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

/* vi: set sw=4 ts=4: */
/*
 * pfsck --- A generic, parallelizing front-end for the fsck program.
 * It will automatically try to run fsck programs in parallel if the
 * devices are on separate spindles.  It is based on the same ideas as
 * the generic front end for fsck by David Engel and Fred van Kempen,
 * but it has been completely rewritten from scratch to support
 * parallel execution.
 *
 * Written by Theodore Ts'o, <[e-mail]>
 *
 * Miquel van Smoorenburg ([e-mail]) 20-Oct-1994:
 *   o Changed -t fstype to behave like with mount when -A (all file
 *     systems) or -M (like mount) is specified.
 *   o fsck looks if it can find the fsck.type program to decide
 *     if it should ignore the fs type. This way more fsck programs
 *     can be added without changing this front-end.
 *   o -R flag skip root file system.
 *
 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
 *      2001, 2002, 2003, 2004, 2005 by  Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <limits.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <errno.h>
#include <paths.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

#include "fsck.h"
#include "blkid/blkid.h"

#include "e2fsbb.h"

#include "libbb.h"

#ifndef _PATH_MNTTAB
#define _PATH_MNTTAB    "/etc/fstab"
#endif

/*
 * fsck.h
 */

#ifndef DEFAULT_FSTYPE
#define DEFAULT_FSTYPE	"ext2"
#endif

#define MAX_DEVICES 32
#define MAX_ARGS 32

/*
 * Internal structure for mount tabel entries.
 */

struct fs_info {
	char  *device;
	char  *mountpt;
	char  *type;
	char  *opts;
	int   freq;
	int   passno;
	int   flags;
	struct fs_info *next;
};

#define FLAG_DONE 1
#define FLAG_PROGRESS 2

/*
 * Structure to allow exit codes to be stored
 */
struct fsck_instance {
	int	pid;
	int	flags;
	int	exit_status;
	time_t	start_time;
	char *	prog;
	char *	type;
	char *	device;
	char *	base_device;
	struct fsck_instance *next;
};

/*
 * base_device.c
 *
 * Return the "base device" given a particular device; this is used to
 * assure that we only fsck one partition on a particular drive at any
 * one time.  Otherwise, the disk heads will be seeking all over the
 * place.  If the base device cannot be determined, return NULL.
 *
 * The base_device() function returns an allocated string which must
 * be freed.
 *
 */


#ifdef CONFIG_FEATURE_DEVFS
/*
 * Required for the uber-silly devfs /dev/ide/host1/bus2/target3/lun3
 * pathames.
 */
static const char *const devfs_hier[] = {
	"host", "bus", "target", "lun", 0
};
#endif

static char *base_device(const char *device)
{
	char *str, *cp;
#ifdef CONFIG_FEATURE_DEVFS
	const char *const *hier;
	const char *disk;
	int len;
#endif

	cp = str = xstrdup(device);

	/* Skip over /dev/; if it's not present, give up. */
	if (strncmp(cp, "/dev/", 5) != 0)
		goto errout;
	cp += 5;

	/*
	 * For md devices, we treat them all as if they were all
	 * on one disk, since we don't know how to parallelize them.
	 */
	if (cp[0] == 'm' && cp[1] == 'd') {
		*(cp+2) = 0;
		return str;
	}

	/* Handle DAC 960 devices */
	if (strncmp(cp, "rd/", 3) == 0) {
		cp += 3;
		if (cp[0] != 'c' || cp[2] != 'd' ||
		    !isdigit(cp[1]) || !isdigit(cp[3]))
			goto errout;
		*(cp+4) = 0;
		return str;
	}

	/* Now let's handle /dev/hd* and /dev/sd* devices.... */
	if ((cp[0] == 'h' || cp[0] == 's') && (cp[1] == 'd')) {
		cp += 2;
		/* If there's a single number after /dev/hd, skip it */
		if (isdigit(*cp))
			cp++;
		/* What follows must be an alpha char, or give up */
		if (!isalpha(*cp))
			goto errout;
		*(cp + 1) = 0;
		return str;
	}

