1 files changed, 456 insertions, 0 deletions

diff --git a/dselect/pkgdepcon.cc b/dselect/pkgdepcon.cc
new file mode 100644
index 0000000..3b54e7f
--- /dev/null
+++ b/dselect/pkgdepcon.cc
@@ -0,0 +1,456 @@
+/*
+ * dselect - Debian package maintenance user interface
+ * pkgdepcon.cc - dependency and conflict resolution
+ *
+ * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright © 2008-2014 Guillem Jover <guillem@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 <string.h>
+#include <stdio.h>
+
+#include <dpkg/dpkg.h>
+#include <dpkg/dpkg-db.h>
+
+#include "dselect.h"
+#include "pkglist.h"
+
+bool
+packagelist::useavailable(pkginfo *pkg)
+{
+  if (pkg->clientdata &&
+      pkg->clientdata->selected == PKG_WANT_INSTALL &&
+      pkg_is_informative(pkg, &pkg->available) &&
+      (!(pkg->status == PKG_STAT_INSTALLED ||
+         pkg->status == PKG_STAT_TRIGGERSAWAITED ||
+         pkg->status == PKG_STAT_TRIGGERSPENDING) ||
+       dpkg_version_compare(&pkg->available.version,
+                            &pkg->installed.version) > 0))
+    return true;
+  else
+    return false;
+}
+
+pkgbin *
+packagelist::find_pkgbin(pkginfo *pkg)
+{
+  pkgbin *pkgbin;
+
+  pkgbin = useavailable(pkg) ? &pkg->available : &pkg->installed;
+  debug(dbg_general, "packagelist[%p]::find_pkgbin(%s) useavailable=%d",
+        this, pkgbin_name(pkg, pkgbin, pnaw_always), useavailable(pkg));
+
+  return pkgbin;
+}
+
+int packagelist::checkdependers(pkginfo *pkg, int changemade) {
+  struct deppossi *possi;
+
+  for (possi = pkg->set->depended.available; possi; possi = possi->rev_next) {
+    if (!useavailable(possi->up->up))
+      continue;
+    changemade = max(changemade, resolvedepcon(possi->up));
+  }
+  for (possi = pkg->set->depended.installed; possi; possi = possi->rev_next) {
+    if (useavailable(possi->up->up))
+      continue;
+    changemade = max(changemade, resolvedepcon(possi->up));
+  }
+  return changemade;
+}
+
+int packagelist::resolvesuggest() {
+  // We continually go around looking for things to change, but we may
+  // only change the ‘suggested’ value if we also increase the ‘priority’
+  // Return 2 if we made a change due to a Recommended, Depends or Conflicts,
+  // or 1 if we offered or made a change because of an Optional line.
+  debug(dbg_general, "packagelist[%p]::resolvesuggest()", this);
+  int changemade, maxchangemade;
+  maxchangemade= 0;
+  for (;;) {
+    changemade= 0;
+    int index;
+    for (index=0; index<nitems; index++) {
+      if (!table[index]->pkg->set->name)
+        continue;
+      debug(dbg_depcon, "packagelist[%p]::resolvesuggest() loop[%i] %s / %d",
+            this, index, pkg_name(table[index]->pkg, pnaw_always), changemade);
+      dependency *depends;
+      for (depends = find_pkgbin(table[index]->pkg)->depends;
+           depends;
+           depends= depends->next) {
+        changemade = max(changemade, resolvedepcon(depends));
+      }
+      changemade= checkdependers(table[index]->pkg,changemade);
+      for (depends = find_pkgbin(table[index]->pkg)->depends;
+           depends;
+           depends= depends->next) {
+        if (depends->type != dep_provides) continue;
+        changemade = checkdependers(&depends->list->ed->pkg, changemade);
+      }
+      debug(dbg_depcon, "packagelist[%p]::resolvesuggest() loop[%i] %s / -> %d",
+            this, index, pkg_name(table[index]->pkg, pnaw_always), changemade);
+    }
+    if (!changemade) break;
+    maxchangemade = max(maxchangemade, changemade);
+  }
+  debug(dbg_general, "packagelist[%p]::resolvesuggest() done; maxchangemade=%d",
+        this, maxchangemade);
+  return maxchangemade;
+}
+
+static bool
+dep_update_best_to_change_stop(perpackagestate *& best, pkginfo *trythis)
+{
+  // There's no point trying to select a pure virtual package.
