HAMMER VFS - Major retooling of the refcount mechanics, and fix a deadlock

[dragonfly.git] / bin / pax / ftree.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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 *
 * @(#)ftree.c  8.2 (Berkeley) 4/18/94
 * $FreeBSD: src/bin/pax/ftree.c,v 1.13.2.1 2001/08/01 05:03:11 obrien Exp $
 * $DragonFly: src/bin/pax/ftree.c,v 1.7 2006/09/27 19:18:00 pavalos Exp $
 */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <fts.h>
#include "pax.h"
#include "ftree.h"
#include "extern.h"

/*
 * routines to interface with the fts library function.
 *
 * file args supplied to pax are stored on a single linked list (of type FTREE)
 * and given to fts to be processed one at a time. pax "selects" files from
 * the expansion of each arg into the corresponding file tree (if the arg is a
 * directory, otherwise the node itself is just passed to pax). The selection
 * is modified by the -n and -u flags. The user is informed when a specific
 * file arg does not generate any selected files. -n keeps expanding the file
 * tree arg until one of its files is selected, then skips to the next file
 * arg. when the user does not supply the file trees as command line args to
 * pax, they are read from stdin
 */

static FTS *ftsp = NULL;                /* current FTS handle */
static int ftsopts;                     /* options to be used on fts_open */
static char *farray[2];                 /* array for passing each arg to fts */
static FTREE *fthead = NULL;            /* head of linked list of file args */
static FTREE *fttail = NULL;            /* tail of linked list of file args */
static FTREE *ftcur = NULL;             /* current file arg being processed */
static FTSENT *ftent = NULL;            /* current file tree entry */
static int ftree_skip;                  /* when set skip to next file arg */

static int ftree_arg (void);

/*
 * ftree_start()
 *      initialize the options passed to fts_open() during this run of pax
 *      options are based on the selection of pax options by the user
 *      fts_start() also calls fts_arg() to open the first valid file arg. We
 *      also attempt to reset directory access times when -t (tflag) is set.
 * Return:
 *      0 if there is at least one valid file arg to process, -1 otherwise
 */

int
ftree_start(void)
{
        /*
         * set up the operation mode of fts, open the first file arg. We must
         * use FTS_NOCHDIR, as the user may have to open multiple archives and
         * if fts did a chdir off into the boondocks, we may create an archive
         * volume in an place where the user did not expect to.
         */
        ftsopts = FTS_NOCHDIR;

        /*
         * optional user flags that effect file traversal
         * -H command line symlink follow only (half follow)
         * -L follow sylinks (logical)
         * -P do not follow sylinks (physical). This is the default.
         * -X do not cross over mount points
         * -t preserve access times on files read.
         * -n select only the first member of a file tree when a match is found
         * -d do not extract subtrees rooted at a directory arg.
         */
        if (Lflag)
                ftsopts |= FTS_LOGICAL;
        else
                ftsopts |= FTS_PHYSICAL;
        if (Hflag)
                ftsopts |= FTS_COMFOLLOW;
        if (Xflag)
                ftsopts |= FTS_XDEV;

        if ((fthead == NULL) && ((farray[0] = malloc(PAXPATHLEN+2)) == NULL)) {
                paxwarn(1, "Unable to allocate memory for file name buffer");
                return(-1);
        }

        if (ftree_arg() < 0)
                return(-1);
        if (tflag && (atdir_start() < 0))
                return(-1);
        return(0);
}

/*
 * ftree_add()
 *      add the arg to the linked list of files to process. Each will be
 *      processed by fts one at a time
 * Return:
 *      0 if added to the linked list, -1 if failed
 */

int
ftree_add(char *str, int chflg)
{
        FTREE *ft;
        int len;

        /*
         * simple check for bad args
         */
        if ((str == NULL) || (*str == '\0')) {
                paxwarn(0, "Invalid file name argument");
                return(-1);
        }

        /*
         * allocate FTREE node and add to the end of the linked list (args are
         * processed in the same order they were passed to pax). Get rid of any
         * trailing / the user may pass us. (watch out for / by itself).
         */
        if ((ft = (FTREE *)malloc(sizeof(FTREE))) == NULL) {
                paxwarn(0, "Unable to allocate memory for filename");
                return(-1);
        }

        if (((len = strlen(str) - 1) > 0) && (str[len] == '/'))
                str[len] = '\0';
        ft->fname = str;
        ft->refcnt = 0;
        ft->chflg = chflg;
        ft->fow = NULL;
        if (fthead == NULL) {
                fttail = fthead = ft;
                return(0);
        }
        fttail->fow = ft;
        fttail = ft;
        return(0);
}

