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[PATCH] solib-svr4: Pass down svr4_info as much as possible (was: [PATCH] Fix "nosharedlibrary + continue + shared lib event" crash)
On 2019-04-10 10:49 p.m., Simon Marchi wrote:
> I am not able to reproduce the problem, and the test doesn't fail here, without
> the rest of the patch applied. I think it's because on my system gdb doesn't use
> the probe based interface.
>
> Anyhow, the fix makes sense. Since the probe is deleted on objfile destruction, the
> corresponding probe_and_action structures should too.
>
> Simon
While reviewing this patch, I had written the patch below to experiment, and
while it's not super important, I think it's a good cleanup.
>From aedf5f7d846672ba6edc2780853baa43f35dd3c4 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Wed, 10 Apr 2019 22:02:33 -0400
Subject: [PATCH] solib-svr4: Pass down svr4_info as much as possible
While reviewing
https://sourceware.org/ml/gdb-patches/2019-04/msg00141.html
I noticed that we relied heavily on global state through the
get_svr4_info function, which uses current_program_space. I thought we
could improve this (make things more explicit and easier to follow) by
- Making get_svr4_info accept a program_space parameter, making it
return the SVR4 info for that program space.
- Passing down the svr4_info object from callers as much as possible.
This means looking up the svr4_info for the appropriate program space at
the entry points of the solib-svr4.c file and passing it down. For now,
these entry points (most of them are "methods" of svr4_so_ops) rely on
current_program_space, but we can later try to change the target_so_ops
interface to pass down the program space.
gdb/ChangeLog:
* solib-svr4.c (get_svr4_info): Add pspace parameter.
(svr4_keep_data_in_core): Pass current_program_space to get_svr4_info.
(open_symbol_file_object): Likewise.
(svr4_default_sos): Add info parameter.
(svr4_read_so_list): Likewise.
(svr4_current_sos_direct): Adjust functions calls to pass down
info.
(svr4_current_sos_1): Add info parameter.
(svr4_current_sos): Call get_svr4_info, pass info down to
svr4_current_sos_1.
(svr4_fetch_objfile_link_map): Pass objfile->pspace to
get_svr4_info.
(svr4_in_dynsym_resolve_code): Pass current_program_space to
get_svr4_info.
(probes_table_htab_remove_objfile_probes): Pass objfile->pspace
to get_svr4_info.
(probes_table_remove_objfile_probes): Likewise.
(register_solib_event_probe): Add info parameter.
(solist_update_incremental): Pass info parameter down to
svr4_read_so_list.
(disable_probes_interface): Add info parameter.
(svr4_handle_solib_event): Pass current_program_space to
get_svr4_info. Adjust disable_probes_interface cleanup.
(svr4_create_probe_breakpoints): Add info parameter, pass it
down to register_solib_event_probe.
(svr4_create_solib_event_breakpoints): Add info parameter,
pass it down to svr4_create_probe_breakpoints.
(enable_break): Pass info down to
svr4_create_solib_event_breakpoints.
(svr4_solib_create_inferior_hook): Pass current_program_space to
get_svr4_info.
(svr4_clear_solib): Likewise.
---
gdb/solib-svr4.c | 84 +++++++++++++++++++++++-------------------------
1 file changed, 41 insertions(+), 43 deletions(-)
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 2c79dfec2bb6..2aa7b95ce6c1 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -391,21 +391,21 @@ svr4_pspace_data_cleanup (struct program_space *pspace, void *arg)
xfree (info);
}
-/* Get the current svr4 data. If none is found yet, add it now. This
- function always returns a valid object. */
+/* Get the svr4 data for program space PSPACE. If none is found yet, add it now.
