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authorchristos <christos@NetBSD.org>2012-11-01 23:30:19 +0000
committerchristos <christos@NetBSD.org>2012-11-01 23:30:19 +0000
commitd1b5215285d025c69b24abae3dcdaa8afaf0f796 (patch)
treeb92ec7b0a9c49d5c49da5fa54ead5d7ee029fb0c /usr.bin/flock
parent291f566eaaa2e5b38deb579fa1716439eea35f1e (diff)
Add an flock program inspired by the linux one with the same name.
Diffstat (limited to 'usr.bin/flock')
-rw-r--r--usr.bin/flock/Makefile8
-rw-r--r--usr.bin/flock/flock.199
-rw-r--r--usr.bin/flock/flock.c211
3 files changed, 318 insertions, 0 deletions
diff --git a/usr.bin/flock/Makefile b/usr.bin/flock/Makefile
new file mode 100644
index 00000000000..ba91e5f790a
--- /dev/null
+++ b/usr.bin/flock/Makefile
@@ -0,0 +1,8 @@
+# $NetBSD: Makefile,v 1.1 2012/11/01 23:30:19 christos Exp $
+# @(#)Makefile 8.1 (Berkeley) 6/6/93
+
+PROG= flock
+#LDADD+= -lutil
+#DPADD+= ${LIBUTIL}
+
+.include <bsd.prog.mk>
diff --git a/usr.bin/flock/flock.1 b/usr.bin/flock/flock.1
new file mode 100644
index 00000000000..5b95f85161f
--- /dev/null
+++ b/usr.bin/flock/flock.1
@@ -0,0 +1,99 @@
+.\" $NetBSD: flock.1,v 1.1 2012/11/01 23:30:19 christos Exp $
+.\"
+.\" Copyright (c) 2012 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Christos Zoulas.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\"
+.Dd November 1, 2012
+.Dt flock 1
+.Os
+.Sh NAME
+.Nm flock
+.Nd Provide locking API for shell scripts
+.Sh SYNOPSIS
+.Nm
+.Op Fl dnosxv
+.Op Fl w Ar timeout
+.Ar lockfile|lockdir
+.Op Ar c
+.Ar command
+.Nm
+.Op Fl dnusxv
+.Op Fl w Ar timeout
+.Ar lockfd
+.Sh DESCRIPTION
+The
+.Nm
+utility provides
+.Xr flock 2
+access to the command line or scripts.
+The first form locks a file or directory while the command provided is executed.
+If the file or directory does not exist, then a file is created.
+.Pp
+The second form can use an arbitrary file descriptor that is provided from a
+shell script for example:
+.nf
+(
+ flock -s 100
+ # commands to be executed under the lock
+) 100> /path/to/lockfile
+.if
+.Pp
+The following options are available:
+.Bl -tag -width "XXXXXXXXXXXXXXXXX"
+.It Fl c Ar command
+Pass a command to a the shell.
+.It Fl d Fl Fl debug
+Provide debugging output.
+.It Fl s Fl Fl shared
+Obtain a shared lock.
+.It Fl e Fl x Fl Fl exclusive
+Obtain an exclusive lock.
+.It Fl u Fl Fl unlock
+Unlock an existing lock.
+This is available only for a file descriptor.
+.It Fl n Fl Fl nb Fl Fl nonblock
+Don't block and fail immediately if the lock could not be obtained.
+.If Fl v Fl Fl verbose
+On error print an explanation of the failure.
+.It Fl w Fl Fl wait Fl Fl timeout Ar seconds
+Fail if the lock could not be obtained after
+.Ar seconds .
+Seconds are truncated to integer values.
+.It Fl o Fl Fl close
+Close the file before executing the command.
+This is useful if the child forks and should not be holding the lock.
