dpkg/src/processarc.c

/*
 * dpkg - main program for package management
 * processarc.c - the huge function process_archive
 *
 * Copyright (C) 1995 Ian Jackson <ian@chiark.greenend.org.uk>
 *
 * This 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.
 *
 * This 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 dpkg; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <config.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <utime.h>
#include <assert.h>
#include <time.h>
#include <ctype.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <dpkg.h>
#include <dpkg-db.h>
#include <tarfn.h>
#include <myopt.h>

#include "filesdb.h"
#include "main.h"
#include "archives.h"

void process_archive(const char *filename) {
  static const struct TarFunctions tf = {
    tarfileread,
    tarobject, tarobject, tarobject, tarobject, tarobject
  };

  /* These need to be static so that we can pass their addresses to
   * push_cleanup as arguments to the cu_xxx routines; if an error occurs
   * we unwind the stack before processing the cleanup list, and these
   * variables had better still exist ...
   */
  static int p1[2];
  static char cidirtmpnambuf[L_tmpnam+100];
  static char *cidirbuf=0, *reasmbuf=0;
  static struct fileinlist *newconffiles, *newfileslist;
  static enum pkgstatus oldversionstatus;
  static struct varbuf infofnvb, fnvb, depprobwhy;
  static struct tarcontext tc;
  
  int c1, r, admindirlen, i, infodirlen, infodirbaseused, status;
  struct pkgiterator *it;
  struct pkginfo *pkg, *otherpkg, *divpkg;
  char *cidir, *cidirrest, *p;
  char *pfilenamebuf, conffilenamebuf[MAXCONFFILENAME];
  const char *pfilename, *newinfofilename, *failed;
  struct fileinlist *newconff, **newconffileslastp;
  struct fileinlist *cfile;
  struct reversefilelistiter rlistit;
  struct conffile *searchconff, **iconffileslastp, *newiconff;
  struct filepackages *packageslump;
  struct dependency *dsearch, *newdeplist, **newdeplistlastp;
  struct dependency *newdep, *dep, *providecheck;
  struct deppossi *psearch, **newpossilastp, *possi, *newpossi, *pdep;
  FILE *conff;
  DIR *dsd;
  struct filenamenode *namenode;
  struct dirent *de;
  struct stat stab, oldfs;
  struct packageinlist *deconpil, *deconpiltemp;
  
  cleanup_pkg_failed= cleanup_conflictor_failed= 0;
  admindirlen= strlen(admindir);

  for (pfilename= filename ; pfilename && strlen(pfilename) > 30 &&
      strchr(pfilename,'/') != NULL ; pfilename++ )
    pfilename= strchr(pfilename,'/');
  if (pfilename && pfilename != filename) {
    pfilenamebuf= (char *)nfmalloc(strlen(pfilename)+5);
    strcpy(pfilenamebuf,".../");
    strcat(pfilenamebuf,pfilename);
    pfilename= pfilenamebuf;
  } else {
    pfilename= filename;
  }

  if (stat(filename,&stab)) ohshite(_("cannot access archive"));

  if (!f_noact) {
    /* We can't `tentatively-reassemble' packages. */
    if (!reasmbuf) {
      reasmbuf= m_malloc(admindirlen+sizeof(REASSEMBLETMP)+5);
      strcpy(reasmbuf,admindir);
      strcat(reasmbuf,"/" REASSEMBLETMP);
    }
    if (unlink(reasmbuf) && errno != ENOENT)
      ohshite(_("error ensuring `%.250s' doesn't exist"),reasmbuf);
    push_cleanup(cu_pathname,~0, 0,0, 1,(void*)reasmbuf);
    c1= m_fork();
    if (!c1) {
      execlp(SPLITTER, SPLITTER, "-Qao", reasmbuf, filename, NULL);
      ohshite(_("failed to exec dpkg-split to see if it's part of a multiparter"));
    }
    while ((r= waitpid(c1,&status,0)) == -1 && errno == EINTR);
    if (r != c1) { onerr_abort++; ohshite(_("wait for dpkg-split failed")); }
    switch (WIFEXITED(status) ? WEXITSTATUS(status) : -1) {
    case 0:
      /* It was a part - is it complete ? */
      if (!stat(reasmbuf,&stab)) { /* Yes. */
        filename= reasmbuf;
        pfilename= _("reassembled package file");
        break;
      } else if (errno == ENOENT) { /* No.  That's it, we skip it. */
        return;
      }
    case 1:
      /* No, it wasn't a part. */
      break;
    default:
      checksubprocerr(status,SPLITTER,0);
    }
  }
  
  /* Verify the package. */
  if (!f_nodebsig && (stat(DEBSIGVERIFY, &stab)==0)) {
    printf(_("Authenticating %s ...\n"), filename);
    fflush(stdout);
    c1 = m_fork();
    if (!c1) {
      execl(DEBSIGVERIFY, DEBSIGVERIFY, "-q", filename, NULL);
      ohshite(_("failed to execl debsig-verify"));
    } else {
      int status;
      waitpid(c1, &status, 0);
      if (!(WIFEXITED(status) && WEXITSTATUS(status) == 0)) {
	if (! fc_badverify) {
	  ohshit(_("Verification on package %s failed!"), filename);
	} else {
	  fprintf(stderr, _("Verification on package %s failed,\nbut installing anyway as you request.\n"), filename);
	}
      } else {
	printf(_("passed\n"));
      }
    }
  }
    

  if (f_noact) {
    cidir= cidirtmpnambuf;
    /* We use tmpnam here, not to get a unique filename, but to get a unique directory. */
    if (!tmpnam(cidir)) ohshite(_("unable to get unique filename for control info"));
    strcat(cidir,"/");
  } else {
    /* We want it to be on the same filesystem so that we can
     * use rename(2) to install the postinst &c.
     */
    if (!cidirbuf)
      cidirbuf= m_malloc(admindirlen+sizeof(CONTROLDIRTMP)+MAXCONTROLFILENAME+10);
    cidir= cidirbuf;
    strcpy(cidir,admindir);
    strcat(cidir, "/" CONTROLDIRTMP);
  }
  cidirrest= cidir + strlen(cidir);