+  if (!trythis->clientdata)
+    return false;
+
+  debug(dbg_depcon, "update_best_to_change(best=%s{%d}, test=%s{%d});",
+        best ? pkg_name(best->pkg, pnaw_always) : "",
+        best ? (int)best->spriority : -1,
+        trythis->set->name, trythis->clientdata->spriority);
+
+  // If the problem is caused by us deselecting one of these packages
+  // we should not try to select another one instead.
+  if (trythis->clientdata->spriority == sp_deselecting)
+    return true;
+
+  // If we haven't found anything yet then this is our best so far.
+  if (!best) goto yes;
+
+  // If only one of the packages is available, use that one
+  if (!pkg_is_informative(trythis, &trythis->available) &&
+      pkg_is_informative(best->pkg, &best->pkg->available))
+    return false;
+  if (pkg_is_informative(trythis, &trythis->available) &&
+      !pkg_is_informative(best->pkg, &best->pkg->available))
+    goto yes;
+
+  // Select the package with the lowest priority (ie, the one of whom
+  // we were least sure we wanted it deselected).
+  if (trythis->clientdata->spriority > best->spriority)
+    return false;
+  if (trythis->clientdata->spriority < best->spriority) goto yes;
+
+  // Pick the package with the must fundamental recommendation level.
+  if (trythis->priority > best->pkg->priority)
+    return false;
+  if (trythis->priority < best->pkg->priority) goto yes;
+
+  // If we're still unsure we'll change the first one in the list.
+  return false;
+
+ yes:
+  debug(dbg_depcon, "update_best_to_change(); yes");
+
+  best = trythis->clientdata;
+  return false;
+}
+
+int
+packagelist::deselect_one_of(pkginfo *per, pkginfo *ped, dependency *dep)
+{
+  perpackagestate *er= per->clientdata;
+  perpackagestate *ed= ped->clientdata;
+
+  if (!er || !would_like_to_install(er->selected,per) ||
+      !ed || !would_like_to_install(ed->selected,ped)) return 0;
+
+  add(dep, dp_must);
+
+  er= per->clientdata;  // these can be changed by add
+  ed= ped->clientdata;
+
+  debug(dbg_depcon,
+        "packagelist[%p]::deselect_one_of(): er %s{%d} ed %s{%d} [%p]",
+        this, pkg_name(er->pkg, pnaw_always), er->spriority,
+        pkg_name(ed->pkg, pnaw_always), ed->spriority, dep);
+
+  perpackagestate *best;
+
+  // Try not keep packages needing reinstallation.
+  if (per->eflag & PKG_EFLAG_REINSTREQ)
+    best = ed;
+  else if (ped->eflag & PKG_EFLAG_REINSTREQ)
+    best = er;
+  else if (er->spriority < ed->spriority) best= er; // We'd rather change the
+  else if (er->spriority > ed->spriority) best= ed; // one with the lowest priority.
+  // ... failing that the one with the highest priority
+  else if (er->pkg->priority > ed->pkg->priority)
+    best = er;
+  else if (er->pkg->priority < ed->pkg->priority)
+    best = ed;
+  else best= ed;                                      // ... failing that, the second
+
+  debug(dbg_depcon, "packagelist[%p]::deselect_one_of(): best %s{%d}",
+        this, pkg_name(best->pkg, pnaw_always), best->spriority);
+
+  if (best->spriority >= sp_deselecting) return 0;
+  best->suggested=
+    best->pkg->status == PKG_STAT_NOTINSTALLED
+      ? PKG_WANT_PURGE : PKG_WANT_DEINSTALL; // FIXME: configurable.
+  best->selected= best->suggested;
+  best->spriority= sp_deselecting;
+
+  return 2;
+}
+
+int packagelist::resolvedepcon(dependency *depends) {
+  perpackagestate *best, *fixbyupgrade;
+  deppossi *possi, *provider;
+  bool foundany;
+  int rc;
+
+  if (debug_has_flag(dbg_depcon)) {
+    varbuf pkg_names;
+
+    for (possi = depends->list; possi; possi = possi->next) {
+      pkg_names(' ');
+      pkg_names(possi->ed->name);
+    }
+
+    debug(dbg_depcon,
+          "packagelist[%p]::resolvedepcon([%p] %s --%s-->%s); (ing)->want=%s",
+          this, depends, pkg_name(depends->up, pnaw_always),
+          relatestrings[depends->type],
+          pkg_names.string(), depends->up->clientdata ?
