/usr.bin/tip/tip/uucplock.c

https://bitbucket.org/freebsd/freebsd-head/ · C · 131 lines · 77 code · 10 blank · 44 comment · 10 complexity · e9b738232ddba928db9d4308d730d4e5 MD5 · raw file

  1. /* $OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $ */
  2. /* $NetBSD: uucplock.c,v 1.7 1997/02/11 09:24:08 mrg Exp $ */
  3. /*
  4. * Copyright (c) 1988, 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. * 3. Neither the name of the University nor the names of its contributors
  16. * may be used to endorse or promote products derived from this software
  17. * without specific prior written permission.
  18. *
  19. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29. * SUCH DAMAGE.
  30. */
  31. #include <sys/cdefs.h>
  32. __FBSDID("$FreeBSD$");
  33. #ifndef lint
  34. #if 0
  35. static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
  36. static const char rcsid[] = "$OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $";
  37. #endif
  38. #endif /* not lint */
  39. #include <sys/types.h>
  40. #include <sys/file.h>
  41. #include <sys/dirent.h>
  42. #include <stdio.h>
  43. #include <string.h>
  44. #include <signal.h>
  45. #include <unistd.h>
  46. #include <stdlib.h>
  47. #include <errno.h>
  48. #include "tip.h"
  49. #include "pathnames.h"
  50. /*
  51. * uucp style locking routines
  52. * return: 0 - success
  53. * -1 - failure
  54. */
  55. int
  56. uu_lock(char *ttyname)
  57. {
  58. int fd, len;
  59. char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
  60. char text_pid[81];
  61. pid_t pid;
  62. (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
  63. fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660);
  64. if (fd < 0) {
  65. /*
  66. * file is already locked
  67. * check to see if the process holding the lock still exists
  68. */
  69. fd = open(tbuf, O_RDWR, 0);
  70. if (fd < 0) {
  71. perror(tbuf);
  72. fprintf(stderr, "Can't open lock file.\n");
  73. return(-1);
  74. }
  75. len = read(fd, text_pid, sizeof(text_pid)-1);
  76. if (len<=0) {
  77. perror(tbuf);
  78. (void)close(fd);
  79. fprintf(stderr, "Can't read lock file.\n");
  80. return(-1);
  81. }
  82. text_pid[len] = 0;
  83. pid = atol(text_pid);
  84. if (kill(pid, 0) == 0 || errno != ESRCH) {
  85. (void)close(fd); /* process is still running */
  86. return(-1);
  87. }
  88. /*
  89. * The process that locked the file isn't running, so
  90. * we'll lock it ourselves
  91. */
  92. fprintf(stderr, "Stale lock on %s PID=%ld... overriding.\n",
  93. ttyname, (long)pid);
  94. if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
  95. perror(tbuf);
  96. (void)close(fd);
  97. fprintf(stderr, "Can't seek lock file.\n");
  98. return(-1);
  99. }
  100. /* fall out and finish the locking process */
  101. }
  102. pid = getpid();
  103. (void)snprintf(text_pid, sizeof text_pid, "%10ld\n", (long)pid);
  104. len = strlen(text_pid);
  105. if (write(fd, text_pid, len) != len) {
  106. (void)close(fd);
  107. (void)unlink(tbuf);
  108. perror("lock write");
  109. return(-1);
  110. }
  111. (void)close(fd);
  112. return(0);
  113. }
  114. int
  115. uu_unlock(char *ttyname)
  116. {
  117. char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
  118. (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
  119. unexcl();
  120. return(unlink(tbuf));
  121. }