  assert(*cidir && cidirrest[-1] == '/'); cidirrest[-1]= 0;
  ensure_pathname_nonexisting(cidir); cidirrest[-1]= '/';
  
  push_cleanup(cu_cidir,~0, 0,0, 2,(void*)cidir,(void*)cidirrest);
  c1= m_fork();
  if (!c1) {
    cidirrest[-1]= 0;
    execlp(BACKEND, BACKEND, "--control", filename, cidir, NULL);
    ohshite(_("failed to exec dpkg-deb to extract control information"));
  }
  waitsubproc(c1,BACKEND " --control",0);
  strcpy(cidirrest,CONTROLFILE);

  parsedb(cidir, pdb_recordavailable | pdb_rejectstatus | pdb_ignorefiles,
          &pkg,NULL,NULL);
  if (!pkg->files) {
    pkg->files= nfmalloc(sizeof(struct filedetails));
    pkg->files->next= 0;
    pkg->files->name= pkg->files->msdosname= pkg->files->md5sum= 0;
  }
  /* Always nfmalloc.  Otherwise, we may overwrite some other field(like md5sum). */
  pkg->files->size= nfmalloc(30);
  sprintf(pkg->files->size,"%lu",(unsigned long)stab.st_size);

  if (cipaction->arg == act_avail) {
    printf(_("Recorded info about %s from %s.\n"),pkg->name,pfilename);
    pop_cleanup(ehflag_normaltidy);
    return;
  }

  if (pkg->available.architecture && *pkg->available.architecture &&
      strcmp(pkg->available.architecture,"all") &&
      strcmp(pkg->available.architecture,architecture))
    forcibleerr(fc_architecture,
                _("package architecture (%s) does not match system (%s)"),
                pkg->available.architecture,architecture);
    
  if (!pkg->installed.valid) blankpackageperfile(&pkg->installed);
  assert(pkg->available.valid);

  for (deconpil= deconfigure;
       deconpil;
       deconpil= deconpiltemp) {
    deconpiltemp= deconpil->next;
    free(deconpil);
  }
  deconfigure= 0;
  clear_istobes();

  if (!wanttoinstall(pkg,&pkg->available.version,1)) {
      pop_cleanup(ehflag_normaltidy);
      return;
  }

  /* Check if anything is installed that we conflict with, or not installed
   * that we need */
  pkg->clientdata->istobe= itb_installnew;

  for (dsearch= pkg->available.depends; dsearch; dsearch= dsearch->next) {
    switch (dsearch->type) {
    case dep_conflicts:
      /* Look for things we conflict with. */
      check_conflict(dsearch, pkg, pfilename);
      break;
    case dep_breaks:
      /* Look for things we break. */
      check_breaks(dsearch, pkg, pfilename);
      break;
    case dep_provides:
      /* Look for things that conflict with what we provide. */
      if (dsearch->list->ed->installed.valid) {
        for (psearch= dsearch->list->ed->installed.depended;
             psearch;
             psearch= psearch->nextrev) {
          if (psearch->up->type != dep_conflicts) continue;
          check_conflict(psearch->up, pkg, pfilename);
        }
      }
      break;
    case dep_suggests:
    case dep_recommends:
    case dep_depends:
    case dep_replaces:
    case dep_enhances:
      /* Ignore these here. */
      break;
    case dep_predepends:
      if (!depisok(dsearch,&depprobwhy,0,1)) {
        varbufaddc(&depprobwhy,0);
        fprintf(stderr, _("dpkg: regarding %s containing %s, pre-dependency problem:\n%s"),
                pfilename, pkg->name, depprobwhy.buf);
        if (!force_depends(dsearch->list))
          ohshit(_("pre-dependency problem - not installing %.250s"),pkg->name);
        fprintf(stderr, _("dpkg: warning - ignoring pre-dependency problem !\n"));
      }
    }
  }
  /* Look for things that conflict with us. */
  for (psearch= pkg->installed.depended; psearch; psearch= psearch->nextrev) {
    if (psearch->up->type != dep_conflicts) continue;
    check_conflict(psearch->up, pkg, pfilename);
  }
  
  ensure_allinstfiles_available();
  filesdbinit();
  
  if (pkg->status != stat_notinstalled && pkg->status != stat_configfiles) {
    log_action("upgrade", pkg);
    printf(_("Preparing to replace %s %s (using %s) ...\n"),
           pkg->name,
           versiondescribe(&pkg->installed.version,vdew_nonambig),
           pfilename);
  } else {
    printf(_("Unpacking %s (from %s) ...\n"),pkg->name,pfilename);
    log_action("install", pkg);
  }

  if (f_noact) {
    pop_cleanup(ehflag_normaltidy);
    return;
  }

  /* OK, we're going ahead.  First we read the conffiles, and copy the
   * hashes across.
   */
  newconffiles= 0; newconffileslastp= &newconffiles;
  push_cleanup(cu_fileslist,~0, 0, 0, 0);
  strcpy(cidirrest,CONFFILESFILE);
  conff= fopen(cidir,"r");
  if (conff) {
    push_cleanup(cu_closefile,ehflag_bombout, 0,0, 1,(void*)conff);
    while (fgets(conffilenamebuf,MAXCONFFILENAME-2,conff)) {
      p= conffilenamebuf + strlen(conffilenamebuf);
      assert(p != conffilenamebuf);
      if (p[-1] != '\n')
        ohshit(_("name of conffile (starting `%.250s') is too long (>%d characters)"),
               conffilenamebuf, MAXCONFFILENAME);
      while (p > conffilenamebuf && isspace(p[-1])) --p;
      if (p == conffilenamebuf) continue;
      *p= 0;
      namenode= findnamenode(conffilenamebuf, 0);
      namenode->oldhash= NEWCONFFILEFLAG;
      newconff= newconff_append(&newconffileslastp, namenode);
      
