general/5694: Startup problems - unchecked return value - when FD_SETSIZE not large enough

[Phil Pennock <pd...@psidev.net>]

>Number:         5694
>Category:       general
>Synopsis:       Startup problems - unchecked return value - when FD_SETSIZE not large enough
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Thu Feb 03 09:10:01 PST 2000
>Closed-Date:
>Last-Modified:
>Originator:     pdp@psidev.net
>Release:        1.3.9
>Organization:
apache
>Environment:
FreeBSD 3.3-RELEASE (rest not relevant - patch information included)
>Description:
In src/main/http_main.c setup_listeners() there is a call to make_sock().
The return value is unchecked.  make_sock can return -1 in certain circumstances.
Have seen this if FD_SETSIZE is too small.

Result: apache complains about FD_SETSIZE (elsewhere), but continues in its
attempt to startup.  Keeps fork()ing and these children keep failing, because
they attempt to perform socket operations on fd -1.
>How-To-Repeat:
Perhaps by setting FD_SETSIZE to a small value in 'apaci' and compiling?
>Fix:
My amendment was to change part of setup_listeners() so that it checks the
return value of make_sock().  I can accept that the exit value is a little
arbitrary:
            fd = make_sock(p, &lr->local_addr);
            if (fd == -1) { /* [ this was my work mail address ] */
                ap_log_error(APLOG_MARK, APLOG_EMERG, NULL,
                        "Failed to create the socket to listen on, "
                        "(attempt was for port %d)", ntohs(lr->local_addr.sin_po
rt));
                exit(42);
            }
>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!     ]