Initial revision

1 files changed, 114 insertions, 0 deletions

diff --git a/readpass.c b/readpass.c
new file mode 100644
index 00000000..3031825e
--- /dev/null
+++ b/readpass.c
@@ -0,0 +1,114 @@
+/*
+
+readpass.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+                   All rights reserved
+
+Created: Mon Jul 10 22:08:59 1995 ylo
+
+Functions for reading passphrases and passwords.
+
+*/
+
+#include "includes.h"
+RCSID("$Id: readpass.c,v 1.1 1999/10/27 03:42:44 damien Exp $");
+
+#include "xmalloc.h"
+#include "ssh.h"
+
+/* Saved old terminal mode for read_passphrase. */
+static struct termios saved_tio;
+
+/* Old interrupt signal handler for read_passphrase. */
+static void (*old_handler)(int sig) = NULL;
+
+/* Interrupt signal handler for read_passphrase. */
+
+void intr_handler(int sig)
+{
+  /* Restore terminal modes. */
+  tcsetattr(fileno(stdin), TCSANOW, &saved_tio);
+  /* Restore the old signal handler. */
+  signal(sig, old_handler);
+  /* Resend the signal, with the old handler. */
+  kill(getpid(), sig);
+}
+
+/* Reads a passphrase from /dev/tty with echo turned off.  Returns the 
+   passphrase (allocated with xmalloc).  Exits if EOF is encountered. 
+   The passphrase if read from stdin if from_stdin is true (as is the
+   case with ssh-keygen).  */
+
+char *read_passphrase(const char *prompt, int from_stdin)
+{
+  char buf[1024], *cp;
+  struct termios tio;
+  FILE *f;
+  
+  if (from_stdin)
+    f = stdin;
+  else
+    {
+      /* Read the passphrase from /dev/tty to make it possible to ask it even 
+	 when stdin has been redirected. */
+      f = fopen("/dev/tty", "r");
+      if (!f)
+	{
+	  /* No controlling terminal and no DISPLAY.  Nowhere to read. */
+	  fprintf(stderr, "You have no controlling tty and no DISPLAY.  Cannot read passphrase.\n");
+	  exit(1);
+	}
+    }
+
+  /* Display the prompt (on stderr because stdout might be redirected). */
+  fflush(stdout);
+  fprintf(stderr, "%s", prompt);
+  fflush(stderr);
+
+  /* Get terminal modes. */
+  tcgetattr(fileno(f), &tio);
+  saved_tio = tio;
+  /* Save signal handler and set the new handler. */
+  old_handler = signal(SIGINT, intr_handler);
+
+  /* Set new terminal modes disabling all echo. */
+  tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
+  tcsetattr(fileno(f), TCSANOW, &tio);
+
+  /* Read the passphrase from the terminal. */
+  if (fgets(buf, sizeof(buf), f) == NULL)
+    {
+      /* Got EOF.  Just exit. */
+      /* Restore terminal modes. */
+      tcsetattr(fileno(f), TCSANOW, &saved_tio);
+      /* Restore the signal handler. */
+      signal(SIGINT, old_handler);
+      /* Print a newline (the prompt probably didn\'t have one). */
+      fprintf(stderr, "\n");
+      /* Close the file. */
+      if (f != stdin)
+	fclose(f);
+      exit(1);
+    }
+  /* Restore terminal modes. */
+  tcsetattr(fileno(f), TCSANOW, &saved_tio);
+  /* Restore the signal handler. */
+  (void)signal(SIGINT, old_handler);
+  /* Remove newline from the passphrase. */
+  if (strchr(buf, '\n'))
+    *strchr(buf, '\n') = 0;
+  /* Allocate a copy of the passphrase. */
+  cp = xstrdup(buf);
+  /* Clear the buffer so we don\'t leave copies of the passphrase laying
+     around. */
+  memset(buf, 0, sizeof(buf));
+  /* Print a newline since the prompt probably didn\'t have one. */
+  fprintf(stderr, "\n");
+  /* Close the file. */
+  if (f != stdin)
+    fclose(f);
+  return cp;
+}