ali@416: /*
ali@475:  * Copyright (C) 2012, 2016  J. Ali Harlow <ali@juiblex.co.uk>
ali@416:  *
ali@416:  * This program is free software; you can redistribute it and/or modify
ali@416:  * it under the terms of the GNU General Public License as published by
ali@416:  * the Free Software Foundation; either version 2 of the License, or
ali@416:  * (at your option) any later version.
ali@416:  *
ali@416:  * This program is distributed in the hope that it will be useful,
ali@416:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
ali@416:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
ali@416:  * GNU General Public License for more details.
ali@416:  *
ali@416:  * You should have received a copy of the GNU General Public License along
ali@416:  * with this program; if not, write to the Free Software Foundation, Inc.,
ali@416:  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
ali@416:  */
ali@416: 
ali@416: #include "config.h"
ali@416: 
ali@416: #if ENABLE_ATOMIC && !HAVE_WINDOWS_KTM
ali@416: 
ali@416: #include <stdlib.h>
ali@416: #include <stdio.h>
ali@416: #include <string.h>
ali@416: #include <limits.h>
ali@416: #include <errno.h>
ali@416: #include <assert.h>
ali@416: #include "razor-internal.h"
ali@416: 
ali@416: char *atomic_action_attic_tmpnam(struct razor_atomic *atomic)
ali@416: {
ali@416: 	char filename[17];
ali@416: 	sprintf(filename,"%03X",atomic->next_file_tag++);
ali@416: 	return razor_concat(atomic->toplevel, "/", filename, NULL);
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_list_pop_head(struct atomic_action **list)
ali@416: {
ali@416: 	struct atomic_action *head;
ali@416: 
ali@416: 	head = *list;
ali@416: 	if (head) {
ali@416: 		*list = head->next;
ali@416: 		head->next = NULL;
ali@416: 	}
ali@416: 
ali@416: 	return head;
ali@416: }
ali@416: 
ali@416: struct atomic_action *
ali@416: atomic_action_list_prepend(struct atomic_action *list,
ali@416: 			   struct atomic_action *action)
ali@416: {
ali@416: 	assert(action->next == NULL);
ali@416: 
ali@416: 	action->next=list;
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_list_concat(struct atomic_action *list1,
ali@416: 			  struct atomic_action *list2)
ali@416: {
ali@416: 	struct atomic_action *action;
ali@416: 
ali@416: 	if (!list1)
ali@416: 		return list2;
ali@416: 
ali@416: 	for(action=list1;action->next;action=action->next)
ali@416: 		;
ali@416: 
ali@416: 	action->next=list2;
ali@416: 
ali@416: 	return list1;
ali@416: }
ali@416: 
ali@416: void atomic_action_free(struct atomic_action *action)
ali@416: {
ali@416: 	struct atomic_action *a;
ali@416: 
ali@416: 	while(action) {
ali@416: 		a = atomic_action_list_pop_head(&action);
ali@416: 
ali@475: 		free(a->args.uri);
ali@416: 
ali@416: 		switch(a->type) {
ali@416: 		case ACTION_MAKE_DIRS:
ali@416: 			free(a->args.u.make_dirs.root);
ali@416: 			break;
ali@416: 		case ACTION_MOVE:
ali@416: 			free(a->args.u.move.dest);
ali@416: 			break;
ali@416: #if HAVE_SYMLINK
ali@416: 		case ACTION_CREATE_SYMLINK:
ali@416: 			free(a->args.u.create_symlink.target);
ali@416: 			break;
ali@416: #endif
ali@416: 		case ACTION_REMOVE:
ali@416: 		case ACTION_CREATE_DIR:
ali@416: 			break;
ali@416: 		}
ali@416: 
ali@416: 		free(a);
ali@416: 	}
ali@416: }
ali@416: 
ali@416: struct atomic_action *atomic_action_new(enum atomic_action_type type)
ali@416: {
ali@416: 	struct atomic_action *action;
ali@416: 
ali@416: 	action = zalloc(sizeof *action);
ali@416: 	action->type = type;
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: struct atomic_action *atomic_action_list_reverse(struct atomic_action *list)
ali@416: {
ali@416: 	struct atomic_action *prev = NULL, *next;
ali@416: 
ali@416: 	while(list) {
ali@416: 		next = list->next;
ali@416: 		list->next = prev;
ali@416: 		prev = list;
ali@416: 		list = next;
ali@416: 	}
ali@416: 
ali@416: 	return prev;
ali@416: }
ali@416: 
ali@416: /*
ali@416:  * All action_ functions take 1 action and return a list of primitive
ali@416:  * actions they took (such that the first action in the list is the
ali@416:  * last action they took). Primitive actions are always reversable.
ali@416:  *
ali@416:  * On failure, an error should be set on the atomic object (if it is
ali@416:  * not already set), the action freed and NULL returned.
ali@416:  *
ali@416:  * Whether they succeed or fail, they take ownership of the passed
ali@416:  * action and should thus either free it or return it back to their
ali@416:  * caller as appropriate.
