daemon.c 3.9 KB

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  1. /* daemon implementation for uClibc
  2. *
  3. * Copyright (c) 1990, 1993
  4. * The Regents of the University of California. 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. * 1. Redistributions of source code must retain the above copyright
  10. * notice, this list of conditions and the following disclaimer.
  11. * 2. Redistributions in binary form must reproduce the above copyright
  12. * notice, this list of conditions and the following disclaimer in the
  13. * documentation and/or other materials provided with the distribution.
  14. *
  15. * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
  16. * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
  17. *
  18. * 4. Neither the name of the University nor the names of its contributors
  19. * may be used to endorse or promote products derived from this software
  20. * without specific prior written permission.
  21. *
  22. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32. * SUCH DAMAGE.
  33. */
  34. /*
  35. * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
  36. *
  37. * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  38. * Modified for uClibc by Erik Andersen <andersen@uclibc.org>
  39. */
  40. #include <stdio.h>
  41. #include <features.h>
  42. #include <fcntl.h>
  43. #include <paths.h>
  44. #include <signal.h>
  45. #include <unistd.h>
  46. #include <not-cancel.h>
  47. #include <errno.h>
  48. #ifdef __UCLIBC_HAS_THREADS_NATIVE__
  49. #include <sys/stat.h>
  50. #endif
  51. #define STAT stat64
  52. #define FSTAT fstat64
  53. #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
  54. #ifndef __ARCH_USE_MMU__
  55. #include <sys/syscall.h>
  56. #include <sched.h>
  57. /* use clone() to get fork() like behavior here -- we just want to disassociate
  58. * from the controlling terminal
  59. */
  60. pid_t _fork_parent(void)
  61. {
  62. INTERNAL_SYSCALL_DECL(err);
  63. register long ret = INTERNAL_SYSCALL(clone, err, 2, CLONE_VM, 0);
  64. if (ret > 0)
  65. /* parent needs to die now w/out touching stack */
  66. INTERNAL_SYSCALL(exit, err, 1, 0);
  67. return ret;
  68. }
  69. static inline pid_t fork_parent(void)
  70. {
  71. /* Block all signals to keep the parent from using the stack */
  72. pid_t ret;
  73. sigset_t new_set, old_set;
  74. sigfillset(&new_set);
  75. sigprocmask(SIG_BLOCK, &new_set, &old_set);
  76. ret = _fork_parent();
  77. sigprocmask(SIG_SETMASK, &old_set, NULL);
  78. return ret;
  79. }
  80. #else
  81. static inline pid_t fork_parent(void)
  82. {
  83. switch (fork()) {
  84. case -1: return -1;
  85. case 0: return 0;
  86. default: _exit(0);
  87. }
  88. }
  89. #endif
  90. int daemon(int nochdir, int noclose)
  91. {
  92. int fd;
  93. if (fork_parent() == -1)
  94. return -1;
  95. if (setsid() == -1)
  96. return -1;
  97. if (!nochdir)
  98. chdir("/");
  99. if (!noclose)
  100. {
  101. struct STAT st;
  102. if ((fd = open_not_cancel_2(_PATH_DEVNULL, O_RDWR)) != -1
  103. && (__builtin_expect (FSTAT (fd, &st), 0) == 0))
  104. {
  105. if (__builtin_expect (S_ISCHR (st.st_mode), 1) != 0) {
  106. dup2(fd, STDIN_FILENO);
  107. dup2(fd, STDOUT_FILENO);
  108. dup2(fd, STDERR_FILENO);
  109. if (fd > 2)
  110. close(fd);
  111. } else {
  112. /* We must set an errno value since no
  113. function call actually failed. */
  114. close_not_cancel_no_status (fd);
  115. __set_errno (ENODEV);
  116. return -1;
  117. }
  118. } else {
  119. close_not_cancel_no_status (fd);
  120. return -1;
  121. }
  122. }
  123. return 0;
  124. }
  125. #endif