+          wantstrings[depends->up->clientdata->suggested] : "(no clientdata)");
+  }
+
+  if (!depends->up->clientdata) return 0;
+
+  switch (depends->type) {
+
+  case dep_provides:
+  case dep_replaces:
+    return 0;
+
+  case dep_enhances:
+  case dep_suggests:
+  case dep_recommends:
+  case dep_depends:
+  case dep_predepends:
+    if (would_like_to_install(depends->up->clientdata->selected,depends->up) <= 0)
+      return 0;
+
+    fixbyupgrade = nullptr;
+
+    possi = depends->list;
+    while (possi && !deppossatisfied(possi, &fixbyupgrade))
+      possi = possi->next;
+    debug(dbg_depcon, "packagelist[%p]::resolvedepcon([%p]): depends found %s",
+          this, depends, possi ? possi->ed->name : "[none]");
+    if (possi) return 0;
+
+    // Ensures all in the recursive list; adds info strings; ups priorities
+    switch (depends->type) {
+    case dep_enhances:
+    case dep_suggests:
+      rc = add(depends, dp_may);
+      return rc;
+    case dep_recommends:
+      rc = add(depends, dp_should);
+	break;
+    default:
+      rc = add(depends, dp_must);
+    }
+
+    if (fixbyupgrade) {
+      debug(dbg_depcon,
+            "packagelist[%p]::resolvedepcon([%p]): fixbyupgrade %s",
+            this, depends, pkg_name(fixbyupgrade->pkg, pnaw_always));
+      best= fixbyupgrade;
+    } else {
+      best = nullptr;
+      for (possi= depends->list;
+           possi;
+           possi= possi->next) {
+        foundany = false;
+        if (possi->ed->pkg.clientdata)
+          foundany = true;
+        if (dep_update_best_to_change_stop(best, &possi->ed->pkg))
+          goto mustdeselect;
+        for (provider = possi->ed->depended.available;
+             provider;
+             provider = provider->rev_next) {
+          if (provider->up->type != dep_provides) continue;
+          if (provider->up->up->clientdata)
+            foundany = true;
+          if (dep_update_best_to_change_stop(best, provider->up->up)) goto mustdeselect;
+        }
+        if (!foundany) addunavailable(possi);
+      }
+      if (!best) {
+        debug(dbg_depcon,
+              "packagelist[%p]::resolvedepcon([%p]): mustdeselect nobest",
+              this, depends);
+        return rc;
+      }
+    }
+    debug(dbg_depcon,
+          "packagelist[%p]::resolvedepcon([%p]): select best=%s{%d}",
+          this, depends, pkg_name(best->pkg, pnaw_always), best->spriority);
+    if (best->spriority >= sp_selecting)
+      return rc;
+    /* Always select depends. Only select recommends if we got here because
+     * of a manually-initiated install request. */
+    if (depends->type != dep_recommends || manual_install) {
+      best->selected = best->suggested = PKG_WANT_INSTALL;
+      best->spriority= sp_selecting;
+    }
+    return rc ? 2 : 0;
+
+  mustdeselect:
+    best= depends->up->clientdata;
+    debug(dbg_depcon,
+          "packagelist[%p]::resolvedepcon([%p]): mustdeselect best=%s{%d}",
+          this, depends, pkg_name(best->pkg, pnaw_always), best->spriority);
+
+    if (best->spriority >= sp_deselecting)
+      return rc;
+    /* Always remove depends, but never remove recommends. */
+    if (depends->type != dep_recommends) {
+      best->selected= best->suggested=
+        best->pkg->status == PKG_STAT_NOTINSTALLED
+          ? PKG_WANT_PURGE : PKG_WANT_DEINSTALL; // FIXME: configurable
+      best->spriority= sp_deselecting;
+    }
+    return rc ? 2 : 0;
+
+  case dep_conflicts:
+  case dep_breaks:
+    debug(dbg_depcon, "packagelist[%p]::resolvedepcon([%p]): conflict",
+          this, depends);
+
+    if (would_like_to_install(depends->up->clientdata->selected,depends->up) == 0)
+      return 0;
+
+    debug(dbg_depcon,
+          "packagelist[%p]::resolvedepcon([%p]): conflict installing 1",
+          this, depends);
+
+    if (!deppossatisfied(depends->list, nullptr))
+      return 0;
+
+    debug(dbg_depcon,
+          "packagelist[%p]::resolvedepcon([%p]): conflict satisfied - ouch",
