kqueue: Only allow one thread to register event to a kqueue

[dragonfly.git] / bin / pax / pax.c

/*-
 * 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.
 *
 * @(#) Copyright (c) 1992, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)pax.c    8.2 (Berkeley) 4/18/94
 * $FreeBSD: src/bin/pax/pax.c,v 1.13.2.4 2002/11/07 15:29:53 imp Exp $
 * $DragonFly: src/bin/pax/pax.c,v 1.6 2006/09/27 21:58:08 pavalos Exp $
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <locale.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "pax.h"
#include "extern.h"
static int gen_init (void);

/*
 * PAX main routines, general globals and some simple start up routines
 */

/*
 * Variables that can be accessed by any routine within pax
 */
int     act = DEFOP;            /* read/write/append/copy */
FSUB    *frmt = NULL;           /* archive format type */
int     cflag;                  /* match all EXCEPT pattern/file */
int     cwdfd;                  /* starting cwd */
int     dflag;                  /* directory member match only  */
int     iflag;                  /* interactive file/archive rename */
int     kflag;                  /* do not overwrite existing files */
int     lflag;                  /* use hard links when possible */
int     nflag;                  /* select first archive member match */
int     tflag;                  /* restore access time after read */
int     uflag;                  /* ignore older modification time files */
int     vflag;                  /* produce verbose output */
int     Dflag;                  /* same as uflag except inode change time */
int     Hflag;                  /* follow command line symlinks (write only) */
int     Lflag;                  /* follow symlinks when writing */
int     Xflag;                  /* archive files with same device id only */
int     Yflag;                  /* same as Dflag except after name mode */
int     Zflag;                  /* same as uflag except after name mode */
int     vfpart;                 /* is partial verbose output in progress */
int     patime = 1;             /* preserve file access time */
int     pmtime = 1;             /* preserve file modification times */
int     nodirs;                 /* do not create directories as needed */
int     pmode;                  /* preserve file mode bits */
int     pids;                   /* preserve file uid/gid */
int     rmleadslash = 0;        /* remove leading '/' from pathnames */
int     exit_val;               /* exit value */
int     docrc;                  /* check/create file crc */
char    *dirptr;                /* destination dir in a copy */
char    *argv0;                 /* root of argv[0] */
sigset_t s_mask;                /* signal mask for cleanup critical sect */
FILE    *listf;                 /* file pointer to print file list to */
char    *tempfile;              /* tempfile to use for mkstemp(3) */
char    *tempbase;              /* basename of tempfile to use for mkstemp(3) */

