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tarfs.c
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/* tarfs - A GNU tar filesystem for the Hurd.
Copyright (C) 2002, 2003 Ludovic Courtès <ludo@chbouib.org>
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA */
#include <hurd.h>
#include <hurd/netfs.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <error.h>
#include <sys/mman.h>
#include <dirent.h>
#include <fcntl.h>
#include <limits.h>
#include <argp.h>
#include <argz.h>
#include "backend.h"
#include "tarfs.h"
#include "fs.h"
#include "cache.h"
#include "zipstores.h"
#include "debug.h"
/* New netfs variables */
char *netfs_server_name = "tarfs";
char *netfs_server_version = "(rw-alpha)";
/* Filesystem options */
struct tarfs_opts tarfs_options;
const char *argp_program_version =
"tarfs(rw-alpha) for the GNU Hurd (compiled: " __DATE__ ")";
/* Argp data */
const char *argp_program_bug_address = "Ludovic Courtès <ludo@chbouib.org>";
const char *args_doc = "ARCHIVE";
const char *doc = "Hurd tar filesystem:\n"
"parses a tar archive and creates the corresponding filesystem\n";
const struct argp_option fs_options[] =
{
#ifdef DEBUG
{ "debug", 'D', "FILE", 0, "Print debug output to FILE" },
#endif
{ "gzip", 'z', NULL, 0, "Archive file is gzipped" },
{ "bzip2", 'j', NULL, 0, "Archive file is bzip2'd" },
{ "no-timeout", 't', NULL, 0, "Parse file in a separate thread "
"(thus avoiding startup timeouts)" },
{ "readonly", 'r', NULL, 0, "Start tarfs read-only" },
{ "writable", 'w', NULL, 0, "Start tarfs writable (default)" },
{ "volatile", 'v', NULL, 0, "Start tarfs volatile "
"(ie writable but not synced)" },
{ "create", 'c', NULL, 0, "Create tar file if not there" },
#if 0
{ "sync", 's', "INTERVAL", 0, "Sync all data not actually written "
"to disk every INTERVAL seconds (by "
"default, the data is *not* synced unless "
"explicitely requested)" },
#endif
{ 0 }
};
/* Tar file store & lock. */
static struct store *tar_file;
static struct mutex tar_file_lock;
/* Archive parsing hook (see tar.c) */
extern int (* tar_header_hook) (tar_record_t *, off_t);
/* List of tar items for this file */
static struct tar_list tar_list;
/* Data used by netfs_get_dirents() */
static struct node *curr_dir;
static struct node *curr_node;
static int curr_entry = 0;
/* A convenience macro */
#define IF_RWFS \
if (tarfs_options.readonly) \
return EROFS;
#define D(_s) strdup(_s)
/* Open the tar file STORE according to TARFS_OPTIONS. Assumes the
store is already locked. */
static error_t
open_store ()
{
error_t err;
int flags = tarfs_options.readonly || tarfs_options.volatil
? STORE_READONLY
: 0;
switch (tarfs_options.compress)
{
case COMPRESS_NONE:
err = store_file_open (tarfs_options.file_name, flags, &tar_file);
break;
case COMPRESS_GZIP:
err = store_gzip_open (tarfs_options.file_name, flags, &tar_file);
break;
case COMPRESS_BZIP2:
err = store_bzip2_open (tarfs_options.file_name, flags, &tar_file);
break;
default:
error (1, EINVAL, "Compression method not implemented (yet)");
}
return err;
}
/* Close the tar file assuming that it is already locked. */
static void
close_store ()
{
store_free (tar_file);
tar_file = NULL;
}
/* Reads NODE from file. This is called by the cache backend. */
static error_t
read_from_file (struct node *node, off_t offset, size_t howmuch,
size_t *actually_read, void *data)
{
error_t err = 0;
store_offset_t start = NODE_INFO(node)->tar->offset;
