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 "klibc_fixups.h"
  32 #include "logging.h"
  33
  34 #define PW_FILE         "/etc/passwd"
  35 #define GR_FILE         "/etc/group"
  36 #define UTMP_FILE       "/var/run/utmp"
  37
  38
  39 /* return the id of a passwd style line, selected by the users name */
  40 static unsigned long get_id_by_name(const char *uname, const char *dbfile)
  41 {
  42         unsigned long id = -1;
  43         FILE *file;
  44         char buf[255];
  45         char *pos;
  46         char *name;
  47         char *idstr;
  48         char *tail;
  49
  50         file = fopen(dbfile, "r");
  51         if (file == NULL) {
  52                 dbg("unable to open file '%s'", dbfile);
  53                 return -1;
  54         }
  55
  56         while (1) {
  57                 pos = fgets(buf, sizeof(buf), file);
  58                 if (pos == NULL)
  59                         break;
  60
  61                 /* get name */
  62                 name = strsep(&pos, ":");
  63                 if (name == NULL)
  64                         continue;
  65
  66                 /* skip pass */
  67                 if (strsep(&pos, ":") == NULL)
  68                         continue;
  69
  70                 /* get id */
  71                 idstr = strsep(&pos, ":");
  72                 if (idstr == NULL)
  73                         continue;
  74
  75                 if (strcmp(uname, name) == 0) {
  76                         id = strtoul(idstr, &tail, 10);
  77                         if (tail == NULL)
  78                                 id = -1;
  79                         else
  80                                 dbg("id for '%s' is '%li'", name, id);
  81                         break;
  82                 }
  83         }
  84
  85         fclose(file);
  86         return id;
  87 }
  88
  89 struct passwd *getpwnam(const char *name)
  90 {
  91         static struct passwd pw;
  92
  93         memset(&pw, 0x00, sizeof(struct passwd));
  94         pw.pw_uid = (uid_t) get_id_by_name(name, PW_FILE);
  95         if (pw.pw_uid < 0)
  96                 return NULL;
  97         else
  98                 return &pw;
  99 }
 100
 101 struct group *getgrnam(const char *name)
 102 {
 103         static struct group gr;
 104
 105         memset(&gr, 0x00, sizeof(struct group));
 106         gr.gr_gid = (gid_t) get_id_by_name(name, GR_FILE);
 107         if (gr.gr_gid < 0)
 108                 return NULL;
 109         else
 110                 return &gr;
 111 }
 112
 113
 114 int ufd = -1;
 115
 116 void setutent()
 117 {
 118         if (ufd < 0)
 119                 ufd = open(UTMP_FILE, O_RDONLY);
 120         fcntl(ufd, F_SETFD, FD_CLOEXEC);
 121         lseek(ufd, 0, SEEK_SET);
 122 }
 123
 124 void endutent() {
 125         if (ufd < 0)
 126                 return;
 127         close(ufd);
 128         ufd = -1;
 129 }
 130
 131 struct utmp *getutent(void)
 132 {
 133         static struct utmp utmp;
 134         int retval;
 135
 136         if (ufd < 0) {
 137                 setutent();
 138                 if (ufd < 0)
 139                         return NULL;
 140         }
 141         retval = read(ufd, &utmp, sizeof(struct utmp));
 142         if (retval < 1)
 143                 return NULL;
 144         return &utmp;
 145 }
 146
 147 #endif