dpkg/src/packages.c

/*
 * dpkg - main program for package management
 * packages.c - common to actions that process packages
 *
 * Copyright © 1994,1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
 * Copyright © 2006-2014 Guillem Jover <guillem@debian.org>
 * Copyright © 2011 Linaro Limited
 * Copyright © 2011 Raphaël Hertzog <hertzog@debian.org>
 *
 * 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 of the License, 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <compat.h>

#include <sys/types.h>
#include <sys/stat.h>

#include <assert.h>
#include <string.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#include <dpkg/i18n.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/pkg-list.h>
#include <dpkg/pkg-queue.h>
#include <dpkg/string.h>
#include <dpkg/options.h>

#include "filesdb.h"
#include "infodb.h"
#include "main.h"

static struct pkginfo *progress_bytrigproc;
static struct pkg_queue queue = PKG_QUEUE_INIT;

int sincenothing = 0, dependtry = 1;

void
enqueue_package(struct pkginfo *pkg)
{
  ensure_package_clientdata(pkg);
  if (pkg->clientdata->enqueued)
    return;
  pkg->clientdata->enqueued = true;
  pkg_queue_push(&queue, pkg);
}

void
enqueue_package_mark_seen(struct pkginfo *pkg)
{
  enqueue_package(pkg);
  pkg->clientdata->cmdline_seen++;
}

static void
enqueue_pending(void)
{
  struct pkgiterator *iter;
  struct pkginfo *pkg;

  iter = pkg_db_iter_new();
  while ((pkg = pkg_db_iter_next_pkg(iter)) != NULL) {
    switch (cipaction->arg_int) {
    case act_configure:
      if (!(pkg->status == PKG_STAT_UNPACKED ||
            pkg->status == PKG_STAT_HALFCONFIGURED ||
            pkg->trigpend_head))
        continue;
      if (pkg->want != PKG_WANT_INSTALL)
        continue;
      break;
    case act_triggers:
      if (!pkg->trigpend_head)
        continue;
      if (pkg->want != PKG_WANT_INSTALL)
        continue;
      break;
    case act_remove:
    case act_purge:
      if (pkg->want != PKG_WANT_PURGE) {
        if (pkg->want != PKG_WANT_DEINSTALL)
          continue;
        if (pkg->status == PKG_STAT_CONFIGFILES)
          continue;
      }
      if (pkg->status == PKG_STAT_NOTINSTALLED)
        continue;
      break;
    default:
      internerr("unknown action '%d'", cipaction->arg_int);
    }
    enqueue_package(pkg);
  }
  pkg_db_iter_free(iter);
}

static void
enqueue_specified(const char *const *argv)
{
  const char *thisarg;

  while ((thisarg = *argv++) != NULL) {
    struct pkginfo *pkg;

    pkg = dpkg_options_parse_pkgname(cipaction, thisarg);
    if (pkg->status == PKG_STAT_NOTINSTALLED &&
        str_match_end(pkg->set->name, DEBEXT)) {
      badusage(_("you must specify packages by their own names, "
                 "not by quoting the names of the files they come in"));
    }
    enqueue_package_mark_seen(pkg);
  }

  if (cipaction->arg_int == act_configure)
    trigproc_populate_deferred();
}

int
packages(const char *const *argv)
{
  trigproc_install_hooks();

  modstatdb_open(f_noact ?    msdbrw_readonly :
                 fc_nonroot ? msdbrw_write :
                              msdbrw_needsuperuser);
  checkpath();
  pkg_infodb_upgrade();

  log_message("startup packages %s", cipaction->olong);

  if (f_pending) {
    if (*argv)
      badusage(_("--%s --pending does not take any non-option arguments"),cipaction->olong);

    enqueue_pending();
  } else {
    if (!*argv)
      badusage(_("--%s needs at least one package name argument"), cipaction->olong);

    enqueue_specified(argv);
  }

  ensure_diversions();

  process_queue();
  trigproc_run_deferred();

  modstatdb_shutdown();

  return 0;
}

void process_queue(void) {
  struct pkg_list *rundown;
  struct pkginfo *volatile pkg;
  volatile enum action action_todo;
  jmp_buf ejbuf;
  enum pkg_istobe istobe = PKG_ISTOBE_NORMAL;

  if (abort_processing)
    return;

  clear_istobes();

  switch (cipaction->arg_int) {
  case act_triggers:
  case act_configure:
  case act_install:
    istobe = PKG_ISTOBE_INSTALLNEW;
    break;
  case act_remove:
  case act_purge:
    istobe = PKG_ISTOBE_REMOVE;
    break;
  default:
    internerr("unknown action '%d'", cipaction->arg_int);
  }
  for (rundown = queue.head; rundown; rundown = rundown->next) {
    ensure_package_clientdata(rundown->pkg);