#ifdef CONFIG_FEATURE_DEVFS
	/* Now let's handle devfs (ugh) names */
	len = 0;
	if (strncmp(cp, "ide/", 4) == 0)
		len = 4;
	if (strncmp(cp, "scsi/", 5) == 0)
		len = 5;
	if (len) {
		cp += len;
		/*
		 * Now we proceed down the expected devfs hierarchy.
		 * i.e., .../host1/bus2/target3/lun4/...
		 * If we don't find the expected token, followed by
		 * some number of digits at each level, abort.
		 */
		for (hier = devfs_hier; *hier; hier++) {
			len = strlen(*hier);
			if (strncmp(cp, *hier, len) != 0)
				goto errout;
			cp += len;
			while (*cp != '/' && *cp != 0) {
				if (!isdigit(*cp))
					goto errout;
				cp++;
			}
			cp++;
		}
		*(cp - 1) = 0;
		return str;
	}

	/* Now handle devfs /dev/disc or /dev/disk names */
	disk = 0;
	if (strncmp(cp, "discs/", 6) == 0)
		disk = "disc";
	else if (strncmp(cp, "disks/", 6) == 0)
		disk = "disk";
	if (disk) {
		cp += 6;
		if (strncmp(cp, disk, 4) != 0)
			goto errout;
		cp += 4;
		while (*cp != '/' && *cp != 0) {
			if (!isdigit(*cp))
				goto errout;
			cp++;
		}
		*cp = 0;
		return str;
	}
#endif

errout:
	free(str);
	return NULL;
}


static const char *const ignored_types[] = {
	"ignore",
	"iso9660",
	"nfs",
	"proc",
	"sw",
	"swap",
	"tmpfs",
	"devpts",
	NULL
};

static const char *const really_wanted[] = {
	"minix",
	"ext2",
	"ext3",
	"jfs",
	"reiserfs",
	"xiafs",
	"xfs",
	NULL
};

#define BASE_MD "/dev/md"

/*
 * Global variables for options
 */
static char *devices[MAX_DEVICES];
static char *args[MAX_ARGS];
static int num_devices, num_args;

static int verbose;
static int doall;
static int noexecute;
static int serialize;
static int skip_root;
static int like_mount;
static int notitle;
static int parallel_root;
static int progress;
static int progress_fd;
static int force_all_parallel;
static int num_running;
static int max_running;
static volatile int cancel_requested;
static int kill_sent;
static char *fstype;
static struct fs_info *filesys_info, *filesys_last;
static struct fsck_instance *instance_list;
static char *fsck_path;
static blkid_cache cache;

static char *string_copy(const char *s)
{
	char    *ret;

	if (!s)
		return 0;
	ret = strdup(s);
	return ret;
}

static int string_to_int(const char *s)
{
	long l;
	char *p;

	l = strtol(s, &p, 0);
	if (*p || l == LONG_MIN || l == LONG_MAX || l < 0 || l > INT_MAX)
		return -1;
	else
		return (int) l;
}

static char *skip_over_blank(char *cp)
{
	while (*cp && isspace(*cp))
		cp++;
	return cp;
}

static char *skip_over_word(char *cp)
{
	while (*cp && !isspace(*cp))
		cp++;
	return cp;
}

static void strip_line(char *line)
{
	char    *p;

	while (*line) {
		p = line + strlen(line) - 1;
		if ((*p == '\n') || (*p == '\r'))
			*p = 0;
		else
			break;
	}
}

static char *parse_word(char **buf)
{
	char *word, *next;

	word = *buf;
	if (*word == 0)
		return 0;

	word = skip_over_blank(word);
	next = skip_over_word(word);
	if (*next)
		*next++ = 0;
	*buf = next;
	return word;
}

static void parse_escape(char *word)
{
	char    *q, c;
	const char *p;

	if (!word)
		return;

	for (p = q = word; *p; q++) {
		c = *p++;
		if (c != '\\') {
			*q = c;
		} else {
			*q = bb_process_escape_sequence(&p);
		}
	}
	*q = 0;
}

static void free_instance(struct fsck_instance *i)
{
	if (i->prog)
		free(i->prog);
	if (i->device)
		free(i->device);
	if (i->base_device)
		free(i->base_device);
	free(i);
}

