Re: Shell Fork Runaway Bug (ITS#1973)

[anthm@cylynx.com]

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hi,

I found the original patched servers/slapd/back-shell/fork.c
that I have. The unpatched version has not changed at all since 
2.0.25


Here is a diff from the unmodified version.
and the mod fork.c is attached.

7a8,10
>
>
>
15a19,22
> #include <ac/wait.h>
> #include <ac/signal.h>
> #include <ac/errno.h>
>
18a26,52
>
>
> static RETSIGTYPE
> wait4child( int sig )
> {
>   int save_errno = errno;
>
> #ifdef WNOHANG
>   errno = 0;
> #ifdef HAVE_WAITPID
>   while ( waitpid( (pid_t)-1, NULL, WNOHANG ) > 0 || errno == EINTR )
>     ;       /* NULL */
> #else
>   while ( wait3( NULL, WNOHANG, NULL ) > 0 || errno == EINTR )
>     ;       /* NULL */
> #endif
> #else
>   (void) wait( NULL );
> #endif
>   (void) SIGNAL_REINSTALL( sig, wait4child );
>   errno = save_errno;
> }
>
>
>
>
>
84a119,121
>       while ( waitpid( (pid_t)-1, NULL, WNOHANG ) > 0 || errno == EINTR )
>         ;       /* NULL */
>
86a124,129
>
>
>
>
>
>




----- Original Message ----- 
From: <openldap-its@OpenLDAP.org>
To: <anthm@cylynx.com>
Sent: Saturday, July 20, 2002 6:47 PM
Subject: Re: Shell Fork Runaway Bug (ITS#1973)



*** THIS IS AN AUTOMATICALLY GENERATED REPLY ***

Thanks for your report to openldap-its@OpenLDAP.org.  Your report
has been placed into our Issue Tracking System and has been assigned
the tracking number ITS#1973.

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	filename="fork.c"

/* fork.c - fork and exec a process, connecting stdin/out w/pipes */
/* $OpenLDAP: pkg/ldap/servers/slapd/back-shell/fork.c,v 1.5.8.4 =
2002/01/04 20:38:35 kurt Exp $ */
/*
 * Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
 */

#include "portable.h"

#include <stdio.h>

#include <ac/string.h>
#include <ac/socket.h>
#include <ac/unistd.h>

#include "slap.h"
#include "shell.h"

pid_t
forkandexec(
    char        **args,
    FILE        **rfp,
    FILE        **wfp
)
{
        int     p2c[2], c2p[2];
        pid_t   pid;

        if ( pipe( p2c ) !=3D 0 || pipe( c2p ) !=3D 0 ) {
                Debug( LDAP_DEBUG_ANY, "pipe failed\n", 0, 0, 0 );
                return( -1 );
        }

        /*
         * what we're trying to set up looks like this:
         *      parent *wfp -> p2c[1] | p2c[0] -> stdin child
         *      parent *rfp <- c2p[0] | c2p[1] <- stdout child
         */

#ifdef HAVE_THR
        switch ( (pid =3D fork1()) )
#else
        switch ( (pid =3D fork()) )
#endif
        {
        case 0:         /* child */
                /*
                 * child could deadlock here due to resources locked
                 * by our parent
                 *
                 * If so, configure --without-threads or implement =
forking
                 * via a surrogate parent.
                 */
                close( p2c[1] );
                close( c2p[0] );
                if ( dup2( p2c[0], 0 ) =3D=3D -1 || dup2( c2p[1], 1 ) =
=3D=3D -1 ) {
                        Debug( LDAP_DEBUG_ANY, "dup2 failed\n", 0, 0, 0 =
);
                        exit( EXIT_FAILURE );
                }

                execv( args[0], args );

                Debug( LDAP_DEBUG_ANY, "execv failed\n", 0, 0, 0 );
                exit( EXIT_FAILURE );

        case -1:        /* trouble */
                Debug( LDAP_DEBUG_ANY, "fork failed\n", 0, 0, 0 );
                return( -1 );

        default:        /* parent */
                close( p2c[0] );
                close( c2p[1] );
                break;
        }

        if ( (*rfp =3D fdopen( c2p[0], "r" )) =3D=3D NULL || (*wfp =3D =
fdopen( p2c[1],
            "w" )) =3D=3D NULL ) {
                Debug( LDAP_DEBUG_ANY, "fdopen failed\n", 0, 0, 0 );
                close( c2p[0] );
                close( p2c[1] );

                return( -1 );
        }

        return( pid );
}

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