From 7fdc15218d384617a3aad142cfeca0594a7c5ff2 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Thu, 25 Jul 2013 14:34:51 +0000 Subject: [PATCH] remove pop_target This patch fixes the target double-close problem (PR remote/15266), and in the process removes pop_target entire (PR remote/15256). The first issue is that pop_target calls target_close. However, it then calls unpush_target, which also calls target_close. This means targets must be able to be closed twice. Not only is this strange, but it also directly contradicts the contract of to_xclose targets. (We currently have just a single such target, and it is never pushed; but I plan to add more, and so this latent bug is triggered.) The second issue is that it seems to me that calling pop_target is often unsafe. This is what cropped up in 15256, where the remote target assumed that it could pop_target -- but there was another target higher on the stack, leading to confusion. But, it is always just as easy to call unpush_target as it is to call pop_target; and it is also safer. So, removing pop_target seemed like an improvement. Finally, this adds an assertion to target_close to ensure that no currently-pushed target can be closed. Built and regtested on x86-64 Fedora 18; both natively and using the native-gdbserver board file. PR remote/15256, PR remote/15266: * bfd-target.c (target_bfd_reopen): Initialize to_magic. * monitor.c (monitor_detach): Use unpush_target. * remote-m32r-sdi.c (m32r_detach): Use unpush_target. * remote-mips.c (mips_detach): Use unpush_target. Don't call mips_close. * remote-sim.c (gdbsim_detach): Use unpush_target. * target.c (pop_target): Remove. (pop_all_targets_above): Don't call target_close. (target_close): Assert that the target is unpushed. * target.h (pop_target): Don't declare. * tracepoint.c (tfile_open): Use unpush_target. --- gdb/ChangeLog | 15 +++++++++++++++ gdb/bfd-target.c | 1 + gdb/monitor.c | 2 +- gdb/remote-m32r-sdi.c | 2 +- gdb/remote-mips.c | 4 +--- gdb/remote-sim.c | 2 +- gdb/target.c | 17 ++--------------- gdb/target.h | 6 +----- gdb/tracepoint.c | 4 ++-- 9 files changed, 25 insertions(+), 28 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 782a262..ff9ff87 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,20 @@ 2013-07-25 Tom Tromey + PR remote/15256, PR remote/15266: + * bfd-target.c (target_bfd_reopen): Initialize to_magic. + * monitor.c (monitor_detach): Use unpush_target. + * remote-m32r-sdi.c (m32r_detach): Use unpush_target. + * remote-mips.c (mips_detach): Use unpush_target. Don't + call mips_close. + * remote-sim.c (gdbsim_detach): Use unpush_target. + * target.c (pop_target): Remove. + (pop_all_targets_above): Don't call target_close. + (target_close): Assert that the target is unpushed. + * target.h (pop_target): Don't declare. + * tracepoint.c (tfile_open): Use unpush_target. + +2013-07-25 Tom Tromey + * linux-thread-db.c (init_thread_db_ops): Call complete_target_initialization. (_initialize_thread_db): Don't call add_target. diff --git a/gdb/bfd-target.c b/gdb/bfd-target.c index a7dee24..8d09831 100644 --- a/gdb/bfd-target.c +++ b/gdb/bfd-target.c @@ -96,6 +96,7 @@ target_bfd_reopen (struct bfd *abfd) t->to_xfer_partial = target_bfd_xfer_partial; t->to_xclose = target_bfd_xclose; t->to_data = data; + t->to_magic = OPS_MAGIC; return t; } diff --git a/gdb/monitor.c b/gdb/monitor.c index beca4e4..3eb2249 100644 --- a/gdb/monitor.c +++ b/gdb/monitor.c @@ -877,7 +877,7 @@ monitor_close (void) static void monitor_detach (struct target_ops *ops, char *args, int from_tty) { - pop_target (); /* calls monitor_close to do the real work. */ + unpush_target (ops); /* calls monitor_close to do the real work. */ if (from_tty) printf_unfiltered (_("Ending remote %s debugging\n"), target_shortname); } diff --git a/gdb/remote-m32r-sdi.c b/gdb/remote-m32r-sdi.c index 2f910e6..81fea53 100644 --- a/gdb/remote-m32r-sdi.c +++ b/gdb/remote-m32r-sdi.c @@ -886,7 +886,7 @@ m32r_detach (struct target_ops *ops, char *args, int from_tty) m32r_resume (ops, inferior_ptid, 0, GDB_SIGNAL_0); /* Calls m32r_close to do the real work. */ - pop_target (); + unpush_target (ops); if (from_tty) fprintf_unfiltered (gdb_stdlog, "Ending remote %s debugging\n", target_shortname); diff --git a/gdb/remote-mips.c b/gdb/remote-mips.c index 1619622..13ea146 100644 --- a/gdb/remote-mips.c +++ b/gdb/remote-mips.c @@ -1755,9 +1755,7 @@ mips_detach (struct target_ops *ops, char *args, int from_tty) if (args) error (_("Argument given to \"detach\" when remotely debugging.")); - pop_target (); - - mips_close (); + unpush_target (ops); if (from_tty) printf_unfiltered ("Ending remote MIPS debugging.\n"); diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c index fda3735..d534e56 100644 --- a/gdb/remote-sim.c +++ b/gdb/remote-sim.c @@ -821,7 +821,7 @@ gdbsim_detach (struct target_ops *ops, char *args, int from_tty) if (remote_debug) printf_filtered ("gdbsim_detach: args \"%s\"\n", args); - pop_target (); /* calls gdbsim_close to do the real work */ + unpush_target (ops); /* calls gdbsim_close to do the real work */ if (from_tty) printf_filtered ("Ending simulator %s debugging\n", target_shortname); } diff --git a/gdb/target.c b/gdb/target.c index 37b0a94..e3dcb47 100644 --- a/gdb/target.c +++ b/gdb/target.c @@ -1094,25 +1094,10 @@ unpush_target (struct target_ops *t) } void -pop_target (void) -{ - target_close (target_stack); /* Let it clean up. */ - if (unpush_target (target_stack) == 1) - return; - - fprintf_unfiltered (gdb_stderr, - "pop_target couldn't find target %s\n", - current_target.to_shortname); - internal_error (__FILE__, __LINE__, - _("failed internal consistency check")); -} - -void pop_all_targets_above (enum strata above_stratum) { while ((int) (current_target.to_stratum) > (int) above_stratum) { - target_close (target_stack); if (!unpush_target (target_stack)) { fprintf_unfiltered (gdb_stderr, @@ -3781,6 +3766,8 @@ debug_to_open (char *args, int from_tty) void target_close (struct target_ops *targ) { + gdb_assert (!target_is_pushed (targ)); + if (targ->to_xclose != NULL) targ->to_xclose (targ); else if (targ->to_close != NULL) diff --git a/gdb/target.h b/gdb/target.h index 1cf198f..1d73bcd 100644 --- a/gdb/target.h +++ b/gdb/target.h @@ -1759,9 +1759,7 @@ int target_verify_memory (const gdb_byte *data, unpush_target: Remove this from the stack of currently used targets, no matter where it is on the list. Returns 0 if no - change, 1 if removed from stack. - - pop_target: Remove the top thing on the stack of current targets. */ + change, 1 if removed from stack. */ extern void add_target (struct target_ops *); @@ -1783,8 +1781,6 @@ extern void target_pre_inferior (int); extern void target_preopen (int); -extern void pop_target (void); - /* Does whatever cleanup is required to get rid of all pushed targets. */ extern void pop_all_targets (void); diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c index 054372a..8b70bd3 100644 --- a/gdb/tracepoint.c +++ b/gdb/tracepoint.c @@ -4366,8 +4366,8 @@ tfile_open (char *filename, int from_tty) } if (ex.reason < 0) { - /* Pop the partially set up target. */ - pop_target (); + /* Remove the partially set up target. */ + unpush_target (&tfile_ops); throw_exception (ex); } -- 2.7.4