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NetBSD/gnu/usr.bin/tar/extract.c

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/* Extract files from a tar archive.
Copyright (C) 1988, 1992, 1993 Free Software Foundation
This file is part of GNU Tar.
GNU Tar 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, or (at your option)
any later version.
GNU Tar 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 GNU Tar; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* Extract files from a tar archive.
*
* Written 19 Nov 1985 by John Gilmore, ihnp4!hoptoad!gnu.
*/
#include <stdio.h>
#include <errno.h>
#ifndef STDC_HEADERS
extern int errno;
#endif
#include <sys/types.h>
#include <time.h>
time_t time ();
#ifdef BSD42
#include <sys/file.h>
#else
#ifndef V7
#include <fcntl.h>
#endif
#endif
#ifdef NO_OPEN3
/* We need the #define's even though we don't use them. */
#include "open3.h"
#endif
#ifdef EMUL_OPEN3
/* Simulated 3-argument open for systems that don't have it */
#include "open3.h"
#endif
#include "tar.h"
#include "port.h"
#if defined(_POSIX_VERSION)
#include <utime.h>
#else
struct utimbuf
{
long actime;
long modtime;
};
#endif
extern FILE *msg_file;
extern union record *head; /* Points to current tape header */
extern struct stat hstat; /* Stat struct corresponding */
extern int head_standard; /* Tape header is in ANSI format */
extern char *save_name;
extern long save_totsize;
extern long save_sizeleft;
int confirm ();
void decode_header ();
void extract_mangle ();
void extract_sparse_file ();
long from_oct ();
void gnu_restore ();
extern void print_header ();
extern void skip_file ();
extern void skip_extended_headers ();
extern void pr_mkdir ();
void saverec ();
int make_dirs (); /* Makes required directories */
static time_t now = 0; /* Current time */
static we_are_root = 0; /* True if our effective uid == 0 */
static int notumask = ~0; /* Masks out bits user doesn't want */
/*
* "Scratch" space to store the information about a sparse file before
* writing the info into the header or extended header
*/
/*struct sp_array *sparsearray;*/
/* number of elts storable in the sparsearray */
/*int sp_array_size = 10;*/
struct saved_dir_info
{
char *path;
int mode;
int atime;
int mtime;
struct saved_dir_info *next;
};
struct saved_dir_info *saved_dir_info_head;
/*
* Set up to extract files.
*/
void
extr_init ()
{
int ourmask;
now = time ((time_t *) 0);
if (geteuid () == 0)
we_are_root = 1;
/*
* We need to know our umask. But if f_use_protection is set,
* leave our kernel umask at 0, and our "notumask" at ~0.
*/
ourmask = umask (0); /* Read it */
if (!f_use_protection)
{
(void) umask (ourmask); /* Set it back how it was */
notumask = ~ourmask; /* Make umask override permissions */
}
}
/*
* Extract a file from the archive.
*/
void
extract_archive ()
{
register char *data;
int fd, check, namelen, written, openflag;
long size;
struct utimbuf acc_upd_times;
register int skipcrud;
register int i;
/* int sparse_ind = 0;*/
union record *exhdr;
struct saved_dir_info *tmp;
/* int end_nulls; */
saverec (&head); /* Make sure it sticks around */
userec (head); /* And go past it in the archive */
decode_header (head, &hstat, &head_standard, 1); /* Snarf fields */
if (f_confirm && !confirm ("extract", current_file_name))
{
if (head->header.isextended)
skip_extended_headers ();
skip_file ((long) hstat.st_size);
saverec ((union record **) 0);
return;
}
/* Print the record from 'head' and 'hstat' */
if (f_verbose)
print_header ();
/*
* Check for fully specified pathnames and other atrocities.
*
* Note, we can't just make a pointer to the new file name,
* since saverec() might move the header and adjust "head".
* We have to start from "head" every time we want to touch
* the header record.
