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[/] [or1k/] [trunk/] [linux/] [uClibc/] [libc/] [stdlib/] [setenv.c] - Rev 1325
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/* Copyright (C) 1992,95,96,97,98,99,2000,2001 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. modified for uClibc by Erik Andersen <andersen@codepoet.org> */ #define _GNU_SOURCE #include <features.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #ifdef __UCLIBC_HAS_THREADS__ #include <pthread.h> static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER; # define LOCK __pthread_mutex_lock(&mylock) # define UNLOCK __pthread_mutex_unlock(&mylock); #else # define LOCK # define UNLOCK #endif /* If this variable is not a null pointer we allocated the current environment. */ static char **last_environ; /* This function is used by `setenv' and `putenv'. The difference between the two functions is that for the former must create a new string which is then placed in the environment, while the argument of `putenv' must be used directly. This is all complicated by the fact that we try to reuse values once generated for a `setenv' call since we can never free the strings. */ int __add_to_environ (const char *name, const char *value, const char *combined, int replace) { register char **ep; register size_t size; const size_t namelen = strlen (name); const size_t vallen = value != NULL ? strlen (value) + 1 : 0; LOCK; /* We have to get the pointer now that we have the lock and not earlier since another thread might have created a new environment. */ ep = __environ; size = 0; if (ep != NULL) { for (; *ep != NULL; ++ep) { if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') break; else ++size; } } if (ep == NULL || *ep == NULL) { char **new_environ; /* We allocated this space; we can extend it. */ new_environ = (char **) realloc (last_environ, (size + 2) * sizeof (char *)); if (new_environ == NULL) { UNLOCK; return -1; } /* If the whole entry is given add it. */ if (combined != NULL) { /* We must not add the string to the search tree since it belongs to the user. */ new_environ[size] = (char *) combined; } else { /* See whether the value is already known. */ new_environ[size] = (char *) malloc (namelen + 1 + vallen); if (new_environ[size] == NULL) { __set_errno (ENOMEM); UNLOCK; return -1; } memcpy (new_environ[size], name, namelen); new_environ[size][namelen] = '='; memcpy (&new_environ[size][namelen + 1], value, vallen); } if (__environ != last_environ) { memcpy ((char *) new_environ, (char *) __environ, size * sizeof (char *)); } new_environ[size + 1] = NULL; last_environ = __environ = new_environ; } else if (replace) { char *np; /* Use the user string if given. */ if (combined != NULL) { np = (char *) combined; } else { np = malloc (namelen + 1 + vallen); if (np == NULL) { UNLOCK; return -1; } memcpy (np, name, namelen); np[namelen] = '='; memcpy (&np[namelen + 1], value, vallen); } *ep = np; } UNLOCK; return 0; } int setenv (const char *name, const char *value, int replace) { return __add_to_environ (name, value, NULL, replace); } int unsetenv (const char *name) { size_t len; char **ep; if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) { __set_errno (EINVAL); return -1; } len = strlen (name); LOCK; ep = __environ; while (*ep != NULL) { if (!strncmp (*ep, name, len) && (*ep)[len] == '=') { /* Found it. Remove this pointer by moving later ones back. */ char **dp = ep; do { dp[0] = dp[1]; } while (*dp++); /* Continue the loop in case NAME appears again. */ } else { ++ep; } } UNLOCK; return 0; } /* The `clearenv' was planned to be added to POSIX.1 but probably never made it. Nevertheless the POSIX.9 standard (POSIX bindings for Fortran 77) requires this function. */ int clearenv (void) { LOCK; if (__environ == last_environ && __environ != NULL) { /* We allocated this environment so we can free it. */ free (__environ); last_environ = NULL; } /* Clear the environment pointer removes the whole environment. */ __environ = NULL; UNLOCK; return 0; } /* Put STRING, which is of the form "NAME=VALUE", in the environment. */ int putenv (char *string) { int result; const char *const name_end = strchr (string, '='); if (name_end != NULL) { char *name = strndup(string, name_end - string); result = __add_to_environ (name, NULL, string, 1); free(name); return(result); } unsetenv (string); return 0; }
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