| /* |
| * Copyright (C) 2010 Timo Teras <timo.teras@iki.fi> |
| * |
| * This is free software, licensed under the GNU General Public License v2. |
| */ |
| //config:config FLOCK |
| //config: bool "flock" |
| //config: default y |
| //config: help |
| //config: Manage locks from shell scripts |
| |
| //applet:IF_FLOCK(APPLET(flock, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_FLOCK) += flock.o |
| |
| //usage:#define flock_trivial_usage |
| //usage: "[-sxun] FD|{FILE [-c] PROG ARGS}" |
| //usage:#define flock_full_usage "\n\n" |
| //usage: "[Un]lock file descriptor, or lock FILE, run PROG\n" |
| //usage: "\n -s Shared lock" |
| //usage: "\n -x Exclusive lock (default)" |
| //usage: "\n -u Unlock FD" |
| //usage: "\n -n Fail rather than wait" |
| |
| #include <sys/file.h> |
| #include "libbb.h" |
| |
| int flock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int flock_main(int argc UNUSED_PARAM, char **argv) |
| { |
| int mode, opt, fd; |
| enum { |
| OPT_s = (1 << 0), |
| OPT_x = (1 << 1), |
| OPT_n = (1 << 2), |
| OPT_u = (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" |
| "unlock\0" No_argument "u" |
| "nonblock\0" No_argument "n" |
| ; |
| applet_long_options = getopt_longopts; |
| #endif |
| opt_complementary = "-1"; |
| |
| opt = getopt32(argv, "+sxnu"); |
| argv += optind; |
| |
| if (argv[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); |
| if (fd < 0) |
| bb_perror_msg_and_die("can't open '%s'", argv[0]); |
| //TODO? close_on_exec_on(fd); |
| } else { |
| fd = xatoi_positive(argv[0]); |
| } |
| argv++; |
| |
| /* If it is "flock FILE -c PROG", then -c isn't caught by getopt32: |
| * we use "+" in order to support "flock -opt FILE PROG -with-opts", |
| * we need to remove -c by hand. |
| */ |
| if (argv[0] |
| && argv[0][0] == '-' |
| && ( (argv[0][1] == 'c' && !argv[0][2]) |
| || (ENABLE_LONG_OPTS && strcmp(argv[0] + 1, "-command") == 0) |
| ) |
| ) { |
| argv++; |
| if (argv[1]) |
| bb_error_msg_and_die("-c takes only one argument"); |
| opt |= OPT_c; |
| } |
| |
| if (OPT_s == LOCK_SH && OPT_x == LOCK_EX && OPT_n == LOCK_NB && OPT_u == LOCK_UN) { |
| /* With suitably matched constants, mode setting is much simpler */ |
| mode = opt & (LOCK_SH + LOCK_EX + LOCK_NB + LOCK_UN); |
| if (!(mode & ~LOCK_NB)) |
| mode |= LOCK_EX; |
| } else { |
| 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) != 0) { |
| if (errno == EWOULDBLOCK) |
| return EXIT_FAILURE; |
| bb_perror_nomsg_and_die(); |
| } |
| |
| if (argv[0]) { |
| int rc; |
| if (opt & OPT_c) { |
| /* -c 'PROG ARGS' means "run sh -c 'PROG ARGS'" */ |
| argv -= 2; |
| argv[0] = (char*)get_shell_name(); |
| argv[1] = (char*)"-c"; |
| /* argv[2] = "PROG ARGS"; */ |
| /* argv[3] = NULL; */ |
| } |
| rc = spawn_and_wait(argv); |
| if (rc < 0) |
| bb_simple_perror_msg(argv[0]); |
| return rc; |
| } |
| |
| return EXIT_SUCCESS; |
| } |