/*	$OpenBSD: file_subs.c,v 1.48 2016/02/16 04:30:07 guenther Exp $	*/

/*	$NetBSD: file_subs.c,v 1.4 1995/03/21 09:07:18 cgd Exp $	*/

/*-

 * Copyright (c) 1992 Keith Muller.

 * Copyright (c) 1992, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Keith Muller of the University of California, San Diego.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <sys/time.h>

#include <sys/stat.h>

#include <err.h>

#include <errno.h>

#include <fcntl.h>

#include <limits.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "pax.h"

#include "options.h"

#include "extern.h"

static int

mk_link(char *, struct stat *, char *, int);

/*

 * routines that deal with file operations such as: creating, removing;

 * and setting access modes, uid/gid and times of files

 */

/*

 * file_creat()

 *	Create and open a file.

 * Return:

 *	file descriptor or -1 for failure

 */

int

file_creat(ARCHD *arcn)

	mode_t file_mode;

	int oerrno;

	/*

	 * Assume file doesn't exist, so just try to create it, most times this

	 * works. We have to take special handling when the file does exist. To

	 * detect this, we use O_EXCL. For example when trying to create a

	 * file and a character device or fifo exists with the same name, we

	 * can accidently open the device by mistake (or block waiting to open).

	 * If we find that the open has failed, then spend the effort to

	 * figure out why. This strategy was found to have better average

	 * performance in common use than checking the file (and the path)

	 * first with lstat.

	 */

	    file_mode)) >= 0)

	/*

	 * the file seems to exist. First we try to get rid of it (found to be

	 * the second most common failure when traced). If this fails, only

	 * then we go to the expense to check and create the path to the file

	 */

	for (;;) {

		/*

		 * try to open it again, if this fails, check all the nodes in

		 * the path and give it a final try. if chk_path() finds that

		 * it cannot fix anything, we will skip the last attempt

		 */

		    file_mode)) >= 0)

		}

	}

}

/*

 * file_close()

 *	Close file descriptor to a file just created by pax. Sets modes,

 *	ownership and times as required.

 * Return:

 *	0 for success, -1 for failure

 */

void

file_close(ARCHD *arcn, int fd)

	/*

	 * set owner/groups first as this may strip off mode bits we want

	 * then set file permission modes. Then set file access and

	 * modification times.

	 */

		    arcn->sb.st_gid);

	/*

	 * IMPORTANT SECURITY NOTE:

	 * if not preserving mode or we cannot set uid/gid, then PROHIBIT

	 * set uid/gid bits

	 */

		    &arcn->sb.st_atim, 0);

		    arcn->name);

}

/*

 * lnk_creat()

 *	Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name

 *	must exist;

 * Return:

 *	0 if ok, -1 otherwise

 */

int

lnk_creat(ARCHD *arcn)

	struct stat sb;

	int res;

	/*

	 * we may be running as root, so we have to be sure that link target

	 * is not a directory, so we lstat and check

	 */

		    arcn->name);

	}

		    arcn->ln_name);

	}

		/* check for a hardlink to a placeholder symlink */

			/* arrgh, it failed, clean up */

		}

	}

}

/*

 * cross_lnk()

 *	Create a hard link to arcn->org_name from arcn->name. Only used in copy

 *	with the -l flag. No warning or error if this does not succeed (we will

 *	then just create the file)

 * Return:

 *	1 if copy() should try to create this file node

 *	0 if cross_lnk() ok, -1 for fatal flaw (like linking to self).

 */

int

cross_lnk(ARCHD *arcn)

{

	/*

	 * try to make a link to original file (-l flag in copy mode). make

	 * sure we do not try to link to directories in case we are running as

	 * root (and it might succeed).

	 */

}

/*

 * chk_same()

 *	In copy mode if we are not trying to make hard links between the src

 *	and destinations, make sure we are not going to overwrite ourselves by

 *	accident. This slows things down a little, but we have to protect all

 *	those people who make typing errors.

 * Return:

 *	1 the target does not exist, go ahead and copy

 *	0 skip it file exists (-k) or may be the same as source file

 */

int

chk_same(ARCHD *arcn)

{

	struct stat sb;

	/*

	 * if file does not exist, return. if file exists and -k, skip it

	 * quietly

	 */

	/*

	 * better make sure the user does not have src == dest by mistake

	 */

		    arcn->name);

	}

}

/*

 * mk_link()

 *	try to make a hard link between two files. if ign set, we do not

 *	complain.

