xxd: allow "-" as file name meaning stdin
[oweals/busybox.git] / libbb / login.c
index 7c1cad3f26f46b0c76e13369a7bc94d85ad436a0..5a7acfcf058c192413b516227f22add01b7eb727 100644 (file)
@@ -4,39 +4,22 @@
  *
  * Copyright (C) 2003 Bastian Blank <waldi@tuxbox.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
  * Optimize and correcting OCRNL by Vladimir Oleynik <dzo@simtreas.ru>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include <sys/param.h>  /* MAXHOSTNAMELEN */
-#include <stdio.h>
-#include <unistd.h>
 #include "libbb.h"
-
+/* After libbb.h, since it needs sys/types.h on some systems */
 #include <sys/utsname.h>
-#include <time.h>
 
 #define LOGIN " login: "
 
-static const char fmtstr_d[] = "%A, %d %B %Y";
-static const char fmtstr_t[] = "%H:%M:%S";
+static const char fmtstr_d[] ALIGN1 = "%A, %d %B %Y";
 
-void print_login_issue(const char *issue_file, const char *tty)
+void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
 {
-       FILE *fd;
+       FILE *fp;
        int c;
        char buf[256+1];
        const char *outbuf;
@@ -46,85 +29,143 @@ void print_login_issue(const char *issue_file, const char *tty)
        time(&t);
        uname(&uts);
 
-       puts("\r");     /* start a new line */
-
-       if ((fd = fopen(issue_file, "r"))) {
-               while ((c = fgetc(fd)) != EOF) {
-                       outbuf = buf;
-                       buf[0] = c;
-                       if(c == '\n') {
-                               buf[1] = '\r';
-                               buf[2] = 0;
-                       } else {
-                               buf[1] = 0;
-                       }
-                       if (c == '\\' || c == '%') {
-                               c = fgetc(fd);
-                               switch (c) {
-                                       case 's':
-                                               outbuf = uts.sysname;
-                                               break;
-
-                                       case 'n':
-                                               outbuf = uts.nodename;
-                                               break;
-
-                                       case 'r':
-                                               outbuf = uts.release;
-                                               break;
-
-                                       case 'v':
-                                               outbuf = uts.version;
-                                               break;
-
-                                       case 'm':
-                                               outbuf = uts.machine;
-                                               break;
-
-                                       case 'D':
-                                       case 'o':
-                                               c = getdomainname(buf, sizeof(buf) - 1);
-                                               buf[c >= 0 ? c : 0] = '\0'; 
-                                               break;
-
-                                       case 'd':
-                                               strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
-                                               break;
-
-                                       case 't':
-                                               strftime(buf, sizeof(buf), fmtstr_t, localtime(&t));
-                                               break;
-
-                                       case 'h':
-                                               gethostname(buf, sizeof(buf) - 1);
-                                               buf[sizeof(buf) - 1] = '\0';
-                                               break;
-
-                                       case 'l':
-                                               outbuf = tty;
-                                               break;
-
-                                       default:
-                                               buf[0] = c;
-                               }
+       puts("\r");  /* start a new line */
+
+       fp = fopen_for_read(issue_file);
+       if (!fp)
+               return;
+       while ((c = fgetc(fp)) != EOF) {
+               outbuf = buf;
+               buf[0] = c;
+               buf[1] = '\0';
+               if (c == '\n') {
+                       buf[1] = '\r';
+                       buf[2] = '\0';
+               }
+               if (c == '\\' || c == '%') {
+                       c = fgetc(fp);
+                       switch (c) {
+//From getty manpage (* - supported by us)
+//========================================
+//4 or 4{interface}
+//  Insert the IPv4 address of the network interface (example: \4{eth0}).
+//  If the interface argument is not specified, then select the first
+//  fully configured (UP, non-LOOPBACK, RUNNING) interface.
+//6 or 6{interface} -- The same as \4 but for IPv6.
+//b -- Insert the baudrate of the current line.
+//*d -- Insert the current date.
+//*t -- Insert the current time.
+//e or e{name}
+//  Translate the human-readable name to an escape sequence and insert it
+//  (for example: \e{red}Alert text.\e{reset}).  If the name argument
+//  is not specified, then insert \033. The currently supported names are:
+//  black, blink, blue, bold, brown, cyan, darkgray, gray, green, halfbright,
+//  lightblue, lightcyan, lightgray, lightgreen, lightmagenta, lightred,
+//  magenta, red, reset, reverse, and yellow. Unknown names are ignored.
+//*s
+//  Insert the system name (the name of the operating system - `uname -s`)
+//*S or S{VARIABLE}
+//  Insert the VARIABLE data from /etc/os-release.
+//  If the VARIABLE argument is not specified, use PRETTY_NAME.
+//  If PRETTY_NAME is not in /etc/os-release, \S is the same as \s.
+//*l -- Insert the name of the current tty line.
+//*m -- Insert the architecture identifier of the machine: `uname -m`.
+//*n -- Insert the nodename of the machine: `uname -n`.
+//*o -- Insert the NIS domainname of the machine.  Same as `hostname -d'.
+//*O -- Insert the DNS domainname of the machine.
+//*r -- Insert the release number of the OS: `uname -r`.
+//u -- Insert the number of current users logged in.
+//U -- Insert the string "1 user" or "N users" (current users logged in).
+//*v -- Insert the version of the OS, e.g. the build-date etc: `uname -v`.
+//We also implement:
+//*D -- same as \O "DNS domainname"
+//*h -- same as \n "nodename"
+
+                       case 'S':
+                               /* minimal implementation, not reading /etc/os-release */
+                               /*FALLTHROUGH*/
+                       case 's':
+                               outbuf = uts.sysname;
+                               break;
+                       case 'n':
+                       case 'h':
+                               outbuf = uts.nodename;
+                               break;
+                       case 'r':
+                               outbuf = uts.release;
+                               break;
+                       case 'v':
+                               outbuf = uts.version;
+                               break;
+                       case 'm':
+                               outbuf = uts.machine;
+                               break;
+/* The field domainname of struct utsname is Linux specific. */
+#if defined(__linux__)
+                       case 'D':
+                       case 'o':
+                       case 'O':
+                               outbuf = uts.domainname;
+                               break;
+#endif
+                       case 'd':
+                               strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
+                               break;
+                       case 't':
+                               strftime_HHMMSS(buf, sizeof(buf), &t);
+                               break;
+                       case 'l':
+                               outbuf = tty;
+                               break;
+                       default:
+                               buf[0] = c;
                        }
-                       fputs(outbuf, stdout);
                }
-
-               fclose(fd);
-
-               fflush(stdout);
+               fputs(outbuf, stdout);
        }
+       fclose(fp);
+       fflush_all();
 }
 
