path: root/lib/libalpm/conflict.c

/*
 *  conflict.c
 * 
 *  Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.org>
 * 
 *  This program 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 program 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 
 *  USA.
 */

#include "config.h"
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#ifdef CYGWIN
#include <limits.h> /* PATH_MAX */
#endif
#include <sys/stat.h>
/* pacman */
#include "util.h"
#include "conflict.h"

PMList *db_find_conflicts(pmdb_t *db, PMList *targets, char *root, PMList **skip_list)
{
  PMList *i, *j, *k;
  char *filestr = NULL;
  char path[PATH_MAX+1];
  char *str = NULL;
  struct stat buf, buf2;
  PMList *conflicts = NULL;

  if(db == NULL || targets == NULL || root == NULL) {
    return(NULL);
  }

  /* CHECK 1: check every target against every target */
  for(i = targets; i; i = i->next) {
    pmpkg_t *p1 = (pmpkg_t*)i->data;
    for(j = i; j; j = j->next) {
      pmpkg_t *p2 = (pmpkg_t*)j->data;
      if(strcmp(p1->name, p2->name)) {
        for(k = p1->files; k; k = k->next) {
          filestr = k->data;
          if(!strcmp(filestr, "._install") || !strcmp(filestr, ".INSTALL")) {
            continue;
          }
          if(rindex(filestr, '/') == filestr+strlen(filestr)-1) {
            /* this filename has a trailing '/', so it's a directory -- skip it. */
            continue;
          }
          if(pm_list_is_strin(filestr, p2->files)) {
            MALLOC(str, 512);
            snprintf(str, 512, "%s: exists in \"%s\" (target) and \"%s\" (target)",
              filestr, p1->name, p2->name);
            conflicts = pm_list_add(conflicts, str);
          }
        }
      }
    }
  }

  /* CHECK 2: check every target against the filesystem */
  for(i = targets; i; i = i->next) {
    pmpkg_t *p = (pmpkg_t*)i->data;
    pmpkg_t *dbpkg = NULL;
    for(j = p->files; j; j = j->next) {
      int isdir = 0;
      filestr = (char*)j->data;
      snprintf(path, PATH_MAX, "%s%s", root, filestr);
      /* is this target a file or directory? */
      if(path[strlen(path)-1] == '/') {
        isdir = 1;
        path[strlen(path)-1] = '\0';
      }
      if(!lstat(path, &buf)) {
        int ok = 0;
        if(!S_ISLNK(buf.st_mode) && ((isdir && !S_ISDIR(buf.st_mode)) || (!isdir && S_ISDIR(buf.st_mode)))) {
          /* if the package target is a directory, and the filesystem target
           * is not (or vice versa) then it's a conflict
           */
          ok = 0;
          goto donecheck;
        }
        /* re-fetch with stat() instead of lstat() */
        stat(path, &buf);
        if(S_ISDIR(buf.st_mode)) {
          /* if it's a directory, then we have no conflict */
          ok = 1;
        } else {
          if(dbpkg == NULL) {
            dbpkg = db_scan(db, p->name, INFRQ_DESC | INFRQ_FILES);
          }
          if(dbpkg && pm_list_is_strin(j->data, dbpkg->files)) {
            ok = 1;
          }
          /* Make sure that the supposedly-conflicting file is not actually just
           * a symlink that points to a path that used to exist in the package.
           */
          /* Check if any part of the conflicting file's path is a symlink */
          if(dbpkg && !ok) {
            char str[PATH_MAX];
            for(k = dbpkg->files; k; k = k->next) {
              snprintf(str, PATH_MAX, "%s%s", root, (char*)k->data);
              stat(str, &buf2);
              if(buf.st_ino == buf2.st_ino) {
                ok = 1;
              }
            }
          }
          /* Check if the conflicting file has been moved to another package/target */
          if(!ok) {
            /* Look at all the targets */
            for(k = targets; k && !ok; k = k->next) {
              pmpkg_t *p1 = (pmpkg_t *)k->data;
              /* As long as they're not the current package */
              if(strcmp(p1->name, p->name)) {
                pmpkg_t *dbpkg2 = NULL;
                dbpkg2 = db_scan(db, p1->name, INFRQ_DESC | INFRQ_FILES);
                /* If it used to exist in there, but doesn't anymore */
                if(dbpkg2 && !pm_list_is_strin(filestr, p1->files) && pm_list_is_strin(filestr, dbpkg2->files)) {
                  ok = 1;
                  /* Add to the "skip list" of files that we shouldn't remove during an upgrade.
                   *
                   * This is a workaround for the following scenario:
                   *
                   *    - the old package A provides file X
                   *    - the new package A does not
                   *    - the new package B provides file X
                   *    - package A depends on B, so B is upgraded first
                   *
                   * Package B is upgraded, so file X is installed.  Then package A
                   * is upgraded, and it *removes* file X, since it no longer exists
                   * in package A.
                   *
                   * Our workaround is to scan through all "old" packages and all "new"
                   * ones, looking for files that jump to different packages.
                   */
                  *skip_list = pm_list_add(*skip_list, strdup(filestr));
                }
                FREEPKG(dbpkg2);
              }
            }
          }
        }
donecheck:
        if(!ok) {
          MALLOC(str, 512);
          snprintf(str, 512, "%s: %s: exists in filesystem", p->name, path);
          conflicts = pm_list_add(conflicts, str);
        }
      }
    }
    FREEPKG(dbpkg);
  }

  return(conflicts);
}

/* vim: set ts=2 sw=2 noet: */