Implemented userland env handling; it longer uses syscalls for this - I even

made it thread-safe, although this is not required by POSIX.
Implemented unsetenv(), improved putenv().


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11668 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kernel/libroot/posix/stdlib/env.c

@@ -1,14 +1,15 @@
 /*
-** Copyright 2004, Axel Dörfler, [email protected]. All rights reserved.
-** Distributed under the terms of the Haiku License.
-**
-** Copyright 2001, Travis Geiselbrecht. All rights reserved.
-** Distributed under the terms of the NewOS License.
-*/
+ * Copyright 2004-2005, Axel Dörfler, [email protected]. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
 
 
-#include <syscalls.h>
+#include <OS.h>
 
+#include <libroot_private.h>
+#include <user_runtime.h>
+
+#include <pthread.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
@@ -22,45 +23,212 @@
 	return err;
 
 
+static sem_id sEnvLock;
+static bool sCopied;
+
 char **environ = NULL;
 
 
-int
-setenv(const char *name, const char *value, int overwrite)
+static int32
+count_variables(void)
 {
-	status_t status = sys_setenv(name, value, overwrite);
+	int32 i = 0;
+	while (environ[i])
+		i++;
 
-	RETURN_AND_SET_ERRNO(status);
+	return i;
 }
 
 
+static int32
+add_variable(void)
+{
+	int32 count = count_variables() + 1;
+	char **newEnv = malloc((count + 1) * sizeof(char *));
+	if (newEnv == NULL)
+		return B_NO_MEMORY;
+
+	memcpy(newEnv, environ, count * sizeof(char *));
+	newEnv[count] = NULL;
+		// null terminate the array
+
+	return count - 1;
+}
+
+
+static char *
+find_variable(const char *name, int32 length, int32 *_index)
+{
+	int32 i;
+
+	for (i = 0; environ[i] != NULL; i++) {
+		if (!strncmp(name, environ[i], length) && environ[i][length] == '=') {
+			if (_index != NULL)
+				*_index = i;
+			return environ[i];
+		}
+	}
+
+	return NULL;
+}
+
+
+static status_t
+copy_environ_to_heap_if_needed(void)
+{
+	char **newEnv;
+	int32 i;
+
+	if (sCopied)
+		return B_OK;
+
+	newEnv = malloc((count_variables() + 1) * sizeof(char *));
+	if (newEnv == NULL)
+		return B_NO_MEMORY;
+
+	for (i = 0; environ[i]; i++) {
+		newEnv[i] = strdup(environ[i]);
+	}
+
+	newEnv[i] = NULL;
+		// null terminate the array
+
+	sCopied = true;
+	return B_OK;
+}
+
+
+static status_t
+update_variable(const char *name, int32 length, const char *value, bool overwrite)
+{
+	status_t status = B_OK;
+	bool update = false;
+	int32 index;
+	char *env;
+
+	acquire_sem(sEnvLock);
+	copy_environ_to_heap_if_needed();
+
+	env = find_variable(name, length, &index);
+	if (env != NULL && overwrite) {
+		// change variable
+		free(environ[index]);
+		update = true;
+	} else if (env == NULL) {
+		// add variable
+		index = add_variable();
+		update = true;
+	}
+
+	if (update) {
+		environ[index] = malloc(length + 2 + strlen(value));
+		if (environ[index] != NULL) {
+			memcpy(environ[index], name, length);
+			environ[index][length] = '=';
+			strcpy(environ[index] + length + 1, value);
+		} else
+			status = B_NO_MEMORY;
+	}
+
+	release_sem(sEnvLock);
+	return status;
+}
+
+
+static void
+environ_fork_hook(void)
+{
+	sEnvLock = create_sem(1, "env lock");
+}
+
+
+void 
+__init_env(const struct uspace_program_args *args)
+{
+	// Following POSIX, there is no need to make any of the
+	// environment functions thread-safe - but we do it anyway
+	sEnvLock = create_sem(1, "env lock");
+	environ = args->envp;
+
+	atfork(environ_fork_hook);
+}
+
+
+//	#pragma mark -
+
+
 char *
 getenv(const char *name)
 {
+	int32 length = strlen(name);
 	char *value;
-	int rc;
-	
-	rc = sys_getenv(name, &value);
-	if (rc < 0)
+
+	acquire_sem(sEnvLock);
+	value = find_variable(name, length, NULL);
+	release_sem(sEnvLock);
+
+	if (value == NULL)
 		return NULL;
-	return value;
+
+	return value + length + 1;
+}
+
+
+int
+setenv(const char *name, const char *value, int overwrite)
+{
+	status_t status;
+
+	if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL) {
+		errno = B_BAD_VALUE;
+		return -1;
+	}
+
+	status = update_variable(name, strlen(name), value, overwrite);
+	RETURN_AND_SET_ERRNO(status);
+}
+
+
+int
+unsetenv(const char *name)
+{
+	int32 index, length;
+	char *env;
+
+	if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL) {
+		errno = B_BAD_VALUE;
+		return -1;
+	}
+
+	length = strlen(name);
+
+	acquire_sem(sEnvLock);
+	copy_environ_to_heap_if_needed();
+
+	env = find_variable(name, length, &index);
+	if (env != NULL) {
+		// we don't free the memory for the slot, we just move the array contents
+		free(env);
+		memmove(environ + index, environ + index + 1, sizeof(char *) * (count_variables() + 1));
+	}
+
+	release_sem(sEnvLock);
+	return 0;
 }
 
 
 int
 putenv(const char *string)
 {
-	char name[64];
 	char *value = strchr(string, '=');
+	status_t status;
 
-	if (value == NULL || value - string >= (int)sizeof(name)) {
-		errno = EINVAL;
+	if (value == NULL) {
+		errno = B_BAD_VALUE;
 		return -1;
 	}
 
-	strlcpy(name, string, value + 1 - string);
-	value++;
-
-	return setenv(name, value, true);
+	status = update_variable(string, value - string, value + 1, true);
+	RETURN_AND_SET_ERRNO(status);
 }