setenv.c 5.4 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. #define strndup __strndup
  18. #define _GNU_SOURCE
  19. #include <features.h>
  20. #include <errno.h>
  21. #include <stdlib.h>
  22. #include <string.h>
  23. #include <unistd.h>
  24. #ifdef __UCLIBC_HAS_THREADS__
  25. # include <pthread.h>
  26. static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
  27. #endif
  28. #define LOCK __pthread_mutex_lock(&mylock)
  29. #define UNLOCK __pthread_mutex_unlock(&mylock)
  30. extern int __unsetenv (__const char *__name) attribute_hidden;
  31. /* If this variable is not a null pointer we allocated the current
  32. environment. */
  33. static char **last_environ;
  34. /* This function is used by `setenv' and `putenv'. The difference between
  35. the two functions is that for the former must create a new string which
  36. is then placed in the environment, while the argument of `putenv'
  37. must be used directly. This is all complicated by the fact that we try
  38. to reuse values once generated for a `setenv' call since we can never
  39. free the strings. */
  40. int attribute_hidden __add_to_environ (const char *name, const char *value,
  41. const char *combined, int replace)
  42. {
  43. register char **ep;
  44. register size_t size;
  45. const size_t namelen = __strlen (name);
  46. const size_t vallen = value != NULL ? __strlen (value) + 1 : 0;
  47. LOCK;
  48. /* We have to get the pointer now that we have the lock and not earlier
  49. since another thread might have created a new environment. */
  50. ep = __environ;
  51. size = 0;
  52. if (ep != NULL) {
  53. for (; *ep != NULL; ++ep) {
  54. if (!__strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
  55. break;
  56. else
  57. ++size;
  58. }
  59. }
  60. if (ep == NULL || *ep == NULL) {
  61. char **new_environ;
  62. /* We allocated this space; we can extend it. */
  63. new_environ = (char **) realloc (last_environ,
  64. (size + 2) * sizeof (char *));
  65. if (new_environ == NULL) {
  66. UNLOCK;
  67. return -1;
  68. }
  69. /* If the whole entry is given add it. */
  70. if (combined != NULL) {
  71. /* We must not add the string to the search tree since it belongs
  72. to the user. */
  73. new_environ[size] = (char *) combined;
  74. } else {
  75. /* See whether the value is already known. */
  76. new_environ[size] = (char *) malloc (namelen + 1 + vallen);
  77. if (new_environ[size] == NULL) {
  78. __set_errno (ENOMEM);
  79. UNLOCK;
  80. return -1;
  81. }
  82. __memcpy (new_environ[size], name, namelen);
  83. new_environ[size][namelen] = '=';
  84. __memcpy (&new_environ[size][namelen + 1], value, vallen);
  85. }
  86. if (__environ != last_environ) {
  87. __memcpy ((char *) new_environ, (char *) __environ,
  88. size * sizeof (char *));
  89. }
  90. new_environ[size + 1] = NULL;
  91. last_environ = __environ = new_environ;
  92. } else if (replace) {
  93. char *np;
  94. /* Use the user string if given. */
  95. if (combined != NULL) {
  96. np = (char *) combined;
  97. } else {
  98. np = malloc (namelen + 1 + vallen);
  99. if (np == NULL) {
  100. UNLOCK;
  101. return -1;
  102. }
  103. __memcpy (np, name, namelen);
  104. np[namelen] = '=';
  105. __memcpy (&np[namelen + 1], value, vallen);
  106. }
  107. *ep = np;
  108. }
  109. UNLOCK;
  110. return 0;
  111. }
  112. int setenv (const char *name, const char *value, int replace)
  113. {
  114. return __add_to_environ (name, value, NULL, replace);
  115. }
  116. int attribute_hidden __unsetenv (const char *name)
  117. {
  118. size_t len;
  119. char **ep;
  120. if (name == NULL || *name == '\0' || __strchr (name, '=') != NULL) {
  121. __set_errno (EINVAL);
  122. return -1;
  123. }
  124. len = __strlen (name);
  125. LOCK;
  126. ep = __environ;
  127. while (*ep != NULL) {
  128. if (!__strncmp (*ep, name, len) && (*ep)[len] == '=') {
  129. /* Found it. Remove this pointer by moving later ones back. */
  130. char **dp = ep;
  131. do {
  132. dp[0] = dp[1];
  133. } while (*dp++);
  134. /* Continue the loop in case NAME appears again. */
  135. } else {
  136. ++ep;
  137. }
  138. }
  139. UNLOCK;
  140. return 0;
  141. }
  142. strong_alias(__unsetenv,unsetenv)
  143. /* The `clearenv' was planned to be added to POSIX.1 but probably
  144. never made it. Nevertheless the POSIX.9 standard (POSIX bindings
  145. for Fortran 77) requires this function. */
  146. int clearenv (void)
  147. {
  148. LOCK;
  149. if (__environ == last_environ && __environ != NULL) {
  150. /* We allocated this environment so we can free it. */
  151. free (__environ);
  152. last_environ = NULL;
  153. }
  154. /* Clear the environment pointer removes the whole environment. */
  155. __environ = NULL;
  156. UNLOCK;
  157. return 0;
  158. }
  159. /* Put STRING, which is of the form "NAME=VALUE", in the environment. */
  160. int putenv (char *string)
  161. {
  162. int result;
  163. const char *const name_end = __strchr (string, '=');
  164. if (name_end != NULL) {
  165. char *name = strndup(string, name_end - string);
  166. result = __add_to_environ (name, NULL, string, 1);
  167. free(name);
  168. return(result);
  169. }
  170. __unsetenv (string);
  171. return 0;
  172. }