      /* Let's see if any packages have this file.  If they do we
       * check to see if they listed it as a conffile, and if they did
       * we copy the hash across.  Since (for plain file conffiles,
       * which is the only kind we are supposed to have) there will
       * only be one package which `has' the file, this will usually
       * mean we only look in the package which we're installing now.
       * The `conffiles' data in the status file is ignored when a
       * package isn't also listed in the file ownership database as
       * having that file.  If several packages are listed as owning
       * the file we pick one at random.
       */
      searchconff= 0;
      for (packageslump= newconff->namenode->packages;
           packageslump;
           packageslump= packageslump->more) {
        for (i=0; i < PERFILEPACKAGESLUMP && packageslump->pkgs[i]; i++) {
          otherpkg= packageslump->pkgs[i];
          debug(dbg_conffdetail,"process_archive conffile `%s' in package %s - conff ?",
                newconff->namenode->name,otherpkg->name);
          for (searchconff= otherpkg->installed.conffiles;
               searchconff && strcmp(newconff->namenode->name,searchconff->name);
               searchconff= searchconff->next)
            debug(dbg_conffdetail,
                  "process_archive conffile `%s' in package %s - conff ? not `%s'",
                  newconff->namenode->name,otherpkg->name,searchconff->name);
          if (searchconff) {
            debug(dbg_conff,"process_archive conffile `%s' package=%s %s hash=%s",
                  newconff->namenode->name,otherpkg->name,
                  otherpkg == pkg ? "same" : "different!",
                  searchconff->hash);
            if (otherpkg == pkg) goto xit_conff_hashcopy_srch;
          }
        }
      }
    xit_conff_hashcopy_srch:
      if (searchconff) {
        newconff->namenode->oldhash= searchconff->hash;
	/* we don't copy `obsolete'; it's not obsolete in the new package */
      } else {
        debug(dbg_conff,"process_archive conffile `%s' no package, no hash",
              newconff->namenode->name);
      }
      newconff->namenode->flags |= fnnf_new_conff;
    }
    if (ferror(conff)) ohshite(_("read error in %.250s"),cidir);
    pop_cleanup(ehflag_normaltidy); /* conff= fopen() */
    if (fclose(conff)) ohshite(_("error closing %.250s"),cidir);
  } else {
    if (errno != ENOENT) ohshite(_("error trying to open %.250s"),cidir);
  }

  /* All the old conffiles are marked with a flag, so that we don't delete
   * them if they seem to disappear completely.
   */
  oldconffsetflags(pkg->installed.conffiles);
  for (i = 0 ; i < cflict_index ; i++) {
    oldconffsetflags(conflictor[i]->installed.conffiles);
  }
  
  oldversionstatus= pkg->status;

  assert(oldversionstatus <= stat_configfiles);
  debug(dbg_general,"process_archive oldversionstatus=%s",
        statusstrings[oldversionstatus]);
  
  if (oldversionstatus == stat_halfconfigured || oldversionstatus == stat_installed) {
    pkg->eflag |= eflagf_reinstreq;
    pkg->status= stat_halfconfigured;
    modstatdb_note(pkg);
    push_cleanup(cu_prermupgrade,~ehflag_normaltidy, 0,0, 1,(void*)pkg);
    maintainer_script_alternative(pkg, PRERMFILE, "pre-removal", cidir, cidirrest,
                                  "upgrade", "failed-upgrade");
    pkg->status= stat_unpacked;
    oldversionstatus= stat_unpacked;
    modstatdb_note(pkg);
  }

  for (deconpil= deconfigure; deconpil; deconpil= deconpil->next) {
    struct pkginfo *removing= deconpil->xinfo;

    if (removing)
      printf(_("De-configuring %s, to allow removal of %s ...\n"),
             deconpil->pkg->name, removing->name);
    else
      printf(_("De-configuring %s ...\n"), deconpil->pkg->name);

    deconpil->pkg->status= stat_halfconfigured;
    modstatdb_note(deconpil->pkg);

    /* This means that we *either* go and run postinst abort-deconfigure,
     * *or* queue the package for later configure processing, depending
     * on which error cleanup route gets taken.
     */
    push_cleanup(cu_prermdeconfigure, ~ehflag_normaltidy,
                 ok_prermdeconfigure, ehflag_normaltidy,
                 3, (void*)deconpil->pkg, (void*)removing, (void*)pkg);

    if (removing) {
      maintainer_script_installed(deconpil->pkg, PRERMFILE, "pre-removal",
                                  "deconfigure", "in-favour", pkg->name,
                                  versiondescribe(&pkg->available.version,
                                                  vdew_nonambig),
                                  "removing", removing->name,
                                  versiondescribe(&removing->installed.version,
                                                  vdew_nonambig),
                                  NULL);
    } else {
      maintainer_script_installed(deconpil->pkg, PRERMFILE, "pre-removal",
                                  "deconfigure", "in-favour", pkg->name,
                                  versiondescribe(&pkg->available.version,
                                                  vdew_nonambig),
                                  NULL);
    }
  }

  for (i = 0 ; i < cflict_index; i++) {
    if (!(conflictor[i]->status == stat_halfconfigured ||
          conflictor[i]->status == stat_installed)) continue;
    conflictor[i]->status= stat_halfconfigured;
    modstatdb_note(conflictor[i]);
    push_cleanup(cu_prerminfavour,~ehflag_normaltidy, 0,0,
                 2,(void*)conflictor[i],(void*)pkg);
    maintainer_script_installed(conflictor[i], PRERMFILE, "pre-removal",
                                "remove", "in-favour", pkg->name,
                                versiondescribe(&pkg->available.version,
                                                vdew_nonambig),
                                NULL);
    conflictor[i]->status= stat_halfinstalled;
    modstatdb_note(conflictor[i]);
  }

