1 files changed, 140 insertions, 0 deletions
diff --git a/src/lib/env-util.c b/src/lib/env-util.c
new file mode 100644
index 0000000..490e4f6
--- /dev/null
+++ b/src/lib/env-util.c
@@ -0,0 +1,140 @@
+/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "array.h"
+#include "env-util.h"
+
+#ifdef __APPLE__
+#  include <crt_externs.h>
+#endif
+
+struct env_backup {
+	pool_t pool;
+	const char **strings;
+};
+
+void env_put(const char *name, const char *value)
+{
+	i_assert(strchr(name, '=') == NULL);
+
+	if (setenv(name, value, 1) != 0)
+		i_fatal("setenv(%s, %s) failed: %m", name, value);
+}
+
+void env_put_array(const char *const *envs)
+{
+	for (unsigned int i = 0; envs[i] != NULL; i++) {
+		const char *value = strchr(envs[i], '=');
+		i_assert(value != NULL);
+		T_BEGIN {
+			const char *name = t_strdup_until(envs[i], value++);
+			env_put(name, value);
+		} T_END;
+	}
+}
+
+void env_remove(const char *name)
+{
+	if (unsetenv(name) < 0)
+		i_fatal("unsetenv(%s) failed: %m", name);
+}
+
+void env_clean(void)
+{
+#ifdef HAVE_CLEARENV
+	if (clearenv() < 0)
+		i_fatal("clearenv() failed");
+#else
+	char ***environ_p = env_get_environ_p();
+
+	/* 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_p = calloc(1, sizeof(**environ_p));
+#endif
+}
+
+static void env_clean_except_real(const char *const preserve_envs[])
+{
+	ARRAY_TYPE(const_string) copy;
+	const char *value, *const *envp;
+	unsigned int i, count;
+
+	t_array_init(&copy, 16);
+	for (i = 0; preserve_envs[i] != NULL; i++) {
+		const char *key = preserve_envs[i];
+
+		value = getenv(key);
+		if (value != NULL) {
+			key = t_strdup(key);
+			value = t_strdup(value);
+			array_push_back(&copy, &key);
+			array_push_back(&copy, &value);
+		}
+	}
+
+	/* Note that if the original environment was set with env_put(), the
+	   environment strings will be invalid after env_clean(). That's why
+	   we t_strdup() them above. */
+	env_clean();
+
+	envp = array_get(&copy, &count);
+	for (i = 0; i < count; i += 2)
+		env_put(envp[i], envp[i+1]);
+}
+
+void env_clean_except(const char *const preserve_envs[])
+{
+	T_BEGIN {
+		env_clean_except_real(preserve_envs);
+	} T_END;
+}
+
+struct env_backup *env_backup_save(void)
+{
+	char **environ = *env_get_environ_p();
+	struct env_backup *env;
+	unsigned int i, count;
+	pool_t pool;
+
+	i_assert(environ != NULL);
+
+	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)
+{
+	env_clean();
+	env_put_array(env->strings);
+}
+
+void env_backup_free(struct env_backup **_env)
+{
+	struct env_backup *env = *_env;
+
+	*_env = NULL;
+	pool_unref(&env->pool);
+}
+
+char ***env_get_environ_p(void)
+{
+#ifdef __APPLE__
+	return _NSGetEnviron();
+#else
+	extern char **environ;
+
+	return &environ;
+#endif
+}