*/
skipcrud = 0;
while (!f_absolute_paths
&& '/' == current_file_name[skipcrud])
{
static int warned_once = 0;
skipcrud++; /* Force relative path */
if (!warned_once++)
{
msg ("Removing leading / from absolute path names in the archive.");
}
}
switch (head->header.linkflag)
{
default:
msg ("Unknown file type '%c' for %s, extracted as normal file",
head->header.linkflag, skipcrud + current_file_name);
/* FALL THRU */
/*
* JK - What we want to do if the file is sparse is loop through
* the array of sparse structures in the header and read in
* and translate the character strings representing 1) the offset
* at which to write and 2) how many bytes to write into numbers,
* which we store into the scratch array, "sparsearray". This
* array makes our life easier the same way it did in creating
* the tar file that had to deal with a sparse file.
*
* After we read in the first five (at most) sparse structures,
* we check to see if the file has an extended header, i.e.,
* if more sparse structures are needed to describe the contents
* of the new file. If so, we read in the extended headers
* and continue to store their contents into the sparsearray.
*/
case LF_SPARSE:
sp_array_size = 10;
sparsearray = (struct sp_array *) ck_malloc (sp_array_size * sizeof (struct sp_array));
for (i = 0; i < SPARSE_IN_HDR; i++)
{
sparsearray[i].offset =
from_oct (1 + 12, head->header.sp[i].offset);
sparsearray[i].numbytes =
from_oct (1 + 12, head->header.sp[i].numbytes);
if (!sparsearray[i].numbytes)
break;
}
/* end_nulls = from_oct(1+12, head->header.ending_blanks);*/
if (head->header.isextended)
{
/* read in the list of extended headers
and translate them into the sparsearray
as before */
/* static */ int ind = SPARSE_IN_HDR;
for (;;)
{
exhdr = findrec ();
for (i = 0; i < SPARSE_EXT_HDR; i++)
{
if (i + ind > sp_array_size - 1)
{
/*
* realloc the scratch area
* since we've run out of room --
*/
sparsearray = (struct sp_array *)
ck_realloc (sparsearray,
2 * sp_array_size * (sizeof (struct sp_array)));
sp_array_size *= 2;
}
if (!exhdr->ext_hdr.sp[i].numbytes)
break;
sparsearray[i + ind].offset =
from_oct (1 + 12, exhdr->ext_hdr.sp[i].offset);
sparsearray[i + ind].numbytes =
from_oct (1 + 12, exhdr->ext_hdr.sp[i].numbytes);
}
if (!exhdr->ext_hdr.isextended)
break;
else
{
ind += SPARSE_EXT_HDR;
userec (exhdr);
}
}
userec (exhdr);
}
/* FALL THRU */
case LF_OLDNORMAL:
case LF_NORMAL:
case LF_CONTIG:
/*
* Appears to be a file.
* See if it's really a directory.
*/
namelen = strlen (skipcrud + current_file_name) - 1;
if (current_file_name[skipcrud + namelen] == '/')
goto really_dir;
/* FIXME, deal with protection issues */
again_file:
openflag = (f_keep ?
O_BINARY | O_NDELAY | O_WRONLY | O_CREAT | O_EXCL :
O_BINARY | O_NDELAY | O_WRONLY | O_CREAT | O_TRUNC)
| ((head->header.linkflag == LF_SPARSE) ? 0 : O_APPEND);
/*
* JK - The last | is a kludge to solve the problem
* the O_APPEND flag causes with files we are
* trying to make sparse: when a file is opened
* with O_APPEND, it writes to the last place
* that something was written, thereby ignoring
* any lseeks that we have done. We add this
* extra condition to make it able to lseek when
* a file is sparse, i.e., we don't open the new
* file with this flag. (Grump -- this bug caused
* me to waste a good deal of time, I might add)
*/
if (f_exstdout)
{
fd = 1;
goto extract_file;
}
#ifdef O_CTG
/*
* Contiguous files (on the Masscomp) have to specify
* the size in the open call that creates them.
