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- /* Virtual File System: GNU Tar file system.
- Copyright (C) 1995, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
- 2006, 2007 Free Software Foundation, Inc.
-
- Written by: 1995 Jakub Jelinek
- Rewritten by: 1998 Pavel Machek
- This program is free software; you can redistribute it and/or
- modify it under the terms of the GNU Library 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 Library General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
- /**
- * \file
- * \brief Source: Virtual File System: GNU Tar file system
- * \author Jakub Jelinek
- * \author Pavel Machek
- * \date 1995, 1998
- *
- * Namespace: init_tarfs
- */
- #include <config.h>
- #include <sys/types.h>
- #include <errno.h>
- #include <ctype.h>
- #include <fcntl.h>
- #ifdef hpux
- /* major() and minor() macros (among other things) defined here for hpux */
- #include <sys/mknod.h>
- #endif
- #include "lib/global.h"
- #include "src/wtools.h" /* message() */
- #include "src/main.h" /* print_vfs_message */
- #include "vfs.h"
- #include "utilvfs.h"
- #include "gc.h" /* vfs_rmstamp */
- #include "xdirentry.h"
- static struct vfs_class vfs_tarfs_ops;
- enum {
- TAR_UNKNOWN = 0,
- TAR_V7,
- TAR_USTAR,
- TAR_POSIX,
- TAR_GNU
- };
- /*
- * Header block on tape.
- *
- * I'm going to use traditional DP naming conventions here.
- * A "block" is a big chunk of stuff that we do I/O on.
- * A "record" is a piece of info that we care about.
- * Typically many "record"s fit into a "block".
- */
- #define RECORDSIZE 512
- #define NAMSIZ 100
- #define PREFIX_SIZE 155
- #define TUNMLEN 32
- #define TGNMLEN 32
- #define SPARSE_EXT_HDR 21
- #define SPARSE_IN_HDR 4
- struct sparse {
- char offset[12];
- char numbytes[12];
- };
- struct sp_array {
- int offset;
- int numbytes;
- };
- union record {
- char charptr[RECORDSIZE];
- struct header {
- char arch_name[NAMSIZ];
- char mode[8];
- char uid[8];
- char gid[8];
- char size[12];
- char mtime[12];
- char chksum[8];
- char linkflag;
- char arch_linkname[NAMSIZ];
- char magic[8];
- char uname[TUNMLEN];
- char gname[TGNMLEN];
- char devmajor[8];
- char devminor[8];
- /* The following bytes of the tar header record were originally unused.
-
- Archives following the ustar specification use almost all of those
- bytes to support pathnames of 256 characters in length.
- GNU tar archives use the "unused" space to support incremental
- archives and sparse files. */
- union unused {
- char prefix[PREFIX_SIZE];
- /* GNU extensions to the ustar (POSIX.1-1988) archive format. */
- struct oldgnu {
- char atime[12];
- char ctime[12];
- char offset[12];
- char longnames[4];
- char pad;
- struct sparse sp[SPARSE_IN_HDR];
- char isextended;
- char realsize[12]; /* true size of the sparse file */
- } oldgnu;
- } unused;
- } header;
- struct extended_header {
- struct sparse sp[21];
- char isextended;
- } ext_hdr;
- };
- /* The checksum field is filled with this while the checksum is computed. */
- #define CHKBLANKS " " /* 8 blanks, no null */
- /* The magic field is filled with this if uname and gname are valid. */
- #define TMAGIC "ustar" /* ustar and a null */
- #define OLDGNU_MAGIC "ustar " /* 7 chars and a null */
- /* The linkflag defines the type of file */
- #define LF_OLDNORMAL '\0' /* Normal disk file, Unix compat */
- #define LF_NORMAL '0' /* Normal disk file */
- #define LF_LINK '1' /* Link to previously dumped file */
- #define LF_SYMLINK '2' /* Symbolic link */
- #define LF_CHR '3' /* Character special file */
