fsck.c

busybox最新版的源码:学习和应用的好东东,多的不说了,大家看后再说吧

		goto ret_inst;
	}

	/*
	 * gcc -Wall fails saving throw against stupidity
	 * (inst and prev are thought to be uninitialized variables)
	 */
	inst = prev = NULL;

	do {
		pid = waitpid(-1, &status, flags);
		if (cancel_requested && !kill_sent) {
			kill_all(SIGTERM);
			kill_sent++;
		}
		if ((pid == 0) && (flags & WNOHANG))
			return NULL;
		if (pid < 0) {
			if ((errno == EINTR) || (errno == EAGAIN))
				continue;
			if (errno == ECHILD) {
				bb_error_msg("wait: no more child process?!?");
				return NULL;
			}
			perror("wait");
			continue;
		}
		for (prev = 0, inst = instance_list;
		     inst;
		     prev = inst, inst = inst->next) {
			if (inst->pid == pid)
				break;
		}
	} while (!inst);

	if (WIFEXITED(status))
		status = WEXITSTATUS(status);
	else if (WIFSIGNALED(status)) {
		sig = WTERMSIG(status);
		if (sig == SIGINT) {
			status = EXIT_UNCORRECTED;
		} else {
			printf("Warning... %s for device %s exited "
			       "with signal %d.\n",
			       inst->prog, inst->device, sig);
			status = EXIT_ERROR;
		}
	} else {
		printf("%s %s: status is %x, should never happen.\n",
		       inst->prog, inst->device, status);
		status = EXIT_ERROR;
	}
	inst->exit_status = status;
	if (progress && (inst->flags & FLAG_PROGRESS) &&
	    !progress_active()) {
		for (inst2 = instance_list; inst2; inst2 = inst2->next) {
			if (inst2->flags & FLAG_DONE)
				continue;
			if (strcmp(inst2->type, "ext2") &&
			    strcmp(inst2->type, "ext3"))
				continue;
			/*
			 * If we've just started the fsck, wait a tiny
			 * bit before sending the kill, to give it
			 * time to set up the signal handler
			 */
			if (inst2->start_time < time(0)+2) {
				if (fork() == 0) {
					sleep(1);
					kill(inst2->pid, SIGUSR1);
					exit(0);
				}
			} else
				kill(inst2->pid, SIGUSR1);
			inst2->flags |= FLAG_PROGRESS;
			break;
		}
	}
ret_inst:
	if (prev)
		prev->next = inst->next;
	else
		instance_list = inst->next;
	if (verbose > 1)
		printf("Finished with %s (exit status %d)\n",
		       inst->device, inst->exit_status);
	num_running--;
	return inst;
}

#define FLAG_WAIT_ALL           0
#define FLAG_WAIT_ATLEAST_ONE   1
/*
 * Wait until all executing child processes have exited; return the
 * logical OR of all of their exit code values.
 */
static int wait_many(int flags)
{
	struct fsck_instance *inst;
	int     global_status = 0;
	int     wait_flags = 0;

	while ((inst = wait_one(wait_flags))) {
		global_status |= inst->exit_status;
		free_instance(inst);
#ifdef RANDOM_DEBUG
		if (noexecute && (flags & WNOHANG) && !(random() % 3))
			break;
#endif
		if (flags & FLAG_WAIT_ATLEAST_ONE)
			wait_flags = WNOHANG;
	}
	return global_status;
}

/*
 * Run the fsck program on a particular device
 *
 * If the type is specified using -t, and it isn't prefixed with "no"
 * (as in "noext2") and only one filesystem type is specified, then
 * use that type regardless of what is specified in /etc/fstab.
 *
 * If the type isn't specified by the user, then use either the type
 * specified in /etc/fstab, or DEFAULT_FSTYPE.
 */
static void fsck_device(struct fs_info *fs, int interactive)
{
	const char *type;
	int retval;

	interpret_type(fs);

	if (strcmp(fs->type, "auto") != 0)
		type = fs->type;
	else if (fstype && strncmp(fstype, "no", 2) &&
	    strncmp(fstype, "opts=", 5) && strncmp(fstype, "loop", 4) &&
	    !strchr(fstype, ','))
		type = fstype;
	else
		type = DEFAULT_FSTYPE;

	num_running++;
	retval = execute(type, fs->device, fs->mountpt, interactive);
	if (retval) {
		bb_error_msg("error %d while executing fsck.%s for %s",
						retval, type, fs->device);
		num_running--;
	}
}


/*
 * Deal with the fsck -t argument.
 */
struct fs_type_compile {
	char **list;
	int *type;
	int  negate;
} fs_type_compiled;

