// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Process id output.

 * Copyright (C) 1998, 1999 Kunihiro Ishiguro

 */

#include <zebra.h>

#include <fcntl.h>

#include <log.h>

#include "lib/version.h"

#include "network.h"

#include "lib_errors.h"

#define PIDFILE_MASK 0644

pid_t pid_output(const char *path)

{

  int tmp;

  int fd;

  pid_t pid;

  char buf[16];

  struct flock lock;

  mode_t oldumask;

  pid = getpid();

  oldumask = umask(0777 & ~PIDFILE_MASK);

  fd = open(path, O_RDWR | O_CREAT, PIDFILE_MASK);

  if (fd < 0) {

    flog_err_sys(EC_LIB_SYSTEM_CALL,

           "Can't create pid lock file %s (%s), exiting",

           path, safe_strerror(errno));

    umask(oldumask);

    exit(1);

  } else {

    size_t pidsize;

    umask(oldumask);

    memset(&lock, 0, sizeof(lock));

    set_cloexec(fd);

    lock.l_type = F_WRLCK;

    lock.l_whence = SEEK_SET;

    if (fcntl(fd, F_SETLK, &lock) < 0) {

      flog_err_sys(EC_LIB_SYSTEM_CALL,

             "Could not lock pid_file %s (%s), exiting.  Please ensure that the daemon is not already running",

             path, safe_strerror(errno));

      exit(1);

    }

    snprintf(buf, sizeof(buf), "%d\n", (int)pid);

    pidsize = strlen(buf);

    if ((tmp = write(fd, buf, pidsize)) != (int)pidsize)

      flog_err_sys(

        EC_LIB_SYSTEM_CALL,

        "Could not write pid %d to pid_file %s, rc was %d: %s",

        (int)pid, path, tmp, safe_strerror(errno));

    else if (ftruncate(fd, pidsize) < 0)

      flog_err_sys(

        EC_LIB_SYSTEM_CALL,

        "Could not truncate pid_file %s to %u bytes: %s",

        path, (unsigned int)pidsize,

        safe_strerror(errno));

  }

  return pid;

}