- #define LF_BLK '4' /* Block special file */
- #define LF_DIR '5' /* Directory */
- #define LF_FIFO '6' /* FIFO special file */
- #define LF_CONTIG '7' /* Contiguous file */
- #define LF_EXTHDR 'x' /* pax Extended Header */
- #define LF_GLOBAL_EXTHDR 'g' /* pax Global Extended Header */
- /* Further link types may be defined later. */
- /* Note that the standards committee allows only capital A through
- capital Z for user-defined expansion. This means that defining something
- as, say '8' is a *bad* idea. */
- #define LF_DUMPDIR 'D' /* This is a dir entry that contains
- the names of files that were in
- the dir at the time the dump
- was made */
- #define LF_LONGLINK 'K' /* Identifies the NEXT file on the tape
- as having a long linkname */
- #define LF_LONGNAME 'L' /* Identifies the NEXT file on the tape
- as having a long name. */
- #define LF_MULTIVOL 'M' /* This is the continuation
- of a file that began on another
- volume */
- #define LF_NAMES 'N' /* For storing filenames that didn't
- fit in 100 characters */
- #define LF_SPARSE 'S' /* This is for sparse files */
- #define LF_VOLHDR 'V' /* This file is a tape/volume header */
- /* Ignore it on extraction */
- /*
- * Exit codes from the "tar" program
- */
- #define EX_SUCCESS 0 /* success! */
- #define EX_ARGSBAD 1 /* invalid args */
- #define EX_BADFILE 2 /* invalid filename */
- #define EX_BADARCH 3 /* bad archive */
- #define EX_SYSTEM 4 /* system gave unexpected error */
- #define EX_BADVOL 5 /* Special error code means
- Tape volume doesn't match the one
- specified on the command line */
- #define isodigit(c) ( ((c) >= '0') && ((c) <= '7') )
- /*
- * Quick and dirty octal conversion.
- *
- * Result is -1 if the field is invalid (all blank, or nonoctal).
- */
- static long tar_from_oct (int digs, char *where)
- {
- register long value;
- while (isspace ((unsigned char) *where)) { /* Skip spaces */
- where++;
- if (--digs <= 0)
- return -1; /* All blank field */
- }
- value = 0;
- while (digs > 0 && isodigit (*where)) { /* Scan till nonoctal */
- value = (value << 3) | (*where++ - '0');
- --digs;
- }
- if (digs > 0 && *where && !isspace ((unsigned char) *where))
- return -1; /* Ended on non-space/nul */
- return value;
- }
- static void tar_free_archive (struct vfs_class *me, struct vfs_s_super *archive)
- {
- (void) me;
- if (archive->u.arch.fd != -1)
- mc_close(archive->u.arch.fd);
- }
- /* As we open one archive at a time, it is safe to have this static */
- static int current_tar_position = 0;
- /* Returns fd of the open tar file */
- static int
- tar_open_archive_int (struct vfs_class *me, const char *name,
- struct vfs_s_super *archive)
- {
- int result, type;
- mode_t mode;
- struct vfs_s_inode *root;
- result = mc_open (name, O_RDONLY);
- if (result == -1) {
- message (D_ERROR, MSG_ERROR, _("Cannot open tar archive\n%s"), name);
- ERRNOR (ENOENT, -1);
- }
- archive->name = g_strdup (name);
- mc_stat (name, &(archive->u.arch.st));
- archive->u.arch.fd = -1;
- archive->u.arch.type = TAR_UNKNOWN;
- /* Find out the method to handle this tar file */
- type = get_compression_type (result, name);
- mc_lseek (result, 0, SEEK_SET);
- if (type != COMPRESSION_NONE) {
- char *s;
- mc_close (result);
- s = g_strconcat (archive->name, decompress_extension (type), (char *) NULL);
- result = mc_open (s, O_RDONLY);
- if (result == -1)
- message (D_ERROR, MSG_ERROR, _("Cannot open tar archive\n%s"), s);
- g_free (s);
- if (result == -1)
- ERRNOR (ENOENT, -1);
- }
- archive->u.arch.fd = result;
- mode = archive->u.arch.st.st_mode & 07777;
