Date: Fri, 11 Jun 1999 21:33:34 -0700 (PDT) From: asaddi@philosophysw.com To: FreeBSD-gnats-submit@freebsd.org Subject: i386/12147: Linux emulator fcntl ignores args (patch included) Message-ID: <199906120433.VAA02996@shell2.ba.best.com>
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>Number: 12147
>Category: i386
>Synopsis: Linux emulator fcntl ignores args
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jun 11 21:40:00 PDT 1999
>Closed-Date:
>Last-Modified:
>Originator: Allan Saddi
>Release: FreeBSD 3.2-STABLE i386
>Organization:
Philosophy SoftWorks
>Environment:
FreeBSD 3.2-STABLE #43: Wed May 19 21:50:31 PDT 1999
>Description:
The Linux emulator's fcntl syscall ignores args for commands that
shouldn't have them ignored: F_DUPFD and F_SETFD. As a result, whenever
fcntl w/ the command of F_DUPFD is called, the descriptor copied is always
descriptor 0. Also, fcntl w/ F_SETFD can't ever set a descriptor's
close-on-exec flag.
The bug was found while installing/running Scriptics' TclPro. Because
descriptors failed to actually close-on-exec (i.e. pipe descriptors),
closing a dup'ed copy of the descriptor did not actually close the file/
pipe. Thus, an EOF cannot be sent between the parent/child through the pipe,
causing both to hang. (The child closes the pipe, thinking it's actually
closed, while the parent waits, read'ing from a pipe that the child will
never write to again.)
>How-To-Repeat:
Attempt to install Scriptics' TclPro (www.scriptics.com). Installation will
hang while unzipping.
>Fix:
--- sys/i386/linux/linux_file.c.orig Sun Jan 10 15:15:35 1999
+++ sys/i386/linux/linux_file.c Fri Jun 11 19:19:17 1999
@@ -219,6 +219,7 @@
switch (args->cmd) {
case LINUX_F_DUPFD:
fcntl_args.cmd = F_DUPFD;
+ fcntl_args.arg = args->arg;
return fcntl(p, &fcntl_args);
case LINUX_F_GETFD:
@@ -227,6 +228,7 @@
case LINUX_F_SETFD:
fcntl_args.cmd = F_SETFD;
+ fcntl_args.arg = args->arg;
return fcntl(p, &fcntl_args);
case LINUX_F_GETFL:
>Release-Note:
>Audit-Trail:
>Unformatted:
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