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40 lines
801 B
40 lines
801 B
/* flock.c - manage advisory file locks
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*
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* Copyright 2015 The Android Open Source Project
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USE_FLOCK(NEWTOY(flock, "<1>1nsux[-sux]", TOYFLAG_USR|TOYFLAG_BIN))
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config FLOCK
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bool "flock"
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default y
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help
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usage: flock [-sxun] fd
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Manage advisory file locks.
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-s Shared lock
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-x Exclusive lock (default)
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-u Unlock
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-n Non-blocking: fail rather than wait for the lock
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*/
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#define FOR_flock
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#include "toys.h"
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#include <sys/file.h>
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void flock_main(void)
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{
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int fd = xstrtol(*toys.optargs, NULL, 10), op;
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if (toys.optflags & FLAG_u) op = LOCK_UN;
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else op = (toys.optflags & FLAG_s) ? LOCK_SH : LOCK_EX;
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if (toys.optflags & FLAG_n) op |= LOCK_NB;
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if (flock(fd, op)) {
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if ((op & LOCK_NB) && errno == EAGAIN) toys.exitval = 1;
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else perror_exit("flock");
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}
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}
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