/*
 * ftree_sel()
 *      this entry has been selected by pax. bump up reference count and handle
 *      -n and -d processing.
 */

void
ftree_sel(ARCHD *arcn)
{
        /*
         * set reference bit for this pattern. This linked list is only used
         * when file trees are supplied pax as args. The list is not used when
         * the trees are read from stdin.
         */
        if (ftcur != NULL)
                ftcur->refcnt = 1;

        /*
         * if -n we are done with this arg, force a skip to the next arg when
         * pax asks for the next file in next_file().
         * if -d we tell fts only to match the directory (if the arg is a dir)
         * and not the entire file tree rooted at that point.
         */
        if (nflag)
                ftree_skip = 1;

        if (!dflag || (arcn->type != PAX_DIR))
                return;

        if (ftent != NULL)
                fts_set(ftsp, ftent, FTS_SKIP);
}

/*
 * ftree_chk()
 *      called at end on pax execution. Prints all those file args that did not
 *      have a selected member (reference count still 0)
 */

void
ftree_chk(void)
{
        FTREE *ft;
        int wban = 0;

        /*
         * make sure all dir access times were reset.
         */
        if (tflag)
                atdir_end();

        /*
         * walk down list and check reference count. Print out those members
         * that never had a match
         */
        for (ft = fthead; ft != NULL; ft = ft->fow) {
                if ((ft->refcnt > 0) || ft->chflg)
                        continue;
                if (wban == 0) {
                        paxwarn(1,"WARNING! These file names were not selected:");
                        ++wban;
                }
                fprintf(stderr, "%s\n", ft->fname);
        }
}

/*
 * ftree_arg()
 *      Get the next file arg for fts to process. Can be from either the linked
 *      list or read from stdin when the user did not them as args to pax. Each
 *      arg is processed until the first successful fts_open().
 * Return:
 *      0 when the next arg is ready to go, -1 if out of file args (or EOF on
 *      stdin).
 */

static int
ftree_arg(void)
{
        char *pt;

        /*
         * close off the current file tree
         */
        if (ftsp != NULL) {
                fts_close(ftsp);
                ftsp = NULL;
        }

        /*
         * keep looping until we get a valid file tree to process. Stop when we
         * reach the end of the list (or get an eof on stdin)
         */
        for(;;) {
                if (fthead == NULL) {
                        /*
                         * the user didn't supply any args, get the file trees
                         * to process from stdin;
                         */
                        if (fgets(farray[0], PAXPATHLEN+1, stdin) == NULL)
                                return(-1);
                        if ((pt = strchr(farray[0], '\n')) != NULL)
                                *pt = '\0';
                } else {
                        /*
                         * the user supplied the file args as arguments to pax
                         */
                        if (ftcur == NULL)
                                ftcur = fthead;
                        else if ((ftcur = ftcur->fow) == NULL)
                                return(-1);
                        if (ftcur->chflg) {
                                /* First fchdir() back... */
                                if (fchdir(cwdfd) < 0) {
                                        syswarn(1, errno,
                                          "Can't fchdir to starting directory");
                                        return(-1);
                                }
                                if (chdir(ftcur->fname) < 0) {
                                        syswarn(1, errno, "Can't chdir to %s",
                                            ftcur->fname);
                                        return(-1);
                                }
                                continue;
                        } else
                                farray[0] = ftcur->fname;
                }

                /*
                 * watch it, fts wants the file arg stored in a array of char
                 * ptrs, with the last one a null. we use a two element array
                 * and set farray[0] to point at the buffer with the file name
                 * in it. We cannot pass all the file args to fts at one shot
                 * as we need to keep a handle on which file arg generates what
                 * files (the -n and -d flags need this). If the open is
                 * successful, return a 0.
                 */
                if ((ftsp = fts_open(farray, ftsopts, NULL)) != NULL)
                        break;
        }
        return(0);
}

/*
 * next_file()
 *      supplies the next file to process in the supplied archd structure.
 * Return:
 *      0 when contents of arcn have been set with the next file, -1 when done.
 */

int
next_file(ARCHD *arcn)
{
        int cnt;
        time_t atime;
        time_t mtime;

        /*
         * ftree_sel() might have set the ftree_skip flag if the user has the
         * -n option and a file was selected from this file arg tree. (-n says
         * only one member is matched for each pattern) ftree_skip being 1
         * forces us to go to the next arg now.
         */
        if (ftree_skip) {
                /*
                 * clear and go to next arg
                 */
                ftree_skip = 0;
                if (ftree_arg() < 0)
                        return(-1);
        }

