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 tarball for details.
  10  */
  11
  12 #include <sys/param.h>  /* MAXHOSTNAMELEN */
  13 #include <sys/utsname.h>
  14 #include "libbb.h"
  15
  16 #define LOGIN " login: "
  17
  18 static const char fmtstr_d[] ALIGN1 = "%A, %d %B %Y";
  19 static const char fmtstr_t[] ALIGN1 = "%H:%M:%S";
  20
  21 void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
  22 {
  23         FILE *fp;
  24         int c;
  25         char buf[256+1];
  26         const char *outbuf;
  27         time_t t;
  28         struct utsname uts;
  29
  30         time(&t);
  31         uname(&uts);
  32
  33         puts("\r");     /* start a new line */
  34
  35         fp = fopen_for_read(issue_file);
  36         if (!fp)
  37                 return;
  38         while ((c = fgetc(fp)) != EOF) {
  39                 outbuf = buf;
  40                 buf[0] = c;
  41                 buf[1] = '\0';
  42                 if (c == '\n') {
  43                         buf[1] = '\r';
  44                         buf[2] = '\0';
  45                 }
  46                 if (c == '\\' || c == '%') {
  47                         c = fgetc(fp);
  48                         switch (c) {
  49                         case 's':
  50                                 outbuf = uts.sysname;
  51                                 break;
  52                         case 'n':
  53                         case 'h':
  54                                 outbuf = uts.nodename;
  55                                 break;
  56                         case 'r':
  57                                 outbuf = uts.release;
  58                                 break;
  59                         case 'v':
  60                                 outbuf = uts.version;
  61                                 break;
  62                         case 'm':
  63                                 outbuf = uts.machine;
  64                                 break;
  65                         case 'D':
  66                         case 'o':
  67                                 outbuf = uts.domainname;
  68                                 break;
  69                         case 'd':
  70                                 strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
  71                                 break;
  72                         case 't':
  73                                 strftime(buf, sizeof(buf), fmtstr_t, localtime(&t));
  74                                 break;
  75                         case 'l':
  76                                 outbuf = tty;
  77                                 break;
  78                         default:
  79                                 buf[0] = c;
  80                         }
  81                 }
  82                 fputs(outbuf, stdout);
  83         }
  84         fclose(fp);
  85         fflush(stdout);
  86 }
  87
  88 void FAST_FUNC print_login_prompt(void)
  89 {
  90         char *hostname = safe_gethostname();
  91
  92         fputs(hostname, stdout);
  93         fputs(LOGIN, stdout);
  94         fflush(stdout);
  95         free(hostname);
  96 }
  97
  98 /* Clear dangerous stuff, set PATH */
  99 static const char forbid[] ALIGN1 =
 100         "ENV" "\0"
 101         "BASH_ENV" "\0"
 102         "HOME" "\0"
 103         "IFS" "\0"
 104         "SHELL" "\0"
 105         "LD_LIBRARY_PATH" "\0"
 106         "LD_PRELOAD" "\0"
 107         "LD_TRACE_LOADED_OBJECTS" "\0"
 108         "LD_BIND_NOW" "\0"
 109         "LD_AOUT_LIBRARY_PATH" "\0"
 110         "LD_AOUT_PRELOAD" "\0"
 111         "LD_NOWARN" "\0"
 112         "LD_KEEPDIR" "\0";
 113
 114 int FAST_FUNC sanitize_env_if_suid(void)
 115 {
 116         const char *p;
 117
 118         if (getuid() == geteuid())
 119                 return 0;
 120
 121         p = forbid;
 122         do {
 123                 unsetenv(p);
 124                 p += strlen(p) + 1;
 125         } while (*p);
 126         putenv((char*)bb_PATH_root_path);
 127
 128         return 1; /* we indeed were run by different user! */
 129 }