#define FS_TYPE_NORMAL  0
#define FS_TYPE_OPT     1
#define FS_TYPE_NEGOPT  2

static const char fs_type_syntax_error[] =
"Either all or none of the filesystem types passed to -t must be prefixed\n"
   "with 'no' or '!'.";

static void compile_fs_type(char *fs_type, struct fs_type_compile *cmp)
{
	char    *cp, *list, *s;
	int     num = 2;
	int     negate, first_negate = 1;

	if (fs_type) {
		for (cp=fs_type; *cp; cp++) {
			if (*cp == ',')
				num++;
		}
	}

	cmp->list = xzalloc(num * sizeof(char *));
	cmp->type = xzalloc(num * sizeof(int));
	cmp->negate = 0;

	if (!fs_type)
		return;

	list = string_copy(fs_type);
	num = 0;
	s = strtok(list, ",");
	while(s) {
		negate = 0;
		if (strncmp(s, "no", 2) == 0) {
			s += 2;
			negate = 1;
		} else if (*s == '!') {
			s++;
			negate = 1;
		}
		if (strcmp(s, "loop") == 0)
			/* loop is really short-hand for opts=loop */
			goto loop_special_case;
		else if (strncmp(s, "opts=", 5) == 0) {
			s += 5;
		loop_special_case:
			cmp->type[num] = negate ? FS_TYPE_NEGOPT : FS_TYPE_OPT;
		} else {
			if (first_negate) {
				cmp->negate = negate;
				first_negate = 0;
			}
			if ((negate && !cmp->negate) ||
			    (!negate && cmp->negate)) {
				bb_error_msg_and_die("%s", fs_type_syntax_error);
			}
		}
		cmp->list[num++] = string_copy(s);
		s = strtok(NULL, ",");
	}
	free(list);
}

/*
 * This function returns true if a particular option appears in a
 * comma-delimited options list
 */
static int opt_in_list(char *opt, char *optlist)
{
	char    *list, *s;

	if (!optlist)
		return 0;
	list = string_copy(optlist);

	s = strtok(list, ",");
	while(s) {
		if (strcmp(s, opt) == 0) {
			free(list);
			return 1;
		}
		s = strtok(NULL, ",");
	}
	free(list);
	return 0;
}

/* See if the filesystem matches the criteria given by the -t option */
static int fs_match(struct fs_info *fs, struct fs_type_compile *cmp)
{
	int n, ret = 0, checked_type = 0;
	char *cp;

	if (cmp->list == 0 || cmp->list[0] == 0)
		return 1;

	for (n=0; (cp = cmp->list[n]); n++) {
		switch (cmp->type[n]) {
		case FS_TYPE_NORMAL:
			checked_type++;
			if (strcmp(cp, fs->type) == 0) {
				ret = 1;
			}
			break;
		case FS_TYPE_NEGOPT:
			if (opt_in_list(cp, fs->opts))
				return 0;
			break;
		case FS_TYPE_OPT:
			if (!opt_in_list(cp, fs->opts))
				return 0;
			break;
		}
	}
	if (checked_type == 0)
		return 1;
	return (cmp->negate ? !ret : ret);
}

/* Check if we should ignore this filesystem. */
static int ignore(struct fs_info *fs)
{
	int wanted;
	char *s;

	/*
	 * If the pass number is 0, ignore it.
	 */
	if (fs->passno == 0)
		return 1;

	interpret_type(fs);

	/*
	 * If a specific fstype is specified, and it doesn't match,
	 * ignore it.
	 */
	if (!fs_match(fs, &fs_type_compiled)) return 1;

	/* Are we ignoring this type? */
	if (index_in_str_array(ignored_types, fs->type) >= 0)
		return 1;

	/* Do we really really want to check this fs? */
	wanted = index_in_str_array(really_wanted, fs->type) >= 0;

	/* See if the <fsck.fs> program is available. */
	s = find_fsck(fs->type);
	if (s == NULL) {
		if (wanted)
			bb_error_msg("cannot check %s: fsck.%s not found",
				fs->device, fs->type);
		return 1;
	}
	free(s);

	/* We can and want to check this file system type. */
	return 0;
}

/*
 * Returns TRUE if a partition on the same disk is already being
 * checked.
 */
static int device_already_active(char *device)
{
	struct fsck_instance *inst;
	char *base;

	if (force_all_parallel)
		return 0;

#ifdef BASE_MD
	/* Don't check a soft raid disk with any other disk */
	if (instance_list &&
	    (!strncmp(instance_list->device, BASE_MD, sizeof(BASE_MD)-1) ||
	     !strncmp(device, BASE_MD, sizeof(BASE_MD)-1)))
		return 1;
#endif

	base = base_device(device);
	/*
	 * If we don't know the base device, assume that the device is
	 * already active if there are any fsck instances running.
	 */
	if (!base)
		return (instance_list != 0);
	for (inst = instance_list; inst; inst = inst->next) {
		if (!inst->base_device || !strcmp(base, inst->base_device)) {
			free(base);
			return 1;
		}
	}
	free(base);
	return 0;
}