    /* We have processed this package more than once. There are no duplicates
     * as we make sure of that when enqueuing them. */
    if (rundown->pkg->clientdata->cmdline_seen > 1) {
      switch (cipaction->arg_int) {
      case act_triggers:
      case act_configure: case act_remove: case act_purge:
        printf(_("Package %s listed more than once, only processing once.\n"),
               pkg_name(rundown->pkg, pnaw_nonambig));
        break;
      case act_install:
        printf(_("More than one copy of package %s has been unpacked\n"
               " in this run !  Only configuring it once.\n"),
               pkg_name(rundown->pkg, pnaw_nonambig));
        break;
      default:
        internerr("unknown action '%d'", cipaction->arg_int);
      }
    }
    rundown->pkg->clientdata->istobe = istobe;
  }

  while (!pkg_queue_is_empty(&queue)) {
    pkg = pkg_queue_pop(&queue);
    if (!pkg)
      continue; /* Duplicate, which we removed earlier. */

    ensure_package_clientdata(pkg);
    pkg->clientdata->enqueued = false;

    action_todo = cipaction->arg_int;

    if (sincenothing++ > queue.length * 3 + 2) {
      /* Make sure that even if we have exceeded the queue since not having
       * made any progress, we are not getting stuck trying to progress by
       * trigger processing, w/o jumping into the next dependtry. */
      dependtry++;
      sincenothing = 0;
      assert(dependtry <= 4);
    } else if (sincenothing > queue.length * 2 + 2) {
      /* XXX: This probably needs moving into a new dependtry instead. */
      if (progress_bytrigproc && progress_bytrigproc->trigpend_head) {
        enqueue_package(pkg);
        pkg = progress_bytrigproc;
        action_todo = act_configure;
      } else {
        dependtry++;
        sincenothing = 0;
        assert(dependtry <= 4);
      }
    }

    debug(dbg_general, "process queue pkg %s queue.len %d progress %d, try %d",
          pkg_name(pkg, pnaw_always), queue.length, sincenothing, dependtry);

    if (pkg->status > PKG_STAT_INSTALLED)
      internerr("package status (%d) > PKG_STAT_INSTALLED", pkg->status);

    if (setjmp(ejbuf)) {
      /* Give up on it from the point of view of other packages, i.e. reset
       * istobe. */
      pkg->clientdata->istobe = PKG_ISTOBE_NORMAL;

      pop_error_context(ehflag_bombout);
      if (abort_processing)
        return;
      continue;
    }
    push_error_context_jump(&ejbuf, print_error_perpackage,
                            pkg_name(pkg, pnaw_nonambig));

    switch (action_todo) {
    case act_triggers:
      if (!pkg->trigpend_head)
        ohshit(_("package %.250s is not ready for trigger processing\n"
                 " (current status '%.250s' with no pending triggers)"),
               pkg_name(pkg, pnaw_nonambig), pkg_status_name(pkg));
      /* Fall through. */
    case act_install:
      /* Don't try to configure pkgs that we've just disappeared. */
      if (pkg->status == PKG_STAT_NOTINSTALLED)
        break;
      /* Fall through. */
    case act_configure:
      /* Do whatever is most needed. */
      if (pkg->trigpend_head)
        trigproc(pkg, TRIGPROC_REQUIRED);
      else
        deferred_configure(pkg);
      break;
    case act_remove: case act_purge:
      deferred_remove(pkg);
      break;
    default:
      internerr("unknown action '%d'", cipaction->arg_int);
    }
    m_output(stdout, _("<standard output>"));
    m_output(stderr, _("<standard error>"));

