lib/roken/write_pid.c

   1 /*
   2  * Copyright (c) 1999 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #include "roken.h"
  37
  38 ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
  39 pid_file_write(const char *progname)
  40 {
  41     const char *pidfile_dir = NULL;
  42     char *ret = NULL;
  43     FILE *fp;
  44
  45     /*
  46      * Maybe we could have a version of this function (and pidfile())
  47      * where we get a directory from the caller.  That would allow us to
  48      * have command-line options for the daemons for this.
  49      *
  50      * For now we use an environment variable.
  51      */
  52     if (!issuid())
  53         pidfile_dir = getenv("HEIM_PIDFILE_DIR");
  54     if (pidfile_dir == NULL)
  55         pidfile_dir = _PATH_VARRUN;
  56
  57     if (asprintf(&ret, "%s%s.pid", pidfile_dir, progname) < 0 || ret == NULL)
  58         return NULL;
  59     fp = fopen(ret, "w");
  60     if (fp == NULL) {
  61         free(ret);
  62         return NULL;
  63     }
  64     fprintf(fp, "%lu\n", (unsigned long)getpid());
  65     fclose(fp);
  66     return ret;
  67 }
  68
  69 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
  70 pid_file_delete(char **filename)
  71 {
  72     if (*filename != NULL) {
  73         unlink(*filename);
  74         free(*filename);
  75         *filename = NULL;
  76     }
  77 }
  78
  79 static char *pidfile_path;
  80 static pid_t pidfile_pid;
  81
  82 static void
  83 pidfile_cleanup(void)
  84 {
  85     if (pidfile_path != NULL && pidfile_pid == getpid())
  86         pid_file_delete(&pidfile_path);
  87 }
  88
  89 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
  90 pidfile(const char *bname)
  91 {
  92     /*
  93      * If the OS has a pidfile(), call that, but still call
  94      * pid_file_write().  Even if both want to write the same file,
  95      * writing it twice will still work.
  96      */
  97 #ifdef HAVE_PIDFILE
  98 #undef pidfile
  99     pidfile(bname);
 100 #endif
 101
 102     if (pidfile_path != NULL)
 103         return;
 104     if (bname == NULL)
 105         bname = getprogname();
 106     pidfile_path = pid_file_write(bname);
 107     pidfile_pid = getpid();
 108 #if defined(HAVE_ATEXIT)
 109     if (pidfile_path != NULL)
 110         atexit(pidfile_cleanup);
 111 #elif defined(HAVE_ON_EXIT)
 112     if (pidfile_path != NULL)
 113         on_exit(pidfile_cleanup);
 114 #endif
 115 }