        /*
         * loop until we get a valid file to process
         */
        for(;;) {
                if ((ftent = fts_read(ftsp)) == NULL) {
                        /*
                         * out of files in this tree, go to next arg, if none
                         * we are done
                         */
                        if (ftree_arg() < 0)
                                return(-1);
                        continue;
                }

                /*
                 * handle each type of fts_read() flag
                 */
                switch(ftent->fts_info) {
                case FTS_D:
                case FTS_DEFAULT:
                case FTS_F:
                case FTS_SL:
                case FTS_SLNONE:
                        /*
                         * these are all ok
                         */
                        break;
                case FTS_DP:
                        /*
                         * already saw this directory. If the user wants file
                         * access times reset, we use this to restore the
                         * access time for this directory since this is the
                         * last time we will see it in this file subtree
                         * remember to force the time (this is -t on a read
                         * directory, not a created directory).
                         */
                        if (!tflag || (get_atdir(ftent->fts_statp->st_dev,
                            ftent->fts_statp->st_ino, &mtime, &atime) < 0))
                                continue;
                        set_ftime(ftent->fts_path, mtime, atime, 1);
                        continue;
                case FTS_DC:
                        /*
                         * fts claims a file system cycle
                         */
                        paxwarn(1,"File system cycle found at %s",ftent->fts_path);
                        continue;
                case FTS_DNR:
                        syswarn(1, ftent->fts_errno,
                            "Unable to read directory %s", ftent->fts_path);
                        continue;
                case FTS_ERR:
                        syswarn(1, ftent->fts_errno,
                            "File system traversal error");
                        continue;
                case FTS_NS:
                case FTS_NSOK:
                        syswarn(1, ftent->fts_errno,
                            "Unable to access %s", ftent->fts_path);
                        continue;
                }

                /*
                 * ok got a file tree node to process. copy info into arcn
                 * structure (initialize as required)
                 */
                arcn->skip = 0;
                arcn->pad = 0;
                arcn->ln_nlen = 0;
                arcn->ln_name[0] = '\0';
                arcn->sb = *(ftent->fts_statp);

                /*
                 * file type based set up and copy into the arcn struct
                 * SIDE NOTE:
                 * we try to reset the access time on all files and directories
                 * we may read when the -t flag is specified. files are reset
                 * when we close them after copying. we reset the directories
                 * when we are done with their file tree (we also clean up at
                 * end in case we cut short a file tree traversal). However
                 * there is no way to reset access times on symlinks.
                 */
                switch(S_IFMT & arcn->sb.st_mode) {
                case S_IFDIR:
                        arcn->type = PAX_DIR;
                        if (!tflag)
                                break;
                        add_atdir(ftent->fts_path, arcn->sb.st_dev,
                            arcn->sb.st_ino, arcn->sb.st_mtime,
                            arcn->sb.st_atime);
                        break;
                case S_IFCHR:
                        arcn->type = PAX_CHR;
                        break;
                case S_IFBLK:
                        arcn->type = PAX_BLK;
                        break;
                case S_IFREG:
                        /*
                         * only regular files with have data to store on the
                         * archive. all others will store a zero length skip.
                         * the skip field is used by pax for actual data it has
                         * to read (or skip over).
                         */
                        arcn->type = PAX_REG;
                        arcn->skip = arcn->sb.st_size;
                        break;
                case S_IFLNK:
                        arcn->type = PAX_SLK;
                        /*
                         * have to read the symlink path from the file
                         */
                        if ((cnt = readlink(ftent->fts_path, arcn->ln_name,
                            PAXPATHLEN - 1)) < 0) {
                                syswarn(1, errno, "Unable to read symlink %s",
                                    ftent->fts_path);
                                continue;
                        }
                        /*
                         * set link name length, watch out readlink does not
                         * always NUL terminate the link path
                         */
                        arcn->ln_name[cnt] = '\0';
                        arcn->ln_nlen = cnt;
                        break;
                case S_IFSOCK:
                        /*
                         * under BSD storing a socket is senseless but we will
                         * let the format specific write function make the
                         * decision of what to do with it.
                         */
                        arcn->type = PAX_SCK;
                        break;
                case S_IFIFO:
                        arcn->type = PAX_FIF;
                        break;
                }
                break;
        }

        /*
         * copy file name, set file name length
         */
        arcn->nlen = l_strncpy(arcn->name, ftent->fts_path, sizeof(arcn->name) - 1);
        arcn->name[arcn->nlen] = '\0';
        arcn->org_name = ftent->fts_path;
        return(0);
}