+ This function always returns a valid object. */
static struct svr4_info *
-get_svr4_info (void)
+get_svr4_info (program_space *pspace)
{
struct svr4_info *info;
- info = (struct svr4_info *) program_space_data (current_program_space,
+ info = (struct svr4_info *) program_space_data (pspace,
solib_svr4_pspace_data);
if (info != NULL)
return info;
info = XCNEW (struct svr4_info);
- set_program_space_data (current_program_space, solib_svr4_pspace_data, info);
+ set_program_space_data (pspace, solib_svr4_pspace_data, info);
return info;
}
@@ -940,7 +940,7 @@ svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
CORE_ADDR ldsomap;
CORE_ADDR name_lm;
- info = get_svr4_info ();
+ info = get_svr4_info (current_program_space);
info->debug_base = 0;
locate_base (info);
@@ -969,7 +969,7 @@ open_symbol_file_object (int from_tty)
struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
int l_name_size = TYPE_LENGTH (ptr_type);
gdb::byte_vector l_name_buf (l_name_size);
- struct svr4_info *info = get_svr4_info ();
+ struct svr4_info *info = get_svr4_info (current_program_space);
symfile_add_flags add_flags = 0;
if (from_tty)
@@ -1264,9 +1264,8 @@ svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
linker, build a fallback list from other sources. */
static struct so_list *
-svr4_default_sos (void)
+svr4_default_sos (svr4_info *info)
{
- struct svr4_info *info = get_svr4_info ();
struct so_list *newobj;
if (!info->debug_loader_offset_p)
@@ -1296,7 +1295,7 @@ svr4_default_sos (void)
represent only part of the inferior library list. */
static int
-svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm,
+svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm,
struct so_list ***link_ptr_ptr, int ignore_first)
{
CORE_ADDR first_l_name = 0;
@@ -1331,8 +1330,6 @@ svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm,
decide when to ignore it. */
if (ignore_first && li->l_prev == 0)
{
- struct svr4_info *info = get_svr4_info ();
-
first_l_name = li->l_name;
info->main_lm_addr = li->lm_addr;
continue;
@@ -1400,7 +1397,7 @@ svr4_current_sos_direct (struct svr4_info *info)
if (library_list.main_lm)
info->main_lm_addr = library_list.main_lm;
- return library_list.head ? library_list.head : svr4_default_sos ();
+ return library_list.head ? library_list.head : svr4_default_sos (info);
}
/* Always locate the debug struct, in case it has moved. */
@@ -1410,7 +1407,7 @@ svr4_current_sos_direct (struct svr4_info *info)
/* If we can't find the dynamic linker's base structure, this
must not be a dynamically linked executable. Hmm. */
if (! info->debug_base)
- return svr4_default_sos ();
+ return svr4_default_sos (info);
/* Assume that everything is a library if the dynamic loader was loaded
late by a static executable. */
@@ -1428,7 +1425,7 @@ svr4_current_sos_direct (struct svr4_info *info)
`struct so_list' nodes. */
lm = solib_svr4_r_map (info);
if (lm)
- svr4_read_so_list (lm, 0, &link_ptr, ignore_first);
+ svr4_read_so_list (info, lm, 0, &link_ptr, ignore_first);
/* On Solaris, the dynamic linker is not in the normal list of
shared objects, so make sure we pick it up too. Having
@@ -1436,12 +1433,12 @@ svr4_current_sos_direct (struct svr4_info *info)
for skipping dynamic linker resolver code. */
lm = solib_svr4_r_ldsomap (info);
if (lm)
- svr4_read_so_list (lm, 0, &link_ptr, 0);
+ svr4_read_so_list (info, lm, 0, &link_ptr, 0);
cleanup.release ();
if (head == NULL)
- return svr4_default_sos ();
+ return svr4_default_sos (info);
return head;
}
@@ -1450,10 +1447,8 @@ svr4_current_sos_direct (struct svr4_info *info)
method. */
static struct so_list *
-svr4_current_sos_1 (void)
+svr4_current_sos_1 (svr4_info *info)
{
- struct svr4_info *info = get_svr4_info ();
-
/* If the solib list has been read and stored by the probes
interface then we return a copy of the stored list. */
if (info->solib_list != NULL)
@@ -1468,7 +1463,8 @@ svr4_current_sos_1 (void)
static struct so_list *
svr4_current_sos (void)
{
- struct so_list *so_head = svr4_current_sos_1 ();
+ svr4_info *info = get_svr4_info (current_program_space);
+ struct so_list *so_head = svr4_current_sos_1 (info);
struct mem_range vsyscall_range;
/* Filter out the vDSO module, if present. Its symbol file would
@@ -1548,7 +1544,7 @@ CORE_ADDR
svr4_fetch_objfile_link_map (struct objfile *objfile)
{
struct so_list *so;
- struct svr4_info *info = get_svr4_info ();
+ struct svr4_info *info = get_svr4_info (objfile->pspace);
/* Cause svr4_current_sos() to be run if it hasn't been already. */
if (info->main_lm_addr == 0)
@@ -1601,7 +1597,7 @@ match_main (const char *soname)
int
svr4_in_dynsym_resolve_code (CORE_ADDR pc)
{
- struct svr4_info *info = get_svr4_info ();
+ struct svr4_info *info = get_svr4_info (current_program_space);
return ((pc >= info->interp_text_sect_low
&& pc < info->interp_text_sect_high)
@@ -1681,7 +1677,7 @@ probes_table_htab_remove_objfile_probes (void **slot, void *info)
struct objfile *objfile = (struct objfile *) info;
