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author | Ulrich Drepper <drepper@redhat.com> | 2005-12-14 15:06:39 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 2005-12-14 15:06:39 +0000 |
commit | 9d13fb2413921c713f83efe331e8e4d219c62c6b (patch) | |
tree | 2d44d7ac45ab2d147eb8361bbff880c365aa8ad5 /stdlib/setenv.c | |
parent | b6ab06cef4670e02756bcdd4d2c33a49369a4346 (diff) | |
download | glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.tar.gz glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.tar.xz glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.zip |
Moved to csu/errno-loc.c.
Diffstat (limited to 'stdlib/setenv.c')
-rw-r--r-- | stdlib/setenv.c | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/stdlib/setenv.c b/stdlib/setenv.c new file mode 100644 index 0000000000..48aaecffe0 --- /dev/null +++ b/stdlib/setenv.c @@ -0,0 +1,353 @@ +/* Copyright (C) 1992,1995-2001,2004 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. */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#include <errno.h> +#if !_LIBC +# if !defined errno && !defined HAVE_ERRNO_DECL +extern int errno; +# endif +# define __set_errno(ev) ((errno) = (ev)) +#endif + +#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 + +#if !_LIBC +# define __environ environ +# ifndef HAVE_ENVIRON_DECL +extern char **environ; +# endif +#endif + +#if _LIBC +/* This lock protects against simultaneous modifications of `environ'. */ +# include <bits/libc-lock.h> +__libc_lock_define_initialized (static, envlock) +# define LOCK __libc_lock_lock (envlock) +# define UNLOCK __libc_lock_unlock (envlock) +#else +# define LOCK +# define UNLOCK +#endif + +/* In the GNU C library we must keep the namespace clean. */ +#ifdef _LIBC +# define setenv __setenv +# define unsetenv __unsetenv +# define clearenv __clearenv +# define tfind __tfind +# define tsearch __tsearch +#endif + +/* In the GNU C library implementation we try to be more clever and + allow arbitrarily many changes of the environment given that the used + values are from a small set. Outside glibc this will eat up all + memory after a while. */ +#if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \ + && defined __GNUC__) +# define USE_TSEARCH 1 +# include <search.h> + +/* This is a pointer to the root of the search tree with the known + values. */ +static void *known_values; + +# define KNOWN_VALUE(Str) \ + ({ \ + void *value = tfind (Str, &known_values, (__compar_fn_t) strcmp); \ + value != NULL ? *(char **) value : NULL; \ + }) +# define STORE_VALUE(Str) \ + tsearch (Str, &known_values, (__compar_fn_t) strcmp) + +#else +# undef USE_TSEARCH + +# define KNOWN_VALUE(Str) NULL +# define STORE_VALUE(Str) do { } while (0) + +#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 (name, value, combined, replace) + 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 || __builtin_expect (*ep == NULL, 1)) + { + 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. */ +#ifdef USE_TSEARCH +# ifdef __GNUC__ + char new_value[namelen + 1 + vallen]; +# else + char *new_value = (char *) alloca (namelen + 1 + vallen); +# endif +# ifdef _LIBC + __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), + value, vallen); +# else + memcpy (new_value, name, namelen); + new_value[namelen] = '='; + memcpy (&new_value[namelen + 1], value, vallen); +# endif + + new_environ[size] = KNOWN_VALUE (new_value); + if (__builtin_expect (new_environ[size] == NULL, 1)) +#endif + { + new_environ[size] = (char *) malloc (namelen + 1 + vallen); + if (__builtin_expect (new_environ[size] == NULL, 0)) + { + __set_errno (ENOMEM); + UNLOCK; + return -1; + } + +#ifdef USE_TSEARCH + memcpy (new_environ[size], new_value, namelen + 1 + vallen); +#else + memcpy (new_environ[size], name, namelen); + new_environ[size][namelen] = '='; + memcpy (&new_environ[size][namelen + 1], value, vallen); +#endif + /* And save the value now. We cannot do this when we remove + the string since then we cannot decide whether it is a + user string or not. */ + STORE_VALUE (new_environ[size]); + } + } + + 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 + { +#ifdef USE_TSEARCH +# ifdef __GNUC__ + char new_value[namelen + 1 + vallen]; +# else + char *new_value = (char *) alloca (namelen + 1 + vallen); +# endif +# ifdef _LIBC + __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), + value, vallen); +# else + memcpy (new_value, name, namelen); + new_value[namelen] = '='; + memcpy (&new_value[namelen + 1], value, vallen); +# endif + + np = KNOWN_VALUE (new_value); + if (__builtin_expect (np == NULL, 1)) +#endif + { + np = malloc (namelen + 1 + vallen); + if (__builtin_expect (np == NULL, 0)) + { + UNLOCK; + return -1; + } + +#ifdef USE_TSEARCH + memcpy (np, new_value, namelen + 1 + vallen); +#else + memcpy (np, name, namelen); + np[namelen] = '='; + memcpy (&np[namelen + 1], value, vallen); +#endif + /* And remember the value. */ + STORE_VALUE (np); + } + } + + *ep = np; + } + + UNLOCK; + + return 0; +} + +int +setenv (name, value, replace) + const char *name; + const char *value; + int replace; +{ + if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) + { + __set_errno (EINVAL); + return -1; + } + + return __add_to_environ (name, value, NULL, replace); +} + +int +unsetenv (name) + 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 () +{ + 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; +} +#ifdef _LIBC +libc_freeres_fn (free_mem) +{ + /* Remove all traces. */ + clearenv (); + + /* Now remove the search tree. */ + __tdestroy (known_values, free); + known_values = NULL; +} + +# undef setenv +# undef unsetenv +# undef clearenv +weak_alias (__setenv, setenv) +weak_alias (__unsetenv, unsetenv) +weak_alias (__clearenv, clearenv) +#endif |