os-aix/7418: Incorrect reporting of bytes sent by send_file()

[Richard Griswold <rg...@us.ibm.com>]

>Number:         7418
>Category:       os-aix
>Synopsis:       Incorrect reporting of bytes sent by send_file()
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Thu Mar 15 09:30:02 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     rgriswol@us.ibm.com
>Release:        2.0.14 Alpha
>Organization:
apache
>Environment:
uname -a output:  AIX engraver 3 4 000669914C00
Compiler:  xlc
>Description:
The apr_sendfile() function in the srclib/apr/network_io/unix/sendrecv.c only
reports the number of bytes sent by the last call to send_file.  The code also
only checks for a return code of -1, and not a return code of 1 which indicates
that send_file() was able to send part of the data, but not all of it.

On AIX this results in a minor performance degradation since Apache has to make
multiple calls to the apr_sendfile() function to send large files.  However, on
a version of one of our operating systems currently under developement (I could
tell you which one, but then I'd have to kill you :)) it causes Apache to fail
to send files larger than twice the send buffer size.
>How-To-Repeat:

>Fix:
Here is the patch for httpd-2_0_14.  It also applies cleanly on apache-2.0a9.
Use "patch p1 < patchfile" to apply it.

diff -bcr httpd-2_0_14.orig/srclib/apr/network_io/unix/sendrecv.c httpd-2_0_14/srclib/apr/network_io/unix/sendrecv.c
*** httpd-2_0_14.orig/srclib/apr/network_io/unix/sendrecv.c	Mon Feb 26 06:41:51 2001
--- httpd-2_0_14/srclib/apr/network_io/unix/sendrecv.c	Thu Mar 15 10:52:59 2001
***************
*** 700,710 ****
          rv = send_file(&(sock->socketdes), /* socket */
                         &(parms),           /* all data */
                         flags);             /* flags */
      } while (rv == -1 && errno == EINTR);
  
!     if (rv == -1 &&
          (errno == EAGAIN || errno == EWOULDBLOCK) &&
          sock->timeout > 0) {
          arv = wait_for_io_or_timeout(sock, 0);
          if (arv != APR_SUCCESS) {
              *len = 0;
--- 700,713 ----
          rv = send_file(&(sock->socketdes), /* socket */
                         &(parms),           /* all data */
                         flags);             /* flags */
+         (*len) = parms.bytes_sent;
      } while (rv == -1 && errno == EINTR);
  
!     if (rv != 0 &&
          (errno == EAGAIN || errno == EWOULDBLOCK) &&
          sock->timeout > 0) {
+ 
+         do {
             arv = wait_for_io_or_timeout(sock, 0);
             if (arv != APR_SUCCESS) {
                 *len = 0;
***************
*** 715,725 ****
                  rv = send_file(&(sock->socketdes), /* socket */
                                 &(parms),           /* all data */
                                 flags);             /* flags */
              } while (rv == -1 && errno == EINTR);
          }
      }
- 
-     (*len) = parms.bytes_sent;
  
  #if 0
      /* Clean up after ourselves */
--- 718,728 ----
                     rv = send_file(&(sock->socketdes), /* socket */
                                    &(parms),           /* all data */
                                    flags);             /* flags */
+                    (*len) += parms.bytes_sent;
                 } while (rv == -1 && errno == EINTR);
             }
+         } while ( rv != 0 && (errno == EAGAIN || errno == EWOULDBLOCK) );
      }
  
  #if 0
      /* Clean up after ourselves */
>Release-Note:
>Audit-Trail:
>Unformatted:
 [In order for any reply to be added to the PR database, you need]
 [to include <ap...@Apache.Org> in the Cc line and make sure the]
 [subject line starts with the report component and number, with ]
 [or without any 'Re:' prefixes (such as "general/1098:" or      ]
 ["Re: general/1098:").  If the subject doesn't match this       ]
 [pattern, your message will be misfiled and ignored.  The       ]
 ["apbugs" address is not added to the Cc line of messages from  ]
 [the database automatically because of the potential for mail   ]
 [loops.  If you do not include this Cc, your reply may be ig-   ]
 [nored unless you are responding to an explicit request from a  ]
 [developer.  Reply only with text; DO NOT SEND ATTACHMENTS!     ]