diff options
Diffstat (limited to 'libc/stdlib/setenv.c')
| -rw-r--r-- | libc/stdlib/setenv.c | 184 |
1 files changed, 126 insertions, 58 deletions
diff --git a/libc/stdlib/setenv.c b/libc/stdlib/setenv.c index f7d597139..b17280562 100644 --- a/libc/stdlib/setenv.c +++ b/libc/stdlib/setenv.c @@ -1,76 +1,144 @@ -/* Copyright (C) 1995,1996 Robert de Bath <rdebath@cix.compulink.co.uk> - * This file is part of the Linux-8086 C library and is distributed - * under the GNU Library General Public License. - */ -#include <string.h> -#include <stdlib.h> -#include <malloc.h> +/* Copyright (C) 1992, 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. -extern char **environ; +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. -#define ADD_NUM 4 +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 +Library General Public License for more details. -int setenv(var, value, overwrite) -const char *var; -const char *value; -int overwrite; -{ - static char **mall_env = 0; - static int extras = 0; - char **p, **d; - char *t; - int len; +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ - len = strlen(var); +#include <stdlib.h> +#include <string.h> +#include <unistd.h> - if (!environ) { - environ = (char **) malloc(ADD_NUM * sizeof(char *)); - memset(environ, 0, sizeof(char *) * ADD_NUM); +#if !defined(HAVE_GNU_LD) && !defined (__ELF__) +#define __environ environ +#endif - extras = ADD_NUM; - } +#if defined(_REENTRENT) || defined(_THREAD_SAFE) +# include <pthread.h> - for (p = environ; *p; p++) { - if (memcmp(var, *p, len) == 0 && (*p)[len] == '=') { - if (!overwrite) - return -1; - /* Overwrite stuff */ - while ((p[0] = p[1])) - p++; - extras++; - break; - } - } +/* We need to initialize the mutex. For this we use a method provided + by pthread function 'pthread_once'. For this we need a once block. */ +static pthread_once__t _once_block = pthread_once_init; + +/* This is the mutex which protects the global environment of simultaneous + modifications. */ +static pthread_mutex_t _setenv_mutex; + +static void +DEFUN_VOID(_init_setenv_mutex) +{ + pthread_mutex_init(&_setenv_mutex, pthread_mutexattr_default); +} - if (extras <= 0) { /* Need more space */ - d = malloc((p - environ + 1 + ADD_NUM) * sizeof(char *)); +# define LOCK() \ + do { pthread_once(&_once_block, _init_setenv_mutex); + pthread_mutex_lock(&_setenv_mutex); } while (0) +# define UNLOCK() pthread_mutex_unlock(&_setenv_mutex) - if (d == 0) - return -1; +#else /* !_REENTRENT && !_THREAD_SAFE */ - memcpy((void *) d, (void *) environ, +# define LOCK() +# define UNLOCK() - (p - environ + 1) * sizeof(char *)); - p = d + (p - environ); - extras = ADD_NUM; +#endif /* _REENTRENT || _THREAD_SAFE */ - if (mall_env) - free(mall_env); - environ = d; - mall_env = d; +int setenv(const char *name, const char *value, int replace) +{ + register char **ep; + register size_t size; + const size_t namelen = strlen (name); + const size_t vallen = strlen (value); + int result = 0; + + LOCK(); + + size = 0; + for (ep = __environ; *ep != NULL; ++ep) + if (!memcmp (*ep, name, namelen) && (*ep)[namelen] == '=') + break; + else + ++size; + + if (*ep == NULL) + { + static char **last_environ = NULL; + char **new_environ = (char **) malloc((size + 2) * sizeof(char *)); + if (new_environ == NULL) + { + result = -1; + goto do_return; + } + (void) memcpy((__ptr_t) new_environ, (__ptr_t) __environ, size * sizeof(char *)); + + new_environ[size] = malloc (namelen + 1 + vallen + 1); + if (new_environ[size] == NULL) + { + free (new_environ); + errno = ENOMEM; + result = -1; + goto do_return; + } + memcpy (new_environ[size], name, namelen); + new_environ[size][namelen] = '='; + memcpy (&new_environ[size][namelen + 1], value, vallen + 1); + + new_environ[size + 1] = NULL; + + if (last_environ != NULL) + free ((__ptr_t) last_environ); + last_environ = new_environ; + __environ = new_environ; + } + else if (replace) + { + size_t len = strlen (*ep); + if (len < namelen + 1 + vallen) + { + char *new = malloc (namelen + 1 + vallen + 1); + if (new == NULL) + { + result = -1; + goto do_return; + } + *ep = new; + memcpy (*ep, name, namelen); + (*ep)[namelen] = '='; } + memcpy (&(*ep)[namelen + 1], value, vallen + 1); + } - t = malloc(len + 1 + strlen(value) + 1); - if (!t) - return -1; +do_return: + UNLOCK(); + return result; +} + + +void unsetenv(const char *name) +{ + register char **ep; + register char **dp; + const size_t namelen = strlen (name); - strcpy(t, var); - strcat(t, "="); - strcat(t, value); + LOCK(); - *p++ = (char *) t; - *p = '\0'; - extras--; + for (dp = ep = __environ; *ep != NULL; ++ep) + if (memcmp (*ep, name, namelen) || (*ep)[namelen] != '=') + { + *dp = *ep; + ++dp; + } + *dp = NULL; - return 0; + UNLOCK(); } |