kostikbel at gmail.com
Thu Feb 12 09:27:38 UTC 2015
On Wed, Feb 11, 2015 at 06:30:15PM -0600, Bryan Drewery wrote:
> On 12/26/2014 10:53 AM, Konstantin Belousov wrote:
> > [Long]
> > Proposed patch does the following:
> It seems libthr.3 needs to be updated for the dlopen(3) support, to
> remove some of r272070. Also note the ordering comment (which I know you
> may not be ready to change yet).
Thanks for noting, I forgot about the man page and about the text.
See the patch at the end of the message.
> As for the dlclose(3) refusing to work on libthr, I cannot find the
> supporting code. Where is it?
libthr is linked with -z nodelete linker flag.
diff --git a/lib/libthr/libthr.3 b/lib/libthr/libthr.3
index 4b636ce..8108e2f 100644
@@ -1,5 +1,5 @@
.\" Copyright (c) 2005 Robert N. M. Watson
-.\" Copyright (c) 2014 The FreeBSD Foundation, Inc.
+.\" Copyright (c) 2014,2015 The FreeBSD Foundation, Inc.
.\" All rights reserved.
.\" Part of this documentation was written by
@@ -29,7 +29,7 @@
-.Dd September 26, 2014
+.Dd February 12, 2015
.Dt LIBTHR 3
@@ -200,45 +200,25 @@ Bigger values reduce the frequency of the FIFO discipline.
The value must be between 0 and 255.
.Sh INTERACTION WITH RUN-TIME LINKER
-library must appear before
-in the global order of depended objects.
-.Xr dlopen 3
-call in the process after the program binary is activated
-is not supported, and causes miscellaneous and hard-to-diagnose misbehaviour.
-This is due to
-interposing several important
-symbols to provide thread-safe services.
-and the locking stubs from
-This requirement is currently not enforced.
-If the program loads any modules at run-time, and those modules may require
-threading services, the main program binary must be linked with
-.Li libpthread ,
-even if it does not require any services from the library.
+installs interposing handlers into the hooks exported by
+.Li libc .
+The interposers provide real locking implementation instead of the
+stubs for single-threaded processes in
+cancellation support and some modifications to the signal operations.
cannot be unloaded; the
.Xr dlclose 3
function does not perform any action when called with a handle for
-One of the reasons is that the interposing of
+One of the reasons is that the internal interposing of
functions cannot be undone.
-The implementation also interposes the user-installed
+The implementation interposes the user-installed
.Xr signal 3
This interposing is done to postpone signal delivery to threads which
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