    pop_error_context(ehflag_normaltidy);
  }
  assert(!queue.length);
}

/*** Dependency processing - common to --configure and --remove. ***/

/*
 * The algorithm for deciding what to configure or remove first is as
 * follows:
 *
 * Loop through all packages doing a ‘try 1’ until we've been round and
 * nothing has been done, then do ‘try 2’ and ‘try 3’ likewise.
 *
 * When configuring, in each try we check to see whether all
 * dependencies of this package are done. If so we do it. If some of
 * the dependencies aren't done yet but will be later we defer the
 * package, otherwise it is an error.
 *
 * When removing, in each try we check to see whether there are any
 * packages that would have dependencies missing if we removed this
 * one. If not we remove it now. If some of these packages are
 * themselves scheduled for removal we defer the package until they
 * have been done.
 *
 * The criteria for satisfying a dependency vary with the various
 * tries. In try 1 we treat the dependencies as absolute. In try 2 we
 * check break any cycles in the dependency graph involving the package
 * we are trying to process before trying to process the package
 * normally. In try 3 (which should only be reached if
 * --force-depends-version is set) we ignore version number clauses in
 * Depends lines. In try 4 (only reached if --force-depends is set) we
 * say "ok" regardless.
 *
 * If we are configuring and one of the packages we depend on is
 * awaiting configuration but wasn't specified in the argument list we
 * will add it to the argument list if --configure-any is specified.
 * In this case we note this as having "done something" so that we
 * don't needlessly escalate to higher levels of dependency checking
 * and breaking.
 */

enum found_status {
  FOUND_NONE = 0,
  FOUND_DEFER = 1,
  FOUND_FORCED = 2,
  FOUND_OK = 3,
};

/*
 * Return values:
 *   0: cannot be satisfied.
 *   1: defer: may be satisfied later, when other packages are better or
 *      at higher dependtry due to --force
 *      will set *fixbytrig to package whose trigger processing would help
 *      if applicable (and leave it alone otherwise).
 *   2: not satisfied but forcing
 *      (*interestingwarnings >= 0 on exit? caller is to print oemsgs).
 *   3: satisfied now.
 */
static enum found_status
deppossi_ok_found(struct pkginfo *possdependee, struct pkginfo *requiredby,
                  struct pkginfo *removing, struct deppossi *provider,
                  struct pkginfo **fixbytrig,
                  bool *matched, struct deppossi *checkversion,
                  int *interestingwarnings, struct varbuf *oemsgs)
{
  enum found_status thisf;

  if (ignore_depends(possdependee)) {
    debug(dbg_depcondetail,"      ignoring depended package so ok and found");
    return FOUND_OK;
  }
  thisf = FOUND_NONE;
  if (possdependee == removing) {
    if (provider) {
      varbuf_printf(oemsgs,
                    _("  Package %s which provides %s is to be removed.\n"),
                    pkg_name(possdependee, pnaw_nonambig),
                    provider->ed->name);
    } else {
      varbuf_printf(oemsgs, _("  Package %s is to be removed.\n"),
                    pkg_name(possdependee, pnaw_nonambig));
    }