- if (mode & 0400)
- mode |= 0100;
- if (mode & 0040)
- mode |= 0010;
- if (mode & 0004)
- mode |= 0001;
- mode |= S_IFDIR;
- root = vfs_s_new_inode (me, archive, &archive->u.arch.st);
- root->st.st_mode = mode;
- root->data_offset = -1;
- root->st.st_nlink++;
- root->st.st_dev = MEDATA->rdev++;
- archive->root = root;
- return result;
- }
- static union record rec_buf;
- static union record *
- tar_get_next_record (struct vfs_s_super *archive, int tard)
- {
- int n;
- (void) archive;
- n = mc_read (tard, rec_buf.charptr, RECORDSIZE);
- if (n != RECORDSIZE)
- return NULL; /* An error has occurred */
- current_tar_position += RECORDSIZE;
- return &rec_buf;
- }
- static void tar_skip_n_records (struct vfs_s_super *archive, int tard, int n)
- {
- (void) archive;
- mc_lseek (tard, n * RECORDSIZE, SEEK_CUR);
- current_tar_position += n * RECORDSIZE;
- }
- static void
- tar_fill_stat (struct vfs_s_super *archive, struct stat *st, union record *header,
- size_t h_size)
- {
- st->st_mode = tar_from_oct (8, header->header.mode);
- /* Adjust st->st_mode because there are tar-files with
- * linkflag==LF_SYMLINK and S_ISLNK(mod)==0. I don't
- * know about the other modes but I think I cause no new
- * problem when I adjust them, too. -- Norbert.
- */
- if (header->header.linkflag == LF_DIR) {
- st->st_mode |= S_IFDIR;
- } else if (header->header.linkflag == LF_SYMLINK) {
- st->st_mode |= S_IFLNK;
- } else if (header->header.linkflag == LF_CHR) {
- st->st_mode |= S_IFCHR;
- } else if (header->header.linkflag == LF_BLK) {
- st->st_mode |= S_IFBLK;
- } else if (header->header.linkflag == LF_FIFO) {
- st->st_mode |= S_IFIFO;
- } else
- st->st_mode |= S_IFREG;
- st->st_rdev = 0;
- switch (archive->u.arch.type) {
- case TAR_USTAR:
- case TAR_POSIX:
- case TAR_GNU:
- st->st_uid =
- *header->header.uname ? vfs_finduid (header->header.
- uname) : tar_from_oct (8,
- header->
- header.
- uid);
- st->st_gid =
- *header->header.gname ? vfs_findgid (header->header.
- gname) : tar_from_oct (8,
- header->
- header.
- gid);
- switch (header->header.linkflag) {
- case LF_BLK:
- case LF_CHR:
- st->st_rdev =
- (tar_from_oct (8, header->header.devmajor) << 8) |
- tar_from_oct (8, header->header.devminor);
- }
- default:
- st->st_uid = tar_from_oct (8, header->header.uid);
- st->st_gid = tar_from_oct (8, header->header.gid);
- }
- st->st_size = h_size;
- st->st_mtime = tar_from_oct (1 + 12, header->header.mtime);
- st->st_atime = 0;
- st->st_ctime = 0;
- if (archive->u.arch.type == TAR_GNU) {
- st->st_atime = tar_from_oct (1 + 12,
- header->header.unused.oldgnu.atime);
- st->st_ctime = tar_from_oct (1 + 12,
- header->header.unused.oldgnu.ctime);
- }
- }
- typedef enum {
- STATUS_BADCHECKSUM,
- STATUS_SUCCESS,
- STATUS_EOFMARK,
- STATUS_EOF
- } ReadStatus;
- /*
- * Return 1 for success, 0 if the checksum is bad, EOF on eof,
- * 2 for a record full of zeros (EOF marker).
- *
- */
- static ReadStatus
- tar_read_header (struct vfs_class *me, struct vfs_s_super *archive,
- int tard, size_t *h_size)
- {
- register int i;
- register long sum, signed_sum, recsum;
- register char *p;
- register union record *header;
- static char *next_long_name = NULL, *next_long_link = NULL;
- recurse:
- header = tar_get_next_record (archive, tard);
- if (NULL == header)
- return STATUS_EOF;
- recsum = tar_from_oct (8, header->header.chksum);
- sum = 0;
- signed_sum = 0;
- p = header->charptr;
- for (i = sizeof (*header); --i >= 0;) {
- /*
- * We can't use unsigned char here because of old compilers,
- * e.g. V7.