/* Check all file systems, using the /etc/fstab table. */
static int check_all(void)
{
	struct fs_info *fs = NULL;
	int status = EXIT_OK;
	int not_done_yet = 1;
	int passno = 1;
	int pass_done;

	if (verbose)
		fputs("Checking all file systems.\n", stdout);

	/*
	 * Do an initial scan over the filesystem; mark filesystems
	 * which should be ignored as done, and resolve any "auto"
	 * filesystem types (done as a side-effect of calling ignore()).
	 */
	for (fs = filesys_info; fs; fs = fs->next) {
		if (ignore(fs))
			fs->flags |= FLAG_DONE;
	}

	/*
	 * Find and check the root filesystem.
	 */
	if (!parallel_root) {
		for (fs = filesys_info; fs; fs = fs->next) {
			if (LONE_CHAR(fs->mountpt, '/'))
				break;
		}
		if (fs) {
			if (!skip_root && !ignore(fs)) {
				fsck_device(fs, 1);
				status |= wait_many(FLAG_WAIT_ALL);
				if (status > EXIT_NONDESTRUCT)
					return status;
			}
			fs->flags |= FLAG_DONE;
		}
	}
	/*
	 * This is for the bone-headed user who enters the root
	 * filesystem twice.  Skip root will skep all root entries.
	 */
	if (skip_root)
		for (fs = filesys_info; fs; fs = fs->next)
			if (LONE_CHAR(fs->mountpt, '/'))
				fs->flags |= FLAG_DONE;

	while (not_done_yet) {
		not_done_yet = 0;
		pass_done = 1;

		for (fs = filesys_info; fs; fs = fs->next) {
			if (cancel_requested)
				break;
			if (fs->flags & FLAG_DONE)
				continue;
			/*
			 * If the filesystem's pass number is higher
			 * than the current pass number, then we don't
			 * do it yet.
			 */
			if (fs->passno > passno) {
				not_done_yet++;
				continue;
			}
			/*
			 * If a filesystem on a particular device has
			 * already been spawned, then we need to defer
			 * this to another pass.
			 */
			if (device_already_active(fs->device)) {
				pass_done = 0;
				continue;
			}
			/*
			 * Spawn off the fsck process
			 */
			fsck_device(fs, serialize);
			fs->flags |= FLAG_DONE;

			/*
			 * Only do one filesystem at a time, or if we
			 * have a limit on the number of fsck's extant
			 * at one time, apply that limit.
			 */
			if (serialize ||
			    (max_running && (num_running >= max_running))) {
				pass_done = 0;
				break;
			}
		}
		if (cancel_requested)
			break;
		if (verbose > 1)
			printf("--waiting-- (pass %d)\n", passno);
		status |= wait_many(pass_done ? FLAG_WAIT_ALL :
				    FLAG_WAIT_ATLEAST_ONE);
		if (pass_done) {
			if (verbose > 1)
				printf("----------------------------------\n");
			passno++;
		} else
			not_done_yet++;
	}
	if (cancel_requested && !kill_sent) {
		kill_all(SIGTERM);
		kill_sent++;
	}
	status |= wait_many(FLAG_WAIT_ATLEAST_ONE);
	return status;
}

static void signal_cancel(int sig FSCK_ATTR((unused)))
{
	cancel_requested++;
}

static void PRS(int argc, char **argv)
{
	int     i, j;
	char    *arg, *dev, *tmp = 0;
	char    options[128];
	int     opt = 0;
	int     opts_for_fsck = 0;
	struct sigaction        sa;

	/*
	 * Set up signal action
	 */
	memset(&sa, 0, sizeof(struct sigaction));
	sa.sa_handler = signal_cancel;
	sigaction(SIGINT, &sa, 0);
	sigaction(SIGTERM, &sa, 0);

	num_devices = 0;
	num_args = 0;
	instance_list = 0;