    *matched = true;
    debug(dbg_depcondetail,"      removing possdependee, returning %d",thisf);
    return thisf;
  }
  switch (possdependee->status) {
  case PKG_STAT_UNPACKED:
  case PKG_STAT_HALFCONFIGURED:
  case PKG_STAT_TRIGGERSAWAITED:
  case PKG_STAT_TRIGGERSPENDING:
  case PKG_STAT_INSTALLED:
    if (checkversion) {
      if (provider) {
        debug(dbg_depcondetail, "      checking package %s provided by pkg %s",
              checkversion->ed->name, pkg_name(possdependee, pnaw_always));
        if (!pkg_virtual_deppossi_satisfied(checkversion, provider)) {
          varbuf_printf(oemsgs,
                        _("  Version of %s on system, provided by %s, is %s.\n"),
                        checkversion->ed->name,
                        pkg_name(possdependee, pnaw_always),
                        versiondescribe(&provider->version, vdew_nonambig));
          if (fc_dependsversion)
            thisf = (dependtry >= 3) ? FOUND_FORCED : FOUND_DEFER;
          debug(dbg_depcondetail, "      bad version");
          goto unsuitable;
        }
      } else {
        debug(dbg_depcondetail, "      checking non-provided pkg %s",
              pkg_name(possdependee, pnaw_always));
        if (!versionsatisfied(&possdependee->installed, checkversion)) {
          varbuf_printf(oemsgs, _("  Version of %s on system is %s.\n"),
                        pkg_name(possdependee, pnaw_nonambig),
                        versiondescribe(&possdependee->installed.version,
                                        vdew_nonambig));
          if (fc_dependsversion)
            thisf = (dependtry >= 3) ? FOUND_FORCED : FOUND_DEFER;
          debug(dbg_depcondetail, "      bad version");
          goto unsuitable;
        }
      }
    }
    if (possdependee->status == PKG_STAT_INSTALLED ||
        possdependee->status == PKG_STAT_TRIGGERSPENDING) {
      debug(dbg_depcondetail,"      is installed, ok and found");
      return FOUND_OK;
    }
    if (possdependee->status == PKG_STAT_TRIGGERSAWAITED) {
      assert(possdependee->trigaw.head);
      if (removing ||
          !(f_triggers ||
            possdependee->clientdata->istobe == PKG_ISTOBE_INSTALLNEW)) {
        if (provider) {
          varbuf_printf(oemsgs,
                        _("  Package %s which provides %s awaits trigger processing.\n"),
                        pkg_name(possdependee, pnaw_nonambig),
                        provider->ed->name);
        } else {
          varbuf_printf(oemsgs,
                        _("  Package %s awaits trigger processing.\n"),
                        pkg_name(possdependee, pnaw_nonambig));
        }
        debug(dbg_depcondetail, "      triggers-awaited, no fixbytrig");
        goto unsuitable;
      }
      /* We don't check the status of trigaw.head->pend here, just in case
       * we get into the pathological situation where Triggers-Awaited but
       * the named package doesn't actually have any pending triggers. In
       * that case we queue the non-pending package for trigger processing
       * anyway, and that trigger processing will be a noop except for
       * sorting out all of the packages which name it in Triggers-Awaited.
       *
       * (This situation can only arise if modstatdb_note success in
       * clearing the triggers-pending status of the pending package
       * but then fails to go on to update the awaiters.) */
      *fixbytrig = possdependee->trigaw.head->pend;
      debug(dbg_depcondetail,
            "      triggers-awaited, fixbytrig '%s', defer",
            pkg_name(*fixbytrig, pnaw_always));
      return FOUND_DEFER;
    }
    if (possdependee->clientdata &&
        possdependee->clientdata->istobe == PKG_ISTOBE_INSTALLNEW) {
      debug(dbg_depcondetail,"      unpacked/halfconfigured, defer");
      return FOUND_DEFER;
    } else if (!removing && fc_configureany &&
               !skip_due_to_hold(possdependee) &&
               !(possdependee->status == PKG_STAT_HALFCONFIGURED)) {
      notice(_("also configuring '%s' (required by '%s')"),
             pkg_name(possdependee, pnaw_nonambig),
             pkg_name(requiredby, pnaw_nonambig));
      enqueue_package(possdependee);
      sincenothing = 0;
      return FOUND_DEFER;
    } else {
      if (provider) {
        varbuf_printf(oemsgs,
                      _("  Package %s which provides %s is not configured yet.\n"),
                      pkg_name(possdependee, pnaw_nonambig),
                      provider->ed->name);
      } else {
        varbuf_printf(oemsgs, _("  Package %s is not configured yet.\n"),
                      pkg_name(possdependee, pnaw_nonambig));
      }

      debug(dbg_depcondetail, "      not configured/able");
      goto unsuitable;
    }

  default:
    if (provider) {
      varbuf_printf(oemsgs,
                    _("  Package %s which provides %s is not installed.\n"),
                    pkg_name(possdependee, pnaw_nonambig),
                    provider->ed->name);
    } else {
      varbuf_printf(oemsgs, _("  Package %s is not installed.\n"),
                    pkg_name(possdependee, pnaw_nonambig));
    }

    debug(dbg_depcondetail, "      not installed");
    goto unsuitable;
  }

unsuitable:
  debug(dbg_depcondetail, "        returning %d", thisf);
  (*interestingwarnings)++;

  return thisf;
}

static void
breaks_check_one(struct varbuf *aemsgs, enum dep_check *ok,
                 struct deppossi *breaks, struct pkginfo *broken,
                 struct pkginfo *breaker, struct deppossi *virtbroken)
{
  struct varbuf depmsg = VARBUF_INIT;

  debug(dbg_depcondetail, "      checking breaker %s virtbroken %s",
        pkg_name(breaker, pnaw_always),
        virtbroken ? virtbroken->ed->name : "<none>");

