klibc_fixups.c

   1 /*
   2  * klibc_fixups.c - very simple implementation of stuff missing in klibc
   3  *
   4  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   5  * Copyright (C) 2004 Kay Sievers <kay@vrfy.org>
   6  *
   7  *      This program is free software; you can redistribute it and/or modify it
   8  *      under the terms of the GNU General Public License as published by the
   9  *      Free Software Foundation version 2 of the License.
  10  *
  11  *      This program is distributed in the hope that it will be useful, but
  12  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *      General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU General Public License along
  17  *      with this program; if not, write to the Free Software Foundation, Inc.,
  18  *      675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #ifdef __KLIBC__
  23
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <fcntl.h>
  29 #include <sys/types.h>
  30
  31 #include "udev.h"
  32 #include "klibc_fixups.h"
  33 #include "udev_lib.h"
  34 #include "logging.h"
  35
  36 #define PW_FILE         "/etc/passwd"
  37 #define GR_FILE         "/etc/group"
  38 #define UTMP_FILE       "/var/run/utmp"
  39
  40 /* return the id of a passwd style line, selected by the users name */
  41 static unsigned long get_id_by_name(const char *uname, const char *dbfile)
  42 {
  43         unsigned long id = -1;
  44         char line[LINE_SIZE];
  45         char *buf;
  46         char *bufline;
  47         size_t bufsize;
  48         size_t cur;
  49         size_t count;
  50         char *pos;
  51         char *name;
  52         char *idstr;
  53         char *tail;
  54
  55         if (file_map(dbfile, &buf, &bufsize) == 0) {
  56                 dbg("reading '%s' as db file", dbfile);
  57         } else {
  58                 dbg("can't open '%s' as db file", dbfile);
  59                 return -1;
  60         }
  61
  62         /* loop through the whole file */
  63         cur = 0;
  64         while (cur < bufsize) {
  65                 count = buf_get_line(buf, bufsize, cur);
  66                 bufline = &buf[cur];
  67                 cur += count+1;
  68
  69                 if (count >= LINE_SIZE)
  70                         continue;
  71
  72                 strncpy(line, bufline, count);
  73                 line[count] = '\0';
  74                 pos = line;
  75
  76                 /* get name */
  77                 name = strsep(&pos, ":");
  78                 if (name == NULL)
  79                         continue;
  80
  81                 /* skip pass */
  82                 if (strsep(&pos, ":") == NULL)
  83                         continue;
  84
  85                 /* get id */
  86                 idstr = strsep(&pos, ":");
  87                 if (idstr == NULL)
  88                         continue;
  89
  90                 if (strcmp(uname, name) == 0) {
  91                         id = strtoul(idstr, &tail, 10);
  92                         if (tail[0] != '\0')
  93                                 id = -1;
  94                         else
  95                                 dbg("id for '%s' is '%li'", name, id);
  96                         break;
  97                 }
  98         }
  99
 100         file_unmap(buf, bufsize);
 101         return id;
 102 }
 103
 104 struct passwd *getpwnam(const char *name)
 105 {
 106         static struct passwd pw;
 107
 108         memset(&pw, 0x00, sizeof(struct passwd));
 109         pw.pw_uid = (uid_t) get_id_by_name(name, PW_FILE);
 110         if (pw.pw_uid < 0)
 111                 return NULL;
 112         else
 113                 return &pw;
 114 }
 115
 116 struct group *getgrnam(const char *name)
 117 {
 118         static struct group gr;
 119
 120         memset(&gr, 0x00, sizeof(struct group));
 121         gr.gr_gid = (gid_t) get_id_by_name(name, GR_FILE);
 122         if (gr.gr_gid < 0)
 123                 return NULL;
 124         else
 125                 return &gr;
 126 }
 127
 128
 129 int ufd = -1;
 130
 131 void setutent()
 132 {
 133         if (ufd < 0)
 134                 ufd = open(UTMP_FILE, O_RDONLY);
 135         fcntl(ufd, F_SETFD, FD_CLOEXEC);
 136         lseek(ufd, 0, SEEK_SET);
 137 }
 138
 139 void endutent() {
 140         if (ufd < 0)
 141                 return;
 142         close(ufd);
 143         ufd = -1;
 144 }
 145
 146 struct utmp *getutent(void)
 147 {
 148         static struct utmp utmp;
 149         int retval;
 150
 151         if (ufd < 0) {
 152                 setutent();
 153                 if (ufd < 0)
 154                         return NULL;
 155         }
 156         retval = read(ufd, &utmp, sizeof(struct utmp));
 157         if (retval < 1)
 158                 return NULL;
 159         return &utmp;
 160 }
 161
 162 #endif