*/
if (head->header.linkflag == LF_CONTIG)
fd = open ((longname ? longname : head->header.name)
+ skipcrud,
openflag | O_CTG,
hstat.st_mode, hstat.st_size);
else
#endif
{
#ifdef NO_OPEN3
/*
* On raw V7 we won't let them specify -k (f_keep), but
* we just bull ahead and create the files.
*/
fd = creat ((longname
? longname
: head->header.name) + skipcrud,
hstat.st_mode);
#else
/*
* With 3-arg open(), we can do this up right.
*/
fd = open (skipcrud + current_file_name,
openflag, hstat.st_mode);
#endif
}
if (fd < 0)
{
if (make_dirs (skipcrud + current_file_name))
goto again_file;
msg_perror ("Could not create file %s",
skipcrud + current_file_name);
if (head->header.isextended)
skip_extended_headers ();
skip_file ((long) hstat.st_size);
goto quit;
}
extract_file:
if (head->header.linkflag == LF_SPARSE)
{
char *name;
int namelen;
/*
* Kludge alert. NAME is assigned to header.name
* because during the extraction, the space that
* contains the header will get scribbled on, and
* the name will get munged, so any error messages
* that happen to contain the filename will look
* REAL interesting unless we do this.
*/
namelen = strlen (skipcrud + current_file_name) + 1;
name = (char *) ck_malloc ((sizeof (char)) * namelen);
bcopy (skipcrud + current_file_name, name, namelen);
size = hstat.st_size;
extract_sparse_file (fd, &size, hstat.st_size, name);
}
else
for (size = hstat.st_size;
size > 0;
size -= written)
{
/* long offset,
numbytes;*/
if (f_multivol)
{
save_name = current_file_name;
save_totsize = hstat.st_size;
save_sizeleft = size;
}
/*
* Locate data, determine max length
* writeable, write it, record that
* we have used the data, then check
* if the write worked.
*/
data = findrec ()->charptr;
if (data == NULL)
{ /* Check it... */
msg ("Unexpected EOF on archive file");
break;
}
/*
* JK - If the file is sparse, use the sparsearray
* that we created before to lseek into the new
* file the proper amount, and to see how many
* bytes we want to write at that position.
*/
/* if (head->header.linkflag == LF_SPARSE) {
off_t pos;
pos = lseek(fd, (off_t) sparsearray[sparse_ind].offset, 0);
printf("%d at %d\n", (int) pos, sparse_ind);
written = sparsearray[sparse_ind++].numbytes;
} else*/
written = endofrecs ()->charptr - data;
if (written > size)
written = size;
errno = 0;
check = write (fd, data, written);
/*
* The following is in violation of strict
* typing, since the arg to userec
* should be a struct rec *. FIXME.
*/
userec ((union record *) (data + written - 1));
if (check == written)
continue;
/*
* Error in writing to file.
* Print it, skip to next file in archive.
*/
if (check < 0)
msg_perror ("couldn't write to file %s",
skipcrud + current_file_name);
else
msg ("could only write %d of %d bytes to file %s",
check, written, skipcrud + current_file_name);
skip_file ((long) (size - written));
break; /* Still do the close, mod time, chmod, etc */
}
if (f_multivol)
save_name = 0;
/* If writing to stdout, don't try to do anything
to the filename; it doesn't exist, or we don't
want to touch it anyway */
if (f_exstdout)
break;
/* if (head->header.isextended) {
register union record *exhdr;
register int i;
for (i = 0; i < 21; i++) {
long offset;
if (!exhdr->ext_hdr.sp[i].numbytes)
break;
offset = from_oct(1+12,
exhdr->ext_hdr.sp[i].offset);
written = from_oct(1+12,
exhdr->ext_hdr.sp[i].numbytes);
lseek(fd, offset, 0);
check = write(fd, data, written);
if (check == written) continue;
}
}*/
check = close (fd);
if (check < 0)
{
msg_perror ("Error while closing %s",
skipcrud + current_file_name);
}
set_filestat:
/*
* If we are root, set the owner and group of the extracted
* file. This does what is wanted both on real Unix and on
* System V. If we are running as a user, we extract as that
* user; if running as root, we extract as the original owner.