static struct fs_info *create_fs_device(const char *device, const char *mntpnt,
					const char *type, const char *opts,
					int freq, int passno)
{
	struct fs_info *fs;

	if (!(fs = malloc(sizeof(struct fs_info))))
		return NULL;

	fs->device = string_copy(device);
	fs->mountpt = string_copy(mntpnt);
	fs->type = string_copy(type);
	fs->opts = string_copy(opts ? opts : "");
	fs->freq = freq;
	fs->passno = passno;
	fs->flags = 0;
	fs->next = NULL;

	if (!filesys_info)
		filesys_info = fs;
	else
		filesys_last->next = fs;
	filesys_last = fs;

	return fs;
}



static int parse_fstab_line(char *line, struct fs_info **ret_fs)
{
	char    *dev, *device, *mntpnt, *type, *opts, *freq, *passno, *cp;
	struct fs_info *fs;

	*ret_fs = 0;
	strip_line(line);
	if ((cp = strchr(line, '#')))
		*cp = 0;        /* Ignore everything after the comment char */
	cp = line;

	device = parse_word(&cp);
	mntpnt = parse_word(&cp);
	type = parse_word(&cp);
	opts = parse_word(&cp);
	freq = parse_word(&cp);
	passno = parse_word(&cp);

	if (!device)
		return 0;       /* Allow blank lines */

	if (!mntpnt || !type)
		return -1;

	parse_escape(device);
	parse_escape(mntpnt);
	parse_escape(type);
	parse_escape(opts);
	parse_escape(freq);
	parse_escape(passno);

	dev = blkid_get_devname(cache, device, NULL);
	if (dev)
		device = dev;

	if (strchr(type, ','))
		type = 0;

	fs = create_fs_device(device, mntpnt, type ? type : "auto", opts,
			      freq ? atoi(freq) : -1,
			      passno ? atoi(passno) : -1);
	if (dev)
		free(dev);

	if (!fs)
		return -1;
	*ret_fs = fs;
	return 0;
}

static void interpret_type(struct fs_info *fs)
{
	char    *t;

	if (strcmp(fs->type, "auto") != 0)
		return;
	t = blkid_get_tag_value(cache, "TYPE", fs->device);
	if (t) {
		free(fs->type);
		fs->type = t;
	}
}

/*
 * Load the filesystem database from /etc/fstab
 */
static void load_fs_info(const char *filename)
{
	FILE    *f;
	char    buf[1024];
	int     lineno = 0;
	int     old_fstab = 1;
	struct fs_info *fs;

	if ((f = fopen(filename, "r")) == NULL) {
		bb_perror_msg("WARNING: cannot open %s", filename);
		return;
	}
	while (!feof(f)) {
		lineno++;
		if (!fgets(buf, sizeof(buf), f))
			break;
		buf[sizeof(buf)-1] = 0;
		if (parse_fstab_line(buf, &fs) < 0) {
			bb_error_msg("WARNING: bad format "
				"on line %d of %s\n", lineno, filename);
			continue;
		}
		if (!fs)
			continue;
		if (fs->passno < 0)
			fs->passno = 0;
		else
			old_fstab = 0;
	}

	fclose(f);

	if (old_fstab) {
		fputs("\007\007\007"
		"WARNING: Your /etc/fstab does not contain the fsck passno\n"
		"       field.  I will kludge around things for you, but you\n"
		"       should fix your /etc/fstab file as soon as you can.\n\n", stderr);

		for (fs = filesys_info; fs; fs = fs->next) {
			fs->passno = 1;
		}
	}
}

/* Lookup filesys in /etc/fstab and return the corresponding entry. */
static struct fs_info *lookup(char *filesys)
{
	struct fs_info *fs;

	/* No filesys name given. */
	if (filesys == NULL)
		return NULL;

	for (fs = filesys_info; fs; fs = fs->next) {
		if (!strcmp(filesys, fs->device) ||
		    (fs->mountpt && !strcmp(filesys, fs->mountpt)))
			break;
	}

	return fs;
}

/* Find fsck program for a given fs type. */
static char *find_fsck(char *type)
{
  char *s;
  const char *tpl;
  char *p = string_copy(fsck_path);
  struct stat st;

