From: Timo Teras To: busybox@busybox.net Subject: [PATCH] flock: new applet Date: Tue, 16 Mar 2010 14:14:22 +0200 Message-Id: <1268741663-8790-1-git-send-email-timo.teras@iki.fi> X-Mailer: git-send-email 1.6.3.3 An utility to manage file locks from scripts. Signed-off-by: Timo Teras --- include/applets.h | 1 + include/usage.h | 11 ++++++ util-linux/Config.in | 6 +++ util-linux/Kbuild | 1 + util-linux/flock.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 112 insertions(+), 0 deletions(-) create mode 100644 util-linux/flock.c diff --git a/include/applets.h b/include/applets.h index 2d784bd..83c1792 100644 --- a/include/applets.h +++ b/include/applets.h @@ -161,6 +161,7 @@ IF_FLASH_ERASEALL(APPLET(flash_eraseall, _BB_DIR_USR_SBIN, _BB_SUID_DROP)) IF_FLASH_LOCK(APPLET_ODDNAME(flash_lock, flash_lock_unlock, _BB_DIR_USR_SBIN, _BB_SUID_DROP, flash_lock)) IF_FLASH_UNLOCK(APPLET_ODDNAME(flash_unlock, flash_lock_unlock, _BB_DIR_USR_SBIN, _BB_SUID_DROP, flash_unlock)) IF_FLASHCP(APPLET(flashcp, _BB_DIR_USR_SBIN, _BB_SUID_DROP)) +IF_FLOCK(APPLET(flock, _BB_DIR_USR_BIN, _BB_SUID_DROP)) IF_FOLD(APPLET(fold, _BB_DIR_USR_BIN, _BB_SUID_DROP)) IF_FREE(APPLET(free, _BB_DIR_USR_BIN, _BB_SUID_DROP)) IF_FREERAMDISK(APPLET(freeramdisk, _BB_DIR_SBIN, _BB_SUID_DROP)) diff --git a/include/usage.h b/include/usage.h index f4259a1..cbf6bef 100644 --- a/include/usage.h +++ b/include/usage.h @@ -1312,6 +1312,17 @@ "\nOptions:" \ "\n -v Verbose" \ +#define flock_trivial_usage \ + "[-sxun] [fd# | FILE] [-c] command" +#define flock_full_usage "\n\n" \ + "Manage file locks from scripts\n" \ + "\nOptions:" \ + "\n -s Get a shared lock" \ + "\n -x Get an exclusive lock" \ + "\n -u Remove a lock (from fd#)" \ + "\n -n Fail rather than wait" \ + "\n -c Command to run" \ + #define fold_trivial_usage \ "[-bs] [-w WIDTH] [FILE]..." #define fold_full_usage "\n\n" \ diff --git a/util-linux/Config.in b/util-linux/Config.in index f04511b..d0d8df3 100644 --- a/util-linux/Config.in +++ b/util-linux/Config.in @@ -191,6 +191,12 @@ config FINDFS WARNING: With all submodules selected, it will add ~8k to busybox. +config FLOCK + bool "flock" + default y + help + Manage locks from shell scripts + config FREERAMDISK bool "freeramdisk" default n diff --git a/util-linux/Kbuild b/util-linux/Kbuild index 72a2ef1..99e3efe 100644 --- a/util-linux/Kbuild +++ b/util-linux/Kbuild @@ -13,6 +13,7 @@ lib-$(CONFIG_FDFLUSH) += freeramdisk.o lib-$(CONFIG_FDFORMAT) += fdformat.o lib-$(CONFIG_FDISK) += fdisk.o lib-$(CONFIG_FINDFS) += findfs.o +lib-$(CONFIG_FLOCK) += flock.o lib-$(CONFIG_FREERAMDISK) += freeramdisk.o lib-$(CONFIG_FSCK_MINIX) += fsck_minix.o lib-$(CONFIG_GETOPT) += getopt.o diff --git a/util-linux/flock.c b/util-linux/flock.c new file mode 100644 index 0000000..e9a22d5 --- /dev/null +++ b/util-linux/flock.c @@ -0,0 +1,93 @@ +/* + * Copyright (C) 2010 Timo Teras + * + * This is free software, licensed under the GNU General Public License v2. + */ +#include +#include +#include +#include +#include +#include +#include +#include "busybox.h" + +int flock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int flock_main(int argc, char **argv) +{ + char *command = NULL; + int mode, opt, fd, status = 0; + enum { + OPT_s = (1 << 0), + OPT_x = (1 << 1), + OPT_u = (1 << 2), + OPT_n = (1 << 3), + OPT_c = (1 << 4), + }; + +#if ENABLE_LONG_OPTS + static const char getopt_longopts[] ALIGN1 = + "shared\0" No_argument "s" + "exclusive\0" No_argument "x" + "unblock\0" No_argument "u" + "nonblock\0" No_argument "n" + "command\0" Required_argument "c" + ; + applet_long_options = getopt_longopts; +#endif + + opt = getopt32(argv, "sxunc:", &command); + argv += optind; + argc -= optind; + + if (argv[0] == NULL) + bb_show_usage(); + + if (command != NULL || argc > 1) { + fd = open(argv[0], O_RDONLY|O_NOCTTY|O_CREAT, 0666); + if (fd < 0 && errno == EISDIR) + fd = open(argv[0], O_RDONLY|O_NOCTTY); + } else { + fd = atoi(argv[0]); + } + if (fd < 0) + bb_perror_msg_and_die("cannot open: '%s'", argv[0]); + + argv++; + if (command == NULL) + command = argv[0]; + + if (opt & OPT_u) + mode = LOCK_UN; + else if (opt & OPT_s) + mode = LOCK_SH; + else + mode = LOCK_EX; + + if (opt & OPT_n) + mode |= LOCK_NB; + + if (flock(fd, mode) && errno == EWOULDBLOCK) + return 1; + + if (command != NULL) { + pid_t pid; + + pid = fork(); + if (pid < 0) + bb_perror_msg_and_die("fork failed"); + if (pid == 0) { + execvp(command, argv); + exit(1); + } + waitpid(pid, &status, 0); + if (WIFEXITED(status)) + status = WEXITSTATUS(status); + else if (WIFSIGNALED(status)) + status = WTERMSIG(status) + 128; + else + status = 1; + } + + return status; +} -- 1.6.3.3