1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
|
/*
* Copyright 2009 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#define _GNU_SOURCE
#ifndef HAVE_CONFIG_H
#error Invalid or missing autoconf build environment
#endif
#include "rng-tools-config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include "rngd.h"
int write_pid_file(const char *pid_fn)
{
char str[32], *s;
size_t bytes;
int fd;
struct flock lock;
int err;
/* build file data */
sprintf(str, "%u\n", (unsigned int) getpid());
/* open non-exclusively (works on NFS v2) */
fd = open(pid_fn, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
if (fd < 0) {
err = errno;
message(LOG_DAEMON|LOG_ERR, "Cannot open PID file %s: %s",
pid_fn, strerror(err));
return -err;
}
/* lock */
memset(&lock, 0, sizeof(lock));
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
if (fcntl(fd, F_SETLK, &lock) != 0) {
err = errno;
if (err == EAGAIN) {
message(LOG_DAEMON|LOG_ERR, "PID file %s is already locked",
pid_fn);
} else {
message(LOG_DAEMON|LOG_ERR, "Cannot lock PID file %s: %s",
pid_fn, strerror(err));
}
close(fd);
return -err;
}
/* write file data */
bytes = strlen(str);
s = str;
while (bytes > 0) {
ssize_t rc = write(fd, s, bytes);
if (rc < 0) {
err = errno;
message(LOG_DAEMON|LOG_ERR, "PID number write failed: %s",
strerror(err));
goto err_out;
}
bytes -= rc;
s += rc;
}
/* make sure file data is written to disk */
if (fsync(fd) < 0) {
err = errno;
message(LOG_DAEMON|LOG_ERR, "PID file fsync failed: %s", strerror(err));
goto err_out;
}
return fd;
err_out:
unlink(pid_fn);
close(fd);
return -err;
}
|