- */
- signed_sum += *p;
- sum += 0xFF & *p++;
- }
- /* Adjust checksum to count the "chksum" field as blanks. */
- for (i = sizeof (header->header.chksum); --i >= 0;) {
- sum -= 0xFF & header->header.chksum[i];
- signed_sum -= (char) header->header.chksum[i];
- }
- sum += ' ' * sizeof header->header.chksum;
- signed_sum += ' ' * sizeof header->header.chksum;
- /*
- * This is a zeroed record...whole record is 0's except
- * for the 8 blanks we faked for the checksum field.
- */
- if (sum == 8 * ' ')
- return STATUS_EOFMARK;
- if (sum != recsum && signed_sum != recsum)
- return STATUS_BADCHECKSUM;
- /*
- * Try to determine the archive format.
- */
- if (archive->u.arch.type == TAR_UNKNOWN) {
- if (!strcmp (header->header.magic, TMAGIC)) {
- if (header->header.linkflag == LF_GLOBAL_EXTHDR)
- archive->u.arch.type = TAR_POSIX;
- else
- archive->u.arch.type = TAR_USTAR;
- } else if (!strcmp (header->header.magic, OLDGNU_MAGIC)) {
- archive->u.arch.type = TAR_GNU;
- }
- }
- /*
- * linkflag on BSDI tar (pax) always '\000'
- */
- if (header->header.linkflag == '\000') {
- if (header->header.arch_name[NAMSIZ - 1] != '\0')
- i = NAMSIZ;
- else
- i = strlen (header->header.arch_name);
- if (i && header->header.arch_name[i - 1] == '/')
- header->header.linkflag = LF_DIR;
- }
- /*
- * Good record. Decode file size and return.
- */
- if (header->header.linkflag == LF_LINK
- || header->header.linkflag == LF_DIR)
- *h_size = 0; /* Links 0 size on tape */
- else
- *h_size = tar_from_oct (1 + 12, header->header.size);
- /*
- * Skip over directory snapshot info records that
- * are stored in incremental tar archives.
- */
- if (header->header.linkflag == LF_DUMPDIR) {
- if (archive->u.arch.type == TAR_UNKNOWN)
- archive->u.arch.type = TAR_GNU;
- return STATUS_SUCCESS;
- }
- /*
- * Skip over pax extended header and global extended
- * header records.
- */
- if (header->header.linkflag == LF_EXTHDR ||
- header->header.linkflag == LF_GLOBAL_EXTHDR) {
- if (archive->u.arch.type == TAR_UNKNOWN)
- archive->u.arch.type = TAR_POSIX;
- return STATUS_SUCCESS;
- }
- if (header->header.linkflag == LF_LONGNAME
- || header->header.linkflag == LF_LONGLINK) {
- char **longp;
- char *bp, *data;
- int size, written;
- if (archive->u.arch.type == TAR_UNKNOWN)
- archive->u.arch.type = TAR_GNU;
- if (*h_size > MC_MAXPATHLEN) {
- message (D_ERROR, MSG_ERROR, _("Inconsistent tar archive"));
- return STATUS_BADCHECKSUM;
- }
- longp = ((header->header.linkflag == LF_LONGNAME)
- ? &next_long_name : &next_long_link);
- g_free (*longp);
- bp = *longp = g_malloc (*h_size + 1);
- for (size = *h_size; size > 0; size -= written) {
- data = tar_get_next_record (archive, tard)->charptr;
- if (data == NULL) {
- g_free (*longp);
- *longp = NULL;
- message (D_ERROR, MSG_ERROR,
- _("Unexpected EOF on archive file"));
- return STATUS_BADCHECKSUM;
- }
- written = RECORDSIZE;
- if (written > size)
- written = size;
- memcpy (bp, data, written);
- bp += written;
- }
- if (bp - *longp == MC_MAXPATHLEN && bp[-1] != '\0') {
- g_free (*longp);
- *longp = NULL;
- message (D_ERROR, MSG_ERROR, _("Inconsistent tar archive"));
- return STATUS_BADCHECKSUM;
- }
- *bp = 0;
- goto recurse;
- } else {
- struct stat st;
- struct vfs_s_entry *entry;
- struct vfs_s_inode *inode = NULL, *parent;
- long data_position;
- char *q;
- int len;
- char *current_file_name, *current_link_name;
- current_link_name =
- (next_long_link ? next_long_link :
- g_strndup (header->header.arch_linkname, NAMSIZ));
- len = strlen (current_link_name);
- if (len > 1 && current_link_name[len - 1] == '/')
- current_link_name[len - 1] = 0;
- current_file_name = NULL;
- switch (archive->u.arch.type) {
- case TAR_USTAR:
- case TAR_POSIX:
- /* The ustar archive format supports pathnames of upto 256
- * characters in length. This is achieved by concatenating
- * the contents of the `prefix' and `arch_name' fields like
- * this:
- *
- * prefix + path_separator + arch_name
- *
- * If the `prefix' field contains an empty string i.e. its
- * first characters is '\0' the prefix field is ignored.