ali@416:  *
ali@416:  * A NULL return means that nothing was done which may, or may not,
ali@416:  * indicate an error.
ali@416:  */
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_make_dirs(struct razor_atomic *atomic,
ali@416: 			struct atomic_action *action)
ali@416: {
ali@416: 	char buffer[PATH_MAX], *p;
ali@416: 	const char *slash, *next;
ali@416: 	struct atomic_action *primitives = NULL;
ali@416: 	struct atomic_action *prim;
ali@416: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	strcpy(buffer, action->args.u.make_dirs.root);
ali@416: 	p = buffer + strlen(buffer);
ali@475: 	slash = action->args.uri;
ali@475: 	if (p > buffer && p[-1] != ':' && p[-1] != '/' && *slash != '/')
ali@475: 		*p++ = '/';
ali@416: 	for (; *slash != '\0'; slash = next) {
ali@416: 		next = strchr(slash + 1, '/');
ali@416: 		if (next == NULL)
ali@416: 			break;
ali@416: 
ali@416: 		memcpy(p, slash, next - slash);
ali@416: 		p += next - slash;
ali@416: 		*p = '\0';
ali@416: 
ali@416: 		if (razor_valid_root_name(buffer))
ali@416: 			continue;
ali@416: 
ali@416: 		prim = atomic_action_new(ACTION_CREATE_DIR);
ali@475: 		prim->args.uri = strdup(buffer);
ali@416: 		prim->args.u.create_dir.mode = S_IRWXU | S_IRWXG | S_IRWXO;
ali@416: 		primitives = atomic_action_list_prepend(primitives, prim);
ali@416: 	}
ali@416: 	primitives = atomic_action_list_reverse(primitives);
ali@416: 
ali@458: 	atomic_action_free(action);
ali@458: 
ali@416: 	return atomic_action_do(atomic, primitives);
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_remove(struct razor_atomic *atomic, struct atomic_action *action)
ali@416: {
ali@475: 	void *dir;
ali@475: 	char *name;
ali@416: 	struct atomic_action *prim;
ali@416: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	/*
ali@416: 	 * Non-empty directories should NOT be removed
ali@416: 	 */
ali@475: 	dir = razor_uri_opendir(action->args.uri, NULL);
ali@475: 	if (dir) {
ali@475: 		name = razor_uri_readdir(dir, NULL);
ali@475: 		razor_uri_closedir(dir, NULL);
ali@475: 		if (name) {
ali@475: 			free(name);
ali@475: 			atomic_action_free(action);
ali@475: 			action = NULL;
ali@475: 		}
ali@416: 	}
ali@416: 
ali@416: 	if (action) {
ali@416: 		prim = atomic_action_new(ACTION_MOVE);
ali@475: 		prim->args.uri = strdup(action->args.uri);
ali@416: 		prim->args.u.move.dest = atomic_action_attic_tmpnam(atomic);
ali@416: 
ali@416: 		atomic_action_free(action);
ali@416: 	} else
ali@416: 		prim = NULL;
ali@416: 
ali@416: 	return prim ? atomic_action_do(atomic, prim) : NULL;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_create_dir(struct razor_atomic *atomic,
ali@416: 			 struct atomic_action *action)
ali@416: {
ali@416: 	mode_t mode;
ali@475: 	struct razor_error **error;
ali@416: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	mode = action->args.u.create_dir.mode & (S_IRWXU | S_IRWXG | S_IRWXO);
ali@416: 
ali@475: 	if (atomic->error)
ali@475: 		error = NULL;
ali@475: 	else
ali@475: 		error = &atomic->error;
ali@475: 
ali@475: 	if (!razor_uri_mkdir(action->args.uri, mode, error))
ali@450: 		return action;
ali@416: 
ali@450: 	atomic_action_free(action);
ali@450: 	return NULL;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *atomic_action_rmdir(struct razor_atomic *atomic,
ali@416: 						 struct atomic_action *action)
ali@416: {
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@475: 	if (rmdir(action->args.uri) < 0) {
ali@423: 		if (!atomic->error)
ali@475: 			atomic->error = razor_error_new_posix(action->args.uri);
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	} else
ali@416: 		return action;
ali@416: }
ali@416: 
ali@416: #if HAVE_SYMLINK
ali@416: static struct atomic_action *
ali@416: atomic_action_create_symlink(struct razor_atomic *atomic,
ali@416: 			     struct atomic_action *action)
ali@416: {
ali@416: 	int r;
ali@416: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@475: 	r = symlink(action->args.u.create_symlink.target, action->args.uri);
ali@416: 	if (r < 0) {
ali@423: 		if (!atomic->error)
ali@475: 			atomic->error = razor_error_new_posix(action->args.uri);
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_remove_symlink(struct razor_atomic *atomic,
ali@416: 			     struct atomic_action *action)
