daemon.c 3.4 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /* daemon implementation for uClibc
  3. *
  4. * Copyright (c) 1990, 1993
  5. * The Regents of the University of California. All rights reserved.
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions
  9. * are met:
  10. * 1. Redistributions of source code must retain the above copyright
  11. * notice, this list of conditions and the following disclaimer.
  12. * 2. Redistributions in binary form must reproduce the above copyright
  13. * notice, this list of conditions and the following disclaimer in the
  14. * documentation and/or other materials provided with the distribution.
  15. *
  16. * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
  17. * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
  18. *
  19. * 4. Neither the name of the University nor the names of its contributors
  20. * may be used to endorse or promote products derived from this software
  21. * without specific prior written permission.
  22. *
  23. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33. * SUCH DAMAGE.
  34. */
  35. /*
  36. * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
  37. *
  38. * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  39. * Modified for uClibc by Erik Andersen <andersen@uclibc.org>
  40. */
  41. #include <stdio.h>
  42. #include <features.h>
  43. #include <fcntl.h>
  44. #include <paths.h>
  45. #include <signal.h>
  46. #include <unistd.h>
  47. #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
  48. #ifndef __ARCH_USE_MMU__
  49. #include <sys/syscall.h>
  50. #include <sched.h>
  51. /* use clone() to get fork() like behavior here -- we just want to disassociate
  52. * from the controlling terminal
  53. */
  54. static inline attribute_optimize("O3")
  55. pid_t _fork_parent(void)
  56. {
  57. INTERNAL_SYSCALL_DECL(err);
  58. register long ret = INTERNAL_SYSCALL(clone, err, 2, CLONE_VM, 0);
  59. if (ret > 0)
  60. /* parent needs to die now w/out touching stack */
  61. INTERNAL_SYSCALL(exit, err, 1, 0);
  62. return ret;
  63. }
  64. static inline pid_t fork_parent(void)
  65. {
  66. /* Block all signals to keep the parent from using the stack */
  67. pid_t ret;
  68. sigset_t new_set, old_set;
  69. sigfillset(&new_set);
  70. sigprocmask(SIG_BLOCK, &new_set, &old_set);
  71. ret = _fork_parent();
  72. sigprocmask(SIG_SETMASK, &old_set, NULL);
  73. return ret;
  74. }
  75. #else
  76. static inline pid_t fork_parent(void)
  77. {
  78. switch (fork()) {
  79. case -1: return -1;
  80. case 0: return 0;
  81. default: _exit(0);
  82. }
  83. }
  84. #endif
  85. int daemon(int nochdir, int noclose)
  86. {
  87. int fd;
  88. if (fork_parent() == -1)
  89. return -1;
  90. if (setsid() == -1)
  91. return -1;
  92. if (!nochdir)
  93. chdir("/");
  94. if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
  95. dup2(fd, STDIN_FILENO);
  96. dup2(fd, STDOUT_FILENO);
  97. dup2(fd, STDERR_FILENO);
  98. if (fd > 2)
  99. close(fd);
  100. }
  101. return 0;
  102. }
  103. #endif