udev_libc_wrapper.c

   1 /*
   2  * udev_libc_wrapper - wrapping of functions missing in a specific libc
   3  *                     or not working in a statically compiled binary
   4  *
   5  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   6  * Copyright (C) 2005 Kay Sievers <kay@vrfy.org>
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <ctype.h>
  27 #include <fcntl.h>
  28 #include <sys/types.h>
  29
  30 #include "../udev_libc_wrapper.h"
  31 #include "../udev.h"
  32 #include "../udev_utils.h"
  33 #include "../logging.h"
  34
  35 #ifdef __KLIBC__
  36 #define __OWN_USERDB_PARSER__
  37 #endif
  38
  39 #ifdef USE_STATIC
  40 #define __OWN_USERDB_PARSER__
  41 #endif
  42
  43 #ifndef strlcpy
  44 size_t strlcpy(char *dst, const char *src, size_t size)
  45 {
  46         size_t bytes = 0;
  47         char *q = dst;
  48         const char *p = src;
  49         char ch;
  50
  51         while ((ch = *p++)) {
  52                 if (bytes < size)
  53                         *q++ = ch;
  54                 bytes++;
  55         }
  56
  57         *q = '\0';
  58         return bytes;
  59 }
  60 #endif
  61
  62 #ifndef strlcat
  63 size_t strlcat(char *dst, const char *src, size_t size)
  64 {
  65         size_t bytes = 0;
  66         char *q = dst;
  67         const char *p = src;
  68         char ch;
  69
  70         while (bytes < size && *q) {
  71                 q++;
  72                 bytes++;
  73         }
  74
  75         while ((ch = *p++)) {
  76                 if (bytes < size)
  77                 *q++ = ch;
  78                 bytes++;
  79         }
  80
  81         *q = '\0';
  82         return bytes;
  83 }
  84 #endif
  85
  86 #ifndef __OWN_USERDB_PARSER__
  87 #include <sys/types.h>
  88 #include <pwd.h>
  89 #include <grp.h>
  90
  91 uid_t lookup_user(const char *user)
  92 {
  93         struct passwd *pw;
  94         uid_t uid = 0;
  95
  96         pw = getpwnam(user);
  97         if (pw == NULL)
  98                 dbg("specified user unknown '%s'", user);
  99         else
 100                 uid = pw->pw_uid;
 101
 102         return uid;
 103 }
 104
 105 gid_t lookup_group(const char *group)
 106 {
 107         struct group *gr;
 108         gid_t gid = 0;
 109
 110         gr = getgrnam(group);
 111         if (gr == NULL)
 112                 dbg("specified group unknown '%s'", group);
 113         else
 114                 gid = gr->gr_gid;
 115
 116         return gid;
 117 }
 118
 119 #else /* __OWN_USERDB_PARSER__ */
 120
 121 #define PASSWD_FILE             "/etc/passwd"
 122 #define GROUP_FILE              "/etc/group"
 123
 124 /* return the id of a passwd style line, selected by the users name */
 125 static unsigned long get_id_by_name(const char *uname, const char *dbfile)
 126 {
 127         unsigned long id = 0;
 128         char line[LINE_SIZE];
 129         char *buf;
 130         char *bufline;
 131         size_t bufsize;
 132         size_t cur;
 133         size_t count;
 134         char *pos;
 135         char *name;
 136         char *idstr;
 137         char *tail;
 138
 139         if (file_map(dbfile, &buf, &bufsize) != 0) {
 140                 dbg("can't open '%s' as db file", dbfile);
 141                 return 0;
 142         }
 143         dbg("reading '%s' as db file", dbfile);
 144
 145         /* loop through the whole file */
 146         cur = 0;
 147         while (cur < bufsize) {
 148                 count = buf_get_line(buf, bufsize, cur);
 149                 bufline = &buf[cur];
 150                 cur += count+1;
 151
 152                 if (count >= sizeof(line))
 153                         continue;
 154
 155                 strlcpy(line, bufline, count);
 156                 pos = line;
 157
 158                 /* get name */
 159                 name = strsep(&pos, ":");
 160                 if (name == NULL)
 161                         continue;
 162
 163                 /* skip pass */
 164                 if (strsep(&pos, ":") == NULL)
 165                         continue;
 166
 167                 /* get id */
 168                 idstr = strsep(&pos, ":");
 169                 if (idstr == NULL)
 170                         continue;
 171
 172                 if (strcmp(uname, name) == 0) {
 173                         id = strtoul(idstr, &tail, 10);
 174                         if (tail[0] != '\0') {
 175                                 id = 0;
 176                                 dbg("no id found for '%s'",  name);
 177                         } else
 178                                 dbg("id for '%s' is '%li'", name, id);
 179                         break;
 180                 }
 181         }
 182
 183         file_unmap(buf, bufsize);
 184         return id;
 185 }
 186
 187 uid_t lookup_user(const char *user)
 188 {
 189         unsigned long id;
 190
 191         id = get_id_by_name(user, PASSWD_FILE);
 192         return (uid_t) id;
 193 }
 194
 195 gid_t lookup_group(const char *group)
 196 {
 197         unsigned long id;
 198
 199         id = get_id_by_name(group, GROUP_FILE);
 200         return (gid_t) id;
 201 }
 202 #endif /* __OWN_USERDB_PARSER__ */