  if (breaker->status == PKG_STAT_NOTINSTALLED ||
      breaker->status == PKG_STAT_CONFIGFILES)
    return;
  if (broken == breaker) return;
  if (!versionsatisfied(&broken->installed, breaks)) return;
  /* The test below can only trigger if dep_breaks start having
   * arch qualifiers different from “any”. */
  if (!archsatisfied(&broken->installed, breaks))
    return;
  if (ignore_depends(breaker)) return;
  if (virtbroken && ignore_depends(&virtbroken->ed->pkg))
    return;
  if (virtbroken && !pkg_virtual_deppossi_satisfied(breaks, virtbroken))
    return;

  varbufdependency(&depmsg, breaks->up);
  varbuf_end_str(&depmsg);
  varbuf_printf(aemsgs, _(" %s (%s) breaks %s and is %s.\n"),
                pkg_name(breaker, pnaw_nonambig),
                versiondescribe(&breaker->installed.version, vdew_nonambig),
                depmsg.buf, gettext(statusstrings[breaker->status]));
  varbuf_destroy(&depmsg);

  if (virtbroken) {
    varbuf_printf(aemsgs, _("  %s (%s) provides %s.\n"),
                  pkg_name(broken, pnaw_nonambig),
                  versiondescribe(&broken->installed.version, vdew_nonambig),
                  virtbroken->ed->name);
  } else if (breaks->verrel != DPKG_RELATION_NONE) {
    varbuf_printf(aemsgs, _("  Version of %s to be configured is %s.\n"),
                  pkg_name(broken, pnaw_nonambig),
                  versiondescribe(&broken->installed.version, vdew_nonambig));
    if (fc_dependsversion) return;
  }
  if (force_breaks(breaks)) return;
  *ok = DEP_CHECK_HALT;
}

static void
breaks_check_target(struct varbuf *aemsgs, enum dep_check *ok,
                    struct pkginfo *broken, struct pkgset *target,
                    struct deppossi *virtbroken)
{
  struct deppossi *possi;

  for (possi = target->depended.installed; possi; possi = possi->rev_next) {
    if (possi->up->type != dep_breaks) continue;
    breaks_check_one(aemsgs, ok, possi, broken, possi->up->up, virtbroken);
  }
}

enum dep_check
breakses_ok(struct pkginfo *pkg, struct varbuf *aemsgs)
{
  struct dependency *dep;
  struct deppossi *virtbroken;
  enum dep_check ok = DEP_CHECK_OK;

  debug(dbg_depcon, "    checking Breaks");

  breaks_check_target(aemsgs, &ok, pkg, pkg->set, NULL);

  for (dep= pkg->installed.depends; dep; dep= dep->next) {
    if (dep->type != dep_provides) continue;
    virtbroken = dep->list;
    debug(dbg_depcondetail, "     checking virtbroken %s", virtbroken->ed->name);
    breaks_check_target(aemsgs, &ok, pkg, virtbroken->ed, virtbroken);
  }
  return ok;
}

/*
 * Checks [Pre]-Depends only.
 */
enum dep_check
dependencies_ok(struct pkginfo *pkg, struct pkginfo *removing,
                struct varbuf *aemsgs)
{
  /* Valid values: 2 = ok, 1 = defer, 0 = halt. */
  enum dep_check ok;
  /* Valid values: 0 = none, 1 = defer, 2 = withwarning, 3 = ok. */
  enum found_status found, thisf;
  int interestingwarnings;
  bool matched, anycannotfixbytrig;
  struct varbuf oemsgs = VARBUF_INIT;
  struct dependency *dep;
  struct deppossi *possi, *provider;
  struct pkginfo *possfixbytrig, *canfixbytrig;

  interestingwarnings= 0;
  ok = DEP_CHECK_OK;
  debug(dbg_depcon,"checking dependencies of %s (- %s)",
        pkg_name(pkg, pnaw_always),
        removing ? pkg_name(removing, pnaw_always) : "<none>");

  anycannotfixbytrig = false;
  canfixbytrig = NULL;
  for (dep= pkg->installed.depends; dep; dep= dep->next) {
    if (dep->type != dep_depends && dep->type != dep_predepends) continue;
    debug(dbg_depcondetail,"  checking group ...");
    matched = false;
    varbuf_reset(&oemsgs);
    found = FOUND_NONE;
    possfixbytrig = NULL;
    for (possi = dep->list; found != FOUND_OK && possi; possi = possi->next) {
      struct deppossi_pkg_iterator *possi_iter;
      struct pkginfo *pkg_pos;

