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 <errno.h>
  29 #include <sys/types.h>
  30
  31 #include "udev.h"
  32
  33 #ifdef __KLIBC__
  34 #define __OWN_USERDB_PARSER__
  35 #endif
  36
  37 #ifdef __GLIBC__
  38 #define __OWN_STRLCPYCAT__
  39 #endif
  40
  41 #ifdef USE_STATIC
  42 #define __OWN_USERDB_PARSER__
  43 #endif
  44
  45 #ifdef __OWN_STRLCPYCAT__
  46 size_t strlcpy(char *dst, const char *src, size_t size)
  47 {
  48         size_t bytes = 0;
  49         char *q = dst;
  50         const char *p = src;
  51         char ch;
  52
  53         while ((ch = *p++)) {
  54                 if (bytes+1 < size)
  55                         *q++ = ch;
  56                 bytes++;
  57         }
  58
  59         /* If size == 0 there is no space for a final null... */
  60         if (size)
  61                 *q = '\0';
  62
  63         return bytes;
  64 }
  65
  66 size_t strlcat(char *dst, const char *src, size_t size)
  67 {
  68         size_t bytes = 0;
  69         char *q = dst;
  70         const char *p = src;
  71         char ch;
  72
  73         while (bytes < size && *q) {
  74                 q++;
  75                 bytes++;
  76         }
  77         if (bytes == size)
  78                 return (bytes + strlen(src));
  79
  80         while ((ch = *p++)) {
  81                 if (bytes+1 < size)
  82                 *q++ = ch;
  83                 bytes++;
  84         }
  85
  86         *q = '\0';
  87         return bytes;
  88 }
  89 #endif /* __OWN_STRLCPYCAT__ */
  90
  91 #ifndef __OWN_USERDB_PARSER__
  92 #include <sys/types.h>
  93 #include <pwd.h>
  94 #include <grp.h>
  95
  96 uid_t lookup_user(const char *user)
  97 {
  98         struct passwd *pw;
  99         uid_t uid = 0;
 100
 101         pw = getpwnam(user);
 102         if (pw == NULL)
 103                 info("specified user unknown '%s'", user);
 104         else
 105                 uid = pw->pw_uid;
 106
 107         return uid;
 108 }
 109
 110 gid_t lookup_group(const char *group)
 111 {
 112         struct group *gr;
 113         gid_t gid = 0;
 114
 115         gr = getgrnam(group);
 116         if (gr == NULL)
 117                 info("specified group unknown '%s'", group);
 118         else
 119                 gid = gr->gr_gid;
 120
 121         return gid;
 122 }
 123
 124 #else /* __OWN_USERDB_PARSER__ */
 125
 126 #define PASSWD_FILE             "/etc/passwd"
 127 #define GROUP_FILE              "/etc/group"
 128
 129 /* return the id of a passwd style line, selected by the users name */
 130 static unsigned long get_id_by_name(const char *uname, const char *dbfile)
 131 {
 132         unsigned long id = 0;
 133         char line[LINE_SIZE];
 134         char *buf;
 135         char *bufline;
 136         size_t bufsize;
 137         size_t cur;
 138         size_t count;
 139         char *pos;
 140         char *name;
 141         char *idstr;
 142         char *tail;
 143
 144         if (file_map(dbfile, &buf, &bufsize) != 0) {
 145                 err("can't open '%s' as db file: %s", dbfile, strerror(errno));
 146                 return 0;
 147         }
 148         dbg("search '%s' in '%s'", uname, dbfile);
 149
 150         /* loop through the whole file */
 151         cur = 0;
 152         while (cur < bufsize) {
 153                 count = buf_get_line(buf, bufsize, cur);
 154                 bufline = &buf[cur];
 155                 cur += count+1;
 156
 157                 if (count >= sizeof(line))
 158                         continue;
 159
 160                 memcpy(line, bufline, count-1);
 161                 line[count-1] = '\0';
 162                 pos = line;
 163
 164                 /* get name */
 165                 name = strsep(&pos, ":");
 166                 if (name == NULL)
 167                         continue;
 168
 169                 /* skip pass */
 170                 if (strsep(&pos, ":") == NULL)
 171                         continue;
 172
 173                 /* get id */
 174                 idstr = strsep(&pos, ":");
 175                 if (idstr == NULL)
 176                         continue;
 177
 178                 if (strcmp(uname, name) == 0) {
 179                         id = strtoul(idstr, &tail, 10);
 180                         if (tail[0] != '\0') {
 181                                 id = 0;
 182                                 dbg("no id found for '%s'",  name);
 183                         } else
 184                                 dbg("id for '%s' is '%li'", name, id);
 185                         break;
 186                 }
 187         }
 188
 189         file_unmap(buf, bufsize);
 190         return id;
 191 }
 192
 193 uid_t lookup_user(const char *user)
 194 {
 195         unsigned long id;
 196
 197         id = get_id_by_name(user, PASSWD_FILE);
 198         return (uid_t) id;
 199 }
 200
 201 gid_t lookup_group(const char *group)
 202 {
 203         unsigned long id;
 204
 205         id = get_id_by_name(group, GROUP_FILE);
 206         return (gid_t) id;
 207 }
 208 #endif /* __OWN_USERDB_PARSER__ */