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			174 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			174 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| --- a/include/applets.src.h
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| +++ b/include/applets.src.h
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| @@ -211,6 +211,7 @@ IF_LN(APPLET_NOEXEC(ln, ln, BB_DIR_BIN, 
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|  IF_LOAD_POLICY(APPLET(load_policy, BB_DIR_USR_SBIN, BB_SUID_DROP))
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|  IF_LOADFONT(APPLET(loadfont, BB_DIR_USR_SBIN, BB_SUID_DROP))
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|  IF_LOADKMAP(APPLET(loadkmap, BB_DIR_SBIN, BB_SUID_DROP))
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| +IF_LOCK(APPLET(lock, BB_DIR_BIN, BB_SUID_DROP))
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|  IF_LOGGER(APPLET(logger, BB_DIR_USR_BIN, BB_SUID_DROP))
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|  /* Needs to be run by root or be suid root - needs to change uid and gid: */
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|  IF_LOGIN(APPLET(login, BB_DIR_BIN, BB_SUID_REQUIRE))
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| --- a/miscutils/Config.src
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| +++ b/miscutils/Config.src
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| @@ -385,6 +385,12 @@ config FEATURE_HDPARM_HDIO_GETSET_DMA
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|  	help
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|  	  Enables the 'hdparm -d' option to get/set using_dma flag.
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|  
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| +config LOCK
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| +	bool "lock"
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| +	default n
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| +	help
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| +	  Small utility for using locks in scripts
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| +
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|  config MAKEDEVS
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|  	bool "makedevs"
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|  	default y
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| --- a/miscutils/Kbuild.src
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| +++ b/miscutils/Kbuild.src
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| @@ -28,6 +28,7 @@ lib-$(CONFIG_INOTIFYD)    += inotifyd.o
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|  lib-$(CONFIG_FEATURE_LAST_SMALL)+= last.o
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|  lib-$(CONFIG_FEATURE_LAST_FANCY)+= last_fancy.o
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|  lib-$(CONFIG_LESS)        += less.o
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| +lib-$(CONFIG_LOCK)        += lock.o
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|  lib-$(CONFIG_MAKEDEVS)    += makedevs.o
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|  lib-$(CONFIG_MAN)         += man.o
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|  lib-$(CONFIG_MICROCOM)    += microcom.o
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| --- /dev/null
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| +++ b/miscutils/lock.c
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| @@ -0,0 +1,135 @@
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| +/*
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| + * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
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| + *
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| + * This is free software, licensed under the GNU General Public License v2.
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| + */
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| +#include <sys/types.h>
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| +#include <sys/file.h>
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| +#include <sys/stat.h>
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| +#include <signal.h>
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| +#include <fcntl.h>
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| +#include <unistd.h>
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| +#include <stdio.h>
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| +#include "busybox.h"
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| +
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| +//usage:#define lock_trivial_usage NOUSAGE_STR
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| +//usage:#define lock_full_usage ""
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| +
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| +static int unlock = 0;
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| +static int shared = 0;
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| +static int waitonly = 0;
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| +static int fd;
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| +static char *file;
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| +
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| +static void usage(char *name)
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| +{
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| +	fprintf(stderr, "Usage: %s [-suw] <filename>\n"
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| +	                "	-s	Use shared locking\n"
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| +	                "	-u	Unlock\n"
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| +	                "	-w	Wait for the lock to become free, don't acquire lock\n"
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| +					"\n", name);
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| +	exit(1);
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| +}
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| +
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| +static void exit_unlock(int sig)
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| +{
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| +	flock(fd, LOCK_UN);
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| +	exit(0);
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| +}
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| +
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| +static int do_unlock(void)
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| +{
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| +	FILE *f;
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| +	int i;
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| +
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| +	if ((f = fopen(file, "r")) == NULL)
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| +		return 0;
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| +
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| +	fscanf(f, "%d", &i);
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| +	if (i > 0)
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| +		kill(i, SIGTERM);
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| +
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| +	fclose(f);
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| +
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| +	return 0;
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| +}
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| +
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| +static int do_lock(void)
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| +{
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| +	int pid;
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| +	char pidstr[8];
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| +
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| +	if ((fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0700)) < 0) {
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| +		if ((fd = open(file, O_RDWR)) < 0) {
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| +			fprintf(stderr, "Can't open %s\n", file);
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| +			return 1;
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| +		}
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| +	}
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| +
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| +	if (flock(fd, (shared ? LOCK_SH : LOCK_EX)) < 0) {
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| +		fprintf(stderr, "Can't lock %s\n", file);
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| +		return 1;
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| +	}
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| +
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| +	pid = fork();
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| +
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| +	if (pid < 0)
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| +		return -1;
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| +
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| +	if (pid == 0) {
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| +		signal(SIGKILL, exit_unlock);
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| +		signal(SIGTERM, exit_unlock);
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| +		signal(SIGINT, exit_unlock);
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| +		if (waitonly)
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| +			exit_unlock(0);
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| +		else
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| +			while (1)
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| +				sleep(1);
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| +	} else {
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| +		if (!waitonly) {
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| +			lseek(fd, 0, SEEK_SET);
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| +			ftruncate(fd, 0);
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| +			sprintf(pidstr, "%d\n", pid);
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| +			write(fd, pidstr, strlen(pidstr));
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| +			close(fd);
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| +		}
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| +
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| +		return 0;
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| +	}
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| +	return 0;
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| +}
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| +
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| +int lock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| +int lock_main(int argc, char **argv)
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| +{
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| +	char **args = &argv[1];
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| +	int c = argc - 1;
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| +
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| +	while ((*args != NULL) && (*args)[0] == '-') {
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| +		char *ch = *args;
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| +		while (*(++ch) > 0) {
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| +			switch(*ch) {
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| +				case 'w':
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| +					waitonly = 1;
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| +					break;
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| +				case 's':
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| +					shared = 1;
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| +					break;
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| +				case 'u':
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| +					unlock = 1;
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| +					break;
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| +			}
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| +		}
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| +		c--;
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| +		args++;
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| +	}
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| +
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| +	if (c != 1)
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| +		usage(argv[0]);
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| +
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| +	file = *args;
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| +	if (unlock)
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| +		return do_unlock();
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| +	else
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| +		return do_lock();
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| +}
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