-void print_login_prompt(void)
+void FAST_FUNC print_login_prompt(void)
 {
-       char buf[MAXHOSTNAMELEN+1];
-
-       if(gethostname(buf, MAXHOSTNAMELEN) == 0)
-               fputs(buf, stdout);
+       char *hostname = safe_gethostname();
 
+       fputs(hostname, stdout);
        fputs(LOGIN, stdout);
-       fflush(stdout);
+       fflush_all();
+       free(hostname);
 }
 
+/* Clear dangerous stuff, set PATH */
+static const char forbid[] ALIGN1 =
+       "ENV" "\0"
+       "BASH_ENV" "\0"
+       "HOME" "\0"
+       "IFS" "\0"
+       "SHELL" "\0"
+       "LD_LIBRARY_PATH" "\0"
+       "LD_PRELOAD" "\0"
+       "LD_TRACE_LOADED_OBJECTS" "\0"
+       "LD_BIND_NOW" "\0"
+       "LD_AOUT_LIBRARY_PATH" "\0"
+       "LD_AOUT_PRELOAD" "\0"
+       "LD_NOWARN" "\0"
+       "LD_KEEPDIR" "\0";
+
+int FAST_FUNC sanitize_env_if_suid(void)
+{
+       const char *p;
+
+       if (getuid() == geteuid())
+               return 0;
+
+       p = forbid;
+       do {
+               unsetenv(p);
+               p += strlen(p) + 1;
+       } while (*p);
+       putenv((char*)bb_PATH_root_path);
+
+       return 1; /* we indeed were run by different user! */
+}