*/
if (we_are_root || f_do_chown)
{
if (chown (skipcrud + current_file_name,
hstat.st_uid, hstat.st_gid) < 0)
{
msg_perror ("cannot chown file %s to uid %d gid %d",
skipcrud + current_file_name,
hstat.st_uid, hstat.st_gid);
}
}
/*
* Set the modified time of the file.
*
* Note that we set the accessed time to "now", which
* is really "the time we started extracting files".
* unless f_gnudump is used, in which case .st_atime is used
*/
if (!f_modified)
{
/* fixme if f_gnudump should set ctime too, but how? */
if (f_gnudump)
acc_upd_times.actime = hstat.st_atime;
else
acc_upd_times.actime = now; /* Accessed now */
acc_upd_times.modtime = hstat.st_mtime; /* Mod'd */
if (utime (skipcrud + current_file_name,
&acc_upd_times) < 0)
{
msg_perror ("couldn't change access and modification times of %s", skipcrud + current_file_name);
}
}
/* We do the utime before the chmod because some versions of
utime are broken and trash the modes of the file. Since
we then change the mode anyway, we don't care. . . */
/*
* If '-k' is not set, open() or creat() could have saved
* the permission bits from a previously created file,
* ignoring the ones we specified.
* Even if -k is set, if the file has abnormal
* mode bits, we must chmod since writing or chown() has
* probably reset them.
*
* If -k is set, we know *we* created this file, so the mode
* bits were set by our open(). If the file is "normal", we
* skip the chmod. This works because we did umask(0) if -p
* is set, so umask will have left the specified mode alone.
*/
if ((!f_keep)
|| (hstat.st_mode & (S_ISUID | S_ISGID | S_ISVTX)))
{
if (chmod (skipcrud + current_file_name,
notumask & (int) hstat.st_mode) < 0)
{
msg_perror ("cannot change mode of file %s to %ld",
skipcrud + current_file_name,
notumask & (int) hstat.st_mode);
}
}
quit:
break;
case LF_LINK:
again_link:
{
struct stat st1, st2;
check = link (current_link_name, skipcrud + current_file_name);
if (check == 0)
break;
if (make_dirs (skipcrud + current_file_name))
goto again_link;
if (f_gnudump && errno == EEXIST)
break;
if (stat (current_link_name, &st1) == 0
&& stat (current_file_name + skipcrud, &st2) == 0
&& st1.st_dev == st2.st_dev
&& st1.st_ino == st2.st_ino)
break;
msg_perror ("Could not link %s to %s",
skipcrud + current_file_name,
current_link_name);
}
break;
#ifdef S_ISLNK
case LF_SYMLINK:
again_symlink:
check = symlink (current_link_name,
skipcrud + current_file_name);
/* FIXME, don't worry uid, gid, etc... */
if (check == 0)
break;
if (make_dirs (current_file_name + skipcrud))
goto again_symlink;
msg_perror ("Could not create symlink to %s",
current_link_name);
break;
#endif
#ifdef S_IFCHR
case LF_CHR:
hstat.st_mode |= S_IFCHR;
goto make_node;
#endif
#ifdef S_IFBLK
case LF_BLK:
hstat.st_mode |= S_IFBLK;
#endif
#if defined(S_IFCHR) || defined(S_IFBLK)
make_node:
check = mknod (current_file_name + skipcrud,
(int) hstat.st_mode, (int) hstat.st_rdev);
if (check != 0)
{
if (make_dirs (skipcrud + current_file_name))
goto make_node;
msg_perror ("Could not make %s",
current_file_name + skipcrud);
break;
};
goto set_filestat;
#endif
#ifdef S_ISFIFO
/* If local system doesn't support FIFOs, use default case */
case LF_FIFO:
make_fifo:
check = mkfifo (current_file_name + skipcrud,
(int) hstat.st_mode);
