libbb/login.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * issue.c: issue printing code
   4  *
   5  * Copyright (C) 2003 Bastian Blank <waldi@tuxbox.org>
   6  *
   7  * Optimize and correcting OCRNL by Vladimir Oleynik <dzo@simtreas.ru>
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  */
  11
  12 #include "libbb.h"
  13 /* After libbb.h, since it needs sys/types.h on some systems */
  14 #include <sys/utsname.h>
  15
  16 #define LOGIN " login: "
  17
  18 static const char fmtstr_d[] ALIGN1 = "%A, %d %B %Y";
  19
  20 void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
  21 {
  22         FILE *fp;
  23         int c;
  24         char buf[256+1];
  25         const char *outbuf;
  26         time_t t;
  27         struct utsname uts;
  28
  29         time(&t);
  30         uname(&uts);
  31
  32         puts("\r");  /* start a new line */
  33
  34         fp = fopen_for_read(issue_file);
  35         if (!fp)
  36                 return;
  37         while ((c = fgetc(fp)) != EOF) {
  38                 outbuf = buf;
  39                 buf[0] = c;
  40                 buf[1] = '\0';
  41                 if (c == '\n') {
  42                         buf[1] = '\r';
  43                         buf[2] = '\0';
  44                 }
  45                 if (c == '\\' || c == '%') {
  46                         c = fgetc(fp);
  47                         switch (c) {
  48                         case 's':
  49                                 outbuf = uts.sysname;
  50                                 break;
  51                         case 'n':
  52                         case 'h':
  53                                 outbuf = uts.nodename;
  54                                 break;
  55                         case 'r':
  56                                 outbuf = uts.release;
  57                                 break;
  58                         case 'v':
  59                                 outbuf = uts.version;
  60                                 break;
  61                         case 'm':
  62                                 outbuf = uts.machine;
  63                                 break;
  64 /* The field domainname of struct utsname is Linux specific. */
  65 #if defined(__linux__)
  66                         case 'D':
  67                         case 'o':
  68                                 outbuf = uts.domainname;
  69                                 break;
  70 #endif
  71                         case 'd':
  72                                 strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
  73                                 break;
  74                         case 't':
  75                                 strftime_HHMMSS(buf, sizeof(buf), &t);
  76                                 break;
  77                         case 'l':
  78                                 outbuf = tty;
  79                                 break;
  80                         default:
  81                                 buf[0] = c;
  82                         }
  83                 }
  84                 fputs(outbuf, stdout);
  85         }
  86         fclose(fp);
  87         fflush_all();
  88 }
  89
  90 void FAST_FUNC print_login_prompt(void)
  91 {
  92         char *hostname = safe_gethostname();
  93
  94         fputs(hostname, stdout);
  95         fputs(LOGIN, stdout);
  96         fflush_all();
  97         free(hostname);
  98 }
  99
 100 /* Clear dangerous stuff, set PATH */
 101 static const char forbid[] ALIGN1 =
 102         "ENV" "\0"
 103         "BASH_ENV" "\0"
 104         "HOME" "\0"
 105         "IFS" "\0"
 106         "SHELL" "\0"
 107         "LD_LIBRARY_PATH" "\0"
 108         "LD_PRELOAD" "\0"
 109         "LD_TRACE_LOADED_OBJECTS" "\0"
 110         "LD_BIND_NOW" "\0"
 111         "LD_AOUT_LIBRARY_PATH" "\0"
 112         "LD_AOUT_PRELOAD" "\0"
 113         "LD_NOWARN" "\0"
 114         "LD_KEEPDIR" "\0";
 115
 116 int FAST_FUNC sanitize_env_if_suid(void)
 117 {
 118         const char *p;
 119
 120         if (getuid() == geteuid())
 121                 return 0;
 122
 123         p = forbid;
 124         do {
 125                 unsetenv(p);
 126                 p += strlen(p) + 1;
 127         } while (*p);
 128         putenv((char*)bb_PATH_root_path);
 129
 130         return 1; /* we indeed were run by different user! */
 131 }