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mirror of git://projects.qi-hardware.com/openwrt-xburst.git synced 2024-11-09 08:12:49 +02:00
openwrt-xburst/package/busybox/patches/340-lock_util.patch
nbd 81ddc1b91c reduce the possibility of race conditions when using the lock utility
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@5297 3c298f89-4303-0410-b956-a3cf2f4a3e73
2006-10-26 01:32:49 +00:00

183 lines
4.4 KiB
Diff

# Copyright (C) 2006 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
diff -ruN busybox-1.2.0-old/include/applets.h busybox-1.2.0-new/include/applets.h
--- busybox-1.2.0-old/include/applets.h 2006-07-31 11:21:00.000000000 +0200
+++ busybox-1.2.0-new/include/applets.h 2006-08-01 10:21:15.000000000 +0200
@@ -169,6 +169,7 @@
USE_LN(APPLET(ln, _BB_DIR_BIN, _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_NOUSAGE(lock, 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(logname, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
diff -ruN busybox-1.2.0-old/miscutils/Config.in busybox-1.2.0-new/miscutils/Config.in
--- busybox-1.2.0-old/miscutils/Config.in 2006-07-01 00:42:09.000000000 +0200
+++ busybox-1.2.0-new/miscutils/Config.in 2006-08-01 10:21:15.000000000 +0200
@@ -231,6 +231,12 @@
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 -ruN busybox-1.2.0-old/miscutils/lock.c busybox-1.2.0-new/miscutils/lock.c
--- busybox-1.2.0-old/miscutils/lock.c 1970-01-01 01:00:00.000000000 +0100
+++ busybox-1.2.0-new/miscutils/lock.c 2006-08-01 10:21:15.000000000 +0200
@@ -0,0 +1,135 @@
+/*
+ * 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);
+ unlink(file);
+ 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;
+ }
+}
+
+#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();
+}
diff -ruN busybox-1.2.0-old/miscutils/Makefile.in busybox-1.2.0-new/miscutils/Makefile.in
--- busybox-1.2.0-old/miscutils/Makefile.in 2006-07-01 00:42:09.000000000 +0200
+++ busybox-1.2.0-new/miscutils/Makefile.in 2006-08-01 10:21:15.000000000 +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