From: Aaron Merey <amerey@redhat.com>
To: Aaron Merey <amerey@redhat.com>
Cc: lsix@lancelotsix.com, Simon Marchi <simon.marchi@polymtl.ca>,
Tom Tromey <tom@tromey.com>,
gdb-patches@sourceware.org
Subject: [PING**2][PATCH 2/3] gdb: Add soname to build-id mapping for corefiles
Date: Mon, 18 Oct 2021 19:06:35 -0400 [thread overview]
Message-ID: <CAJDtP-R=Ukmf+Hn2XqoLXAc=hf0rYW5cgeBJW2kBOrAkGexNNA@mail.gmail.com> (raw)
In-Reply-To: <CAJDtP-S85WS3PuJ3cu44DurFCvOTTddFsNTRpzz+yCGQsXbZcA@mail.gmail.com>
Ping
Thanks,
Aaron
On Tue, Sep 28, 2021 at 9:12 PM Aaron Merey <amerey@redhat.com> wrote:
>
> Ping.
>
> Thanks,
> Aaron
>
> On Wed, Aug 18, 2021 at 10:22 PM Aaron Merey via Gdb-patches
> <gdb-patches@sourceware.org> wrote:
> >
> > Hi Lancelot and Simon,
> >
> > Thanks for the reviews. The updated patch is included below.
> >
> > On Tue, Aug 17, 2021 at 9:59 AM Simon Marchi <simon.marchi@polymtl.ca> wrote:
> > >>> + /* Check that bfd is an ET_DYN ELF file. */
> > >>> + bfd_check_format (abfd.get (), bfd_object);
> > >
> > > I asked this in my previous review, still applies here:
> > >
> > > What's the point of calling bfd_check_format without checking the
> > > result? It looks like a function without side-effects.
> >
> > I included a few comments in the [PATCH 0/3] email for this series[1].
> > I mentioned that for some reason bfd_check_format appears to update
> > the bfd 'flags' field with the correct value. If bfd_check_format is not
> > called here the check for the DYNAMIC flag fails even for ET_DYN files.
> >
> > [1] https://sourceware.org/pipermail/gdb-patches/2021-August/181416.html
> >
> > ---
> > gdb/arch-utils.c | 15 +++++----------
> > gdb/arch-utils.h | 23 +++++++++++++----------
> > gdb/build-id.h | 2 ++
> > gdb/corelow.c | 13 ++++++++++++-
> > gdb/gdbarch.c | 2 +-
> > gdb/gdbarch.h | 4 ++--
> > gdb/gdbarch.sh | 2 +-
> > gdb/linux-tdep.c | 46 ++++++++++++++++++++++++++++++++++------------
> > gdb/progspace.c | 32 ++++++++++++++++++++++++++++++++
> > gdb/progspace.h | 17 +++++++++++++++++
> > gdb/solib.c | 35 +++++++++++++++++++++++++++++++++++
> > gdb/solib.h | 5 +++++
> > 12 files changed, 159 insertions(+), 37 deletions(-)
> >
> > diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
> > index 862f26b6cf7..ffb32cb203f 100644
> > --- a/gdb/arch-utils.c
> > +++ b/gdb/arch-utils.c
> > @@ -1075,16 +1075,11 @@ default_get_pc_address_flags (frame_info *frame, CORE_ADDR pc)
> >
> > /* See arch-utils.h. */
> > void
> > -default_read_core_file_mappings (struct gdbarch *gdbarch,
> > - struct bfd *cbfd,
> > - gdb::function_view<void (ULONGEST count)>
> > - pre_loop_cb,
> > - gdb::function_view<void (int num,
> > - ULONGEST start,
> > - ULONGEST end,
> > - ULONGEST file_ofs,
> > - const char *filename)>
> > - loop_cb)
> > +default_read_core_file_mappings
> > + (struct gdbarch *gdbarch,
> > + struct bfd *cbfd,
> > + gdb::function_view<void (ULONGEST count)> pre_loop_cb,
> > + loop_cb_ftype loop_cb)
> > {
> > }
> >
> > diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
> > index 03e9082f6d7..2243c3fb85b 100644
> > --- a/gdb/arch-utils.h
> > +++ b/gdb/arch-utils.h
> > @@ -294,15 +294,18 @@ extern ULONGEST default_type_align (struct gdbarch *gdbarch,
> > extern std::string default_get_pc_address_flags (frame_info *frame,
> > CORE_ADDR pc);
> >
> > +
> > +using loop_cb_ftype = gdb::function_view<void (int num,
> > + ULONGEST start,
> > + ULONGEST end,
> > + ULONGEST file_ofs,
> > + const char *filename,
> > + const bfd_build_id *build_id)>;
> > +
> > /* Default implementation of gdbarch read_core_file_mappings method. */
> > -extern void default_read_core_file_mappings (struct gdbarch *gdbarch,
> > - struct bfd *cbfd,
> > - gdb::function_view<void (ULONGEST count)>
> > - pre_loop_cb,