void *d = data;
mutex_lock (&tar_file_lock);
if (!tar_file)
err = open_store ();
if (!err)
err = store_read (tar_file,
start + offset,
howmuch,
&d,
actually_read);
mutex_unlock (&tar_file_lock);
if (err)
return err;
assert (*actually_read <= howmuch);
/* Checks whether store_read() has allocated a new buffer. */
if (data != d)
{
memcpy (data, d, *actually_read);
munmap (d, *actually_read);
}
return 0;
}
/* Argp options parser. */
error_t
tarfs_parse_opts (int key, char *arg, struct argp_state *sate)
{
switch (key)
{
#ifdef DEBUG
case 'D':
debug_set_file (arg);
break;
#endif
case 'c':
tarfs_options.create = 1;
break;
case 'v':
tarfs_options.volatil = 1;
break;
case 'r':
tarfs_options.readonly = 1;
break;
case 'w':
tarfs_options.readonly = 0;
break;
case 't':
tarfs_options.threaded = 1;
break;
case 'z':
tarfs_options.compress = COMPRESS_GZIP;
break;
case 'j':
tarfs_options.compress = COMPRESS_BZIP2;
break;
case 's':
tarfs_options.interval = atoi (arg);
break;
case ARGP_KEY_ARG:
tarfs_options.file_name = strdup (arg);
if (!tarfs_options.file_name || !strlen (tarfs_options.file_name))
error (1, 1, "No archive specified.");
}
return 0;
}
/* Returns the tarfs' struct argp. */
void
tarfs_get_argp (struct argp *a)
{
bzero (a, sizeof (struct argp));
a->options = fs_options;
a->parser = tarfs_parse_opts;
a->args_doc = args_doc;
a->doc = doc;
}
/* Append to the malloced string *ARGZ of len *ARGZ_LEN a NULL-separated list
of arguments. */
error_t
tarfs_get_args (char **argz, unsigned *argz_len)
{
error_t err = 0;
if (!err && tarfs_options.volatil)
err = argz_add (argz, argz_len, "--volatile");
else
{
if (tarfs_options.readonly)
err = argz_add (argz, argz_len, "--readonly");
else
err = argz_add (argz, argz_len, "--writable");
}
if (err)
return err;
switch (tarfs_options.compress)
{
case COMPRESS_GZIP:
err = argz_add (argz, argz_len, "--gzip");
break;
case COMPRESS_BZIP2:
err = argz_add (argz, argz_len, "--bzip2");
}
if (err)
return err;
err = argz_add (argz, argz_len, tarfs_options.file_name);
return err;
}
/* A basic set_options (). Only runtime options can be changed (using
fsysopts): for instance, --no-timeout won't work (it doesn't make
sense when tarfs is already running). */
error_t
tarfs_set_options (char *argz, size_t argz_len)
{
error_t err = 0;
/* If going readonly (resp. read-write) while the store is currently
opened read-write (resp. read-only) then close it first. */
if (!strcmp (argz, "-r") || !strcmp (argz, "--readonly"))
{
if (!tarfs_options.readonly)
{
mutex_lock (&tar_file_lock);
tarfs_options.readonly = 1;
close_store ();
err = open_store ();
mutex_unlock (&tar_file_lock);
if (err)
tarfs_options.readonly = 0;
else
tarfs_options.volatil = 0;
}
}
else if (!strcmp (argz, "-w") || !strcmp (argz, "--writable"))
{
if (tarfs_options.readonly)
{
mutex_lock (&tar_file_lock);
tarfs_options.readonly = 0;
close_store ();
err = open_store ();
mutex_unlock (&tar_file_lock);
if (err)
tarfs_options.readonly = 1;
else
tarfs_options.volatil = 0;
}
}
else if (!strcmp (argz, "-v") || !strcmp (argz, "--volatile"))
tarfs_options.readonly = 0, tarfs_options.volatil = 1;
else
err = EINVAL;
return err;
}
error_t tarfs_create_node (struct node **newnode, struct node *dir,
char *name, mode_t mode);
/* This function is called every time a header has been successfully parsed.
It simply creates the node corresponding to the header.
