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run_shell.c 3.3 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
  4. * 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. * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
  15. * may be used to endorse or promote products derived from this software
  16. * without specific prior written permission.
  17. *
  18. * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ''AS IS'' AND
  19. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21. * ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
  22. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28. * SUCH DAMAGE.
  29. */
  30. #include "libbb.h"
  31. #if ENABLE_SELINUX
  32. #include <selinux/selinux.h> /* for setexeccon */
  33. #endif
  34. #if ENABLE_SELINUX
  35. static security_context_t current_sid;
  36. void FAST_FUNC renew_current_security_context(void)
  37. {
  38. freecon(current_sid); /* Release old context */
  39. getcon(&current_sid); /* update */
  40. }
  41. void FAST_FUNC set_current_security_context(security_context_t sid)
  42. {
  43. freecon(current_sid); /* Release old context */
  44. current_sid = sid;
  45. }
  46. #endif
  47. /* Exec SHELL, or DEFAULT_SHELL if SHELL is "" or NULL.
  48. * If ADDITIONAL_ARGS is not NULL, pass them to the shell.
  49. */
  50. void FAST_FUNC exec_shell(const char *shell, int loginshell, const char **additional_args)
  51. {
  52. const char **args;
  53. args = additional_args;
  54. while (args && *args)
  55. args++;
  56. args = xzalloc(sizeof(args[0]) * (2 + (args - additional_args)));
  57. if (!shell || !shell[0])
  58. shell = DEFAULT_SHELL;
  59. args[0] = bb_get_last_path_component_nostrip(shell);
  60. if (loginshell)
  61. args[0] = xasprintf("-%s", args[0]);
  62. /*args[1] = NULL; - already is */
  63. if (additional_args) {
  64. int cnt = 0;
  65. while (*additional_args)
  66. args[++cnt] = *additional_args++;
  67. }
  68. #if ENABLE_SELINUX
  69. if (current_sid)
  70. setexeccon(current_sid);
  71. if (ENABLE_FEATURE_CLEAN_UP)
  72. freecon(current_sid);
  73. #endif
  74. execv(shell, (char **) args);
  75. bb_perror_msg_and_die("can't execute '%s'", shell);
  76. }
  77. void FAST_FUNC exec_login_shell(const char *shell)
  78. {
  79. exec_shell(shell, 1, NULL);
  80. }
  81. /* Typical idiom for applets which exec *optional* PROG [ARGS] */
  82. void FAST_FUNC exec_prog_or_SHELL(char **argv)
  83. {
  84. if (argv[0]) {
  85. BB_EXECVP_or_die(argv);
  86. }
  87. /* Both users (nsenter and unshare) do indeed exec
  88. * a _login_ shell (with dash in argv[0])!
  89. */
  90. exec_login_shell(getenv("SHELL"));
  91. }