	for (i=1; i < argc; i++) {
		arg = argv[i];
		if (!arg)
			continue;
		if ((arg[0] == '/' && !opts_for_fsck) || strchr(arg, '=')) {
			if (num_devices >= MAX_DEVICES) {
				bb_error_msg_and_die("too many devices");
			}
			dev = blkid_get_devname(cache, arg, NULL);
			if (!dev && strchr(arg, '=')) {
				/*
				 * Check to see if we failed because
				 * /proc/partitions isn't found.
				 */
				if (access("/proc/partitions", R_OK) < 0) {
					bb_perror_msg_and_die("cannot open /proc/partitions "
							"(is /proc mounted?)");
				}
				/*
				 * Check to see if this is because
				 * we're not running as root
				 */
				if (geteuid())
					bb_error_msg_and_die(
		"must be root to scan for matching filesystems: %s\n", arg);
				else
					bb_error_msg_and_die(
		"cannot find matching filesystem: %s", arg);
			}
			devices[num_devices++] = dev ? dev : string_copy(arg);
			continue;
		}
		if (arg[0] != '-' || opts_for_fsck) {
			if (num_args >= MAX_ARGS) {
				bb_error_msg_and_die("too many arguments");
			}
			args[num_args++] = string_copy(arg);
			continue;
		}
		for (j=1; arg[j]; j++) {
			if (opts_for_fsck) {
				options[++opt] = arg[j];
				continue;
			}
			switch (arg[j]) {
			case 'A':
				doall++;
				break;
			case 'C':
				progress++;
				if (arg[j+1]) {
					progress_fd = string_to_int(arg+j+1);
					if (progress_fd < 0)
						progress_fd = 0;
					else
						goto next_arg;
				} else if ((i+1) < argc
				 && argv[i+1][0] != '-') {
					progress_fd = string_to_int(argv[i]);
					if (progress_fd < 0)
						progress_fd = 0;
					else {
						goto next_arg;
						i++;
					}
				}
				break;
			case 'V':
				verbose++;
				break;
			case 'N':
				noexecute++;
				break;
			case 'R':
				skip_root++;
				break;
			case 'T':
				notitle++;
				break;
			case 'M':
				like_mount++;
				break;
			case 'P':
				parallel_root++;
				break;
			case 's':
				serialize++;
				break;
			case 't':
				tmp = 0;
				if (fstype)
					bb_show_usage();
				if (arg[j+1])
					tmp = arg+j+1;
				else if ((i+1) < argc)
					tmp = argv[++i];
				else
					bb_show_usage();
				fstype = string_copy(tmp);
				compile_fs_type(fstype, &fs_type_compiled);
				goto next_arg;
			case '-':
				opts_for_fsck++;
				break;
			case '?':
				bb_show_usage();
				break;
			default:
				options[++opt] = arg[j];
				break;
			}
		}
	next_arg:
		if (opt) {
			options[0] = '-';
			options[++opt] = '\0';
			if (num_args >= MAX_ARGS) {
				bb_error_msg("too many arguments");
			}
			args[num_args++] = string_copy(options);
			opt = 0;
		}
	}
	if (getenv("FSCK_FORCE_ALL_PARALLEL"))
		force_all_parallel++;
	if ((tmp = getenv("FSCK_MAX_INST")))
	    max_running = atoi(tmp);
}

int fsck_main(int argc, char **argv);
int fsck_main(int argc, char **argv)
{
	int i, status = 0;
	int interactive = 0;
	const char *fstab;
	struct fs_info *fs;

	setvbuf(stdout, NULL, _IONBF, BUFSIZ);
	setvbuf(stderr, NULL, _IONBF, BUFSIZ);

	blkid_get_cache(&cache, NULL);
	PRS(argc, argv);

	if (!notitle)
		printf("fsck %s (%s)\n", E2FSPROGS_VERSION, E2FSPROGS_DATE);

	fstab = getenv("FSTAB_FILE");
	if (!fstab)
		fstab = _PATH_MNTTAB;
	load_fs_info(fstab);

	fsck_path = e2fs_set_sbin_path();

	if ((num_devices == 1) || (serialize))
		interactive = 1;

	/* If -A was specified ("check all"), do that! */
	if (doall)
		return check_all();

	if (num_devices == 0) {
		serialize++;
		interactive++;
		return check_all();
	}
	for (i = 0; i < num_devices; i++) {
		if (cancel_requested) {
			if (!kill_sent) {
				kill_all(SIGTERM);
				kill_sent++;
			}
			break;
		}
		fs = lookup(devices[i]);
		if (!fs) {
			fs = create_fs_device(devices[i], 0, "auto",
					      0, -1, -1);
			if (!fs)
				continue;
		}
		fsck_device(fs, interactive);
		if (serialize ||
		    (max_running && (num_running >= max_running))) {
			struct fsck_instance *inst;

			inst = wait_one(0);
			if (inst) {
				status |= inst->exit_status;
				free_instance(inst);
			}
			if (verbose > 1)
				printf("----------------------------------\n");
		}
	}
	status |= wait_many(FLAG_WAIT_ALL);
	blkid_put_cache(cache);
	return status;
}