if (pa->objfile == objfile)
- htab_clear_slot (get_svr4_info ()->probes_table, slot);
+ htab_clear_slot (get_svr4_info (objfile->pspace)->probes_table, slot);
return 1;
}
@@ -1691,7 +1687,7 @@ probes_table_htab_remove_objfile_probes (void **slot, void *info)
static void
probes_table_remove_objfile_probes (struct objfile *objfile)
{
- svr4_info *info = get_svr4_info ();
+ svr4_info *info = get_svr4_info (objfile->pspace);
if (info->probes_table != nullptr)
htab_traverse_noresize (info->probes_table,
probes_table_htab_remove_objfile_probes, objfile);
@@ -1701,11 +1697,10 @@ probes_table_remove_objfile_probes (struct objfile *objfile)
probes table. */
static void
-register_solib_event_probe (struct objfile *objfile,
+register_solib_event_probe (svr4_info *info, struct objfile *objfile,
probe *prob, CORE_ADDR address,
enum probe_action action)
{
- struct svr4_info *info = get_svr4_info ();
struct probe_and_action lookup, *pa;
void **slot;
@@ -1857,7 +1852,7 @@ solist_update_incremental (struct svr4_info *info, CORE_ADDR lm)
above check and deferral to solist_update_full ensures
that this call to svr4_read_so_list will never see the
first element. */
- if (!svr4_read_so_list (lm, prev_lm, &link, 0))
+ if (!svr4_read_so_list (info, lm, prev_lm, &link, 0))
return 0;
}
@@ -1869,10 +1864,8 @@ solist_update_incremental (struct svr4_info *info, CORE_ADDR lm)
ones set up for the probes-based interface are adequate. */
static void
-disable_probes_interface ()
+disable_probes_interface (svr4_info *info)
{
- struct svr4_info *info = get_svr4_info ();
-
warning (_("Probes-based dynamic linker interface failed.\n"
"Reverting to original interface.\n"));
@@ -1887,7 +1880,7 @@ disable_probes_interface ()
static void
svr4_handle_solib_event (void)
{
- struct svr4_info *info = get_svr4_info ();
+ struct svr4_info *info = get_svr4_info (current_program_space);
struct probe_and_action *pa;
enum probe_action action;
struct value *val = NULL;
@@ -1900,7 +1893,10 @@ svr4_handle_solib_event (void)
/* If anything goes wrong we revert to the original linker
interface. */
- auto cleanup = make_scope_exit (disable_probes_interface);
+ auto cleanup = make_scope_exit ([info] ()
+ {
+ disable_probes_interface (info);
+ });
pc = regcache_read_pc (get_current_regcache ());
pa = solib_event_probe_at (info, pc);
@@ -2055,7 +2051,7 @@ svr4_update_solib_event_breakpoints (void)
probe. */
static void
-svr4_create_probe_breakpoints (struct gdbarch *gdbarch,
+svr4_create_probe_breakpoints (svr4_info *info, struct gdbarch *gdbarch,
const std::vector<probe *> *probes,
struct objfile *objfile)
{
@@ -2068,7 +2064,7 @@ svr4_create_probe_breakpoints (struct gdbarch *gdbarch,
CORE_ADDR address = p->get_relocated_address (objfile);
create_solib_event_breakpoint (gdbarch, address);
- register_solib_event_probe (objfile, p, address, action);
+ register_solib_event_probe (info, objfile, p, address, action);
}
}
@@ -2088,7 +2084,7 @@ svr4_create_probe_breakpoints (struct gdbarch *gdbarch,
marker function. */
static void
-svr4_create_solib_event_breakpoints (struct gdbarch *gdbarch,
+svr4_create_solib_event_breakpoints (svr4_info *info, struct gdbarch *gdbarch,
CORE_ADDR address)
{
struct obj_section *os;
@@ -2151,7 +2147,7 @@ svr4_create_solib_event_breakpoints (struct gdbarch *gdbarch,
}
if (all_probes_found)
- svr4_create_probe_breakpoints (gdbarch, probes, os->objfile);
+ svr4_create_probe_breakpoints (info, gdbarch, probes, os->objfile);
if (all_probes_found)
return;
@@ -2282,7 +2278,7 @@ enable_break (struct svr4_info *info, int from_tty)
+ bfd_section_size (tmp_bfd, interp_sect);
}
- svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (), sym_addr);
return 1;
}
}
@@ -2444,7 +2440,7 @@ enable_break (struct svr4_info *info, int from_tty)
if (sym_addr != 0)
{
- svr4_create_solib_event_breakpoints (target_gdbarch (),
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
load_addr + sym_addr);
return 1;
}
@@ -2470,7 +2466,8 @@ enable_break (struct svr4_info *info, int from_tty)
sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
sym_addr,
current_top_target ());
- svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
+ sym_addr);
return 1;
}
}
@@ -2487,7 +2484,8 @@ enable_break (struct svr4_info *info, int from_tty)
sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
sym_addr,
current_top_target ());
- svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
+ sym_addr);
return 1;
}
}
@@ -3010,7 +3008,7 @@ svr4_solib_create_inferior_hook (int from_tty)
{
struct svr4_info *info;
- info = get_svr4_info ();
+ info = get_svr4_info (current_program_space);
/* Clear the probes-based interface's state. */
free_probes_table (info);
@@ -3036,7 +3034,7 @@ svr4_clear_solib (void)
{
struct svr4_info *info;
- info = get_svr4_info ();
+ info = get_svr4_info (current_program_space);
info->debug_base = 0;
info->debug_loader_offset_p = 0;
info->debug_loader_offset = 0;
--
2.21.0