 * Return:

 *	0 if successful (or we are done with this file but no error, such as

 *	finding the from file exists and the user has set -k).

 *	1 when ign was set to indicates we could not make the link but we

 *	should try to copy/extract the file as that might work (and is an

 *	allowed option). -1 an error occurred.

 */

static int

mk_link(char *to, struct stat *to_sb, char *from, int ign)

	struct stat sb;

	int oerrno;

	/*

	 * if from file exists, it has to be unlinked to make the link. If the

	 * file exists and -k is set, skip it quietly

	 */

		/*

		 * make sure it is not the same file, protect the user

		 */

		}

		/*

		 * try to get rid of the file, based on the type

		 */

			}

			}

		}

	}

	/*

	 * from file is gone (or did not exist), try to make the hard link.

	 * if it fails, check the path and try it again (if chk_path() says to

	 * try again)

	 */

	for (;;) {

			    from);

		}

	}

	/*

	 * all right the link was made

	 */

}

/*

 * node_creat()

 *	create an entry in the file system (other than a file or hard link).

 *	If successful, sets uid/gid modes and times as required.

 * Return:

 *	0 if ok, -1 otherwise

 */

int

node_creat(ARCHD *arcn)

	int res;

	int oerrno;

	mode_t file_mode;

	struct stat sb;

	char target[PATH_MAX];

	/*

	 * create node based on type, if that fails try to unlink the node and

	 * try again. finally check the path and try again. As noted in the

	 * file and link creation routines, this method seems to exhibit the

	 * best performance in general use workloads.

	 */

	for (;;) {

		case PAX_DIR:

			/*

			 * If -h (or -L) was given in tar-mode, follow the

			 * potential symlink chain before trying to create the

			 * directory.

			 */

				    S_ISLNK(sb.st_mode)) {

					    sizeof target - 1);

						   "cannot follow symlink %s in chain for %s",

						    nm, arcn->name);

					}

				}

			}

			break;

		case PAX_CHR:

		case PAX_BLK:

		case PAX_FIF:

		case PAX_SCK:

			/*

			 * Skip sockets, operation has no meaning under BSD

			 */

			    "%s skipped. Sockets cannot be copied or extracted",

			    nm);

		case PAX_SLK:

			    !has_dotdot(arcn->ln_name))

			else {

				/*

				 * absolute symlinks and symlinks with ".."

				 * have to be deferred to prevent the archive

				 * from bootstrapping itself to outside the

				 * working directory.

				 */

				    arcn->sb.st_mode);

			}

			break;

		case PAX_CTG:

		case PAX_HLK:

		case PAX_HRG:

		case PAX_REG:

		default:

			/*

			 * we should never get here

			 */

				nm);

		}

		/*

		 * if we were able to create the node break out of the loop,

		 * otherwise try to unlink the node and try again. if that

		 * fails check the full path and try a final time.

		 */

		/*

		 * we failed to make the node

		 */

		}

	}

	/*

	 * we were able to create the node. set uid/gid, modes and times

	 */

	else

	/*

	 * IMPORTANT SECURITY NOTE:

	 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any

	 * set uid/gid bits

	 */

		/*

		 * Dirs must be processed again at end of extract to set times

		 * and modes to agree with those stored in the archive. However

		 * to allow extract to continue, we may have to also set owner

		 * rights. This allows nodes in the archive that are children

		 * of this directory to be extracted without failure. Both time

		 * and modes will be fixed after the entire archive is read and

		 * before pax exits.  To do that safely, we want the dev+ino

		 * of the directory we created.

		 */

			/*

			 * We have to add rights to the dir, so we make

			 * sure to restore the mode. The mode must be

			 * restored AS CREATED and not as stored if

			 * pmode is not set.

			 */

			    ((sb.st_mode & FILEBITS) | S_IRWXU));

			/*

			 * we have to force the mode to what was set

			 * here, since we changed it from the default

			 * as created.

			 */

		}

	}

}

/*

 * unlnk_exist()

 *	Remove node from file system with the specified name. We pass the type

 *	of the node that is going to replace it. When we try to create a

 *	directory and find that it already exists, we allow processing to

 *	continue as proper modes etc will always be set for it later on.

