lib/dpkg/depcon.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * depcon.c - dependency and conflict checking
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2008-2014 Guillem Jover <guillem@debian.org>
   7  * Copyright © 2009 Canonical Ltd.
   8  *
   9  * This is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  21  */
  22
  23 #include <config.h>
  24 #include <compat.h>
  25
  26 #include <dpkg/dpkg.h>
  27 #include <dpkg/dpkg-db.h>
  28 #include <dpkg/arch.h>
  29
  30 bool
  31 versionsatisfied(struct pkgbin *it, struct deppossi *against)
  32 {
  33         return dpkg_version_relate(&it->version,
  34                                    against->verrel,
  35                                    &against->version);
  36 }
  37
  38 /**
  39  * Check if the architecture qualifier in the dependency is satisfied.
  40  *
  41  * The rules are supposed to be:
  42  * - unqualified Depends/Pre-Depends/Recommends/Suggests are only
  43  *   satisfied by a package of a different architecture if the target
  44  *   package is Multi-Arch: foreign.
  45  * - Depends/Pre-Depends/Recommends/Suggests on pkg:any are satisfied by
  46  *   a package of a different architecture if the target package is
  47  *   Multi-Arch: allowed.
  48  * - all other Depends/Pre-Depends/Recommends/Suggests are only
  49  *   satisfied by packages of the same architecture.
  50  * - Architecture: all packages are treated the same as packages of the
  51  *   native architecture.
  52  * - Conflicts/Replaces/Breaks are assumed to apply to packages of any arch.
  53  */
  54 bool
  55 deparchsatisfied(struct pkgbin *it, const struct dpkg_arch *it_arch,
  56                  struct deppossi *against)
  57 {
  58         const struct dpkg_arch *dep_arch, *pkg_arch;
  59
  60         if (against->arch_is_implicit &&
  61             it->multiarch == PKG_MULTIARCH_FOREIGN)
  62                 return true;
  63
  64         dep_arch = against->arch;
  65         if (dep_arch->type == DPKG_ARCH_WILDCARD &&
  66             (it->multiarch == PKG_MULTIARCH_ALLOWED ||
  67              against->up->type == dep_conflicts ||
  68              against->up->type == dep_replaces ||
  69              against->up->type == dep_breaks))
  70                 return true;
  71
  72         pkg_arch = it_arch;
  73         if (dep_arch->type == DPKG_ARCH_NONE || dep_arch->type == DPKG_ARCH_ALL)
  74                 dep_arch = dpkg_arch_get(DPKG_ARCH_NATIVE);
  75         if (pkg_arch->type == DPKG_ARCH_NONE || pkg_arch->type == DPKG_ARCH_ALL)
  76                 pkg_arch = dpkg_arch_get(DPKG_ARCH_NATIVE);
  77
  78         return (dep_arch == pkg_arch);
  79 }
  80
  81 bool
  82 archsatisfied(struct pkgbin *it, struct deppossi *against)
  83 {
  84         return deparchsatisfied(it, it->arch, against);
  85 }
  86
  87 /**
  88  * Check if the dependency is satisfied by a virtual package.
  89  *
  90  * For versioned depends, we only check providers with #DPKG_RELATION_EQ. It
  91  * does not make sense to check ones without a version since we have nothing
  92  * to verify against. Also, it is way too complex to allow anything but an
  93  * equal in a provided version. A few examples below to deter you from trying:
  94  *
  95  * - pkg1 depends on virt (>= 0.6), pkg2 provides virt (<= 1.0).
  96  *   Should pass (easy enough).
  97  *
  98  * - pkg1 depends on virt (>= 0.7) and (<= 1.1), pkg2 provides virt (>= 1.2).
  99  *   Should fail (little harder).
 100  *
 101  * - pkg1 depends on virt (>= 0.4), pkg2 provides virt (<= 1.0) and (>= 0.5),
 102  *   IOW, inclusive of only those versions. This would require backchecking
 103  *   the other provided versions in the possi, which would make things sickly
 104  *   complex and overly time consuming. Should fail (very hard to implement).
 105  *
 106  * This could be handled by switching to a SAT solver, but that would imply
 107  * lots of work for very little gain. Packages can easily get around most of
 108  * these by providing multiple #DPKG_RELATION_EQ versions.
 109  */
 110 bool
 111 pkg_virtual_deppossi_satisfied(struct deppossi *dependee,
 112                                struct deppossi *provider)
 113 {
 114         if (provider->verrel != DPKG_RELATION_NONE &&
 115             provider->verrel != DPKG_RELATION_EQ)
 116                 return false;
 117
 118         if (provider->verrel == DPKG_RELATION_NONE &&
 119             dependee->verrel != DPKG_RELATION_NONE)
 120                 return false;
 121
 122         return dpkg_version_relate(&provider->version,
 123                                    dependee->verrel,
 124                                    &dependee->version);
 125 }