An utility to manage file locks from scripts.
Signed-off-by: Timo Teras <[email protected]>
---
include/applets.h | 1 +
include/usage.h | 11 ++++++
util-linux/Config.in | 6 +++
util-linux/Kbuild | 1 +
util-linux/flock.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 112 insertions(+), 0 deletions(-)
create mode 100644 util-linux/flock.c
diff --git a/include/applets.h b/include/applets.h
index 2d784bd..83c1792 100644
--- a/include/applets.h
+++ b/include/applets.h
@@ -161,6 +161,7 @@ IF_FLASH_ERASEALL(APPLET(flash_eraseall, _BB_DIR_USR_SBIN,
_BB_SUID_DROP))
IF_FLASH_LOCK(APPLET_ODDNAME(flash_lock, flash_lock_unlock, _BB_DIR_USR_SBIN,
_BB_SUID_DROP, flash_lock))
IF_FLASH_UNLOCK(APPLET_ODDNAME(flash_unlock, flash_lock_unlock,
_BB_DIR_USR_SBIN, _BB_SUID_DROP, flash_unlock))
IF_FLASHCP(APPLET(flashcp, _BB_DIR_USR_SBIN, _BB_SUID_DROP))
+IF_FLOCK(APPLET(flock, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_FOLD(APPLET(fold, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_FREE(APPLET(free, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_FREERAMDISK(APPLET(freeramdisk, _BB_DIR_SBIN, _BB_SUID_DROP))
diff --git a/include/usage.h b/include/usage.h
index f4259a1..cbf6bef 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1312,6 +1312,17 @@
"\nOptions:" \
"\n -v Verbose" \
+#define flock_trivial_usage \
+ "[-sxun] [fd# | FILE] [-c] command"
+#define flock_full_usage "\n\n" \
+ "Manage file locks from scripts\n" \
+ "\nOptions:" \
+ "\n -s Get a shared lock" \
+ "\n -x Get an exclusive lock" \
+ "\n -u Remove a lock (from fd#)" \
+ "\n -n Fail rather than wait" \
+ "\n -c Command to run" \
+
#define fold_trivial_usage \
"[-bs] [-w WIDTH] [FILE]..."
#define fold_full_usage "\n\n" \
diff --git a/util-linux/Config.in b/util-linux/Config.in
index f04511b..d0d8df3 100644
--- a/util-linux/Config.in
+++ b/util-linux/Config.in
@@ -191,6 +191,12 @@ config FINDFS
WARNING:
With all submodules selected, it will add ~8k to busybox.
+config FLOCK
+ bool "flock"
+ default y
+ help
+ Manage locks from shell scripts
+
config FREERAMDISK
bool "freeramdisk"
default n
diff --git a/util-linux/Kbuild b/util-linux/Kbuild
index 72a2ef1..99e3efe 100644
--- a/util-linux/Kbuild
+++ b/util-linux/Kbuild
@@ -13,6 +13,7 @@ lib-$(CONFIG_FDFLUSH) += freeramdisk.o
lib-$(CONFIG_FDFORMAT) += fdformat.o
lib-$(CONFIG_FDISK) += fdisk.o
lib-$(CONFIG_FINDFS) += findfs.o
+lib-$(CONFIG_FLOCK) += flock.o
lib-$(CONFIG_FREERAMDISK) += freeramdisk.o
lib-$(CONFIG_FSCK_MINIX) += fsck_minix.o
lib-$(CONFIG_GETOPT) += getopt.o
diff --git a/util-linux/flock.c b/util-linux/flock.c
new file mode 100644
index 0000000..e9a22d5
--- /dev/null
+++ b/util-linux/flock.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2010 Timo Teras <[email protected]>
+ *
+ * This is free software, licensed under the GNU General Public License v2.
+ */
+#include <sys/types.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include "busybox.h"
+
+int flock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int flock_main(int argc, char **argv)
+{
+ char *command = NULL;
+ int mode, opt, fd, status = 0;
+ enum {
+ OPT_s = (1 << 0),
+ OPT_x = (1 << 1),
+ OPT_u = (1 << 2),
+ OPT_n = (1 << 3),
+ OPT_c = (1 << 4),
+ };
+
+#if ENABLE_LONG_OPTS
+ static const char getopt_longopts[] ALIGN1 =
+ "shared\0" No_argument "s"
+ "exclusive\0" No_argument "x"
+ "unblock\0" No_argument "u"
+ "nonblock\0" No_argument "n"
+ "command\0" Required_argument "c"
+ ;
+ applet_long_options = getopt_longopts;
+#endif
+
+ opt = getopt32(argv, "sxunc:", &command);
+ argv += optind;
+ argc -= optind;
+
+ if (argv[0] == NULL)
+ bb_show_usage();
+
+ if (command != NULL || argc > 1) {
+ fd = open(argv[0], O_RDONLY|O_NOCTTY|O_CREAT, 0666);
+ if (fd < 0 && errno == EISDIR)
+ fd = open(argv[0], O_RDONLY|O_NOCTTY);
+ } else {
+ fd = atoi(argv[0]);
+ }
+ if (fd < 0)
+ bb_perror_msg_and_die("cannot open: '%s'", argv[0]);
+
+ argv++;
+ if (command == NULL)
+ command = argv[0];
+
+ if (opt & OPT_u)
+ mode = LOCK_UN;
+ else if (opt & OPT_s)
+ mode = LOCK_SH;
+ else
+ mode = LOCK_EX;
+
+ if (opt & OPT_n)
+ mode |= LOCK_NB;
+
+ if (flock(fd, mode) && errno == EWOULDBLOCK)
+ return 1;
+
+ if (command != NULL) {
+ pid_t pid;
+
+ pid = fork();
+ if (pid < 0)
+ bb_perror_msg_and_die("fork failed");
+ if (pid == 0) {
+ execvp(command, argv);
+ exit(1);
+ }
+ waitpid(pid, &status, 0);
+ if (WIFEXITED(status))
+ status = WEXITSTATUS(status);
+ else if (WIFSIGNALED(status))
+ status = WTERMSIG(status) + 128;
+ else
+ status = 1;
+ }
+
+ return status;
+}
--
1.6.3.3
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