 * Return:

 *	0 is ok to proceed, no file with the specified name exists

 *	-1 we were unable to remove the node, or we should not remove it (-k)

 *	1 we found a directory and we were going to create a directory.

 */

int

unlnk_exist(char *name, int type)

{

	struct stat sb;

	/*

	 * the file does not exist, or -k we are done

	 */

		/*

		 * try to remove a directory, if it fails and we were going to

		 * create a directory anyway, tell the caller (return a 1)

		 */

		}

	}

	/*

	 * try to get rid of all non-directory type nodes

	 */

	}

}

/*

 * chk_path()

 *	We were trying to create some kind of node in the file system and it

 *	failed. chk_path() makes sure the path up to the node exists and is

 *	writeable. When we have to create a directory that is missing along the

 *	path somewhere, the directory we create will be set to the same

 *	uid/gid as the file has (when uid and gid are being preserved).

 *	NOTE: this routine is a real performance loss. It is only used as a

 *	last resort when trying to create entries in the file system.

 * Return:

 *	-1 when it could find nothing it is allowed to fix.

 *	0 otherwise

 */

int

chk_path(char *name, uid_t st_uid, gid_t st_gid)

{

	char *next;

	struct stat sb;

	/*

	 * watch out for paths with nodes stored directly in / (e.g. /bozo)

	 */

	for (;;) {

		/*

		 * work forward from the first / and check each part of the path

		 */

		/*

		 * skip over duplicate slashes; stop if there're only

		 * trailing slashes left

		 */

		/*

		 * if it exists we assume it is a directory, it is not within

		 * the spec (at least it seems to read that way) to alter the

		 * file system for nodes NOT EXPLICITLY stored on the archive.

		 * If that assumption is changed, you would test the node here

		 * and figure out how to get rid of it (probably like some

		 * recursive unlink()) or fix up the directory permissions if

		 * required (do an access()).

		 */

		}

		/*

		 * the path fails at this point, see if we can create the

		 * needed directory and continue on

		 */

		}

		/*

		 * we were able to create the directory. We will tell the

		 * caller that we found something to fix, and it is ok to try

		 * and create the node again.

		 */

		/*

		 * make sure the user doesn't have some strange umask that

		 * causes this newly created directory to be unusable. We fix

		 * the modes and restore them back to the creation default at

		 * the end of pax

		 */

		    (lstat(name, &sb) == 0)) {

		}

		continue;

	}

}

/*

 * set_ftime()

 *	Set the access time and modification time for a named file. If frc

 *	is non-zero we force these times to be set even if the user did not

 *	request access and/or modification time preservation (this is also

 *	used by -t to reset access times).

 *	When ign is zero, only those times the user has asked for are set, the

 *	other ones are left alone.

 */

void

set_ftime(const char *fnm, const struct timespec *mtimp,

    const struct timespec *atimp, int frc)

	struct timespec tv[2];

		/*

		 * if we are not forcing, only set those times the user wants

		 * set.

		 */

	}

	/*

	 * set the times

	 */

		    fnm);

void

fset_ftime(const char *fnm, int fd, const struct timespec *mtimp,

    const struct timespec *atimp, int frc)

	struct timespec tv[2];

		/*

		 * if we are not forcing, only set those times the user wants

		 * set.

		 */

	}

	/*

	 * set the times

	 */

		    fnm);

/*

 * set_ids()

 *	set the uid and gid of a file system node

 * Return:

 *	0 when set, -1 on failure

 */

int

set_ids(char *fnm, uid_t uid, gid_t gid)

{

		/*

		 * ignore EPERM unless in verbose mode or being run by root.

		 * if running as pax, POSIX requires a warning.

		 */

		    geteuid() == 0)

			    fnm);

	}

}

int

fset_ids(char *fnm, int fd, uid_t uid, gid_t gid)

{

		/*

		 * ignore EPERM unless in verbose mode or being run by root.

		 * if running as pax, POSIX requires a warning.