  pkg->eflag |= eflagf_reinstreq;
  if (pkg->status == stat_notinstalled)
    pkg->installed.version= pkg->available.version;
  pkg->status= stat_halfinstalled;
  modstatdb_note(pkg);
  if (oldversionstatus == stat_notinstalled) {
    push_cleanup(cu_preinstverynew,~ehflag_normaltidy, 0,0,
                 3,(void*)pkg,(void*)cidir,(void*)cidirrest);
    maintainer_script_new(pkg->name, PREINSTFILE, "pre-installation", cidir, cidirrest,
                          "install", NULL);
  } else if (oldversionstatus == stat_configfiles) {
    push_cleanup(cu_preinstnew,~ehflag_normaltidy, 0,0,
                 3,(void*)pkg,(void*)cidir,(void*)cidirrest);
    maintainer_script_new(pkg->name, PREINSTFILE, "pre-installation", cidir, cidirrest,
                          "install", versiondescribe(&pkg->installed.version,
                                                     vdew_nonambig),
                          NULL);
  } else {
    push_cleanup(cu_preinstupgrade,~ehflag_normaltidy, 0,0,
                 4,(void*)pkg,(void*)cidir,(void*)cidirrest,(void*)&oldversionstatus);
    maintainer_script_new(pkg->name, PREINSTFILE, "pre-installation", cidir, cidirrest,
                          "upgrade", versiondescribe(&pkg->installed.version,
                                                     vdew_nonambig),
                          NULL);
    printf(_("Unpacking replacement %.250s ...\n"),pkg->name);
  }
  
  /*
   * Now we unpack the archive, backing things up as we go.
   * For each file, we check to see if it already exists.
   * There are several possibilities:
   * + We are trying to install a non-directory ...
   *  - It doesn't exist.  In this case we simply extract it.
   *  - It is a plain file, device, symlink, &c.  We do an `atomic
   *    overwrite' using link() and rename(), but leave a backup copy.
   *    Later, when we delete the backup, we remove it from any other
   *    packages' lists.
   * -  It is a directory.  In this case it depends on whether we're
   *    trying to install a symlink or something else.
   *   = If we're not trying to install a symlink we move the directory
   *     aside and extract the node.  Later, when we recursively remove
   *     the backed-up directory, we remove it from any other packages'
   *     lists.
   *   = If we are trying to install a symlink we do nothing - ie,
   *     dpkg will never replace a directory tree with a symlink.  This
   *     is to avoid embarrassing effects such as replacing a directory
   *     tree with a link to a link to the original directory tree.
   * + We are trying to install a directory ...
   *  - It doesn't exist.  We create it with the appropriate modes.
   *  - It exists as a directory or a symlink to one.  We do nothing.
   *  - It is a plain file or a symlink (other than to a directory).
   *    We move it aside and create the directory.  Later, when we
   *    delete the backup, we remove it from any other packages' lists.
   *
   *                   Install non-dir   Install symlink   Install dir
   *  Exists not               X               X                X
   *  File/node/symlink       LXR             LXR              BXR
   *  Directory               BXR              -                -
   *
   *    X: extract file/node/link/directory
   *   LX: atomic overwrite leaving backup
   *    B: ordinary backup
   *    R: later remove from other packages' lists
   *    -: do nothing
   * 
   * After we've done this we go through the remaining things in the
   * lists of packages we're trying to remove (including the old
   * version of the current package).  This happens in reverse order,
   * so that we process files before the directories (or symlinks-to-
   * directories) containing them.
   * + If the thing is a conffile then we leave it alone for the purge
   *   operation.
   * + Otherwise, there are several possibilities too:
   *  - The listed thing does not exist.  We ignore it.
   *  - The listed thing is a directory or a symlink to a directory.
   *    We delete it only if it isn't listed in any other package.
   *  - The listed thing is not a directory, but was part of the package
   *    that was upgraded, we check to make sure the files aren't the
   *    same ones from the old package by checking dev/inode
   *  - The listed thing is not a directory or a symlink to one (ie,
   *    it's a plain file, device, pipe, &c, or a symlink to one, or a
   *    dangling symlink).  We delete it.
   * The removed packages' list becomes empty (of course, the new
   * version of the package we're installing will have a new list,
   * which replaces the old version's list).
   *
   * If at any stage we remove a file from a package's list, and the
   * package isn't one we're already processing, and the package's
   * list becomes empty as a result, we `vanish' the package.  This
   * means that we run its postrm with the `disappear' argument, and
   * put the package in the `not-installed' state.  If it had any
   * conffiles, their hashes and ownership will have been transferred
   * already, so we just ignore those and forget about them from the
   * point of view of the disappearing package.
   *
   * NOTE THAT THE OLD POSTRM IS RUN AFTER THE NEW PREINST, since the
   * files get replaced `as we go'.
   */

  m_pipe(p1);
  push_cleanup(cu_closepipe,ehflag_bombout, 0,0, 1,(void*)&p1[0]);
  c1= m_fork();
  if (!c1) {
    m_dup2(p1[1],1); close(p1[0]); close(p1[1]);
    execlp(BACKEND, BACKEND, "--fsys-tarfile", filename, NULL);
    ohshite(_("unable to exec dpkg-deb to get filesystem archive"));
  }
  close(p1[1]);

  newfileslist= 0; tc.newfilesp= &newfileslist;
  push_cleanup(cu_fileslist,~0, 0, 0, 0);
  tc.pkg= pkg;
  tc.backendpipe= p1[0];
  push_cleanup(cu_closefd,~ehflag_bombout, 0,0, 1,&tc.backendpipe);

  r= TarExtractor((void*)&tc, &tf);
  if (r) {
    if (errno) {
      ohshite(_("error reading dpkg-deb tar output"));
    } else {
      ohshit(_("corrupted filesystem tarfile - corrupted package archive"));
    }
  }
  fd_null_copy(tc.backendpipe,-1,_("dpkg-deb: zap possible trailing zeros"));
  close(tc.backendpipe);
  waitsubproc(c1,BACKEND " --fsys-tarfile",PROCPIPE);

  if (oldversionstatus == stat_halfinstalled || oldversionstatus == stat_unpacked) {
    /* Packages that were in `installed' and `postinstfailed' have been reduced
     * to `unpacked' by now, by the running of the prerm script.
     */
    pkg->status= stat_halfinstalled;
    modstatdb_note(pkg);
    push_cleanup(cu_postrmupgrade,~ehflag_normaltidy, 0,0, 1,(void*)pkg);
    maintainer_script_alternative(pkg, POSTRMFILE, "post-removal", cidir, cidirrest,
                                  "upgrade", "failed-upgrade");
  }

