libopkg/pkg_alternatives.c

   1 /* pkg_alternatives.c - the opkg package management system
   2
   3    Copyright (C) 2017 Yousong Zhou
   4
   5    This program is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License as
   7    published by the Free Software Foundation; either version 2, or (at
   8    your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful, but
  11    WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    General Public License for more details.
  14 */
  15
  16 #include <stdio.h>
  17 #include <sys/types.h>          /* stat */
  18 #include <sys/stat.h>
  19 #include <unistd.h>
  20
  21 #include "libbb/libbb.h"
  22 #include "opkg_message.h"
  23 #include "pkg.h"
  24 #include "pkg_hash.h"
  25 #include "pkg_alternatives.h"
  26 #include "sprintf_alloc.h"
  27
  28 static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, const char *path)
  29 {
  30         struct pkg_alternatives *pkg_alts;
  31         struct pkg_alternative *the_alt = NULL;
  32         pkg_t *the_pkg = pkg;
  33         int i, j;
  34         int r;
  35         char *path_in_dest;
  36
  37         for (i = 0; i < installed->len; i++) {
  38                 pkg_t *pkg = installed->pkgs[i];
  39                 pkg_alts = pkg_get_ptr(pkg, PKG_ALTERNATIVES);
  40                 if (!pkg_alts)
  41                         continue;
  42
  43                 for (j = 0; j < pkg_alts->nalts; j++) {
  44                         struct pkg_alternative *alt = pkg_alts->alts[j];
  45
  46                         if (strcmp(path, alt->path))
  47                                 continue;
  48                         if (!the_alt || the_alt->prio < alt->prio) {
  49                                 the_pkg = pkg;
  50                                 the_alt = alt;
  51                         }
  52                 }
  53         }
  54
  55         /* path is assumed to be an absolute one */
  56         sprintf_alloc(&path_in_dest, "%s%s", the_pkg->dest->root_dir, &path[1]);
  57         if (!path_in_dest)
  58                 return -1;
  59
  60         if (the_alt) {
  61                 struct stat sb;
  62
  63                 r = lstat(path_in_dest, &sb);
  64                 if (!r) {
  65                         char *realpath;
  66
  67                         if (!S_ISLNK(sb.st_mode)) {
  68                                 opkg_msg(ERROR, "%s exists but is not a symlink\n", path_in_dest);
  69                                 r = -1;
  70                                 goto out;
  71                         }
  72                         realpath = xreadlink(path_in_dest);
  73                         if (realpath && strcmp(realpath, the_alt->altpath))
  74                                 unlink(path_in_dest);
  75                         free(realpath);
  76                 } else if (errno != ENOENT) {
  77                         goto out;
  78                 }
  79                 r = symlink(the_alt->altpath, path_in_dest);
  80                 if (r)
  81                         opkg_msg(INFO, "failed symlinking %s -> %s\n", path_in_dest, the_alt->altpath);
  82         } else {
  83                 unlink(path_in_dest);
  84                 r = 0;
  85         }
  86
  87 out:
  88         free(path_in_dest);
  89         return r;
  90 }
  91
  92 int pkg_alternatives_update(pkg_t * pkg)
  93 {
  94         int r = 0;
  95         int i;
  96         struct pkg_alternatives *pkg_alts;
  97         struct pkg_alternative *alt = NULL;
  98         pkg_vec_t *installed;
  99
 100         pkg_alts = pkg_get_ptr(pkg, PKG_ALTERNATIVES);
 101         if (!pkg_alts)
 102                 return 0;
 103
 104         installed = pkg_vec_alloc();
 105         pkg_hash_fetch_all_installed(installed);
 106         for (i = 0; i < pkg_alts->nalts; i++) {
 107                 alt = pkg_alts->alts[i];
 108                 r |= pkg_alternatives_update_path(pkg, installed, alt->path);
 109         }
 110         pkg_vec_free(installed);
 111
 112         return r;
 113 }