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. #include <bits/uClibc_mutex.h>
  29. __UCLIBC_MUTEX_STATIC(mylock, PTHREAD_MUTEX_INITIALIZER);
  30. /* If this variable is not a null pointer we allocated the current
  31. environment. */
  32. static char **last_environ;
  33. /* This function is used by `setenv' and `putenv'. The difference between
  34. the two functions is that for the former must create a new string which
  35. is then placed in the environment, while the argument of `putenv'
  36. must be used directly. This is all complicated by the fact that we try
  37. to reuse values once generated for a `setenv' call since we can never
  38. free the strings. */
  39. int __add_to_environ (const char *name, const char *value,
  40. const char *combined, int replace) attribute_hidden;
  41. int __add_to_environ (const char *name, const char *value,
  42. const char *combined, int replace)
  43. {
  44. register char **ep;
  45. register size_t size;
  46. const size_t namelen = strlen (name);
  47. const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
  48. int rv = -1;
  49. __UCLIBC_MUTEX_LOCK(mylock);
  50. /* We have to get the pointer now that we have the lock and not earlier
  51. since another thread might have created a new environment. */
  52. ep = __environ;
  53. size = 0;
  54. if (ep != NULL) {
  55. for (; *ep != NULL; ++ep) {
  56. if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
  57. break;
  58. else
  59. ++size;
  60. }
  61. }
  62. if (ep == NULL || *ep == NULL) {
  63. char **new_environ;
  64. /* We allocated this space; we can extend it. */
  65. new_environ = (char **) realloc (last_environ, (size + 2) * sizeof (char *));
  66. if (new_environ == NULL) {
  67. goto DONE;
  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. goto DONE;
  80. }
  81. memcpy (new_environ[size], name, namelen);
  82. new_environ[size][namelen] = '=';
  83. memcpy (&new_environ[size][namelen + 1], value, vallen);
  84. }
  85. if (__environ != last_environ) {
  86. memcpy ((char *) new_environ, (char *) __environ,
  87. size * sizeof (char *));
  88. }
  89. new_environ[size + 1] = NULL;
  90. last_environ = __environ = new_environ;
  91. } else if (replace) {
  92. char *np;
  93. /* Use the user string if given. */
  94. if (combined != NULL) {
  95. np = (char *) combined;
  96. } else {
  97. np = malloc (namelen + 1 + vallen);
  98. if (np == NULL) {
  99. goto DONE;
  100. }
  101. memcpy (np, name, namelen);
  102. np[namelen] = '=';
  103. memcpy (&np[namelen + 1], value, vallen);
  104. }
  105. *ep = np;
  106. }
  107. rv = 0;
  108. DONE:
  109. __UCLIBC_MUTEX_UNLOCK(mylock);
  110. return rv;
  111. }
  112. libc_hidden_proto(setenv)
  113. int setenv (const char *name, const char *value, int replace)
  114. {
  115. return __add_to_environ (name, value, NULL, replace);
  116. }
  117. libc_hidden_def(setenv)
  118. libc_hidden_proto(unsetenv)
  119. int unsetenv (const char *name)
  120. {
  121. size_t len;
  122. char **ep;
  123. if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) {
  124. __set_errno (EINVAL);
  125. return -1;
  126. }
  127. len = strlen (name);
  128. __UCLIBC_MUTEX_LOCK(mylock);
  129. ep = __environ;
  130. while (*ep != NULL) {
  131. if (!strncmp (*ep, name, len) && (*ep)[len] == '=') {
  132. /* Found it. Remove this pointer by moving later ones back. */
  133. char **dp = ep;
  134. do {
  135. dp[0] = dp[1];
  136. } while (*dp++);
  137. /* Continue the loop in case NAME appears again. */
  138. } else {
  139. ++ep;
  140. }
  141. }
  142. __UCLIBC_MUTEX_UNLOCK(mylock);
  143. return 0;
  144. }
  145. libc_hidden_def(unsetenv)
  146. /* The `clearenv' was planned to be added to POSIX.1 but probably
  147. never made it. Nevertheless the POSIX.9 standard (POSIX bindings
  148. for Fortran 77) requires this function. */
  149. int clearenv (void)
  150. {
  151. __UCLIBC_MUTEX_LOCK(mylock);
  152. if (__environ == last_environ && __environ != NULL) {
  153. /* We allocated this environment so we can free it. */
  154. free (__environ);
  155. last_environ = NULL;
  156. }
  157. /* Clear the environment pointer removes the whole environment. */
  158. __environ = NULL;
  159. __UCLIBC_MUTEX_UNLOCK(mylock);
  160. return 0;
  161. }
  162. /* Put STRING, which is of the form "NAME=VALUE", in the environment. */
  163. int putenv (char *string)
  164. {
  165. int result;
  166. const char *const name_end = strchr (string, '=');
  167. if (name_end != NULL) {
  168. char *name = strndup(string, name_end - string);
  169. result = __add_to_environ (name, NULL, string, 1);
  170. free(name);
  171. return(result);
  172. }
  173. unsetenv (string);
  174. return 0;
  175. }