if (check != 0)
{
if (make_dirs (current_file_name + skipcrud))
goto make_fifo;
msg_perror ("Could not make %s",
skipcrud + current_file_name);
break;
};
goto set_filestat;
#endif
case LF_DIR:
case LF_DUMPDIR:
namelen = strlen (current_file_name + skipcrud) - 1;
really_dir:
/* Check for trailing /, and zap as many as we find. */
while (namelen
&& current_file_name[skipcrud + namelen] == '/')
current_file_name[skipcrud + namelen--] = '\0';
if (f_gnudump)
{ /* Read the entry and delete files
that aren't listed in the archive */
gnu_restore (skipcrud);
}
else if (head->header.linkflag == LF_DUMPDIR)
skip_file ((long) (hstat.st_size));
again_dir:
check = mkdir (skipcrud + current_file_name,
(we_are_root ? 0 : 0300) | (int) hstat.st_mode);
if (check != 0)
{
struct stat st1;
if (make_dirs (skipcrud + current_file_name))
goto again_dir;
/* If we're trying to create '.', let it be. */
if (current_file_name[skipcrud + namelen] == '.' &&
(namelen == 0 ||
current_file_name[skipcrud + namelen - 1] == '/'))
goto check_perms;
if (errno == EEXIST
&& stat (skipcrud + current_file_name, &st1) == 0
&& (S_ISDIR (st1.st_mode)))
break;
msg_perror ("Could not create directory %s", skipcrud + current_file_name);
break;
}
check_perms:
if (!we_are_root && 0300 != (0300 & (int) hstat.st_mode))
{
hstat.st_mode |= 0300;
msg ("Added write and execute permission to directory %s",
skipcrud + current_file_name);
}
/*
* If we are root, set the owner and group of the extracted
* file. This does what is wanted both on real Unix and on
* System V. If we are running as a user, we extract as that
* user; if running as root, we extract as the original owner.
*/
if (we_are_root || f_do_chown)
{
if (chown (skipcrud + current_file_name,
hstat.st_uid, hstat.st_gid) < 0)
{
msg_perror ("cannot chown file %s to uid %d gid %d",
skipcrud + current_file_name,
hstat.st_uid, hstat.st_gid);
}
}
if (!f_modified)
{
tmp = ((struct saved_dir_info *)
ck_malloc (sizeof (struct saved_dir_info)));
tmp->path = (char *) ck_malloc (strlen (skipcrud
+ current_file_name) + 1);
strcpy (tmp->path, skipcrud + current_file_name);
tmp->mode = hstat.st_mode;
tmp->atime = hstat.st_atime;
tmp->mtime = hstat.st_mtime;
tmp->next = saved_dir_info_head;
saved_dir_info_head = tmp;
}
else
{
/* This functions exactly as the code for set_filestat above. */
if ((!f_keep)
|| (hstat.st_mode & (S_ISUID | S_ISGID | S_ISVTX)))
{
if (chmod (skipcrud + current_file_name,
notumask & (int) hstat.st_mode) < 0)
{
msg_perror ("cannot change mode of file %s to %ld",
skipcrud + current_file_name,
notumask & (int) hstat.st_mode);
}
}
}
break;
case LF_VOLHDR:
if (f_verbose)
{
printf ("Reading %s\n", current_file_name);
}
break;
case LF_NAMES:
extract_mangle (head);
break;
case LF_MULTIVOL:
msg ("Can't extract '%s'--file is continued from another volume\n", current_file_name);
skip_file ((long) hstat.st_size);
break;
case LF_LONGNAME:
case LF_LONGLINK:
msg ("Visible long name error\n");
skip_file ((long) hstat.st_size);
break;
}
/* We don't need to save it any longer. */
saverec ((union record **) 0);/* Unsave it */
}
/*
* After a file/link/symlink/dir creation has failed, see if
* it's because some required directory was not present, and if
* so, create all required dirs.
