/* * Unix SMB/CIFS implementation. * * A general tdb content validation mechanism * * Copyright (C) Michael Adam 2007 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "tdb_validate.h" #include "includes.h" /* * internal validation function, executed by the child. */ static int tdb_validate_child(struct tdb_context *tdb, tdb_validate_data_func validate_fn) { int ret = 1; int num_entries = 0; struct tdb_validation_status v_status; v_status.tdb_error = False; v_status.bad_freelist = False; v_status.bad_entry = False; v_status.unknown_key = False; v_status.success = True; if (!tdb) { v_status.tdb_error = True; v_status.success = False; goto out; } /* * we can simplify this by passing a check function, * but I don't want to change all the callers... */ ret = tdb_check(tdb, NULL, NULL); if (ret == -1) { v_status.tdb_error = True; v_status.success = False; goto out; } /* Check if the tdb's freelist is good. */ if (tdb_validate_freelist(tdb, &num_entries) == -1) { v_status.bad_freelist = True; v_status.success = False; goto out; } DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n", tdb_name(tdb), num_entries)); /* Now traverse the tdb to validate it. */ num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status); if (!v_status.success) { goto out; } else if (num_entries == -1) { v_status.tdb_error = True; v_status.success = False; goto out; } DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n", tdb_name(tdb), num_entries)); ret = 0; /* Cache is good. */ out: DEBUG(10, ("tdb_validate_child: summary of validation status:\n")); DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no")); DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no")); DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no")); DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no")); DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no")); return ret; } /* * tdb validation function. * returns 0 if tdb is ok, != 0 if it isn't. * this function expects an opened tdb. */ int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn) { pid_t child_pid = -1; int child_status = 0; int wait_pid = 0; int ret = 1; if (tdb == NULL) { DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n")); return ret; } DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb))); /* fork and let the child do the validation. * benefit: no need to twist signal handlers and panic functions. * just let the child panic. we catch the signal. */ DEBUG(10, ("tdb_validate: forking to let child do validation.\n")); child_pid = sys_fork(); if (child_pid == 0) { /* child code */ DEBUG(10, ("tdb_validate (validation child): created\n")); DEBUG(10, ("tdb_validate (validation child): " "calling tdb_validate_child\n")); exit(tdb_validate_child(tdb, validate_fn)); } else if (child_pid < 0) { DEBUG(1, ("tdb_validate: fork for validation failed.\n")); goto done; } /* parent */ DEBUG(10, ("tdb_validate: fork succeeded, child PID = %u\n", (unsigned int)child_pid)); DEBUG(10, ("tdb_validate: waiting for child to finish...\n")); while ((wait_pid = sys_waitpid(child_pid, &child_status, 0)) < 0) { if (errno == EINTR) { DEBUG(10, ("tdb_validate: got signal during waitpid, " "retrying\n")); errno = 0; continue; } DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n", strerror(errno))); goto done; } if (wait_pid != child_pid) { DEBUG(1, ("tdb_validate: waitpid returned pid %d, " "but %u was expected\n", wait_pid, (unsigned int)child_pid)); goto done; } DEBUG(10, ("tdb_validate: validating child returned.\n")); if (WIFEXITED(child_status)) { DEBUG(10, ("tdb_validate: child exited, code %d.\n", WEXITSTATUS(child_status))); ret = WEXITSTATUS(child_status); } if (WIFSIGNALED(child_status)) { DEBUG(10, ("tdb_validate: child terminated by signal %d\n", WTERMSIG(child_status))); #ifdef WCOREDUMP if (WCOREDUMP(child_status)) { DEBUGADD(10, ("core dumped\n")); } #endif ret = WTERMSIG(child_status); } if (WIFSTOPPED(child_status)) { DEBUG(10, ("tdb_validate: child was stopped by signal %d\n", WSTOPSIG(child_status))); ret = WSTOPSIG(child_status); } done: DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret, tdb_name(tdb))); return ret; } /* * tdb validation function. * returns 0 if tdb is ok, != 0 if it isn't. * this is a wrapper around the actual validation function that opens and closes * the tdb. */ int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn) { TDB_CONTEXT *tdb = NULL; int ret = 1; DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path)); tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDWR, 0); if (!tdb) { DEBUG(1, ("Error opening tdb %s\n", tdb_path)); return ret; } ret = tdb_validate(tdb, validate_fn); tdb_close(tdb); return ret; } /* * tdb backup function and helpers for tdb_validate wrapper with backup * handling. */ /* this structure eliminates the need for a global overall status for * the traverse-copy */ struct tdb_copy_data { struct tdb_context *dst; bool success; }; static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, void *private_data) { struct tdb_copy_data *data = (struct tdb_copy_data *)private_data; if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) { DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst), strerror(errno))); data->success = False; return 1; } return 0; } static int tdb_copy(struct tdb_context *src, struct tdb_context *dst) { struct tdb_copy_data data; int count; data.dst = dst; data.success = True; count = tdb_traverse(src, traverse_copy_fn, (void *)(&data)); if ((count < 0) || (data.success == False)) { return -1; } return count; } static int tdb_verify_basic(struct tdb_context *tdb) { return tdb_traverse(tdb, NULL, NULL); } /* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb */ static int tdb_backup(TALLOC_CTX *ctx, const char *src_path, const char *dst_path, int hash_size) { struct tdb_context *src_tdb = NULL; struct tdb_context *dst_tdb = NULL; char *tmp_path = NULL; struct stat st; int count1, count2; int saved_errno = 0; int ret = -1; if (stat(src_path, &st) != 0) { DEBUG(3, ("Could not stat '%s': %s\n", src_path, strerror(errno))); goto done; } /* open old tdb RDWR - so we can lock it */ src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0); if (src_tdb == NULL) { DEBUG(3, ("Failed to open tdb '%s'\n", src_path)); goto done; } if (tdb_lockall(src_tdb) != 0) { DEBUG(3, ("Failed to lock tdb '%s'\n", src_path)); goto done; } tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp"); unlink(tmp_path); dst_tdb = tdb_open_log(tmp_path, hash_size ? hash_size : tdb_hash_size(src_tdb), TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL, st.st_mode & 0777); if (dst_tdb == NULL) { DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path, strerror(errno))); saved_errno = errno; unlink(tmp_path); goto done; } count1 = tdb_copy(src_tdb, dst_tdb); if (count1 < 0) { DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path, strerror(errno))); tdb_close(dst_tdb); goto done; } /* reopen ro and do basic verification */ tdb_close(dst_tdb); dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0); if (!dst_tdb) { DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path, strerror(errno))); goto done; } count2 = tdb_verify_basic(dst_tdb); if (count2 != count1) { DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n", src_path)); tdb_close(dst_tdb); goto done; } DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1)); /* make sure the new tdb has reached stable storage * then rename it to its destination */ fsync(tdb_fd(dst_tdb)); tdb_close(dst_tdb); unlink(dst_path); if (rename(tmp_path, dst_path) != 0) { DEBUG(3, ("Failed to rename '%s' to '%s': %s\n", tmp_path, dst_path, strerror(errno))); goto done; } /* success */ ret = 0; done: if (src_tdb != NULL) { tdb_close(src_tdb); } if (tmp_path != NULL) { unlink(tmp_path); TALLOC_FREE(tmp_path); } if (saved_errno != 0) { errno = saved_errno; } return ret; } static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path, const char *suffix) { int ret = -1; char *dst_path; dst_path = talloc_asprintf(ctx, "%s%s", path, suffix); ret = (rename(path, dst_path) != 0); if (ret == 0) { DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path)); } else if (errno == ENOENT) { DEBUG(3, ("file '%s' does not exist - so not moved\n", path)); ret = 0; } else { DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path, strerror(errno))); } TALLOC_FREE(dst_path); return ret; } /* * do a backup of a tdb, moving the destination out of the way first */ static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path, const char *dst_path, int hash_size, const char *rotate_suffix, bool retry_norotate_if_nospc, bool rename_as_last_resort_if_nospc) { int ret; rename_file_with_suffix(ctx, dst_path, rotate_suffix); ret = tdb_backup(ctx, src_path, dst_path, hash_size); if (ret != 0) { DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno))); } if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc) { char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path, rotate_suffix); DEBUG(10, ("backup of %s failed due to lack of space\n", src_path)); DEBUGADD(10, ("trying to free some space by removing rotated " "dst %s\n", rotate_path)); if (unlink(rotate_path) == -1) { DEBUG(10, ("unlink of %s failed: %s\n", rotate_path, strerror(errno))); } else { ret = tdb_backup(ctx, src_path, dst_path, hash_size); } TALLOC_FREE(rotate_path); } if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc) { DEBUG(10, ("backup of %s failed due to lack of space\n", src_path)); DEBUGADD(10, ("using 'rename' as a last resort\n")); ret = rename(src_path, dst_path); } return ret; } /* * validation function with backup handling: * * - calls tdb_validate * - if the tdb is ok, create a backup "name.bak", possibly moving * existing backup to name.bak.old, * return 0 (success) even if the backup fails * - if the tdb is corrupt: * - move the tdb to "name.corrupt" * - check if there is valid backup. * if so, restore the backup. * if restore is successful, return 0 (success), * - otherwise return -1 (failure) */ int tdb_validate_and_backup(const char *tdb_path, tdb_validate_data_func validate_fn) { int ret = -1; const char *backup_suffix = ".bak"; const char *corrupt_suffix = ".corrupt"; const char *rotate_suffix = ".old"; char *tdb_path_backup; struct stat st; TALLOC_CTX *ctx = NULL; ctx = talloc_new(NULL); if (ctx == NULL) { DEBUG(0, ("tdb_validate_and_backup: out of memory\n")); goto done; } tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix); ret = tdb_validate_open(tdb_path, validate_fn); if (ret == 0) { DEBUG(1, ("tdb '%s' is valid\n", tdb_path)); ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0, rotate_suffix, True, False); if (ret != 0) { DEBUG(1, ("Error creating backup of tdb '%s'\n", tdb_path)); /* the actual validation was successful: */ ret = 0; } else { DEBUG(1, ("Created backup '%s' of tdb '%s'\n", tdb_path_backup, tdb_path)); } } else { DEBUG(1, ("tdb '%s' is invalid\n", tdb_path)); ret =stat(tdb_path_backup, &st); if (ret != 0) { DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup, strerror(errno))); DEBUG(1, ("No backup found.\n")); } else { DEBUG(1, ("backup '%s' found.\n", tdb_path_backup)); ret = tdb_validate_open(tdb_path_backup, validate_fn); if (ret != 0) { DEBUG(1, ("Backup '%s' is invalid.\n", tdb_path_backup)); } } if (ret != 0) { int renamed = rename_file_with_suffix(ctx, tdb_path, corrupt_suffix); if (renamed != 0) { DEBUG(1, ("Error moving tdb to '%s%s'\n", tdb_path, corrupt_suffix)); } else { DEBUG(1, ("Corrupt tdb stored as '%s%s'\n", tdb_path, corrupt_suffix)); } goto done; } DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup)); ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0, corrupt_suffix, True, True); if (ret != 0) { DEBUG(1, ("Error restoring backup from '%s'\n", tdb_path_backup)); } else { DEBUG(1, ("Restored tdb backup from '%s'\n", tdb_path_backup)); } } done: TALLOC_FREE(ctx); return ret; }