forked from Imagelibrary/binutils-gdb
43fac29628
Currently, if - you're in all-stop mode, - the inferior last stopped because of a fork catchpoint, when you next resume the program, gdb checks whether it had last stopped for a fork/vfork, and if so, a) if the current thread is the one that forked, gdb follows the parent/child, depending on "set follow-fork" mode. b) if the current thread is some other thread (because you switched threads meanwhile), gdb switches back to that thread, gdb follows the parent/child, and stops the resumption command. There's a problem in b), however -- if you have "set schedule-multiple off", which is the default, or "set scheduler-locking on", gdb will still switch back to the forking thread, even if you didn't want to resume it. For example, with: (gdb) catch fork (gdb) c * thread 1 stops for fork (gdb) thread 2 (gdb) set scheduler-locking on (gdb) c gdb switches back to thread 1, and follows the fork. Or with: (gdb) add-inferior -exec prog (gdb) inferior 2 (gdb) start (gdb) inferior 1 (gdb) catch fork (gdb) c * thread 1.1 stops for fork (gdb) inferior 2 (gdb) set schedule-multiple off # this is the default (gdb) c gdb switches back to thread 1.1, and follows the fork. Another issue is that, because follow_fork relies on get_last_target_status to find the thread that has a pending fork, it is possible to confuse it. For example, "run" or "start" call init_wait_for_inferior, which clears the last target status, so this: (gdb) catch fork (gdb) c * thread 1 stops for fork (gdb) add-inferior -exec prog (gdb) inferior 2 (gdb) start (gdb) set follow-fork child (gdb) inferior 1 (gdb) n ... does not follow to the fork child of inferior 1, because the get_last_target_status call in follow_fork doesn't return a TARGET_WAITKIND_FORKED. Thanks to Simon for this example. All of the above are fixed by this patch. It changes follow_fork to not look at get_last_target_status, but to instead iterate over the set of threads that the user is resuming, and find the one that has a pending_follow kind of fork/vfork. gdb.base/foll-fork.exp is augmented to exercise the last "start" scenario described above. The other cases will be exercised in the testcase added by the following patch. Change-Id: Ifcca77e7b2456277387f40660ef06cec2b93b97e
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.