> > - gdb::function_view<void (int num,
> > - ULONGEST start,
> > - ULONGEST end,
> > - ULONGEST file_ofs,
> > - const char *filename)>
> > - loop_cb);
> > +extern void default_read_core_file_mappings
> > + (struct gdbarch *gdbarch,
> > + struct bfd *cbfd,
> > + gdb::function_view<void (ULONGEST count)> pre_loop_cb,
> > + loop_cb_ftype loop_cb);
> > #endif /* ARCH_UTILS_H */
> > diff --git a/gdb/build-id.h b/gdb/build-id.h
> > index 42f8d57ede1..3c9402ee71b 100644
> > --- a/gdb/build-id.h
> > +++ b/gdb/build-id.h
> > @@ -20,8 +20,10 @@
> > #ifndef BUILD_ID_H
> > #define BUILD_ID_H
> >
> > +#include "defs.h"
> > #include "gdb_bfd.h"
> > #include "gdbsupport/rsp-low.h"
> > +#include <string>
> >
> > /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
> >
> > diff --git a/gdb/corelow.c b/gdb/corelow.c
> > index eb785a08633..31af0f22584 100644
> > --- a/gdb/corelow.c
> > +++ b/gdb/corelow.c
> > @@ -214,7 +214,7 @@ core_target::build_file_mappings ()
> > /* read_core_file_mappings will invoke this lambda for each mapping
> > that it finds. */
> > [&] (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs,
> > - const char *filename)
> > + const char *filename, const bfd_build_id *build_id)
> > {
> > /* Architecture-specific read_core_mapping methods are expected to
> > weed out non-file-backed mappings. */
> > @@ -282,6 +282,16 @@ core_target::build_file_mappings ()
> >
> > /* Set target_section fields. */
> > m_core_file_mappings.emplace_back (start, end, sec);
> > +
> > + /* If this is a bfd of a shared library, record its soname
> > + and build id. */
> > + if (build_id != nullptr)
> > + {
> > + gdb::optional<std::string> soname = gdb_bfd_read_elf_soname (bfd);
> > + if (soname)
> > + current_program_space->set_cbfd_soname_build_id
> > + (std::move (*soname), build_id);
> > + }
> > });
> >
> > normalize_mem_ranges (&m_core_unavailable_mappings);
> > @@ -305,6 +315,7 @@ core_target::close ()
> > comments in clear_solib in solib.c. */
> > clear_solib ();
> >
> > + current_program_space->clear_cbfd_soname_build_ids ();
> > current_program_space->cbfd.reset (nullptr);
> > }
> >
> > diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
> > index f89dcc57754..35464115039 100644
> > --- a/gdb/gdbarch.c
> > +++ b/gdb/gdbarch.c
> > @@ -5411,7 +5411,7 @@ set_gdbarch_get_pc_address_flags (struct gdbarch *gdbarch,
> > }
> >
> > void
> > -gdbarch_read_core_file_mappings (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename)> loop_cb)
> > +gdbarch_read_core_file_mappings (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename, const bfd_build_id *build_id)> loop_cb)
> > {
> > gdb_assert (gdbarch != NULL);
> > gdb_assert (gdbarch->read_core_file_mappings != NULL);
> > diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
> > index 979159ba2f5..baf80580d60 100644
> > --- a/gdb/gdbarch.h
> > +++ b/gdb/gdbarch.h
> > @@ -1710,8 +1710,8 @@ extern void set_gdbarch_get_pc_address_flags (struct gdbarch *gdbarch, gdbarch_g
> >
> > /* Read core file mappings */
> >
> > -typedef void (gdbarch_read_core_file_mappings_ftype) (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename)> loop_cb);
> > -extern void gdbarch_read_core_file_mappings (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename)> loop_cb);
> > +typedef void (gdbarch_read_core_file_mappings_ftype) (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename, const bfd_build_id *build_id)> loop_cb);
> > +extern void gdbarch_read_core_file_mappings (struct gdbarch *gdbarch, struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename, const bfd_build_id *build_id)> loop_cb);
> > extern void set_gdbarch_read_core_file_mappings (struct gdbarch *gdbarch, gdbarch_read_core_file_mappings_ftype *read_core_file_mappings);
> >
