xtrlock custom password [PATCH 2.7]

--- xtrlock.c   2014-01-07 14:20:33.000000000 +0000
+++ xtrlock.c.new   2015-11-27 16:20:42.148166109 +0000
@@ -37,6 +37,9 @@
 #include <ctype.h>
 #include <values.h>

+/* required for custom passwd prompt --tetris11 */
+#include <unistd.h>
+
 #ifdef SHADOW_PWD
 #include <shadow.h>
 #endif
@@ -54,7 +57,15 @@
 #define GOODWILLPORTION 0.3

 struct passwd *pw;
+
+int c_pass = 0; /* custom_password flag */
+
 int passwordok(const char *s) {
+
+  if ( c_pass == 1 ) {
+      return strcmp(s+1, pw->pw_passwd); /* skip first character to work --tetris11 */
+  }
+
 #if 0
   char key[3];
   char *encr;
@@ -82,39 +93,71 @@
   Pixmap csr_source,csr_mask;
   XColor csr_fg, csr_bg, dummy, black;
   int ret, screen, blank = 0;
+  char *custom_passwd = 0;
+
+#define USAGE_EXIT \
+ fprintf(stderr,"xtrlock (version %s); usage: xtrlock [-b] [-p]\n", program_version); \
+ exit(1);
+
+#define CUSTOM_PROMPT "custom passphrase: "
+
 #ifdef SHADOW_PWD
   struct spwd *sp;
 #endif
   struct timeval tv;
   int tvt, gs;

-  if ((argc == 2) && (strcmp(argv[1], "-b") == 0)) {
-    blank = 1;
-  } else if (argc > 1) {
-    fprintf(stderr,"xtrlock (version %s); usage: xtrlock [-b]\n",
-            program_version);
-    exit(1);
+  if (argc == 2){
+    if (strcmp(argv[1], "-b") == 0 ) {
+      blank = 1;
+    }
+    else if (strcmp(argv[1],"-p") == 0 ) {
+      c_pass = 1;
+      custom_passwd = getpass(CUSTOM_PROMPT);
+    }
+    else {USAGE_EXIT}
   }
-
+  else if (argc == 3) {
+    if (\
+     (strcmp(argv[1], "-b") == 0 ) && (strcmp(argv[2], "-p") == 0) || \
+     (strcmp(argv[1], "-p") == 0 ) && (strcmp(argv[2], "-b") == 0)\
+    ) {
+      blank = c_pass = 1;
+      custom_passwd = getpass(CUSTOM_PROMPT);
+    }
+    else {USAGE_EXIT}
+  }
+  else if (argc > 1) {USAGE_EXIT}
+
+
+
   errno=0;  pw= getpwuid(getuid());
-  if (!pw) { perror("password entry for uid not found"); exit(1); }
+
+  if (c_pass == 1) {
+  /* custom password bypasses gid uid checks, but still requires
+     a valid pw struct --tetris11 */
+    pw->pw_passwd = custom_passwd;
+  }
+  else {
+    if (!pw) { perror("password entry for uid not found"); exit(1); }
 #ifdef SHADOW_PWD
-  sp = getspnam(pw->pw_name);
-  if (sp)
-    pw->pw_passwd = sp->sp_pwdp;
-  endspent();
+      sp = getspnam(pw->pw_name);
+      if (sp)
+        pw->pw_passwd = sp->sp_pwdp;
+      endspent();
 #endif

-  /* logically, if we need to do the following then the same
-     applies to being installed setgid shadow.
-     we do this first, because of a bug in linux. --jdamery */
-  if (setgid(getgid())) { perror("setgid"); exit(1); }
-  /* we can be installed setuid root to support shadow passwords,
-     and we don't need root privileges any longer.  --marekm */
-  if (setuid(getuid())) { perror("setuid"); exit(1); }
-
-  if (strlen(pw->pw_passwd) < 13) {
-    fputs("password entry has no pwd\n",stderr); exit(1);
+      /* logically, if we need to do the following then the same
+         applies to being installed setgid shadow.
+         we do this first, because of a bug in linux. --jdamery */
+      if (setgid(getgid())) { perror("setgid"); exit(1); }
+      /* we can be installed setuid root to support shadow passwords,
+         and we don't need root privileges any longer.  --marekm */
+      if (setuid(getuid())) { perror("setuid"); exit(1); }
+
+      if (strlen(pw->pw_passwd) < 13) {
+        fputs("password entry has no pwd\n",stderr); exit(1);
+      }
   }

   display= XOpenDisplay(0);