mirror of
https://github.com/troglobit/libite.git
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Joachim Nilsson
c2d0ed0d12
- Simplify pidfile_read(), no need to call access() when fopen() is more than capable of failing on its own if we do not have READ access. - The remove() syscall requires that you check the return value, but we don't care about that when having signalled a TERM signal to a process. Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/* Functions for dealing with PID files (client side)
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*
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* Copyright (c) 2009-2015 Joachim Nilsson <troglobit@gmail.com>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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extern char *chomp(char *str);
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/**
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* pidfile_read - Reads a PID value from a pidfile.
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* @pidfile: File containing PID, usually in /var/run/<PROC>.pid
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*
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* This function takes a @pidfile and returns the PID found therein.
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*
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* Returns:
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* On invalid @pidfile -1 and errno set to %EINVAL, when @pidfile does not exist -1
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* and errno set to %ENOENT. When the pidfile is empty or when its contents cannot
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* be translated this function returns zero (0), on success this function returns
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* a PID value greater than one. PID 1 is reserved for the system init process.
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*/
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int pidfile_read(const char *pidfile)
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{
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int pid = 0;
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char buf[16];
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FILE *fp;
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if (!pidfile) {
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errno = EINVAL;
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return -1;
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}
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fp = fopen(pidfile, "r");
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if (!fp)
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return -1;
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if (fgets(buf, sizeof(buf), fp)) {
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char *ptr = chomp(buf);
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if (ptr) {
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errno = 0;
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pid = strtoul(ptr, NULL, 0);
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if (errno)
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pid = 0; /* Failed conversion. */
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}
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}
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fclose(fp);
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return pid;
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}
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/**
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* pidfile_signal - Send signal to a PID and cleanup pidfile afterwards
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* @pidfile: File containing PID, usually in /var/run/<PROC>.pid
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* @signal: Signal to send to PID found in @pidfile.
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*
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* If @signal is any of %SIGTERM, %SIGKILL, or if kill() returns -1 the
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* @pidfile is removed.
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*
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* Returns:
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* POSIX OK(0) on success, non-zero otherwise.
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*/
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int pidfile_signal(const char *pidfile, int signal)
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{
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int pid = -1, ret = -1;
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pid = pidfile_read(pidfile);
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if (pid <= 0)
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return 1;
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ret = kill(pid, signal);
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if ((ret == -1) || (signal == SIGTERM) || (signal == SIGKILL))
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(void)remove(pidfile);
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return 0;
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}
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/********************************* UNIT TESTS ************************************/
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#ifdef UTEST_PIDFN
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#define PIDFILE "/var/run/unittest.pid"
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static void sig_handler(int signo)
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{
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fprintf(stderr, "Exiting ...\n");
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}
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int main(void)
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{
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signal(SIGTERM, sig_handler);
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fprintf(stderr, "Testing pidfile() ...\n");
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pidfile(NULL);
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system("ls -ld " PIDFILE);
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fprintf(stderr, "Reading pid file, should be %d ...\n", getpid());
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fprintf(stderr, "=> %d\n", pidfile_read(PIDFILE));
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fprintf(stderr, "Signalling ourselves ...\n");
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return pidfile_signal(PIDFILE, SIGTERM);
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}
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#endif /* UTEST_PIDFN */
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/**
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* Local Variables:
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* compile-command: "gcc -g -o unittest -DUTEST_PIDFN pidfile.c chomp.c pidfilefn.c && ./unittest"
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* version-control: t
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* indent-tabs-mode: t
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* c-file-style: "linux"
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* End:
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*/
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