- */
- if (header->header.unused.prefix[0] != '\0') {
- char *temp_name, *temp_prefix;
- temp_name = g_strndup (header->header.arch_name, NAMSIZ);
- temp_prefix = g_strndup (header->header.unused.prefix,
- PREFIX_SIZE);
- current_file_name = g_strconcat (temp_prefix, PATH_SEP_STR,
- temp_name, (char *) NULL);
- g_free (temp_name);
- g_free (temp_prefix);
- }
- break;
- case TAR_GNU:
- if (next_long_name != NULL)
- current_file_name = next_long_name;
- break;
- default:
- break;
- }
- if (current_file_name == NULL)
- current_file_name = g_strndup (header->header.arch_name, NAMSIZ);
- canonicalize_pathname (current_file_name);
- len = strlen (current_file_name);
- data_position = current_tar_position;
- p = strrchr (current_file_name, '/');
- if (p == NULL) {
- p = current_file_name;
- q = current_file_name + len; /* "" */
- } else {
- *(p++) = 0;
- q = current_file_name;
- }
- parent =
- vfs_s_find_inode (me, archive, q, LINK_NO_FOLLOW, FL_MKDIR);
- if (parent == NULL) {
- message (D_ERROR, MSG_ERROR, _("Inconsistent tar archive"));
- return STATUS_BADCHECKSUM;
- }
- if (header->header.linkflag == LF_LINK) {
- inode =
- vfs_s_find_inode (me, archive, current_link_name,
- LINK_NO_FOLLOW, 0);
- if (inode == NULL) {
- message (D_ERROR, MSG_ERROR, _("Inconsistent tar archive"));
- } else {
- entry = vfs_s_new_entry (me, p, inode);
- vfs_s_insert_entry (me, parent, entry);
- g_free (current_link_name);
- goto done;
- }
- }
- tar_fill_stat (archive, &st, header, *h_size);
- if (S_ISDIR(st.st_mode)) {
- entry = MEDATA->find_entry (me, parent, p, LINK_NO_FOLLOW, FL_NONE);
- if (entry)
- goto done;
- }
- inode = vfs_s_new_inode (me, archive, &st);
- inode->data_offset = data_position;
- if (*current_link_name) {
- inode->linkname = current_link_name;
- } else if (current_link_name != next_long_link) {
- g_free (current_link_name);
- }
- entry = vfs_s_new_entry (me, p, inode);
- vfs_s_insert_entry (me, parent, entry);
- g_free (current_file_name);
- done:
- next_long_link = next_long_name = NULL;
- if (archive->u.arch.type == TAR_GNU &&
- header->header.unused.oldgnu.isextended) {
- while (tar_get_next_record (archive, tard)->ext_hdr.
- isextended);
- inode->data_offset = current_tar_position;
- }
- return STATUS_SUCCESS;
- }
- }
- /*
- * Main loop for reading an archive.
- * Returns 0 on success, -1 on error.
