From 048094accce2110432bf7d44c34acc17865cf85a Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 12 Apr 2016 16:49:32 +0100 Subject: target remote: Don't rely on immediate_quit (introduce quit handlers) remote.c is the last user of immediate_quit. It's relied on to immediately break the initial remote connection sync up, if the user does Ctrl-C, assuming that was because the target isn't responding. At that stage, since the connection isn't synced yet, disconnecting is the only safe thing to do. This commit reworks that, to not rely on throwing from the SIGINT signal handler. So, this commit: - Introduces the concept of a "quit handler". This is used to override what does the QUIT macro do when the quit flag is set. - Makes the "struct serial" reachar / write code call QUIT in the partial read/write loops, so the current quit handler is invoked whenever a serial->read_prim / serial->write_prim returns EINTR. - Makes the "struct serial" reachar / write code call interruptible_select instead of gdb_select, so that QUITs are detected in a race-free manner. - Stops remote.c from setting immediate_quit during the initial connection. - Instead, we install a custom quit handler whenever we're calling into the serial code. This custom quit handler knows to immediately throw a quit when we're in the initial connection setup, and otherwise defer handling the quit/Ctrl-C request to later, when we're safely out of a packet command/response sequence. This also is what is now responsible for handling "double Ctrl-C because target connection is stuck/wedged." - remote.c no longer installs a specialized SIGINT handlers, and instead re-uses the quit flag. Since we want to rely on the QUIT macro, the SIGINT handler must also set the quit. And the easiest is just to not install custom SIGINT handler in remote.c. Let the standard SIGINT handler do its job of setting the quit flag. Centralizing SIGINT handlers seems like a good thing to me, anyway. gdb/ChangeLog: 2016-04-12 Pedro Alves * defs.h (quit_handler_ftype, quit_handler) (make_cleanup_override_quit_handler, default_quit_handler): New. (QUIT): Adjust comments. * event-top.c (default_quit_handler): New function. (quit_handler): New global. (struct quit_handler_cleanup_data): New. (restore_quit_handler, restore_quit_handler_dtor) (make_cleanup_override_quit_handler): New. (async_request_quit): Call QUIT. * remote.c (struct remote_state) : New field. (async_sigint_remote_twice_token, async_sigint_remote_token): Delete. (remote_close): Update comments. (remote_start_remote): Don't set immediate_quit. Set starting_up earlier. (remote_serial_quit_handler, remote_unpush_and_throw): New functions. (remote_open_1): Clear got_ctrlc_during_io. Set remote_async_terminal_ours_p unconditionally. (async_initialize_sigint_signal_handler) (async_handle_remote_sigint, async_handle_remote_sigint_twice) (remote_check_pending_interrupt, async_remote_interrupt) (async_remote_interrupt_twice) (async_cleanup_sigint_signal_handler, ofunc) (sync_remote_interrupt, sync_remote_interrupt_twice): Delete. (remote_terminal_inferior, remote_terminal_ours): Remove async checks. (remote_wait_as): Don't install a SIGINT handler in sync mode. (readchar, remote_serial_write): Override the quit handler with remote_serial_quit_handler. (getpkt_or_notif_sane_1): Don't call QUIT. (initialize_remote_ops): Don't install remote_check_pending_interrupt. (_initialize_remote): Don't create async_sigint_remote_token and async_sigint_remote_twice_token. * ser-base.c (ser_base_wait_for): Call QUIT and use interruptible_select. (ser_base_write): Call QUIT. * ser-go32.c (dos_readchar, dos_write): Call QUIT. * ser-unix.c (wait_for): Don't use VTIME. Always take the gdb_select path, but call QUIT and interruptible_select. * utils.c (maybe_quit): Call the current quit handler. Don't call target_check_pending_interrupt. (defaulted_query, prompt_for_continue): Override the quit handler with the default quit handler. --- gdb/ser-base.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'gdb/ser-base.c') diff --git a/gdb/ser-base.c b/gdb/ser-base.c index 25af66a..c51be07 100644 --- a/gdb/ser-base.c +++ b/gdb/ser-base.c @@ -213,6 +213,7 @@ ser_base_wait_for (struct serial *scb, int timeout) int numfds; struct timeval tv; fd_set readfds, exceptfds; + int nfds; /* NOTE: Some OS's can scramble the READFDS when the select() call fails (ex the kernel with Red Hat 5.2). Initialize all @@ -226,10 +227,13 @@ ser_base_wait_for (struct serial *scb, int timeout) FD_SET (scb->fd, &readfds); FD_SET (scb->fd, &exceptfds); + QUIT; + + nfds = scb->fd + 1; if (timeout >= 0) - numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, &tv); + numfds = interruptible_select (nfds, &readfds, 0, &exceptfds, &tv); else - numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, 0); + numfds = interruptible_select (nfds, &readfds, 0, &exceptfds, 0); if (numfds <= 0) { @@ -455,6 +459,8 @@ ser_base_write (struct serial *scb, const void *buf, size_t count) while (count > 0) { + QUIT; + cc = scb->ops->write_prim (scb, str, count); if (cc < 0) -- cgit v1.1