unix4lyfe git - darkstat-debian/blob - pidfile.c

   1 /* darkstat 3
   2  * copyright (c) 2007-2014 Emil Mikulic.
   3  *
   4  * pidfile.h: pidfile manglement
   5  *
   6  * Permission to use, copy, modify, and distribute this file for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "err.h"
  20 #include "str.h"
  21 #include "pidfile.h"
  22
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <pwd.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28
  29 static int pidfd = -1;
  30 static const char *pidname = NULL;
  31
  32 void pidfile_create(const char *chroot_dir,
  33                     const char *filename,
  34                     const char *privdrop_user) {
  35    struct passwd *pw;
  36
  37    if (pidfd != -1)
  38       errx(1, "pidfile already created");
  39
  40    errno = 0;
  41    pw = getpwnam(privdrop_user);
  42
  43    if (pw == NULL) {
  44       if (errno == 0)
  45          errx(1, "getpwnam(\"%s\") failed: no such user", privdrop_user);
  46       else
  47          err(1, "getpwnam(\"%s\") failed", privdrop_user);
  48    }
  49
  50    if (chroot_dir != NULL) {
  51       if (chdir(chroot_dir) == -1) {
  52          err(1, "chdir(\"%s\") failed", chroot_dir);
  53       }
  54    }
  55    pidname = filename;
  56    pidfd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0600);
  57    if (pidfd == -1)
  58       err(1, "couldn't not create pidfile");
  59    if (chown(filename, pw->pw_uid, pw->pw_gid) == -1)
  60       err(1, "couldn't chown pidfile");
  61 }
  62
  63 void
  64 pidfile_write_close(void)
  65 {
  66    struct str *s;
  67    size_t len;
  68    char *buf;
  69
  70    if (pidfd == -1)
  71       errx(1, "cannot write pidfile: not created");
  72
  73    s = str_make();
  74    str_appendf(s, "%u\n", (unsigned int)getpid());
  75    str_extract(s, &len, &buf);
  76
  77    if (write(pidfd, buf, len) != (int)len)
  78       err(1, "couldn't write to pidfile");
  79    free(buf);
  80    if (close(pidfd) == -1)
  81       warn("problem closing pidfile");
  82 }
  83
  84 void
  85 pidfile_unlink(void)
  86 {
  87    if (pidname == NULL)
  88       return; /* pidfile wasn't created */
  89    if (unlink(pidname) == -1)
  90       warn("problem unlinking pidfile");
  91 }
  92
  93 /* vim:set ts=3 sw=3 tw=78 et: */