2 * Copyright (C) 2010 Timo Teras <timo.teras@iki.fi>
4 * This is free software, licensed under the GNU General Public License v2.
7 //usage:#define flock_trivial_usage
8 //usage: "[-sxun] FD|{FILE [-c] PROG ARGS}"
9 //usage:#define flock_full_usage "\n\n"
10 //usage: "[Un]lock file descriptor, or lock FILE, run PROG\n"
11 //usage: "\n -s Shared lock"
12 //usage: "\n -x Exclusive lock (default)"
13 //usage: "\n -u Unlock FD"
14 //usage: "\n -n Fail rather than wait"
19 int flock_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
20 int flock_main(int argc UNUSED_PARAM
, char **argv
)
32 static const char getopt_longopts
[] ALIGN1
=
33 "shared\0" No_argument
"s"
34 "exclusive\0" No_argument
"x"
35 "unlock\0" No_argument
"u"
36 "nonblock\0" No_argument
"n"
38 applet_long_options
= getopt_longopts
;
40 opt_complementary
= "-1";
42 opt
= getopt32(argv
, "+sxnu");
46 fd
= open(argv
[0], O_RDONLY
|O_NOCTTY
|O_CREAT
, 0666);
47 if (fd
< 0 && errno
== EISDIR
)
48 fd
= open(argv
[0], O_RDONLY
|O_NOCTTY
);
50 bb_perror_msg_and_die("can't open '%s'", argv
[0]);
51 //TODO? close_on_exec_on(fd);
53 fd
= xatoi_positive(argv
[0]);
57 /* If it is "flock FILE -c PROG", then -c isn't caught by getopt32:
58 * we use "+" in order to support "flock -opt FILE PROG -with-opts",
59 * we need to remove -c by hand.
60 * TODO: in upstream, -c 'PROG ARGS' means "run sh -c 'PROG ARGS'"
64 && ( (argv
[0][1] == 'c' && !argv
[0][2])
65 || (ENABLE_LONG_OPTS
&& strcmp(argv
[0] + 1, "-command") == 0)
71 if (OPT_s
== LOCK_SH
&& OPT_x
== LOCK_EX
&& OPT_n
== LOCK_NB
&& OPT_u
== LOCK_UN
) {
72 /* With suitably matched constants, mode setting is much simpler */
73 mode
= opt
& (LOCK_SH
+ LOCK_EX
+ LOCK_NB
+ LOCK_UN
);
74 if (!(mode
& ~LOCK_NB
))
87 if (flock(fd
, mode
) != 0) {
88 if (errno
== EWOULDBLOCK
)
90 bb_perror_nomsg_and_die();
94 return spawn_and_wait(argv
);