  /* If anything goes wrong while tidying up it's a bit late to do
   * anything about it.  However, we don't install the new status
   * info yet, so that a future dpkg installation will put everything
   * right (we hope).
   *
   * If something does go wrong later the `conflictor' package will be
   * left in the `removal_failed' state.  Removing or installing it
   * will be impossible if it was required because of the conflict with
   * the package we're installing now and (presumably) the dependency
   * by other packages.  This means that the files it contains in
   * common with this package will hang around until we successfully
   * get this package installed, after which point we can trust the
   * conflicting package's file list, which will have been updated to
   * remove any files in this package.
   */
  push_checkpoint(~ehflag_bombout, ehflag_normaltidy);
  
  /* Now we delete all the files that were in the old version of
   * the package only, except (old or new) conffiles, which we leave
   * alone.
   */
  reversefilelist_init(&rlistit,pkg->clientdata->files);
  while ((namenode= reversefilelist_next(&rlistit))) {
    if ((namenode->flags & fnnf_new_conff) ||
        (namenode->flags & fnnf_new_inarchive))
      continue;
    if (!stat(namenode->name,&stab) && S_ISDIR(stab.st_mode)) {
      debug(dbg_eachfiledetail, "process_archive: %s is a directory",
	    namenode->name);
      if (isdirectoryinuse(namenode,pkg)) continue;
    }
    fnamevb.used= fnameidlu;
    varbufaddstr(&fnamevb, namenodetouse(namenode,pkg)->name);
    varbufaddc(&fnamevb,0);

    if (lstat(fnamevb.buf, &oldfs)) {
      if (!(errno == ENOENT || errno == ELOOP || errno == ENOTDIR))
	fprintf(stderr,
		_("dpkg: warning - could not stat old file `%.250s'"
		  " so not deleting it: %s"),
		fnamevb.buf, strerror(errno));
      continue;
    }
    if (S_ISDIR(oldfs.st_mode)) {
      if (rmdir(fnamevb.buf)) {
	fprintf(stderr,
		_("dpkg: warning - unable to delete old directory"
		  " `%.250s': %s\n"), namenode->name, strerror(errno));
      } else if ((namenode->flags & fnnf_old_conff)) {
	fprintf(stderr,
		_("dpkg: warning - old conffile `%.250s' was an empty"
		  " directory (and has now been deleted)\n"),
		namenode->name);
      }
    } else {
      /* Ok, it's an old file, but is it really not in the new package?
       * It might be known by a different name because of symlinks.
       *
       * We need to check to make sure, so we stat the file, then compare
       * it to the new list. If we find a dev/inode match, we assume they
       * are the same file, and leave it alone. NOTE: we don't check in
       * other packages for sanity reasons (we don't want to stat _all_
       * the files on the system).
       *
       * We run down the list of _new_ files in this package. This keeps
       * the process a little leaner. We are only worried about new ones
       * since ones that stayed the same don't really apply here.
       */
      struct fileinlist *sameas= 0;
      /* If we can't stat the old or new file, or it's a directory,
       * we leave it up to the normal code
       */
      debug(dbg_eachfile, "process_archive: checking %s for same files on "
	    "upgrade/downgrade", fnamevb.buf);

      for (cfile= newfileslist; cfile; cfile= cfile->next) {
	if (!cfile->namenode->filestat) {
	  cfile->namenode->filestat= nfmalloc(sizeof(struct stat));
	  if (lstat(cfile->namenode->name, cfile->namenode->filestat)) {
	    if (!(errno == ENOENT || errno == ELOOP || errno == ENOTDIR))
	      ohshite(_("unable to stat other new file `%.250s'"),
		      cfile->namenode->name);
	    memset(cfile->namenode->filestat, 0,
		   sizeof(cfile->namenode->filestat));
	    continue;
	  }
	}
	if (!cfile->namenode->filestat->st_mode) continue;
	if (oldfs.st_dev == cfile->namenode->filestat->st_dev &&
	    oldfs.st_ino == cfile->namenode->filestat->st_ino) {
	  if (sameas)
	    fprintf(stderr, _("dpkg: warning - old file `%.250s' is the same"
		    " as several new files!  (both `%.250s' and `%.250s')\n"),
		    fnamevb.buf,
		    sameas->namenode->name, cfile->namenode->name);
	  sameas= cfile;
	  debug(dbg_eachfile, "process_archive: not removing %s,"
		" since it matches %s", fnamevb.buf, cfile->namenode->name);
	}
      }

      if ((namenode->flags & fnnf_old_conff)) {
	if (sameas) {
	  if (sameas->namenode->flags & fnnf_new_conff) {
	    if (!strcmp(sameas->namenode->oldhash, NEWCONFFILEFLAG)) {
	      sameas->namenode->oldhash= namenode->oldhash;
	      debug(dbg_eachfile, "process_archive: old conff %s"
		    " is same as new conff %s, copying hash",
		    namenode->name, sameas->namenode->name);
	    } else {
	      debug(dbg_eachfile, "process_archive: old conff %s"
		    " is same as new conff %s but latter already has hash",
		    namenode->name, sameas->namenode->name);
	    }
	  }
	} else {
	  debug(dbg_eachfile, "process_archive: old conff %s"
		" is disappearing", namenode->name);
	  namenode->flags |= fnnf_obs_conff;
	  newconff_append(&newconffileslastp, namenode);
	  addfiletolist(&tc, namenode);
	}
	continue;
      }
      
      if (sameas)
	continue;

      failed= N_("delete");
      if (chmodsafe_unlink_statted(fnamevb.buf, &oldfs, &failed)) {
	char mbuf[250];
	snprintf(mbuf, sizeof(mbuf),
		 N_("dpkg: warning - unable to %s old file `%%.250s': %%s\n"),
		 failed);
	fprintf(stderr, _(mbuf), namenode->name, strerror(errno));
      }