*/
int
make_dirs (pathname)
char *pathname;
{
char *p; /* Points into path */
int madeone = 0; /* Did we do anything yet? */
int save_errno = errno; /* Remember caller's errno */
int check;
if (errno != ENOENT)
return 0; /* Not our problem */
for (p = index (pathname, '/'); p != NULL; p = index (p + 1, '/'))
{
/* Avoid mkdir of empty string, if leading or double '/' */
if (p == pathname || p[-1] == '/')
continue;
/* Avoid mkdir where last part of path is '.' */
if (p[-1] == '.' && (p == pathname + 1 || p[-2] == '/'))
continue;
*p = 0; /* Truncate the path there */
check = mkdir (pathname, 0777); /* Try to create it as a dir */
if (check == 0)
{
/* Fix ownership */
if (we_are_root)
{
if (chown (pathname, hstat.st_uid,
hstat.st_gid) < 0)
{
msg_perror ("cannot change owner of %s to uid %d gid %d", pathname, hstat.st_uid, hstat.st_gid);
}
}
pr_mkdir (pathname, p - pathname, notumask & 0777);
madeone++; /* Remember if we made one */
*p = '/';
continue;
}
*p = '/';
if (errno == EEXIST) /* Directory already exists */
continue;
/*
* Some other error in the mkdir. We return to the caller.
*/
break;
}
errno = save_errno; /* Restore caller's errno */
return madeone; /* Tell them to retry if we made one */
}
void
extract_sparse_file (fd, sizeleft, totalsize, name)
int fd;
long *sizeleft, totalsize;
char *name;
{
/* register char *data;*/
union record *datarec;
int sparse_ind = 0;
int written, count;
/* assuming sizeleft is initially totalsize */
while (*sizeleft > 0)
{
datarec = findrec ();
if (datarec == NULL)
{
msg ("Unexpected EOF on archive file");
return;
}
lseek (fd, sparsearray[sparse_ind].offset, 0);
written = sparsearray[sparse_ind++].numbytes;
while (written > RECORDSIZE)
{
count = write (fd, datarec->charptr, RECORDSIZE);
if (count < 0)
msg_perror ("couldn't write to file %s", name);
written -= count;
*sizeleft -= count;
userec (datarec);
datarec = findrec ();
}
count = write (fd, datarec->charptr, written);
if (count < 0)
{
msg_perror ("couldn't write to file %s", name);
}
else if (count != written)
{
msg ("could only write %d of %d bytes to file %s", count,
totalsize, name);
skip_file ((long) (*sizeleft));
}
written -= count;
*sizeleft -= count;
userec (datarec);
}
free (sparsearray);
/* if (end_nulls) {
register int i;
printf("%d\n", (int) end_nulls);
for (i = 0; i < end_nulls; i++)
write(fd, "\000", 1);
}*/
userec (datarec);
}
/* Set back the utime and mode for all the extracted directories. */
void
restore_saved_dir_info ()
{
struct utimbuf acc_upd_times;
while (saved_dir_info_head != NULL)
{
/* fixme if f_gnudump should set ctime too, but how? */
if (f_gnudump)
acc_upd_times.actime = saved_dir_info_head->atime;
else
acc_upd_times.actime = now; /* Accessed now */
acc_upd_times.modtime = saved_dir_info_head->mtime; /* Mod'd */
if (utime (saved_dir_info_head->path, &acc_upd_times) < 0)
{
msg_perror ("couldn't change access and modification times of %s",
saved_dir_info_head->path);
}
if ((!f_keep) || (saved_dir_info_head->mode & (S_ISUID | S_ISGID | S_ISVTX)))
{
if (chmod (saved_dir_info_head->path,
notumask & saved_dir_info_head->mode) < 0)
{
msg_perror ("cannot change mode of file %s to %ld",
saved_dir_info_head->path,
notumask & saved_dir_info_head->mode);
}
}
saved_dir_info_head = saved_dir_info_head->next;
}
}
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