ali@416: {
ali@475: 	struct razor_error **error;
ali@475: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@475: 	if (atomic->error)
ali@475: 		error = NULL;
ali@475: 	else
ali@475: 		error = &atomic->error;
ali@475: 
ali@475: 	if (razor_uri_unlink(action->args.uri, error)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: #endif
ali@416: 
ali@416: static int
ali@475: move_file(struct razor_atomic *atomic, const char *uri, const char *dest)
ali@416: {
ali@475: 	struct razor_error **error;
ali@416: 
ali@475: 	if (atomic->error)
ali@475: 		error = NULL;
ali@475: 	else
ali@475: 		error = &atomic->error;
ali@416: 
ali@475: 	return razor_uri_move(uri, dest, error);
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_move(struct razor_atomic *atomic, struct atomic_action *action)
ali@416: {
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@475: 	if (move_file(atomic, action->args.uri, action->args.u.move.dest)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *
ali@416: atomic_action_unmove(struct razor_atomic *atomic, struct atomic_action *action)
ali@416: {
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@475: 	if (move_file(atomic, action->args.u.move.dest, action->args.uri)) {
ali@416: 		atomic_action_free(action);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *atomic_action_apply(struct razor_atomic *atomic,
ali@416: 						 struct atomic_action *action)
ali@416: {
ali@416: 	switch(action->type) {
ali@416: 	case ACTION_MAKE_DIRS:
ali@416: 		action = atomic_action_make_dirs(atomic, action);
ali@416: 		break;
ali@416: 	case ACTION_REMOVE:
ali@416: 		action = atomic_action_remove(atomic, action);
ali@416: 		break;
ali@416: 	case ACTION_CREATE_DIR:
ali@416: 		action = atomic_action_create_dir(atomic, action);
ali@416: 		break;
ali@416: 	case ACTION_MOVE:
ali@416: 		action = atomic_action_move(atomic, action);
ali@416: 		break;
ali@416: #if HAVE_SYMLINK
ali@416: 	case ACTION_CREATE_SYMLINK:
ali@416: 		action = atomic_action_create_symlink(atomic, action);
ali@416: 		break;
ali@416: #endif
ali@416: 	}
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: static struct atomic_action *atomic_action_reverse(struct razor_atomic *atomic,
ali@416: 						   struct atomic_action *action)
ali@416: {
ali@416: 	switch(action->type) {
ali@416: 	case ACTION_MAKE_DIRS:
ali@416: 	case ACTION_REMOVE:
ali@416: 		/* Complex actions: should never happen */
ali@416: 		break;
ali@416: 	case ACTION_CREATE_DIR:
ali@416: 		action = atomic_action_rmdir(atomic, action);
ali@416: 		break;
ali@416: 	case ACTION_MOVE:
ali@416: 		action = atomic_action_unmove(atomic, action);
ali@416: 		break;
ali@416: #if HAVE_SYMLINK
ali@416: 	case ACTION_CREATE_SYMLINK:
ali@416: 		action = atomic_action_remove_symlink(atomic, action);
ali@416: 		break;
ali@416: #endif
ali@416: 	}
ali@416: 	return action;
ali@416: }
ali@416: 
ali@416: /*
ali@416:  * Note that undo has no error checking.
ali@416:  */
ali@416: 
ali@416: void atomic_action_undo(struct razor_atomic *atomic,
ali@416: 			struct atomic_action *actions)
ali@416: {
ali@416: 	struct atomic_action *a;
ali@416: 
ali@416: 	atomic->in_undo = 1;
ali@416: 
ali@416: 	while (actions) {
ali@416: 		a = atomic_action_list_pop_head(&actions);
ali@416: 		a = atomic_action_reverse(atomic, a);
ali@416: 		atomic_action_free(a);
ali@416: 	}
ali@416: 
ali@416: 	atomic->in_undo = 0;
ali@416: }
ali@416: 
ali@416: struct atomic_action *atomic_action_do(struct razor_atomic *atomic,
ali@416: 				       struct atomic_action *actions)
ali@416: {
ali@416: 	struct atomic_action *done = NULL, *a;
ali@416: 
ali@416: 	if (razor_atomic_in_error_state(atomic)) {
ali@416: 		atomic_action_free(actions);
ali@416: 		return NULL;
ali@416: 	}
ali@416: 
ali@416: 	while (actions) {
ali@416: 		a = atomic_action_list_pop_head(&actions);
ali@416: 		a = atomic_action_apply(atomic, a);
ali@416: 		if (a)
ali@416: 			done = atomic_action_list_concat(a, done);
ali@416: 		if (razor_atomic_in_error_state(atomic)) {
ali@416: 			atomic_action_undo(atomic, done);
ali@416: 			done = NULL;
ali@444: 			atomic_action_free(a);
ali@416: 		}
ali@416: 	}
ali@416: 
ali@416: 	return done;
ali@416: }
ali@416: 
ali@416: #endif	/* ENABLE_ATOMIC && !HAVE_WINDOWS_KTM */