    } /* !S_ISDIR */
  }

  /* OK, now we can write the updated files-in-this package list,
   * since we've done away (hopefully) with all the old junk.
   */
  write_filelist_except(pkg,newfileslist,0);

  /* We also install the new maintainer scripts, and any other
   * cruft that may have come along with the package.  First
   * we go through the existing scripts replacing or removing
   * them as appropriate; then we go through the new scripts
   * (any that are left) and install them.
   */
  debug(dbg_general, "process_archive updating info directory");
  varbufreset(&infofnvb);
  varbufaddstr(&infofnvb,admindir);
  varbufaddstr(&infofnvb,"/" INFODIR "/");
  infodirlen= infofnvb.used;
  varbufaddc(&infofnvb,0);
  dsd= opendir(infofnvb.buf);
  if (!dsd) ohshite(_("cannot read info directory"));
  push_cleanup(cu_closedir,~0, 0,0, 1,(void*)dsd);
  while ((de= readdir(dsd)) != 0) {
    debug(dbg_veryverbose, "process_archive info file `%s'", de->d_name);
    if (de->d_name[0] == '.') continue; /* ignore dotfiles, including `.' and `..' */
    p= strrchr(de->d_name,'.'); if (!p) continue; /* ignore anything odd */
    if (strlen(pkg->name) != (size_t)(p-de->d_name) ||
        strncmp(de->d_name,pkg->name,p-de->d_name)) continue;
    debug(dbg_stupidlyverbose, "process_archive info this pkg");
    /* Right do we have one ? */
    p++; /* skip past the full stop */
    if (!strcmp(p,LISTFILE)) continue; /* We do the list separately */
    if (strlen(p) > MAXCONTROLFILENAME)
      ohshit(_("old version of package has overly-long info file name starting `%.250s'"),
             de->d_name);
    infofnvb.used= infodirlen;
    varbufaddstr(&infofnvb,de->d_name);
    varbufaddc(&infofnvb,0);
    strcpy(cidirrest,p);
    if (!rename(cidir,infofnvb.buf)) {
      debug(dbg_scripts, "process_archive info installed %s as %s",
            cidir, infofnvb.buf);
    } else if (errno == ENOENT) {
      /* Right, no new version. */
      if (unlink(infofnvb.buf))
        ohshite(_("unable to remove obsolete info file `%.250s'"),infofnvb.buf);
      debug(dbg_scripts, "process_archive info unlinked %s",infofnvb.buf);
    } else {
      ohshite(_("unable to install (supposed) new info file `%.250s'"),cidir);
    }
  }
  pop_cleanup(ehflag_normaltidy); /* closedir */
  
  *cidirrest= 0; /* the directory itself */
  dsd= opendir(cidir);
  if (!dsd) ohshite(_("unable to open temp control directory"));
  push_cleanup(cu_closedir,~0, 0,0, 1,(void*)dsd);
  while ((de= readdir(dsd))) {
    if (strchr(de->d_name,'.')) {
      debug(dbg_scripts,"process_archive tmp.ci script/file `%s' contains dot",
            de->d_name);
      continue;
    }
    if (strlen(de->d_name) > MAXCONTROLFILENAME)
      ohshit(_("package contains overly-long control info file name (starting `%.50s')"),
             de->d_name);
    strcpy(cidirrest,de->d_name);
    /* First we check it's not a directory. */
    if (!rmdir(cidir))
      ohshit(_("package control info contained directory `%.250s'"),cidir);
    else if (errno != ENOTDIR)
      ohshite(_("package control info rmdir of `%.250s' didn't say not a dir"),de->d_name);
    if (!strcmp(de->d_name,CONTROLFILE)) {
      debug(dbg_scripts,"process_archive tmp.ci script/file `%s' is control",cidir);
      continue; /* ignore the control file */
    }
    if (!strcmp(de->d_name,LISTFILE)) {
      fprintf(stderr, _("dpkg: warning - package %s"
              " contained list as info file"), pkg->name);
      continue;
    }
    /* Right, install it */
    newinfofilename= pkgadminfile(pkg,de->d_name);
    if (rename(cidir,newinfofilename))
      ohshite(_("unable to install new info file `%.250s' as `%.250s'"),
              cidir,newinfofilename);
    debug(dbg_scripts,"process_archive tmp.ci script/file `%s' installed as `%s'",
          cidir, newinfofilename);
  }
  pop_cleanup(ehflag_normaltidy); /* closedir */

  /* Update the status database.
   * This involves copying each field across from the `available'
   * to the `installed' half of the pkg structure.
   * For some of the fields we have to do a complicated construction
   * operation; for others we can just copy the value.
   * We tackle the fields in the order they appear, so that
   * we don't miss any out :-).
   * At least we don't have to copy any strings that are referred
   * to, because these are never modified and never freed.
   */

  /* The dependencies are the most difficult.  We have to build
   * a whole new forward dependency tree.  At least the reverse
   * links (linking our deppossi's into the reverse chains)
   * can be done by copy_dependency_links.
   */
  newdeplist= 0; newdeplistlastp= &newdeplist;
  for (dep= pkg->available.depends; dep; dep= dep->next) {
    newdep= nfmalloc(sizeof(struct dependency));
    newdep->up= pkg;
    newdep->next= 0;
    newdep->list= 0; newpossilastp= &newdep->list;
    for (possi= dep->list; possi; possi= possi->next) {
      newpossi= nfmalloc(sizeof(struct deppossi));
      newpossi->up= newdep;
      newpossi->ed= possi->ed;
      newpossi->next= 0; newpossi->nextrev= newpossi->backrev= 0;
      newpossi->verrel= possi->verrel;
      if (possi->verrel != dvr_none)
        newpossi->version= possi->version;
      else
        blankversion(&newpossi->version);
      newpossi->cyclebreak= 0;
      *newpossilastp= newpossi;
      newpossilastp= &newpossi->next;
    }
    newdep->type= dep->type;
    *newdeplistlastp= newdep;
    newdeplistlastp= &newdep->next;
  }
  /* Right, now we've replicated the forward tree, we
   * get copy_dependency_links to remove all the old dependency
   * structures from the reverse links and add the new dependency
   * structures in instead.  It also copies the new dependency
   * structure pointer for this package into the right field.
   */
  copy_dependency_links(pkg,&pkg->installed.depends,newdeplist,0);