OFFSET denotes the offset of the header in the archive. */
int
tarfs_add_header (tar_record_t *hdr, off_t offset)
{
error_t err;
static struct tar_item *last_item = NULL;
struct node *dir, *new = NULL;
char *name, *notfound, *retry;
char arch_name[NAMSIZ + 1];
assert (hdr != NULL);
dir = netfs_root_node;
memcpy (arch_name, hdr->header.arch_name, NAMSIZ);
arch_name[NAMSIZ] = '\0';
name = strdup (arch_name);
assert (name);
debug (("name = %s", name));
/* Find the new node's parent directory. */
do
{
err = fs_find_node_path (&dir, &retry, ¬found, name);
/* If a subdirectory wasn't found, then complain, create it and go on.
eg.: if we wan't to create "/foo/bar" and "/foo" does not exist
yet, then create "/foo" first and then continue with "bar". */
if (retry)
{
error (0, 0, "Inconsistent tar archive "
"(directory \"%s\" not found)", notfound);
err = tarfs_create_node (&new, dir, notfound, S_IFDIR | 755);
assert_perror (err);
/*fs_make_subdir (&new, dir, notfound);
NEW_NODE_INFO (new);*/
free (name);
name = retry;
dir = new;
}
}
while (retry);
if (!notfound)
{
/* Means that this node is already here: do nothing. Complain only
if the node we found is not the root dir ("tar cf x ." creates
'./' as the first tar entry). */
if (dir != netfs_root_node)
error (0, 0, "Warning: node \"%s\" already exists", name);
return 0;
}
/* Now, go ahead and create the node. */
name = notfound;
assert (strlen (name) > 0);
switch (hdr->header.linkflag)
{
/* Hard link. */
case LF_LINK:
{
char *tgname;
struct node *target;
debug (("Hard linking \"%s\"", name));
/* Get the target's node first. */
tgname = malloc (NAMSIZ + 1);
memcpy (tgname, hdr->header.arch_linkname, NAMSIZ);
tgname [NAMSIZ] = '\0';
target = netfs_root_node;
fs_find_node_path (&target, &retry, ¬found, tgname);
if ((!retry) && (!notfound))
{
/* FIXME: Call tarfs_create_node () and tarfs_link_node instead */
fs_hard_link_node (&new, dir, name, target->nn_stat.st_mode, target);
/* Update node info & stats */
if (new)
{
NEW_NODE_INFO (new);
/* No need to create a cache for hard links. */
/* Add the tar item into the list. */
err = tar_make_item (&NODE_INFO(new)->tar, new,
0, offset);
assert_perror (err);
}
}
else
error (0, 0, "Hard link target not found (%s -> %s)", name, tgname);
break;
}
/* Other node types. */
default:
err = fs_make_node (&new, dir, name, 0);
assert_perror (err);
/* Update node info & stats */
if (new)
{
NEW_NODE_INFO (new);
tar_header2stat (&new->nn_stat, hdr);
/* Create a cache for the new node. */
err = cache_create (new);
if (err)
error (1, err, "An error occured while creating the filesystem");
/* Add the tar item into the list. */
err = tar_make_item (&NODE_INFO(new)->tar, new,
new->nn_stat.st_size, offset);
assert_perror (err);
}
}
if (!new || err)
error (1, err, "Filesystem could not be built");
tar_insert_item (&tar_list, last_item, NODE_INFO(new)->tar);
last_item = NODE_INFO(new)->tar;
#if 0
debug (("%s: Created node \"%s\" (size=%li)\n",
__FUNCTION__, name, new->nn_stat.st_size));
#endif
/* Symlinks handling */
if (S_ISLNK (new->nn_stat.st_mode))
{
if (hdr->header.arch_linkname[0])
fs_link_node_path (new, strdup (hdr->header.arch_linkname));
else
{
error (0, 0, "Warning: empty symlink target for node \"%s\"",
new->nn->name);
fs_link_node_path (new, strdup (""));
}
}
/* Directories */
if (S_ISDIR (new->nn_stat.st_mode))
{
new->nn_stat.st_nlink = 2;
new->nn->dir->nn_stat.st_nlink++;
}
return 0;
}
error_t
tarfs_init (struct node **root, struct iouser *user)
{
error_t err = 0;
io_statbuf_t st;
int flags;
file_t tarfile;
mode_t mode = 0644;
