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diff -urN busybox.old/include/applets.h busybox.dev/include/applets.h
--- busybox.old/include/applets.h 2006-04-05 01:06:29.000000000 +0200
+++ busybox.dev/include/applets.h 2006-04-05 01:19:09.000000000 +0200
@@ -167,6 +167,7 @@
USE_LN(APPLET(ln, ln_main, _BB_DIR_BIN, _BB_SUID_NEVER))
USE_LOADFONT(APPLET(loadfont, loadfont_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
USE_LOADKMAP(APPLET(loadkmap, loadkmap_main, _BB_DIR_SBIN, _BB_SUID_NEVER))
+USE_LOCK(APPLET_NOUSAGE(lock, lock_main, _BB_DIR_BIN, _BB_SUID_NEVER))
USE_LOGGER(APPLET(logger, logger_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
USE_LOGIN(APPLET(login, login_main, _BB_DIR_BIN, _BB_SUID_ALWAYS))
USE_LOGNAME(APPLET(logname, logname_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
diff -urN busybox.old/miscutils/Config.in busybox.dev/miscutils/Config.in
--- busybox.old/miscutils/Config.in 2006-03-22 22:16:24.000000000 +0100
+++ busybox.dev/miscutils/Config.in 2006-04-05 01:07:12.000000000 +0200
@@ -209,6 +209,12 @@
Enables the 'hdparm -d' option to get/set using_dma flag.
This is dangerous stuff, so you should probably say N.
+config CONFIG_LOCK
+ bool "lock"
+ default y
+ help
+ Small utility for using locks in scripts
+
config CONFIG_MAKEDEVS
bool "makedevs"
default n
diff -urN busybox.old/miscutils/Makefile.in busybox.dev/miscutils/Makefile.in
--- busybox.old/miscutils/Makefile.in 2006-03-22 22:16:24.000000000 +0100
+++ busybox.dev/miscutils/Makefile.in 2006-04-05 01:10:50.000000000 +0200
@@ -20,6 +20,7 @@
MISCUTILS-$(CONFIG_EJECT) += eject.o
MISCUTILS-$(CONFIG_HDPARM) += hdparm.o
MISCUTILS-$(CONFIG_LAST) += last.o
+MISCUTILS-$(CONFIG_LOCK) += lock.o
MISCUTILS-${CONFIG_LESS} += less.o
MISCUTILS-$(CONFIG_MAKEDEVS) += makedevs.o
MISCUTILS-$(CONFIG_MOUNTPOINT) += mountpoint.o
diff -urN busybox.old/miscutils/lock.c busybox.dev/miscutils/lock.c
--- busybox.old/miscutils/lock.c 1970-01-01 01:00:00.000000000 +0100
+++ busybox.dev/miscutils/lock.c 2006-04-05 01:07:12.000000000 +0200
@@ -0,0 +1,125 @@
+#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);
+ unlink(file);
+ exit(0);
+}
+
+static int do_unlock(void)
+{
+ FILE *f;
+ int i;
+
+ f = fopen(file, "r");
+ 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, 0700)) < 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;
+ }
+}
+
+#ifndef CONFIG_LOCK
+int main(int argc, char **argv)
+#else
+int lock_main(int argc, char **argv)
+#endif
+{
+ 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();
+}
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