		 */

		    geteuid() == 0)

			    fnm);

	}

}

/*

 * set_pmode()

 *	Set file access mode

 */

void

set_pmode(char *fnm, mode_t mode)

{

}

void

fset_pmode(char *fnm, int fd, mode_t mode)

{

}

/*

 * set_attr()

 *	Given a DIRDATA, restore the mode and times as indicated, but

 *	only after verifying that it's the directory that we wanted.

 */

int

set_attr(const struct file_times *ft, int force_times, mode_t mode,

    int do_mode, int in_sig)

	struct stat sb;

	int fd, r;

	/*

	 * We could legitimately go through a symlink here,

	 * so do *not* use O_NOFOLLOW.  The dev+ino check will

	 * protect us from evil.

	 */

			    " for directory: %s", ft->ft_name);

	}

			    ft->ft_name);

			    " mode and times: %s", ft->ft_name);

	} else {

		/* Whew, it's a match!  Is there anything to change? */

		    timespeccmp(&ft->ft_atim, &sb.st_atim, !=)) ||

		    ((force_times || pmtime) &&

		    timespeccmp(&ft->ft_mtim, &sb.st_mtim, !=)))

			    &ft->ft_atim, force_times);

	}

}

/*

 * file_write()

 *	Write/copy a file (during copy or archive extract). This routine knows

 *	how to copy files with lseek holes in it. (Which are read as file

 *	blocks containing all 0's but do not have any file blocks associated

 *	with the data). Typical examples of these are files created by dbm

 *	variants (.pag files). While the file size of these files are huge, the

 *	actual storage is quite small (the files are sparse). The problem is

 *	the holes read as all zeros so are probably stored on the archive that

 *	way (there is no way to determine if the file block is really a hole,

 *	we only know that a file block of all zero's can be a hole).

 *	At this writing, no major archive format knows how to archive files

 *	with holes. However, on extraction (or during copy, -rw) we have to

 *	deal with these files. Without detecting the holes, the files can

 *	consume a lot of file space if just written to disk. This replacement

 *	for write when passed the basic allocation size of a file system block,

 *	uses lseek whenever it detects the input data is all 0 within that

 *	file block. In more detail, the strategy is as follows:

 *	While the input is all zero keep doing an lseek. Keep track of when we

 *	pass over file block boundaries. Only write when we hit a non zero

 *	input. once we have written a file block, we continue to write it to

 *	the end (we stop looking at the input). When we reach the start of the

 *	next file block, start checking for zero blocks again. Working on file

 *	block boundaries significantly reduces the overhead when copying files

 *	that are NOT very sparse. This overhead (when compared to a write) is

 *	almost below the measurement resolution on many systems. Without it,

 *	files with holes cannot be safely copied. It does has a side effect as

 *	it can put holes into files that did not have them before, but that is

 *	not a problem since the file contents are unchanged (in fact it saves

 *	file space). (Except on paging files for diskless clients. But since we

 *	cannot determine one of those file from here, we ignore them). If this

 *	ever ends up on a system where CTG files are supported and the holes

 *	are not desired, just do a conditional test in those routines that

 *	call file_write() and have it call write() instead. BEFORE CLOSING THE

 *	FILE, make sure to call file_flush() when the last write finishes with

 *	an empty block. A lot of file systems will not create an lseek hole at

 *	the end. In this case we drop a single 0 at the end to force the

 *	trailing 0's in the file.

 *	---Parameters---

 *	rem: how many bytes left in this file system block

 *	isempt: have we written to the file block yet (is it empty)

 *	sz: basic file block allocation size

 *	cnt: number of bytes on this write

 *	str: buffer to write

 * Return:

 *	number of bytes written, -1 on write (or lseek) error.

 */

int

file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz,

	char *name)

{

	char *pt;

	char *end;

	int wcnt;

	char **strp;

	/*

	 * while we have data to process

	 */

			/*

			 * We are now at the start of file system block again

			 * (or what we think one is...). start looking for

			 * empty blocks again

			 */

		}

		/*

		 * only examine up to the end of the current file block or

		 * remaining characters to write, whatever is smaller

		 */

			/*

			 * have not written to this block yet, so we keep

			 * looking for zero's

			 */

			/*

			 * look for a zero filled buffer

			 */

				/*

				 * skip, buf is empty so far

				 */

				    lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) {

					    name);

				}

			}

			/*

			 * drat, the buf is not zero filled

			 */

		}