/* Sync the archive. */
void
sync_archive ()
{
error_t tarfs_sync_fs (int wait);
while (1)
{
sleep (tarfs_options.interval);
if (!tarfs_options.readonly)
tarfs_sync_fs (0);
}
}
/* Reads and parses a tar archive, possibly in a separate thread. */
void
read_archive ()
{
error_t err;
/* Go ahead: parse and build. */
mutex_lock (&tar_file_lock);
err = tar_open_archive (tar_file);
mutex_unlock (&tar_file_lock);
if (err)
error (1, 0, "Invalid tar archive (%s)", tarfs_options.file_name);
#if 0
else
cthread_fork ((cthread_fn_t) sync_archive, NULL);
#endif
}
/* Init. */
if ((! tarfs_options.file_name) || (! strlen (tarfs_options.file_name)))
error (1, 0, "No file specified");
if (tarfs_options.create)
tarfs_options.readonly = 0, flags = O_CREAT | O_READ | O_WRITE;
else
flags = tarfs_options.readonly || tarfs_options.volatil
? O_READ
: O_READ | O_WRITE;
/* Get the tarfile's stat. */
tarfile = file_name_lookup (tarfs_options.file_name, flags, mode);
if (tarfile != MACH_PORT_NULL)
{
/* Check permissions */
err = io_stat (tarfile, &st);
if (!err && (flags & O_READ))
err = fshelp_access (&st, S_IREAD, user);
if (!err && (flags & O_WRITE))
err = fshelp_access (&st, S_IWRITE, user);
}
else
err = errno;
if (err)
{
error (1, err, "%s", tarfs_options.file_name);
return err;
}
mach_port_deallocate (mach_task_self (), tarfile);
err = fs_init ();
if (err)
return err;
/* Create root node */
st.st_mode &= ~S_IFMT;
st.st_mode |= S_IFDIR | S_IROOT | S_IATRANS;
err = fs_make_node (&netfs_root_node, NULL, NULL, st.st_mode);
if (err)
return err;
/* Parse the archive and build the filesystem */
cache_init (read_from_file);
tar_header_hook = tarfs_add_header;
tar_list_init (&tar_list);
/* Open the corresponding store */
err = open_store ();
if (err)
error (1, err, "%s", tarfs_options.file_name);
assert (tar_file);
/* We make the following assumption because this is the way it's gotta
be with these stores. */
assert (tar_file->block_size == 1);
if (st.st_size)
{
if (tarfs_options.threaded)
cthread_fork ((cthread_fn_t) read_archive, NULL);
else
read_archive ();
}
return 0;
}
int
tarfs_set_cd (struct node *dir)
{
curr_dir = dir;
curr_node = dir->nn->entries;
/* Skip anonymous nodes (created by dir_mkfile ()). */
while (curr_node && (! curr_node->nn->name))
curr_node = curr_node->next;
curr_entry = 0;
return 0;
}
int
tarfs_skip_entries (int n)
{
assert (n >= 0);
/* Skip N first DIR entries. */
curr_node = curr_dir->nn->entries;
if (n > 2)
{
/* Skip more than `.' and `..' */
curr_entry = 2;
while ((curr_entry < n) && (curr_node))
{
/* Skip anonymous nodes (created by dir_mkfile ()). */
do
curr_node = curr_node->next;
while (curr_node && (! curr_node->nn->name));
curr_entry++;
}
}
else
curr_entry = n;
/* Returns non-null if could not skip N entries. */
return (curr_entry<=n)?0:1;
}
static inline int
_new_dirent (struct dirent** e, const struct node *n, const char* nodename)
{
size_t namelen;
char* name;
assert (nodename != NULL);
/* N==NULL means that we are considering the node on which the
translator is set. */
namelen = (n) ? strlen (nodename) : 2;
/* Allocate it. */
*e = mmap (NULL, sizeof (struct dirent) + namelen,
PROT_READ|PROT_WRITE, MAP_ANONYMOUS, 0, 0);
assert (*e != NULL);
/* Copy node name */
name = &(*e)->d_name[0];
if (n == NULL)
{
/* `..' */
memcpy (name, nodename, 3);
namelen = 2;
(*e)->d_type = DT_DIR;
(*e)->d_ino = netfs_root_node->nn_stat.st_ino;
}
else
{
memcpy (name, nodename, namelen);
/* Set the type corresponding to n->nn_stat.st_mode */
if (n->nn_stat.st_mode & S_IFREG)
(*e)->d_type = DT_REG;
