(EX_USAGE);
+ }
+
+ cmd_argv = sh_c_argv;
+
+ cmd_argv[0] = getenv("SHELL");
+ if ( !cmd_argv[0] || !*cmd_argv[0] )
+ cmd_argv[0] = _PATH_BSHELL;
+
+ cmd_argv[1] = "-c";
+ cmd_argv[2] = argv[optind+2];
+ cmd_argv[3] = 0;
+ } else {
+ cmd_argv = &argv[optind+1];
+ }
+
+ filename = argv[optind];
+ fd = open(filename, O_RDONLY|O_CREAT, 0666);
+
+ if ( fd < 0 ) {
+ err = errno;
+ fprintf(stderr, "%s: cannot open lock file %s: %s\n",
+ program, argv[optind], strerror(err));
+ exit((err == ENOMEM||err == EMFILE||err == ENFILE) ? EX_OSERR :
+ (err == EROFS||err == ENOSPC) ? EX_CANTCREAT :
+ EX_NOINPUT);
+ }
+
+ } else {
+ /* Use provided file descriptor */
+
+ fd = (int)strtol(argv[optind], &eon, 10);
+ if ( *eon || !argv[optind] ) {
+ fprintf(stderr, "%s: bad number: %s\n", program, argv[optind]);
+ exit(EX_USAGE);
+ }
+
+ }
+
+ if ( have_timeout ) {
+ if ( timeout.it_value.tv_sec == 0 &&
+ timeout.it_value.tv_usec == 0 ) {
+ /* -w 0 is equivalent to -n; this has to be special-cased
+ because setting an itimer to zero means disabled! */
+
+ have_timeout = 0;
+ block = LOCK_NB;
+ } else {
+ memset(&sa, 0, sizeof sa);
+
+ sa.sa_handler = timeout_handler;
+ sa.sa_flags = SA_ONESHOT;
+ sigaction(SIGALRM, &sa, &old_sa);
+
+ setitimer(ITIMER_REAL, &timeout, &old_timer);
+ }
+ }
+
+ while ( flock(fd, type|block) ) {
+ switch( (err = errno) ) {
+ case EWOULDBLOCK: /* -n option set and failed to lock */
+ exit(1);
+ case EINTR: /* Signal received */
+ if ( timeout_expired )
+ exit(1); /* -w option set and failed to lock */
+ continue; /* otherwise try again */
+ default: /* Other errors */
+ if ( filename )
+ fprintf(stderr, "%s: %s: %s\n", program, filename, strerror(err));
+ else
+ fprintf(stderr, "%s: %d: %s\n", program, fd, strerror(err));
+ exit((err == ENOLCK||err == ENOMEM) ? EX_OSERR : EX_DATAERR);
+ }
+ }
+
+ if ( have_timeout ) {
+ setitimer(ITIMER_REAL, &old_timer, NULL); /* Cancel itimer */
+ sigaction(SIGALRM, &old_sa, NULL); /* Cancel signal handler */
+ }
+
+ status = 0;
+
+ if ( cmd_argv ) {
+ pid_t w, f;
+
+ f = fork();
+
+ if ( f < 0 ) {
+ err = errno;
+ fprintf(stderr, "%s: fork: %s\n", program, strerror(err));
+ exit(EX_OSERR);
+ } else if ( f == 0 ) {
+ if ( do_close )
+ close(fd);
+ err = errno;
+ execvp(cmd_argv[0], cmd_argv);
+ /* execvp() failed */
+ fprintf(stderr, "%s: %s: %s\n", program, cmd_argv[0], strerror(err));
+ _exit((err == ENOMEM) ? EX_OSERR: EX_UNAVAILABLE);
+ } else {
+ do {
+ w = waitpid(f, &status, 0);
+ } while ( w != f );
+
+ if ( WIFEXITED(status) )
+ status = WEXITSTATUS(status);
+ else if ( WIFSIGNALED(status) )
+ status = WTERMSIG(status) + 128;
+ else
+ status = EX_OSERR; /* WTF? */
+ }
+ }
+
+ return status;
}
+
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