system.c 2.5 KB

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  1. /*
  2. * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
  3. * The President and Fellows of Harvard College.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions
  7. * are met:
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * 2. Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in the
  12. * documentation and/or other materials provided with the distribution.
  13. * 3. Neither the name of the University nor the names of its contributors
  14. * may be used to endorse or promote products derived from this software
  15. * without specific prior written permission.
  16. *
  17. * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
  18. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20. * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
  21. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27. * SUCH DAMAGE.
  28. */
  29. #include <errno.h>
  30. #include <stdlib.h>
  31. #include <unistd.h>
  32. #include <string.h>
  33. /*
  34. * system(): ANSI C
  35. *
  36. * Run a command.
  37. */
  38. #define MAXCMDSIZE 2048
  39. #define MAXARGS 128
  40. int
  41. system(const char *cmd)
  42. {
  43. /*
  44. * Ordinarily, you call the shell to process the command.
  45. * But we don't know that the shell can do that. So, do it
  46. * ourselves.
  47. */
  48. char tmp[MAXCMDSIZE];
  49. char *argv[MAXARGS+1];
  50. int nargs=0;
  51. char *s;
  52. int pid, status;
  53. if (strlen(cmd) >= sizeof(tmp)) {
  54. errno = E2BIG;
  55. return -1;
  56. }
  57. strcpy(tmp, cmd);
  58. for (s = strtok(tmp, " \t"); s; s = strtok(NULL, " \t")) {
  59. if (nargs < MAXARGS) {
  60. argv[nargs++] = s;
  61. }
  62. else {
  63. errno = E2BIG;
  64. return 1;
  65. }
  66. }
  67. argv[nargs] = NULL;
  68. pid = fork();
  69. switch (pid) {
  70. case -1:
  71. return -1;
  72. case 0:
  73. /* child */
  74. execv(argv[0], argv);
  75. /* exec only returns if it fails */
  76. _exit(255);
  77. default:
  78. /* parent */
  79. waitpid(pid, &status, 0);
  80. return status;
  81. }
  82. }