else if (n->nn_stat.st_mode & S_IFDIR)
(*e)->d_type = DT_DIR;
else if (n->nn_stat.st_mode & S_IFLNK)
(*e)->d_type = DT_LNK;
else
(*e)->d_type = DT_UNKNOWN;
/* if FILENO==0 then the node won't appear. */
(*e)->d_fileno = n->nn_stat.st_ino;
}
assert (namelen != 0);
(*e)->d_namlen = namelen;
(*e)->d_reclen = sizeof (struct dirent) + namelen;
return 0;
}
int
tarfs_get_next_entry (struct dirent **entry)
{
switch (curr_entry++)
{
case 0:
_new_dirent (entry, curr_dir, ".");
break;
case 1:
_new_dirent (entry, curr_dir->nn->dir, "..");
break;
default:
if (!curr_node)
return 1; /* no more entries */
else
{
_new_dirent (entry, curr_node, curr_node->nn->name);
/* Skip anonymous nodes (created by dir_mkfile ()). */
do
curr_node = curr_node->next;
while (curr_node && (! curr_node->nn->name));
}
break;
}
return 0;
}
/* Looks up node named NAME and returns the result in NODE. */
error_t
tarfs_lookup_node (struct node** node, struct node* dir, const char* name)
{
struct node *n = dir->nn->entries;
/* Look for NAME in DIR entries. */
while (n)
{
char *this = n->nn->name;
if (this)
if (!strcmp (this, name))
break;
n = n->next;
}
*node = n;
if (!n)
return ENOENT;
return 0;
}
error_t
tarfs_read_node (struct node *node, off_t offset, size_t *len, void* data)
{
if (S_ISDIR (node->nn_stat.st_mode))
{
*len = 0;
return EISDIR;
}
else
return cache_read (node, offset, *len, data, len);
}
/* Write to NODE through its cache. */
error_t
tarfs_write_node (struct node *node, off_t offset, size_t *len, void *data)
{
IF_RWFS;
if (S_ISDIR (node->nn_stat.st_mode))
{
*len = 0;
return EISDIR;
}
else
{
error_t err;
/* Checks whether we need to actually write to another node.
(hard links are not handled by cache_write ()). */
struct node *what = node->nn->hardlink ? node->nn->hardlink : node;
err = cache_write (node, offset, data, *len, len);
/* Synchronize stat with hard link's target. */
if ((! err) && (what != node))
node->nn_stat.st_size = what->nn_stat.st_size;
return err;
}
}
/* Update NODE stat structure and mark it as dirty. */
error_t
tarfs_change_stat (struct node *node, const io_statbuf_t *st)
{
error_t err = 0;
struct node *what = node->nn->hardlink ? node->nn->hardlink : node;
IF_RWFS;
if (st->st_size != what->nn_stat.st_size)
/* Update the cache size */
err = cache_set_size (what, st->st_size);
if (!err)
{
what->nn_stat = *st;
NODE_INFO(what)->stat_changed = 1;
/* Synchronize NODE with its TARGET if it's a hard link. */
if (what != node)
{
node->nn_stat = what->nn_stat;
NODE_INFO(node)->stat_changed = 1;
}
}
return err;
}
/* Create a node named NAME in directory DIR. If NEWNODE is non-zero then
it will point to the new node. NAME is duplicated. */
error_t
tarfs_create_node (struct node **newnode, struct node *dir,
char *name, mode_t mode)
{
error_t err;
struct node *new = NULL;
IF_RWFS;
/* Allow anonymous (nameless) nodes (created by dir_mkfile ()). */
if (name)
{
/* NODE's path has to be at most NAMSIZ long. */
char *path = fs_get_path_from_root (netfs_root_node, dir);
if (strlen (name) + strlen (path) + 1 > NAMSIZ)
return ENAMETOOLONG;
debug (("Creating node %s", name));
}
else
{
debug (("Creating anonymous node", dir->nn->name));
/* Don't add anonymous nodes into the tar list. */
err = fs_make_node (&new, dir, NULL, mode);
if (!err && new)
NEW_NODE_INFO (new);
*newnode = new;
err = cache_create (new);
return err;
}
err = fs_make_node (&new, dir, strdup (name), mode);
if (!err && new)
{
struct tar_item *tar, *prev_tar;
NEW_NODE_INFO (new);
err = cache_create (new);
if (!err)
{
/* Insert a corresponding tar item into the list.
