src/lib/env-util.c

	env-util.c revision 3768e5f626cac81f7f2703ffb6bb9c10efe8e882
/* Copyright (c) 2002-2009 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "env-util.h"

#include <stdlib.h>

struct env_backup {
    pool_t pool;
    const char **strings;
};

static pool_t env_pool = NULL;

void env_put(const char *env)
{
    if (env_pool == NULL) {
        env_pool = pool_alloconly_create(MEMPOOL_GROWING"Environment",
                         2048);
    }
    if (putenv(p_strdup(env_pool, env)) != 0)
        i_fatal("putenv(%s) failed: %m", env);
}

void env_remove(const char *name)
{
#ifdef HAVE_UNSETENV
    if (unsetenv(name) < 0)
        i_fatal("unsetenv(%s) failed: %m", name);
#else
    extern char **environ;
    unsigned int len;
    char **envp;

    len = strlen(name);
    for (envp = environ; *envp != NULL; envp++) {
        if (strncmp(name, *envp, len) == 0 &&
            (*envp)[len] == '=') {
            do {
                envp[0] = envp[1];
            } while (*++envp != NULL);
            break;
        }
    }
#endif
}

void env_clean(void)
{
#ifdef HAVE_CLEARENV
    if (clearenv() < 0)
        i_fatal("clearenv() failed");
#else
    extern char **environ;

    /* Try to clear the environment.

       a) environ = NULL crashes on OS X.
       b) *environ = NULL doesn't work on FreeBSD 7.0.
       c) environ = emptyenv doesn't work on Haiku OS
       d) environ = calloc() should work everywhere
    */
    environ = calloc(1, sizeof(*environ));
#endif
    if (env_pool != NULL)
        p_clear(env_pool);
}

struct env_backup *env_backup_save(void)
{
    struct env_backup *env;
    extern char **environ;
    unsigned int i, count;
    pool_t pool;

    for (count = 0; environ[count] != NULL; count++) ;

    pool = pool_alloconly_create("saved environment", 4096);
    env = p_new(pool, struct env_backup, 1);
    env->pool = pool;
    env->strings = p_new(pool, const char *, count + 1);
    for (i = 0; i < count; i++)
        env->strings[i] = p_strdup(pool, environ[i]);
    return env;
}

void env_backup_restore(struct env_backup *env)
{
    unsigned int i;

    env_clean();
    for (i = 0; env->strings[i] != NULL; i++)
        env_put(env->strings[i]);
}

void env_backup_free(struct env_backup **_env)
{
    struct env_backup *env = *_env;

    *_env = NULL;
    pool_unref(&env->pool);
}

void env_deinit(void)
{
    if (env_pool != NULL)
        pool_unref(&env_pool);
}