Root/package/busybox/patches/340-lock_util.patch

1--- a/include/applets.h
2+++ b/include/applets.h
3@@ -233,6 +233,7 @@ IF_LN(APPLET_NOEXEC(ln, ln, _BB_DIR_BIN,
4 IF_LOAD_POLICY(APPLET(load_policy, _BB_DIR_USR_SBIN, _BB_SUID_DROP))
5 IF_LOADFONT(APPLET(loadfont, _BB_DIR_USR_SBIN, _BB_SUID_DROP))
6 IF_LOADKMAP(APPLET(loadkmap, _BB_DIR_SBIN, _BB_SUID_DROP))
7+IF_LOCK(APPLET(lock, _BB_DIR_BIN, _BB_SUID_DROP))
8 IF_LOGGER(APPLET(logger, _BB_DIR_USR_BIN, _BB_SUID_DROP))
9 IF_LOGIN(APPLET(login, _BB_DIR_BIN, _BB_SUID_REQUIRE))
10 IF_LOGNAME(APPLET_NOFORK(logname, logname, _BB_DIR_USR_BIN, _BB_SUID_DROP, logname))
11--- a/include/usage.h
12+++ b/include/usage.h
13@@ -2325,6 +2325,9 @@
14 #define loadkmap_example_usage \
15        "$ loadkmap < /etc/i18n/lang-keymap\n"
16 
17+#define lock_trivial_usage NOUSAGE_STR
18+#define lock_full_usage ""
19+
20 #define logger_trivial_usage \
21        "[OPTIONS] [MESSAGE]"
22 #define logger_full_usage "\n\n" \
23--- a/miscutils/Config.in
24+++ b/miscutils/Config.in
25@@ -456,6 +456,11 @@ config FEATURE_HDPARM_HDIO_GETSET_DMA
26     help
27       Enables the 'hdparm -d' option to get/set using_dma flag.
28 
29+config LOCK
30+ bool "lock"
31+ help
32+ Small utility for using locks in scripts
33+
34 config MAKEDEVS
35     bool "makedevs"
36     default n
37--- a/miscutils/Kbuild
38+++ b/miscutils/Kbuild
39@@ -26,6 +26,7 @@ lib-$(CONFIG_INOTIFYD) += inotifyd.o
40 lib-$(CONFIG_FEATURE_LAST_SMALL)+= last.o
41 lib-$(CONFIG_FEATURE_LAST_FANCY)+= last_fancy.o
42 lib-$(CONFIG_LESS) += less.o
43+lib-$(CONFIG_LOCK) += lock.o
44 lib-$(CONFIG_MAKEDEVS) += makedevs.o
45 lib-$(CONFIG_MAN) += man.o
46 lib-$(CONFIG_MICROCOM) += microcom.o
47--- /dev/null
48+++ b/miscutils/lock.c
49@@ -0,0 +1,132 @@
50+/*
51+ * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
52+ *
53+ * This is free software, licensed under the GNU General Public License v2.
54+ */
55+#include <sys/types.h>
56+#include <sys/file.h>
57+#include <sys/stat.h>
58+#include <signal.h>
59+#include <fcntl.h>
60+#include <unistd.h>
61+#include <stdio.h>
62+#include "busybox.h"
63+
64+static int unlock = 0;
65+static int shared = 0;
66+static int waitonly = 0;
67+static int fd;
68+static char *file;
69+
70+static void usage(char *name)
71+{
72+ fprintf(stderr, "Usage: %s [-suw] <filename>\n"
73+ " -s Use shared locking\n"
74+ " -u Unlock\n"
75+ " -w Wait for the lock to become free, don't acquire lock\n"
76+ "\n", name);
77+ exit(1);
78+}
79+
80+static void exit_unlock(int sig)
81+{
82+ flock(fd, LOCK_UN);
83+ exit(0);
84+}
85+
86+static int do_unlock(void)
87+{
88+ FILE *f;
89+ int i;
90+
91+ if ((f = fopen(file, "r")) == NULL)
92+ return 0;
93+
94+ fscanf(f, "%d", &i);
95+ if (i > 0)
96+ kill(i, SIGTERM);
97+
98+ fclose(f);
99+
100+ return 0;
101+}
102+
103+static int do_lock(void)
104+{
105+ int pid;
106+ char pidstr[8];
107+
108+ if ((fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0700)) < 0) {
109+ if ((fd = open(file, O_RDWR)) < 0) {
110+ fprintf(stderr, "Can't open %s\n", file);
111+ return 1;
112+ }
113+ }
114+
115+ if (flock(fd, (shared ? LOCK_SH : LOCK_EX)) < 0) {
116+ fprintf(stderr, "Can't lock %s\n", file);
117+ return 1;
118+ }
119+
120+ pid = fork();
121+
122+ if (pid < 0)
123+ return -1;
124+
125+ if (pid == 0) {
126+ signal(SIGKILL, exit_unlock);
127+ signal(SIGTERM, exit_unlock);
128+ signal(SIGINT, exit_unlock);
129+ if (waitonly)
130+ exit_unlock(0);
131+ else
132+ while (1)
133+ sleep(1);
134+ } else {
135+ if (!waitonly) {
136+ lseek(fd, 0, SEEK_SET);
137+ ftruncate(fd, 0);
138+ sprintf(pidstr, "%d\n", pid);
139+ write(fd, pidstr, strlen(pidstr));
140+ close(fd);
141+ }
142+
143+ return 0;
144+ }
145+ return 0;
146+}
147+
148+int lock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
149+int lock_main(int argc, char **argv)
150+{
151+ char **args = &argv[1];
152+ int c = argc - 1;
153+
154+ while ((*args != NULL) && (*args)[0] == '-') {
155+ char *ch = *args;
156+ while (*(++ch) > 0) {
157+ switch(*ch) {
158+ case 'w':
159+ waitonly = 1;
160+ break;
161+ case 's':
162+ shared = 1;
163+ break;
164+ case 'u':
165+ unlock = 1;
166+ break;
167+ }
168+ }
169+ c--;
170+ args++;
171+ }
172+
173+ if (c != 1)
174+ usage(argv[0]);
175+
176+ file = *args;
177+ if (unlock)
178+ return do_unlock();
179+ else
180+ return do_lock();
181+}
182

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