Offset `-1' denotes a note that does not exist inside the tar file. */
err = tar_make_item (&tar, new, 0, -1);
assert_perror (err);
/* Find a place to put TAR. */
tar_put_item (&prev_tar, tar);
tar_insert_item (&tar_list, prev_tar, tar);
}
}
if (newnode)
*newnode = new;
return err;
}
/* Unlink NODE. NODE's tar_item will remain in the list until the filesystem
is linked, *except* if its offset is `-1' (new node). */
error_t
tarfs_unlink_node (struct node *node)
{
error_t err = 0;
struct tar_item *tar = NODE_INFO(node)->tar;
IF_RWFS;
debug (("Unlinking %s", node->nn->name));
/* Delete NODE. */
err = fs_unlink_node (node);
if (err)
return err;
/* If NODE has never existed inside the tar file, then remove its tar_item
from the list. */
if (tar->offset == -1)
tar_unlink_item (&tar_list, tar);
return err;
}
void
tarfs_free_node (struct node *node)
{
struct tar_item *tar = NODE_INFO (node)->tar;
/* Free all related resources */
cache_free (node);
free (NODE_INFO (node));
fs_free_node (node);
tar->node = NULL;
}
/* Tries to create a hard link named NAME in DIR to file NODE. */
error_t
tarfs_link_node (struct node *dir, struct node *target,
char *name, int excl)
{
error_t err = 0;
struct tar_item *prev_tar, *tar;
struct node *new;
if (fs_find_node (dir, name))
return excl ? EEXIST : 0;
/* If the link's target is anonymous (nameless), then don't create
a new node, just change its name. */
if (!target->nn->name)
{
new = target;
new->nn->name = strdup (name);
/* Insert NEW into the tar list */
err = tar_make_item (&tar, new, 0, -1);
if (!err)
tar_put_item (&prev_tar, tar);
}
else
{
err = fs_hard_link_node (&new, dir, strdup (name),
target->nn_stat.st_mode, target);
if (! err && new)
{
struct tar_item *t;
NEW_NODE_INFO (new);
/* Insert NEW into the tar list */
err = tar_make_item (&tar, new, 0, -1);
if (!err)
{
tar_put_item (&prev_tar, tar);
/* Since NEW must appear after TARGET in the tar list,
Make sure that PREV_TAR comes *before* TARGET's tar, otherwise
set PREV_TAR to be TARGET's tar item. */
for (t = NODE_INFO(target)->tar;
t && (t != prev_tar);
t = t->next);
if (!t)
prev_tar = NODE_INFO(new)->tar;
}
}
}
if (!err)
{
tar_insert_item (&tar_list, prev_tar, tar);
NODE_INFO(new)->tar = tar;
}
return err;
}
/* Tries to turn NODE into a symlink to TARGET. */
error_t
tarfs_symlink_node (struct node *node, const char *target)
{
error_t err;
err = fs_link_node_path (node, target);
return err;
}
/* Tries to turn NODE into a device of type TYPE (either S_IFBLK or S_IFCHR).
*/
error_t
tarfs_mkdev_node (struct node *node, mode_t type, dev_t indexes)