+.El
+.Sh EXIT STATUS
+.Ex -std
+.Sh SEE ALSO
+.Xr flock 2
+.Sh HISTORY
+A
+.Nm
+utility appeared in
+.Nx 7
diff --git a/usr.bin/flock/flock.c b/usr.bin/flock/flock.c
new file mode 100644
index 00000000000..632a86e4d3f
--- /dev/null
+++ b/usr.bin/flock/flock.c
@@ -0,0 +1,211 @@
+/* $NetBSD: flock.c,v 1.1 2012/11/01 23:30:19 christos Exp $ */
+
+/*-
+ * Copyright (c) 2012 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__RCSID("$NetBSD: flock.c,v 1.1 2012/11/01 23:30:19 christos Exp $");
+
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <err.h>
+#include <errno.h>
+#include <getopt.h>
+#include <paths.h>
+
+struct option flock_longopts[] = {
+ { "debug", no_argument, 0, 'd' },
+ { "help", no_argument, 0, 'h' },
+ { "nonblock", no_argument, 0, 'n' },
+ { "nb", no_argument, 0, 'n' },
+ { "close", no_argument, 0, 'o' },
+ { "shared", no_argument, 0, 's' },
+ { "exclusive", no_argument, 0, 'x' },
+ { "unlock", no_argument, 0, 'u' },
+ { "verbose", no_argument, 0, 'v' },
+ { "command", required_argument, 0, 'c' },
+ { "wait", required_argument, 0, 'w' },
+ { "timeout", required_argument, 0, 'w' },
+ { NULL, 0, 0, 0 },
+};
+
+static int verbose = 0;
+
+static __dead void usage(void)
+{
+ fprintf(stderr, "Usage: %s [-dnosxv] [-w <timeout>] file|directory [-c] "
+ "<command>\n\t%s [-dnusxv] [-w <timeout>] fd\n", getprogname(),
+ getprogname());
+ exit(EXIT_FAILURE);
+}
+
+static __dead void
+sigalrm(int sig)
+{
+ if (verbose) {
+ errno = ETIMEDOUT;
+ errx(EXIT_FAILURE, "");
+ } else
+ exit(EXIT_FAILURE);
+}
+
+static const char *
+lock2name(int l)
+{
+ static char buf[1024];
+ int nb = l & LOCK_NB;
+
+ l &= ~LOCK_NB;
+ if (nb)
+ strlcpy(buf, "LOCK_NB|", sizeof(buf));
+ else
+ buf[0] = '\0';
+
+ switch (l) {
+ case LOCK_SH:
+ strlcat(buf, "LOCK_SH", sizeof(buf));
+ return buf;
+ case LOCK_EX:
+ strlcat(buf, "LOCK_EX", sizeof(buf));
+ return buf;
+ case LOCK_UN:
+ strlcat(buf, "LOCK_UN", sizeof(buf));
+ return buf;
+ default:
+ snprintf(buf, sizeof(buf), "*%d*", l | nb);
+ return buf;
+ }
+}
+
+int
+main(int argc, char *argv[])
+{
+ int c;
+ int lock = 0;
+ double timeout = 0;
+ int cls = 0;
+ int fd = -1;
+ int debug = 0;
+ char *command = NULL;
+
+ setprogname(argv[0]);
+
+ while ((c = getopt_long(argc, argv, "c:dnosxuw:", flock_longopts, NULL))
+ != -1)
+ switch (c) {
+ case 'c':
+ command = optarg;
+ break;
+ case 'd':
+ debug++;
+ break;
+ case 'e':
+ case 'x':
+ lock |= LOCK_EX;
+ break;
+ case 'n':
+ lock |= LOCK_NB;
+ break;
+ case 's':
+ lock |= LOCK_SH;
+ break;
+ case 'u':
+ lock |= LOCK_UN;
+ break;
+ case 'w':
+ timeout = strtod(optarg, NULL);
+ break;
+ case 'v':
+ verbose = 1;
+ break;
+ case 'o':
+ cls = 1;
+ break;
+ default:
+ usage();
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (command) {
+ if (lock == LOCK_UN)
+ usage();
+ if ((fd = open(argv[0], O_RDONLY)) == -1) {
+ if (errno != ENOENT ||
+ (fd = open(argv[0], O_RDWR|O_CREAT, 0600)) == -1)
+ err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
+ }
+ if (debug)
+ fprintf(stderr, "file %s lock %s command %s\n",
+ argv[0], lock2name(lock), command);
+
+
+ } else {
+ if (cls)
+ usage();
+ fd = strtol(argv[0], NULL, 0); // XXX: error checking
+ if (debug)
+ fprintf(stderr, "descriptor %s lock %s\n",
+ argv[0], lock2name(lock));
+ }
+
+ if (timeout) {
+ signal(SIGALRM, sigalrm);
+ alarm((int)timeout); // XXX: User timer_create()
+ if (debug)
+ fprintf(stderr, "alarm %d\n", (int)timeout);
+ }
+
+ if (flock(fd, lock) == -1) {
+ if (verbose)
+ err(EXIT_FAILURE, "flock(%d, %s)", fd, lock2name(lock));
+ else
+ return EXIT_FAILURE;
+ }
+
+ if (timeout)
+ alarm(0);
+
+ if (cls)
+ (void)close(fd);
+
+ if (command == NULL)
+ return 0;
+ if (debug)
+ fprintf(stderr, "execute %s -c '%s'\n", _PATH_BSHELL, command);
+ execlp(_PATH_BSHELL, "sh", "-c", command, NULL);
+ err(EXIT_FAILURE, "exec %s -c '%s'", _PATH_BSHELL, command);
+ return 0;
+}