- */
- static int
- tar_open_archive (struct vfs_class *me, struct vfs_s_super *archive,
- const char *name, char *op)
- {
- /* Initial status at start of archive */
- ReadStatus status = STATUS_EOFMARK;
- ReadStatus prev_status;
- int tard;
- (void) op;
- current_tar_position = 0;
- /* Open for reading */
- tard = tar_open_archive_int (me, name, archive);
- if (tard == -1)
- return -1;
- for (;;) {
- size_t h_size;
- prev_status = status;
- status = tar_read_header (me, archive, tard, &h_size);
- switch (status) {
- case STATUS_SUCCESS:
- tar_skip_n_records (archive, tard,
- (h_size + RECORDSIZE -
- 1) / RECORDSIZE);
- continue;
- /*
- * Invalid header:
- *
- * If the previous header was good, tell them
- * that we are skipping bad ones.
- */
- case STATUS_BADCHECKSUM:
- switch (prev_status) {
- /* Error on first record */
- case STATUS_EOFMARK:
- message (D_ERROR, MSG_ERROR,
- _
- ("%s\ndoesn't look like a tar archive."),
- name);
- /* FALL THRU */
- /* Error after header rec */
- case STATUS_SUCCESS:
- /* Error after error */
- case STATUS_BADCHECKSUM:
- return -1;
- case STATUS_EOF:
- return 0;
- }
- /* Record of zeroes */
- case STATUS_EOFMARK:
- status = prev_status; /* If error after 0's */
- /* FALL THRU */
- case STATUS_EOF: /* End of archive */
- break;
- }
- break;
- };
- return 0;
- }
- static void *
- tar_super_check (struct vfs_class *me, const char *archive_name, char *op)
- {
- static struct stat stat_buf;
- (void) me;
- (void) op;
- if (mc_stat (archive_name, &stat_buf))
- return NULL;
- return &stat_buf;
- }
- static int
- tar_super_same (struct vfs_class *me, struct vfs_s_super *parc,
- const char *archive_name, char *op, void *cookie)
- {
- struct stat *archive_stat = cookie; /* stat of main archive */
- (void) me;
- (void) op;
- if (strcmp (parc->name, archive_name))
- return 0;
- /* Has the cached archive been changed on the disk? */
- if (parc->u.arch.st.st_mtime < archive_stat->st_mtime) {
- /* Yes, reload! */
- (*vfs_tarfs_ops.free) ((vfsid) parc);
- vfs_rmstamp (&vfs_tarfs_ops, (vfsid) parc);
- return 2;
- }
- /* Hasn't been modified, give it a new timeout */
- vfs_stamp (&vfs_tarfs_ops, (vfsid) parc);
- return 1;
- }
- static ssize_t tar_read (void *fh, char *buffer, int count)
- {
- off_t begin = FH->ino->data_offset;
- int fd = FH_SUPER->u.arch.fd;
- struct vfs_class *me = FH_SUPER->me;
- if (mc_lseek (fd, begin + FH->pos, SEEK_SET) !=
- begin + FH->pos) ERRNOR (EIO, -1);
- count = MIN(count, FH->ino->st.st_size - FH->pos);
- count = mc_read (fd, buffer, count);
- if (count == -1)
- ERRNOR (errno, -1);
- FH->pos += count;
- return count;
- }
- static int tar_fh_open (struct vfs_class *me, struct vfs_s_fh *fh, int flags, int mode)
- {
- (void) fh;
- (void) mode;
- if ((flags & O_ACCMODE) != O_RDONLY) ERRNOR (EROFS, -1);
- return 0;
- }
- void
- init_tarfs (void)
- {
- static struct vfs_s_subclass tarfs_subclass;
- tarfs_subclass.flags = VFS_S_READONLY;
- tarfs_subclass.archive_check = tar_super_check;
- tarfs_subclass.archive_same = tar_super_same;
- tarfs_subclass.open_archive = tar_open_archive;
- tarfs_subclass.free_archive = tar_free_archive;
- tarfs_subclass.fh_open = tar_fh_open;
- vfs_s_init_class (&vfs_tarfs_ops, &tarfs_subclass);
- vfs_tarfs_ops.name = "tarfs";
- vfs_tarfs_ops.prefix = "utar";
- vfs_tarfs_ops.read = tar_read;
- vfs_tarfs_ops.setctl = NULL;
- vfs_register_class (&vfs_tarfs_ops);
- }
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