      debug(dbg_depcondetail,"    checking possibility  -> %s",possi->ed->name);
      if (possi->cyclebreak) {
        debug(dbg_depcondetail,"      break cycle so ok and found");
        found = FOUND_OK;
        break;
      }

      thisf = FOUND_NONE;
      possi_iter = deppossi_pkg_iter_new(possi, wpb_installed);
      while ((pkg_pos = deppossi_pkg_iter_next(possi_iter))) {
        thisf = deppossi_ok_found(pkg_pos, pkg, removing, NULL,
                                  &possfixbytrig, &matched, possi,
                                  &interestingwarnings, &oemsgs);
        if (thisf > found)
          found = thisf;
        if (found == FOUND_OK)
          break;
      }
      deppossi_pkg_iter_free(possi_iter);

      if (found != FOUND_OK) {
        for (provider = possi->ed->depended.installed;
             found != FOUND_OK && provider;
             provider = provider->rev_next) {
          if (provider->up->type != dep_provides)
            continue;
          debug(dbg_depcondetail, "     checking provider %s",
                pkg_name(provider->up->up, pnaw_always));
          if (!deparchsatisfied(&provider->up->up->installed, provider->arch,
                                possi)) {
            debug(dbg_depcondetail, "       provider does not satisfy arch");
            continue;
          }
          thisf = deppossi_ok_found(provider->up->up, pkg, removing, provider,
                                    &possfixbytrig, &matched, possi,
                                    &interestingwarnings, &oemsgs);
          if (thisf == FOUND_DEFER && provider->up->up == pkg && !removing) {
            /* IOW, if the pkg satisfies its own dep (via a provide), then
             * we let it pass, even if it isn't configured yet (as we're
             * installing it). */
             thisf = FOUND_OK;
          }
          if (thisf > found)
            found = thisf;
        }
      }
      debug(dbg_depcondetail,"    found %d",found);
      if (thisf > found) found= thisf;
    }
    if (fc_depends) {
      thisf = (dependtry >= 4) ? FOUND_FORCED : FOUND_DEFER;
      if (thisf > found) {
        found = thisf;
        debug(dbg_depcondetail, "  rescued by force-depends, found %d", found);
      }
    }
    debug(dbg_depcondetail, "  found %d matched %d possfixbytrig %s",
          found, matched,
          possfixbytrig ? pkg_name(possfixbytrig, pnaw_always) : "-");
    if (removing && !matched) continue;
    switch (found) {
    case FOUND_NONE:
      anycannotfixbytrig = true;
      ok = DEP_CHECK_HALT;
      /* Fall through. */
    case FOUND_FORCED:
      varbuf_add_str(aemsgs, " ");
      varbuf_add_pkgbin_name(aemsgs, pkg, &pkg->installed, pnaw_nonambig);
      varbuf_add_str(aemsgs, _(" depends on "));
      varbufdependency(aemsgs, dep);
      if (interestingwarnings) {
        /* Don't print the line about the package to be removed if
         * that's the only line. */
        varbuf_end_str(&oemsgs);
        varbuf_add_str(aemsgs, _("; however:\n"));
        varbuf_add_str(aemsgs, oemsgs.buf);
      } else {
        varbuf_add_str(aemsgs, ".\n");
      }
      break;
    case FOUND_DEFER:
      if (possfixbytrig)
        canfixbytrig = possfixbytrig;
      else
        anycannotfixbytrig = true;
      if (ok > DEP_CHECK_DEFER)
        ok = DEP_CHECK_DEFER;
      break;
    case FOUND_OK:
      break;
    default:
      internerr("unknown value for found '%d'", found);
    }
  }
  if (ok == DEP_CHECK_HALT &&
      (pkg->clientdata && pkg->clientdata->istobe == PKG_ISTOBE_REMOVE))
    ok = DEP_CHECK_DEFER;
  if (!anycannotfixbytrig && canfixbytrig)
    progress_bytrigproc = canfixbytrig;

  varbuf_destroy(&oemsgs);
  debug(dbg_depcon,"ok %d msgs >>%.*s<<", ok, (int)aemsgs->used, aemsgs->buf);
  return ok;
}