  /* The `depended' pointer in the structure doesn't represent anything
   * that is actually specified by this package - it's there so we
   * can find out what other packages refer to this one.  So,
   * we don't copy it.  We go straight on to copy the text fields.
   */
  pkg->installed.essential= pkg->available.essential;
  pkg->installed.description= pkg->available.description;
  pkg->installed.maintainer= pkg->available.maintainer;
  pkg->installed.source= pkg->available.source;
  pkg->installed.architecture= pkg->available.architecture;
  pkg->installed.installedsize= pkg->available.installedsize;
  pkg->installed.version= pkg->available.version;
  pkg->installed.origin = pkg->available.origin;                               
  pkg->installed.bugs = pkg->available.bugs;                                   

  /* We have to generate our own conffiles structure. */
  pkg->installed.conffiles= 0; iconffileslastp= &pkg->installed.conffiles;
  for (cfile= newconffiles; cfile; cfile= cfile->next) {
    newiconff= nfmalloc(sizeof(struct conffile));
    newiconff->next= 0;
    newiconff->name= nfstrsave(cfile->namenode->name);
    newiconff->hash= nfstrsave(cfile->namenode->oldhash);
    newiconff->obsolete= !!(cfile->namenode->flags & fnnf_obs_conff);
    *iconffileslastp= newiconff;
    iconffileslastp= &newiconff->next;
  }

  /* We can just copy the arbitrary fields list, because it is
   * never even rearragned.  Phew !
   */
  pkg->installed.arbs= pkg->available.arbs;

  /* Check for disappearing packages:
   * We go through all the packages on the system looking for ones
   * whose files are entirely part of the one we've just unpacked
   * (and which actually *have* some files!).
   *
   * Any that we find are removed - we run the postrm with `disappear'
   * as an argument, and remove their info/... files and status info.
   * Conffiles are ignored (the new package had better do something
   * with them !).
   */
  it= iterpkgstart();
  while ((otherpkg= iterpkgnext(it)) != 0) {
    ensure_package_clientdata(otherpkg);
    if (otherpkg == pkg ||
        otherpkg->status == stat_notinstalled ||
        otherpkg->status == stat_configfiles ||
	otherpkg->clientdata->istobe == itb_remove ||
        !otherpkg->clientdata->files) continue;
    debug(dbg_veryverbose, "process_archive checking disappearance %s",otherpkg->name);
    assert(otherpkg->clientdata->istobe == itb_normal ||
           otherpkg->clientdata->istobe == itb_deconfigure);
    for (cfile= otherpkg->clientdata->files;
         cfile && !strcmp(cfile->namenode->name,"/.");
         cfile= cfile->next);
    if (!cfile) {
      debug(dbg_stupidlyverbose, "process_archive no non-root, no disappear");
      continue;
    }
    for (cfile= otherpkg->clientdata->files;
         cfile && !filesavespackage(cfile,otherpkg,pkg);
         cfile= cfile->next);
    if (cfile) continue;

    /* So dependency things will give right answers ... */
    otherpkg->clientdata->istobe= itb_remove; 
    debug(dbg_veryverbose, "process_archive disappear checking dependencies");
    for (pdep= otherpkg->installed.depended;
         pdep;
         pdep= pdep->nextrev) {
      if (pdep->up->type != dep_depends && pdep->up->type != dep_predepends &&
          pdep->up->type != dep_recommends) continue;
      if (depisok(pdep->up, &depprobwhy, 0,0)) continue;
      varbufaddc(&depprobwhy,0);
      debug(dbg_veryverbose,"process_archive cannot disappear: %s",depprobwhy.buf);
      break;
    }
    if (!pdep) {
      /* If we haven't found a reason not to yet, let's look some more. */
      for (providecheck= otherpkg->installed.depends;
           providecheck;
           providecheck= providecheck->next) {
        if (providecheck->type != dep_provides) continue;
        for (pdep= providecheck->list->ed->installed.depended;
             pdep;
             pdep= pdep->nextrev) {
          if (pdep->up->type != dep_depends && pdep->up->type != dep_predepends &&
              pdep->up->type != dep_recommends)
            continue;
          if (depisok(pdep->up, &depprobwhy, 0,0)) continue;
          varbufaddc(&depprobwhy,0);
          debug(dbg_veryverbose,"process_archive cannot disappear (provides %s): %s",
                providecheck->list->ed->name, depprobwhy.buf);
          goto break_from_both_loops_at_once;
        }
      }
    break_from_both_loops_at_once:;
    }
    otherpkg->clientdata->istobe= itb_normal;
    if (pdep) continue;

    printf(_("(Noting disappearance of %s, which has been completely replaced.)\n"),
           otherpkg->name);
    debug(dbg_general, "process_archive disappearing %s",otherpkg->name);
    /* No, we're disappearing it.  This is the wrong time to go and
     * run maintainer scripts and things, as we can't back out.  But
     * what can we do ?  It has to be run this late.
     */
    maintainer_script_installed(otherpkg, POSTRMFILE,
                                "post-removal script (for disappearance)",
                                "disappear", pkg->name, 
                                versiondescribe(&pkg->available.version,
                                                vdew_nonambig),
                                NULL);

