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--- a/include/applets.h
+++ b/include/applets.h
@@ -220,6 +220,7 @@
USE_LOAD_POLICY(APPLET(load_policy, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
USE_LOADFONT(APPLET(loadfont, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
USE_LOADKMAP(APPLET(loadkmap, _BB_DIR_SBIN, _BB_SUID_NEVER))
+USE_LOCK(APPLET(lock, _BB_DIR_BIN, _BB_SUID_NEVER))
USE_LOGGER(APPLET(logger, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
USE_LOGIN(APPLET(login, _BB_DIR_BIN, _BB_SUID_ALWAYS))
USE_LOGNAME(APPLET_NOFORK(logname, logname, _BB_DIR_USR_BIN, _BB_SUID_NEVER, logname))
--- a/include/usage.h
+++ b/include/usage.h
@@ -2138,6 +2138,9 @@
#define loadkmap_example_usage \
"$ loadkmap < /etc/i18n/lang-keymap\n"
+#define lock_trivial_usage NOUSAGE_STR
+#define lock_full_usage ""
+
#define logger_trivial_usage \
"[OPTION]... [MESSAGE]"
#define logger_full_usage "\n\n" \
--- a/miscutils/Config.in
+++ b/miscutils/Config.in
@@ -364,6 +364,12 @@
Enables the 'hdparm -d' option to get/set using_dma flag.
This is dangerous stuff, so you should probably say N.
+config LOCK
+ bool "lock"
+ default y
+ help
+ Small utility for using locks in scripts
+
config MAKEDEVS
bool "makedevs"
default n
--- a/miscutils/Kbuild
+++ b/miscutils/Kbuild
@@ -20,6 +20,7 @@
lib-$(CONFIG_FEATURE_LAST_SMALL)+= last.o
lib-$(CONFIG_FEATURE_LAST_FANCY)+= last_fancy.o
lib-$(CONFIG_LESS) += less.o
+lib-$(CONFIG_LOCK) += lock.o
lib-$(CONFIG_MAKEDEVS) += makedevs.o
lib-$(CONFIG_MAN) += man.o
lib-$(CONFIG_MICROCOM) += microcom.o
--- /dev/null
+++ b/miscutils/lock.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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"
+
+static int unlock = 0;
+static int shared = 0;
+static int waitonly = 0;
+static int fd;
+static char *file;
+
+static void usage(char *name)
+{
+ fprintf(stderr, "Usage: %s [-suw] <filename>\n"
+ " -s Use shared locking\n"
+ " -u Unlock\n"
+ " -w Wait for the lock to become free, don't acquire lock\n"
+ "\n", name);
+ exit(1);
+}
+
+static void exit_unlock(int sig)
+{
+ flock(fd, LOCK_UN);
+ exit(0);
+}
+
+static int do_unlock(void)
+{
+ FILE *f;
+ int i;
+
+ if ((f = fopen(file, "r")) == NULL)
+ return 0;
+
+ fscanf(f, "%d", &i);
+ if (i > 0)
+ kill(i, SIGTERM);
+
+ fclose(f);
+
+ return 0;
+}
+
+static int do_lock(void)
+{
+ int pid;
+ char pidstr[8];
+
+ if ((fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0700)) < 0) {
+ if ((fd = open(file, O_RDWR)) < 0) {
+ fprintf(stderr, "Can't open %s\n", file);
+ return 1;
+ }
+ }
+
+ if (flock(fd, (shared ? LOCK_SH : LOCK_EX)) < 0) {
+ fprintf(stderr, "Can't lock %s\n", file);
+ return 1;
+ }
+
+ pid = fork();
+
+ if (pid < 0)
+ return -1;
+
+ if (pid == 0) {
+ signal(SIGKILL, exit_unlock);
+ signal(SIGTERM, exit_unlock);
+ signal(SIGINT, exit_unlock);
+ if (waitonly)
+ exit_unlock(0);
+ else
+ while (1)
+ sleep(1);
+ } else {
+ if (!waitonly) {
+ lseek(fd, 0, SEEK_SET);
+ ftruncate(fd, 0);
+ sprintf(pidstr, "%d\n", pid);
+ write(fd, pidstr, strlen(pidstr));
+ close(fd);
+ }
+
+ return 0;
+ }
+ return 0;
+}
+
+int lock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int lock_main(int argc, char **argv)
+{
+ char **args = &argv[1];
+ int c = argc - 1;
+
+ while ((*args != NULL) && (*args)[0] == '-') {
+ char *ch = *args;
+ while (*(++ch) > 0) {
+ switch(*ch) {
+ case 'w':
+ waitonly = 1;
+ break;
+ case 's':
+ shared = 1;
+ break;
+ case 'u':
+ unlock = 1;
+ break;
+ }
+ }
+ c--;
+ args++;
+ }
+
+ if (c != 1)
+ usage(argv[0]);
+
+ file = *args;
+ if (unlock)
+ return do_unlock();
+ else
+ return do_lock();
+}
|