+          this, depends);
+
+    if (depends->up->set != depends->list->ed) {
+      rc = deselect_one_of(depends->up, &depends->list->ed->pkg, depends);
+      if (rc)
+        return rc;
+    }
+    for (provider = depends->list->ed->depended.available;
+         provider;
+         provider = provider->rev_next) {
+      if (provider->up->type != dep_provides) continue;
+      if (provider->up->up == depends->up) continue; // conflicts & provides same thing
+      rc = deselect_one_of(depends->up, provider->up->up, depends);
+      if (rc)
+        return rc;
+    }
+    debug(dbg_depcon, "packagelist[%p]::resolvedepcon([%p]): no desel",
+          this, depends);
+    return 0;
+
+  default:
+    internerr("unknown deptype %d", depends->type);
+  }
+  /* never reached, make gcc happy */
+  return 1;
+}
+
+bool
+packagelist::deppossatisfied(deppossi *possi, perpackagestate **fixbyupgrade)
+{
+  // ‘satisfied’ here for Conflicts and Breaks means that the
+  //  restriction is violated ie that the target package is wanted
+  int would;
+  pkgwant want = PKG_WANT_PURGE;
+
+  if (possi->ed->pkg.clientdata) {
+    want = possi->ed->pkg.clientdata->selected;
+    would = would_like_to_install(want, &possi->ed->pkg);
+  } else {
+    would= 0;
+  }
+
+  if ((possi->up->type == dep_conflicts || possi->up->type == dep_breaks)
+      ? possi->up->up->set != possi->ed && would != 0
+      : would > 0) {
+    // If it's to be installed or left installed, then either it's of
+    // the right version, and therefore OK, or a version must have
+    // been specified, in which case we don't need to look at the rest
+    // anyway.
+    if (useavailable(&possi->ed->pkg)) {
+      if (want != PKG_WANT_INSTALL)
+        internerr("depossi package is not want-install, is %d", want);
+      return versionsatisfied(&possi->ed->pkg.available, possi);
+    } else {
+      if (versionsatisfied(&possi->ed->pkg.installed, possi))
+        return true;
+      if (want == PKG_WANT_HOLD && fixbyupgrade && !*fixbyupgrade &&
+          versionsatisfied(&possi->ed->pkg.available, possi) &&
+          dpkg_version_compare(&possi->ed->pkg.available.version,
+                               &possi->ed->pkg.installed.version) > 1)
+        *fixbyupgrade = possi->ed->pkg.clientdata;
+      return false;
+    }
+  }
+
+  deppossi *provider;
+
+  for (provider = possi->ed->depended.installed;
+       provider;
+       provider = provider->rev_next) {
+    if (provider->up->type == dep_provides &&
+        ((possi->up->type != dep_conflicts && possi->up->type != dep_breaks) ||
+         provider->up->up->set != possi->up->up->set) &&
+        provider->up->up->clientdata &&
+        !useavailable(provider->up->up) &&
+        would_like_to_install(provider->up->up->clientdata->selected,
+                              provider->up->up) &&
+        pkg_virtual_deppossi_satisfied(possi, provider))
+      return true;
+  }
+  for (provider = possi->ed->depended.available;
+       provider;
+       provider = provider->rev_next) {
+    if (provider->up->type != dep_provides ||
+        ((possi->up->type == dep_conflicts || possi->up->type == dep_breaks) &&
+         provider->up->up->set == possi->up->up->set) ||
+        !provider->up->up->clientdata ||
+        !would_like_to_install(provider->up->up->clientdata->selected,
+                               provider->up->up) ||
+        !pkg_virtual_deppossi_satisfied(possi, provider))
+      continue;
+    if (useavailable(provider->up->up))
+      return true;
+    if (fixbyupgrade && !*fixbyupgrade &&
+        (!(provider->up->up->status == PKG_STAT_INSTALLED ||
+           provider->up->up->status == PKG_STAT_TRIGGERSPENDING ||
+           provider->up->up->status == PKG_STAT_TRIGGERSAWAITED) ||
+         dpkg_version_compare(&provider->up->up->available.version,
+                              &provider->up->up->installed.version) > 1))
+      *fixbyupgrade = provider->up->up->clientdata;
+  }
+  return false;
+}