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[PATCH v2] xfsdump: handle Ctrl-D during prompts

To: xfs@xxxxxxxxxxx
Subject: [PATCH v2] xfsdump: handle Ctrl-D during prompts
From: Bill Kendall <wkendall@xxxxxxx>
Date: Thu, 10 Nov 2011 12:55:42 -0600
Cc: Bill Kendall <wkendall@xxxxxxx>
xfsdump does not currently handle Ctrl-D well during a dialog
prompt. If some text is entered followed by Ctrl-D, an assert
will trip because xfsdump expects a new-line character at the
end of the user's input (or if asserts are disabled, the last
character the user entered will be dropped).

If Ctrl-D is entered without entering any response, some dialog
callers (e.g., tree_subtree_inter()) will abort because they
receive an unexpected response code.

This patch changes xfsdump to behave like other interactive
commands (xfs_db, bash, parted, ...) with respect to Ctrl-D.
If Ctrl-D precedes any input, an empty string is returned.
If Ctrl-D follows some input, it is ignored and xfsdump will
continue to wait for more input.

Signed-off-by: Bill Kendall <wkendall@xxxxxxx>
---
Changed in v2:
   - Handle Ctrl-D like other commands do, rather than
     treating it as if the user typed 'enter'.

 common/dlog.c |   33 ++++++++++++++++++++++-----------
 1 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/common/dlog.c b/common/dlog.c
index 51666cf..ac0cafc 100644
--- a/common/dlog.c
+++ b/common/dlog.c
@@ -382,6 +382,7 @@ promptinput( char *buf,
        time32_t now = time( NULL );
        intgen_t nread = -1;
        sigset_t orig_set;
+       char *bufp = buf;
 
        /* display the pre-prompt
         */
@@ -447,8 +448,27 @@ promptinput( char *buf,
 
                rc = select( dlog_ttyfd + 1, &rfds, NULL, NULL, &tv );
                if ( rc > 0 && FD_ISSET( dlog_ttyfd, &rfds ) ) {
-                       nread = read( dlog_ttyfd, buf, bufsz - 1 );
-                       break;
+                       nread = read( dlog_ttyfd, bufp, bufsz );
+                       if ( nread < 0 ) {
+                               break; // error handled below
+                       } else if ( nread == 0 && buf == bufp ) {
+                               mlog( MLOG_NORMAL | MLOG_NOLOCK | MLOG_BARE, 
"\n" );
+                               *bufp = 0;
+                               break; // no input, return an empty string
+                       } else if ( nread > 0 && bufp[nread-1] == '\n' ) {
+                               // received a full line, chomp the newline
+                               bufp[nread-1] = 0;
+                               break;
+                       } else if ( nread == bufsz ) {
+                               // no more room, truncate and return
+                               bufp[nread-1] = 0;
+                               break;
+                       }
+
+                       // keep waiting for a full line of input
+                       bufp += nread;
+                       bufsz -= nread;
+                       nread = -1;
                }
                now = time( NULL );
        }
@@ -489,17 +509,8 @@ promptinput( char *buf,
                        *exceptionixp = sigquitix;
                }
                return BOOL_FALSE;
-       } else if ( nread == 0 ) {
-               *exceptionixp = timeoutix;
-               if ( bufsz > 0 ) {
-                       buf[ 0 ] = 0;
-               }
-               return BOOL_FALSE;
        } else {
                ASSERT( dlog_signo_received == -1 );
-               ASSERT( ( size_t )nread < bufsz );
-               ASSERT( buf[ nread - 1 ] == '\n' );
-               buf[ nread - 1 ] = 0;
                *exceptionixp = 0;
                return BOOL_TRUE;
        }
-- 
1.7.0.4

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