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| -rw-r--r-- | lib/setenv.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/setenv.c b/lib/setenv.c new file mode 100644 index 000000000..d397753d9 --- /dev/null +++ b/lib/setenv.c @@ -0,0 +1,128 @@ +/* Copyright (C) 1992, 1995 Free Software Foundation, Inc. + +NOTE: The canonical source of this file is maintained with the GNU C Library. +Bugs can be reported to bug-glibc@prep.ai.mit.edu. + +This program is free software; you can redistribute it and/or modify it +under the terms of the GNU General Public License as published by the +Free Software Foundation; either version 2, or (at your option) any +later version. + +This program 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 General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, +USA. */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <errno.h> + +#if _LIBC || HAVE_STDLIB_H +#include <stdlib.h> +#endif +#if _LIBC || HAVE_STRING_H +#include <string.h> +#endif +#if _LIBC || HAVE_UNISTD_H +#include <unistd.h> +#endif + +#ifndef HAVE_GNU_LD +#define __environ environ +#endif + +int +setenv (name, value, replace) + 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) + 1; + + size = 0; + for (ep = __environ; *ep != NULL; ++ep) + if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') + break; + else + ++size; + + if (*ep == NULL) + { + static char **last_environ; + char **new_environ; + if (__environ == last_environ) + /* We allocated this space; we can extend it. */ + new_environ = (char **) realloc (last_environ, + (size + 2) * sizeof (char *)); + else + new_environ = (char **) malloc ((size + 2) * sizeof (char *)); + + if (new_environ == NULL) + return -1; + + new_environ[size] = malloc (namelen + 1 + vallen); + if (new_environ[size] == NULL) + { + free ((char *) new_environ); + errno = ENOMEM; + return -1; + } + + if (__environ != last_environ) + memcpy ((char *) new_environ, (char *) __environ, + size * sizeof (char *)); + + memcpy (new_environ[size], name, namelen); + new_environ[size][namelen] = '='; + memcpy (&new_environ[size][namelen + 1], value, vallen); + + new_environ[size + 1] = NULL; + + last_environ = __environ = new_environ; + } + else if (replace) + { + size_t len = strlen (*ep); + if (len + 1 < namelen + 1 + vallen) + { + /* The existing string is too short; malloc a new one. */ + char *new = malloc (namelen + 1 + vallen); + if (new == NULL) + return -1; + *ep = new; + } + memcpy (*ep, name, namelen); + (*ep)[namelen] = '='; + memcpy (&(*ep)[namelen + 1], value, vallen); + } + + return 0; +} + +void +unsetenv (const char *name) +{ + const size_t len = strlen (name); + char **ep; + + for (ep = __environ; *ep; ++ep) + 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. */ + } +} |