  /* Are we looking for a program or just a type? */
  tpl = (strncmp(type, "fsck.", 5) ? "%s/fsck.%s" : "%s/%s");

  for(s = strtok(p, ":"); s; s = strtok(NULL, ":")) {
	s = xasprintf(tpl, s, type);
	if (stat(s, &st) == 0) break;
	free(s);
  }
  free(p);
  return s;
}

static int progress_active(void)
{
	struct fsck_instance *inst;

	for (inst = instance_list; inst; inst = inst->next) {
		if (inst->flags & FLAG_DONE)
			continue;
		if (inst->flags & FLAG_PROGRESS)
			return 1;
	}
	return 0;
}

/*
 * Execute a particular fsck program, and link it into the list of
 * child processes we are waiting for.
 */
static int execute(const char *type, const char *device, const char *mntpt,
		   int interactive)
{
	char *s, *argv[80];
	char *prog;
	int  argc, i;
	struct fsck_instance *inst, *p;
	pid_t   pid;

	inst = malloc(sizeof(struct fsck_instance));
	if (!inst)
		return ENOMEM;
	memset(inst, 0, sizeof(struct fsck_instance));

	prog = xasprintf("fsck.%s", type);
	argv[0] = prog;
	argc = 1;

	for (i=0; i <num_args; i++)
		argv[argc++] = string_copy(args[i]);

	if (progress && !progress_active()) {
		if ((strcmp(type, "ext2") == 0) ||
		    (strcmp(type, "ext3") == 0)) {
			char tmp[80];
			snprintf(tmp, 80, "-C%d", progress_fd);
			argv[argc++] = string_copy(tmp);
			inst->flags |= FLAG_PROGRESS;
		}
	}

	argv[argc++] = string_copy(device);
	argv[argc] = 0;

	s = find_fsck(prog);
	if (s == NULL) {
		bb_error_msg("%s: not found", prog);
		return ENOENT;
	}

	if (verbose || noexecute) {
		printf("[%s (%d) -- %s] ", s, num_running,
		       mntpt ? mntpt : device);
		for (i=0; i < argc; i++)
			printf("%s ", argv[i]);
		puts("");
	}

	/* Fork and execute the correct program. */
	if (noexecute)
		pid = -1;
	else if ((pid = fork()) < 0) {
		perror("fork");
		return errno;
	} else if (pid == 0) {
		if (!interactive)
			close(0);
		(void) execv(s, argv);
		bb_perror_msg_and_die("%s", argv[0]);
	}

	for (i = 1; i < argc; i++)
		free(argv[i]);

	free(s);
	inst->pid = pid;
	inst->prog = prog;
	inst->type = string_copy(type);
	inst->device = string_copy(device);
	inst->base_device = base_device(device);
	inst->start_time = time(0);
	inst->next = NULL;

	/*
	 * Find the end of the list, so we add the instance on at the end.
	 */
	for (p = instance_list; p && p->next; p = p->next);

	if (p)
		p->next = inst;
	else
		instance_list = inst;

	return 0;
}

/*
 * Send a signal to all outstanding fsck child processes
 */
static int kill_all(int signum)
{
	struct fsck_instance *inst;
	int     n = 0;

	for (inst = instance_list; inst; inst = inst->next) {
		if (inst->flags & FLAG_DONE)
			continue;
		kill(inst->pid, signum);
		n++;
	}
	return n;
}

/*
 * Wait for one child process to exit; when it does, unlink it from
 * the list of executing child processes, and return it.
 */
static struct fsck_instance *wait_one(int flags)
{
	int     status;
	int     sig;
	struct fsck_instance *inst, *inst2, *prev;
	pid_t   pid;

	if (!instance_list)
		return NULL;

	if (noexecute) {
		inst = instance_list;
		prev = 0;
#ifdef RANDOM_DEBUG
		while (inst->next && (random() & 1)) {
			prev = inst;
			inst = inst->next;
		}
#endif
		inst->exit_status = 0;