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

   1 /* darkstat 3
   2  * copyright (c) 2007-2011 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
  33 pidfile_create(const char *chroot_dir, const char *filename,
  34    const char *privdrop_user)
  35 {
  36    struct passwd *pw;
  37
  38    if (pidfd != -1)
  39       errx(1, "pidfile already created");
  40
  41    errno = 0;
  42    pw = getpwnam(privdrop_user);
  43
  44    if (pw == NULL) {
  45       if (errno == 0)
  46          errx(1, "getpwnam(\"%s\") failed: no such user", privdrop_user);
  47       else
  48          err(1, "getpwnam(\"%s\") failed", privdrop_user);
  49    }
  50
  51    if (chdir(chroot_dir) == -1)
  52       err(1, "chdir(\"%s\") failed", chroot_dir);
  53    pidname = filename;
  54    pidfd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0600);
  55    if (pidfd == -1)
  56       err(1, "couldn't not create pidfile");
  57    if (chown(filename, pw->pw_uid, pw->pw_gid) == -1)
  58       err(1, "couldn't chown pidfile");
  59 }
  60
  61 void
  62 pidfile_write_close(void)
  63 {
  64    struct str *s;
  65    size_t len;
  66    char *buf;
  67
  68    if (pidfd == -1)
  69       errx(1, "cannot write pidfile: not created");
  70
  71    s = str_make();
  72    str_appendf(s, "%u\n", (unsigned int)getpid());
  73    str_extract(s, &len, &buf);
  74
  75    if (write(pidfd, buf, len) != (int)len)
  76       err(1, "couldn't write to pidfile");
  77    free(buf);
  78    if (close(pidfd) == -1)
  79       warn("problem closing pidfile");
  80 }
  81
  82 void
  83 pidfile_unlink(void)
  84 {
  85    if (pidname == NULL)
  86       return; /* pidfile wasn't created */
  87    if (unlink(pidname) == -1)
  88       warn("problem unlinking pidfile");
  89 }
  90
  91 /* vim:set ts=3 sw=3 tw=78 et: */