/*
 *      PAX - Portable Archive Interchange
 *
 *      A utility to read, write, and write lists of the members of archive
 *      files and copy directory hierarchies. A variety of archive formats
 *      are supported (some are described in POSIX 1003.1 10.1):
 *
 *              ustar - 10.1.1 extended tar interchange format
 *              cpio  - 10.1.2 extended cpio interchange format
 *              tar - old BSD 4.3 tar format
 *              binary cpio - old cpio with binary header format
 *              sysVR4 cpio -  with and without CRC
 *
 * This version is a superset of IEEE Std 1003.2b-d3
 *
 * Summary of Extensions to the IEEE Standard:
 *
 * 1    READ ENHANCEMENTS
 * 1.1  Operations which read archives will continue to operate even when
 *      processing archives which may be damaged, truncated, or fail to meet
 *      format specs in several different ways. Damaged sections of archives
 *      are detected and avoided if possible. Attempts will be made to resync
 *      archive read operations even with badly damaged media.
 * 1.2  Blocksize requirements are not strictly enforced on archive read.
 *      Tapes which have variable sized records can be read without errors.
 * 1.3  The user can specify via the non-standard option flag -E if error
 *      resync operation should stop on a media error, try a specified number
 *      of times to correct, or try to correct forever.
 * 1.4  Sparse files (lseek holes) stored on the archive (but stored with blocks
 *      of all zeros will be restored with holes appropriate for the target
 *      filesystem
 * 1.5  The user is notified whenever something is found during archive
 *      read operations which violates spec (but the read will continue).
 * 1.6  Multiple archive volumes can be read and may span over different
 *      archive devices
 * 1.7  Rigidly restores all file attributes exactly as they are stored on the
 *      archive.
 * 1.8  Modification change time ranges can be specified via multiple -T
 *      options. These allow a user to select files whose modification time
 *      lies within a specific time range.
 * 1.9  Files can be selected based on owner (user name or uid) via one or more
 *      -U options.
 * 1.10 Files can be selected based on group (group name or gid) via one o
 *      more -G options.
 * 1.11 File modification time can be checked against existing file after
 *      name modification (-Z)
 *
 * 2    WRITE ENHANCEMENTS
 * 2.1  Write operation will stop instead of allowing a user to create a flawed
 *      flawed archive (due to any problem).
 * 2.2  Archives written by pax are forced to strictly conform to both the
 *      archive and pax the specific format specifications.
 * 2.3  Blocking size and format is rigidly enforced on writes.
 * 2.4  Formats which may exhibit header overflow problems (they have fields
 *      too small for large file systems, such as inode number storage), use
 *      routines designed to repair this problem. These techniques still
 *      conform to both pax and format specifications, but no longer truncate
 *      these fields. This removes any restrictions on using these archive
 *      formats on large file systems.
 * 2.5  Multiple archive volumes can be written and may span over different
 *      archive devices
 * 2.6  A archive volume record limit allows the user to specify the number
 *      of bytes stored on an archive volume. When reached the user is
 *      prompted for the next archive volume. This is specified with the
 *      non-standard -B flag. The limit is rounded up to the next blocksize.
 * 2.7  All archive padding during write use zero filled sections. This makes
 *      it much easier to pull data out of flawed archive during read
 *      operations.
 * 2.8  Access time reset with the -t applies to all file nodes (including
 *      directories).
 * 2.9  Symbolic links can be followed with -L (optional in the spec).
 * 2.10 Modification or inode change time ranges can be specified via
 *      multiple -T options. These allow a user to select files whose
 *      modification or inode change time lies within a specific time range.
 * 2.11 Files can be selected based on owner (user name or uid) via one or more
 *      -U options.
 * 2.12 Files can be selected based on group (group name or gid) via one o
 *      more -G options.
 * 2.13 Symlinks which appear on the command line can be followed (without
 *      following other symlinks; -H flag)
 *
 * 3    COPY ENHANCEMENTS
 * 3.1  Sparse files (lseek holes) can be copied without expanding the holes
 *      into zero filled blocks. The file copy is created with holes which are
 *      appropriate for the target filesystem
 * 3.2  Access time as well as modification time on copied file trees can be
 *      preserved with the appropriate -p options.
 * 3.3  Access time reset with the -t applies to all file nodes (including
 *      directories).
 * 3.4  Symbolic links can be followed with -L (optional in the spec).
 * 3.5  Modification or inode change time ranges can be specified via
 *      multiple -T options. These allow a user to select files whose
 *      modification or inode change time lies within a specific time range.
 * 3.6  Files can be selected based on owner (user name or uid) via one or more
 *      -U options.
 * 3.7  Files can be selected based on group (group name or gid) via one o
 *      more -G options.
 * 3.8  Symlinks which appear on the command line can be followed (without
 *      following other symlinks; -H flag)
 * 3.9  File inode change time can be checked against existing file before
 *      name modification (-D)
 * 3.10 File inode change time can be checked against existing file after
 *      name modification (-Y)
 * 3.11 File modification time can be checked against existing file after
 *      name modification (-Z)
 *
 * 4    GENERAL ENHANCEMENTS
 * 4.1  Internal structure is designed to isolate format dependent and
 *      independent functions. Formats are selected via a format driver table.
 *      This encourages the addition of new archive formats by only having to
 *      write those routines which id, read and write the archive header.
 */

/*
 * main()
 *      parse options, set up and operate as specified by the user.
 *      any operational flaw will set exit_val to non-zero
 * Return: 0 if ok, 1 otherwise
 */

int
main(int argc, char **argv)
{
        char *tmpdir;
        size_t tdlen;

        setlocale(LC_ALL, "");
        listf = stderr;
        /*
         * Keep a reference to cwd, so we can always come back home.
         */
        cwdfd = open(".", O_RDONLY);
        if (cwdfd < 0) {
                syswarn(0, errno, "Can't open current working directory.");
                return(exit_val);
        }

        /*
         * Where should we put temporary files?
         */
        if ((tmpdir = getenv("TMPDIR")) == NULL || *tmpdir == '\0')
                tmpdir = _PATH_TMP;
        tdlen = strlen(tmpdir);
        while(tdlen > 0 && tmpdir[tdlen - 1] == '/')
                tdlen--;
        tempfile = malloc(tdlen + 1 + sizeof(_TFILE_BASE));
        if (tempfile == NULL) {
                paxwarn(1, "Cannot allocate memory for temp file name.");
                return(exit_val);
        }
        if (tdlen)
                memcpy(tempfile, tmpdir, tdlen);
        tempbase = tempfile + tdlen;
        *tempbase++ = '/';

        /*
         * parse options, determine operational mode, general init
         */
        options(argc, argv);
        if ((gen_init() < 0) || (tty_init() < 0))
                return(exit_val);

        /*
         * select a primary operation mode
         */
        switch(act) {
        case EXTRACT:
                extract();
                break;
        case ARCHIVE:
                archive();
                break;
        case APPND:
                if (gzip_program != NULL)
                        err(1, "can not gzip while appending");
                append();
                break;
        case COPY:
                copy();
                break;
        default:
        case LIST:
                list();
                break;
        }
        return(exit_val);
}