    /* OK, now we delete all the stuff in the `info' directory .. */
    varbufreset(&fnvb);
    varbufaddstr(&fnvb,admindir);
    varbufaddstr(&fnvb,"/" INFODIR);
    infodirbaseused= fnvb.used;
    varbufaddc(&fnvb,0);
    dsd= opendir(fnvb.buf); if (!dsd) ohshite(_("cannot read info directory"));
    push_cleanup(cu_closedir,~0, 0,0, 1,(void*)dsd);

    debug(dbg_general, "process_archive disappear cleaning info directory");
      
    while ((de= readdir(dsd)) != 0) {
      debug(dbg_veryverbose, "process_archive info file `%s'", de->d_name);
      if (de->d_name[0] == '.') continue;
      p= strrchr(de->d_name,'.'); if (!p) continue;
      if (strlen(otherpkg->name) != (size_t)(p-de->d_name) ||
          strncmp(de->d_name,otherpkg->name,p-de->d_name)) continue;
      debug(dbg_stupidlyverbose, "process_archive info this pkg");
      fnvb.used= infodirbaseused;
      varbufaddstr(&fnvb,de->d_name);
      varbufaddc(&fnvb,0);
      if (unlink(fnvb.buf))
        ohshite(_("unable to delete disappearing control info file `%.250s'"),fnvb.buf);
      debug(dbg_scripts, "process_archive info unlinked %s",fnvb.buf);
    }
    pop_cleanup(ehflag_normaltidy); /* closedir */
    
    otherpkg->status= stat_notinstalled;
    otherpkg->want= want_purge;
    otherpkg->eflag= eflagv_ok;

    otherpkg->installed.depends= 0;
    otherpkg->installed.essential= 0;
    otherpkg->installed.description= otherpkg->installed.maintainer= 0;
    otherpkg->installed.installedsize= otherpkg->installed.source= 0;
    otherpkg->installed.origin= otherpkg->installed.bugs= 0;
    otherpkg->installed.architecture= 0;
    otherpkg->installed.conffiles= 0;
    blankversion(&otherpkg->installed.version);
    otherpkg->installed.arbs= 0;
    otherpkg->clientdata->fileslistvalid= 0;

    modstatdb_note(otherpkg);

  } /* while (otherpkg= ... */
  iterpkgend(it);
  
  /* Delete files from any other packages' lists.
   * We have to do this before we claim this package is in any
   * sane kind of state, as otherwise we might delete by mistake
   * a file that we overwrote, when we remove the package which
   * had the version we overwrote.  To prevent this we make
   * sure that we don't claim this package is OK until we
   * have claimed `ownership' of all its files.
   */
  for (cfile= newfileslist; cfile; cfile= cfile->next) {
    if (!(cfile->namenode->flags & fnnf_elide_other_lists)) continue;
    if (cfile->namenode->divert && cfile->namenode->divert->useinstead) {
      divpkg= cfile->namenode->divert->pkg;
      if (divpkg == pkg) {
        debug(dbg_eachfile,
              "process_archive not overwriting any `%s' (overriding, `%s')",
              cfile->namenode->name, cfile->namenode->divert->useinstead->name);
        continue;
      } else {
        debug(dbg_eachfile,
              "process_archive looking for overwriting `%s' (overridden by %s)",
              cfile->namenode->name, divpkg ? divpkg->name : "<local>");
      }        
    } else {
      divpkg= 0;
      debug(dbg_eachfile, "process_archive looking for overwriting `%s'",
            cfile->namenode->name);
    }
    for (packageslump= cfile->namenode->packages;
         packageslump;
         packageslump= packageslump->more) {
      for (i=0; i < PERFILEPACKAGESLUMP && packageslump->pkgs[i]; i++) {
        otherpkg= packageslump->pkgs[i];
        debug(dbg_eachfiledetail, "process_archive ... found in %s\n",otherpkg->name);
        /* If !fileslistvalid then it's one of the disappeared packages above
         * and we don't bother with it here, clearly.
         */
        if (otherpkg == pkg || !otherpkg->clientdata->fileslistvalid) continue;
        if (otherpkg == divpkg) {
          debug(dbg_eachfiledetail, "process_archive ... diverted, skipping\n");
          continue;
        }

        /* Found one.  We delete remove the list entry for this file,
         * (and any others in the same package) and then mark the package
         * as requiring a reread.
         */
        write_filelist_except(otherpkg, otherpkg->clientdata->files, 1);
        ensure_package_clientdata(otherpkg);
        debug(dbg_veryverbose, "process_archive overwrote from %s",otherpkg->name);
      }
    }
  }

  /* Right, the package we've unpacked is now in a reasonable state.
   * The only thing that we have left to do with it is remove
   * backup files, and we can leave the user to fix that if and when
   * it happens (we leave the reinstall required flag, of course).
   */
  pkg->status= stat_unpacked;
  modstatdb_note(pkg);
  
  /* Now we delete all the backup files that we made when
   * extracting the archive - except for files listed as conffiles
   * in the new package.
   * This time we count it as an error if something goes wrong.
   *
   * Note that we don't ever delete things that were in the old
   * package as a conffile and don't appear at all in the new.
   * They stay recorded as obsolete conffiles and will eventually
   * (if not taken over by another package) be forgotten.
   */
  for (cfile= newfileslist; cfile; cfile= cfile->next) {
    if (cfile->namenode->flags & fnnf_new_conff) continue;
    fnametmpvb.used= fnameidlu;
    varbufaddstr(&fnametmpvb,namenodetouse(cfile->namenode,pkg)->name);
    varbufaddstr(&fnametmpvb,DPKGTEMPEXT);
    varbufaddc(&fnametmpvb,0);
    ensure_pathname_nonexisting(fnametmpvb.buf);
  }

  /* OK, we're now fully done with the main package.
   * This is quite a nice state, so we don't unwind past here.
   */
  pkg->eflag= eflagv_ok;
  modstatdb_note(pkg);
  push_checkpoint(~ehflag_bombout, ehflag_normaltidy);

  /* Only the removal of the conflictor left to do.
   * The files list for the conflictor is still a little inconsistent in-core,
   * as we have not yet updated the filename->packages mappings; however,
   * the package->filenames mapping is 
   */
  for (i = 0 ; i < cflict_index ; i++) {
    /* We need to have the most up-to-date info about which files are what ... */
    ensure_allinstfiles_available();
    removal_bulk(conflictor[i]);
  }

  if (cipaction->arg == act_install) add_to_queue(pkg);
}