setenv.c 5.6 KB

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  1. /* Copyright (C) 1992,95,96,97,98,99,2000,2001 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, write to the Free
  13. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  14. 02111-1307 USA.
  15. modified for uClibc by Erik Andersen <andersen@codepoet.org>
  16. */
  17. #include <features.h>
  18. #include <errno.h>
  19. #include <stdlib.h>
  20. #include <string.h>
  21. #include <unistd.h>
  22. libc_hidden_proto(memcpy)
  23. libc_hidden_proto(strchr)
  24. libc_hidden_proto(strlen)
  25. libc_hidden_proto(strncmp)
  26. libc_hidden_proto(strndup)
  27. libc_hidden_proto(unsetenv)
  28. libc_hidden_proto(__environ)
  29. #ifdef __UCLIBC_HAS_THREADS__
  30. # include <pthread.h>
  31. static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
  32. #endif
  33. #define LOCK __pthread_mutex_lock(&mylock)
  34. #define UNLOCK __pthread_mutex_unlock(&mylock)
  35. /* If this variable is not a null pointer we allocated the current
  36. environment. */
  37. static char **last_environ;
  38. /* This function is used by `setenv' and `putenv'. The difference between
  39. the two functions is that for the former must create a new string which
  40. is then placed in the environment, while the argument of `putenv'
  41. must be used directly. This is all complicated by the fact that we try
  42. to reuse values once generated for a `setenv' call since we can never
  43. free the strings. */
  44. int __add_to_environ (const char *name, const char *value,
  45. const char *combined, int replace) attribute_hidden;
  46. int __add_to_environ (const char *name, const char *value,
  47. const char *combined, int replace)
  48. {
  49. register char **ep;
  50. register size_t size;
  51. const size_t namelen = strlen (name);
  52. const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
  53. LOCK;
  54. /* We have to get the pointer now that we have the lock and not earlier
  55. since another thread might have created a new environment. */
  56. ep = __environ;
  57. size = 0;
  58. if (ep != NULL) {
  59. for (; *ep != NULL; ++ep) {
  60. if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
  61. break;
  62. else
  63. ++size;
  64. }
  65. }
  66. if (ep == NULL || *ep == NULL) {
  67. char **new_environ;
  68. /* We allocated this space; we can extend it. */
  69. new_environ = (char **) realloc (last_environ,
  70. (size + 2) * sizeof (char *));
  71. if (new_environ == NULL) {
  72. UNLOCK;
  73. return -1;
  74. }
  75. /* If the whole entry is given add it. */
  76. if (combined != NULL) {
  77. /* We must not add the string to the search tree since it belongs
  78. to the user. */
  79. new_environ[size] = (char *) combined;
  80. } else {
  81. /* See whether the value is already known. */
  82. new_environ[size] = (char *) malloc (namelen + 1 + vallen);
  83. if (new_environ[size] == NULL) {
  84. __set_errno (ENOMEM);
  85. UNLOCK;
  86. return -1;
  87. }
  88. memcpy (new_environ[size], name, namelen);
  89. new_environ[size][namelen] = '=';
  90. memcpy (&new_environ[size][namelen + 1], value, vallen);
  91. }
  92. if (__environ != last_environ) {
  93. memcpy ((char *) new_environ, (char *) __environ,
  94. size * sizeof (char *));
  95. }
  96. new_environ[size + 1] = NULL;
  97. last_environ = __environ = new_environ;
  98. } else if (replace) {
  99. char *np;
  100. /* Use the user string if given. */
  101. if (combined != NULL) {
  102. np = (char *) combined;
  103. } else {
  104. np = malloc (namelen + 1 + vallen);
  105. if (np == NULL) {
  106. UNLOCK;
  107. return -1;
  108. }
  109. memcpy (np, name, namelen);
  110. np[namelen] = '=';
  111. memcpy (&np[namelen + 1], value, vallen);
  112. }
  113. *ep = np;
  114. }
  115. UNLOCK;
  116. return 0;
  117. }
  118. libc_hidden_proto(setenv)
  119. int setenv (const char *name, const char *value, int replace)
  120. {
  121. return __add_to_environ (name, value, NULL, replace);
  122. }
  123. libc_hidden_def(setenv)
  124. libc_hidden_proto(unsetenv)
  125. int unsetenv (const char *name)
  126. {
  127. size_t len;
  128. char **ep;
  129. if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) {
  130. __set_errno (EINVAL);
  131. return -1;
  132. }
  133. len = strlen (name);
  134. LOCK;
  135. ep = __environ;
  136. while (*ep != NULL) {
  137. if (!strncmp (*ep, name, len) && (*ep)[len] == '=') {
  138. /* Found it. Remove this pointer by moving later ones back. */
  139. char **dp = ep;
  140. do {
  141. dp[0] = dp[1];
  142. } while (*dp++);
  143. /* Continue the loop in case NAME appears again. */
  144. } else {
  145. ++ep;
  146. }
  147. }
  148. UNLOCK;
  149. return 0;
  150. }
  151. libc_hidden_def(unsetenv)
  152. /* The `clearenv' was planned to be added to POSIX.1 but probably
  153. never made it. Nevertheless the POSIX.9 standard (POSIX bindings
  154. for Fortran 77) requires this function. */
  155. int clearenv (void)
  156. {
  157. LOCK;
  158. if (__environ == last_environ && __environ != NULL) {
  159. /* We allocated this environment so we can free it. */
  160. free (__environ);
  161. last_environ = NULL;
  162. }
  163. /* Clear the environment pointer removes the whole environment. */
  164. __environ = NULL;
  165. UNLOCK;
  166. return 0;
  167. }
  168. /* Put STRING, which is of the form "NAME=VALUE", in the environment. */
  169. int putenv (char *string)
  170. {
  171. int result;
  172. const char *const name_end = strchr (string, '=');
  173. if (name_end != NULL) {
  174. char *name = strndup(string, name_end - string);
  175. result = __add_to_environ (name, NULL, string, 1);
  176. free(name);
  177. return(result);
  178. }
  179. unsetenv (string);
  180. return 0;
  181. }