/*
 * sig_cleanup()
 *      when interrupted we try to do whatever delayed processing we can.
 *      This is not critical, but we really ought to limit our damage when we
 *      are aborted by the user.
 * Return:
 *      never....
 */

void
sig_cleanup(int which_sig)
{
        /*
         * restore modes and times for any dirs we may have created
         * or any dirs we may have read. Set vflag and vfpart so the user
         * will clearly see the message on a line by itself.
         */
        vflag = vfpart = 1;
        if (which_sig == SIGXCPU)
                paxwarn(0, "Cpu time limit reached, cleaning up.");
        else
                paxwarn(0, "Signal caught, cleaning up.");

        ar_close();
        proc_dir();
        if (tflag)
                atdir_end();
        exit(1);
}

/*
 * gen_init()
 *      general setup routines. Not all are required, but they really help
 *      when dealing with a medium to large sized archives.
 */

static int
gen_init(void)
{
        struct rlimit reslimit;
        struct sigaction n_hand;
        struct sigaction o_hand;

        /*
         * Really needed to handle large archives. We can run out of memory for
         * internal tables really fast when we have a whole lot of files...
         */
        if (getrlimit(RLIMIT_DATA , &reslimit) == 0){
                reslimit.rlim_cur = reslimit.rlim_max;
                setrlimit(RLIMIT_DATA , &reslimit);
        }

        /*
         * should file size limits be waived? if the os limits us, this is
         * needed if we want to write a large archive
         */
        if (getrlimit(RLIMIT_FSIZE , &reslimit) == 0){
                reslimit.rlim_cur = reslimit.rlim_max;
                setrlimit(RLIMIT_FSIZE , &reslimit);
        }

        /*
         * increase the size the stack can grow to
         */
        if (getrlimit(RLIMIT_STACK , &reslimit) == 0){
                reslimit.rlim_cur = reslimit.rlim_max;
                setrlimit(RLIMIT_STACK , &reslimit);
        }

        /*
         * not really needed, but doesn't hurt
         */
        if (getrlimit(RLIMIT_RSS , &reslimit) == 0){
                reslimit.rlim_cur = reslimit.rlim_max;
                setrlimit(RLIMIT_RSS , &reslimit);
        }

        /*
         * signal handling to reset stored directory times and modes. Since
         * we deal with broken pipes via failed writes we ignore it. We also
         * deal with any file size limit through failed writes. Cpu time
         * limits are caught and a cleanup is forced.
         */
        if ((sigemptyset(&s_mask) < 0) || (sigaddset(&s_mask, SIGTERM) < 0) ||
            (sigaddset(&s_mask,SIGINT) < 0)||(sigaddset(&s_mask,SIGHUP) < 0) ||
            (sigaddset(&s_mask,SIGPIPE) < 0)||(sigaddset(&s_mask,SIGQUIT)<0) ||
            (sigaddset(&s_mask,SIGXCPU) < 0)||(sigaddset(&s_mask,SIGXFSZ)<0)) {
                paxwarn(1, "Unable to set up signal mask");
                return(-1);
        }
        memset(&n_hand, 0, sizeof n_hand);
        n_hand.sa_mask = s_mask;
        n_hand.sa_flags = 0;
        n_hand.sa_handler = sig_cleanup;

        if ((sigaction(SIGHUP, &n_hand, &o_hand) < 0) &&
            (o_hand.sa_handler == SIG_IGN) &&
            (sigaction(SIGHUP, &o_hand, &o_hand) < 0))
                goto out;

        if ((sigaction(SIGTERM, &n_hand, &o_hand) < 0) &&
            (o_hand.sa_handler == SIG_IGN) &&
            (sigaction(SIGTERM, &o_hand, &o_hand) < 0))
                goto out;

        if ((sigaction(SIGINT, &n_hand, &o_hand) < 0) &&
            (o_hand.sa_handler == SIG_IGN) &&
            (sigaction(SIGINT, &o_hand, &o_hand) < 0))
                goto out;

        if ((sigaction(SIGQUIT, &n_hand, &o_hand) < 0) &&
            (o_hand.sa_handler == SIG_IGN) &&
            (sigaction(SIGQUIT, &o_hand, &o_hand) < 0))
                goto out;

        if ((sigaction(SIGXCPU, &n_hand, &o_hand) < 0) &&
            (o_hand.sa_handler == SIG_IGN) &&
            (sigaction(SIGXCPU, &o_hand, &o_hand) < 0))
                goto out;

        n_hand.sa_handler = SIG_IGN;
        if ((sigaction(SIGPIPE, &n_hand, &o_hand) < 0) ||
            (sigaction(SIGXFSZ, &n_hand, &o_hand) < 0))
                goto out;
        return(0);

    out:
        syswarn(1, errno, "Unable to set up signal handler");
        return(-1);
}