> > extern struct gdbarch_tdep *gdbarch_tdep (struct gdbarch *gdbarch);
> > diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
> > index 39a99d0d5f3..c24079d34f3 100755
> > --- a/gdb/gdbarch.sh
> > +++ b/gdb/gdbarch.sh
> > @@ -1210,7 +1210,7 @@ m;ULONGEST;type_align;struct type *type;type;;default_type_align;;0
> > f;std::string;get_pc_address_flags;frame_info *frame, CORE_ADDR pc;frame, pc;;default_get_pc_address_flags;;0
> >
> > # Read core file mappings
> > -m;void;read_core_file_mappings;struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename)> loop_cb;cbfd, pre_loop_cb, loop_cb;;default_read_core_file_mappings;;0
> > +m;void;read_core_file_mappings;struct bfd *cbfd, gdb::function_view<void (ULONGEST count)> pre_loop_cb, gdb::function_view<void (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs, const char *filename, const bfd_build_id *build_id)> loop_cb;cbfd, pre_loop_cb, loop_cb;;default_read_core_file_mappings;;0
> >
> > EOF
> > }
> > diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
> > index ae2f7c14f6d..812ca1f99bf 100644
> > --- a/gdb/linux-tdep.c
> > +++ b/gdb/linux-tdep.c
> > @@ -44,6 +44,7 @@
> > #include "solib-svr4.h"
> >
> > #include <ctype.h>
> > +#include <unordered_map>
> >
> > /* This enum represents the values that the user can choose when
> > informing the Linux kernel about which memory mappings will be
> > @@ -1097,16 +1098,11 @@ linux_info_proc (struct gdbarch *gdbarch, const char *args,
> > for each mapping. */
> >
> > static void
> > -linux_read_core_file_mappings (struct gdbarch *gdbarch,
> > - struct bfd *cbfd,
> > - gdb::function_view<void (ULONGEST count)>
> > - pre_loop_cb,
> > - gdb::function_view<void (int num,
> > - ULONGEST start,
> > - ULONGEST end,
> > - ULONGEST file_ofs,
> > - const char *filename)>
> > - loop_cb)
> > +linux_read_core_file_mappings
> > + (struct gdbarch *gdbarch,
> > + struct bfd *cbfd,
> > + gdb::function_view<void (ULONGEST count)> pre_loop_cb,
> > + loop_cb_ftype loop_cb)
> > {
> > /* Ensure that ULONGEST is big enough for reading 64-bit core files. */
> > gdb_static_assert (sizeof (ULONGEST) >= 8);
> > @@ -1175,6 +1171,23 @@ linux_read_core_file_mappings (struct gdbarch *gdbarch,
> > if (f != descend)
> > warning (_("malformed note - filename area is too big"));
> >
> > + const bfd_build_id *orig_build_id = cbfd->build_id;
> > + std::unordered_map<ULONGEST, const bfd_build_id *> vma_map;
> > + std::unordered_map<char *, const bfd_build_id *> filename_map;
> > +
> > + /* Search for solib build-ids in the core file. Each time one is found,
> > + map the start vma of the corresponding elf header to the build-id. */
> > + for (bfd_section *sec = cbfd->sections; sec != nullptr; sec = sec->next)
> > + {
> > + cbfd->build_id = nullptr;
> > +
> > + if (sec->flags & SEC_LOAD
> > + && get_elf_backend_data (cbfd)->elf_backend_core_find_build_id
> > + (cbfd, (bfd_vma) sec->filepos))
> > + vma_map[sec->vma] = cbfd->build_id;
> > + }
> > +
> > + cbfd->build_id = orig_build_id;
> > pre_loop_cb (count);
> >
> > for (int i = 0; i < count; i++)
> > @@ -1188,8 +1201,17 @@ linux_read_core_file_mappings (struct gdbarch *gdbarch,
> > descdata += addr_size;
> > char * filename = filenames;
> > filenames += strlen ((char *) filenames) + 1;
> > + const bfd_build_id *build_id = vma_map[start];
> > +
> > + /* Map filename to the build-id associated with this start vma,
> > + if such a build-id was found. Otherwise use the build-id
> > + already associated with this filename if it exists. */
> > + if (build_id != nullptr)
> > + filename_map[filename] = build_id;
> > + else
> > + build_id = filename_map[filename];
> >
> > - loop_cb (i, start, end, file_ofs, filename);
> > + loop_cb (i, start, end, file_ofs, filename, build_id);
> > }
> > }
> >
> > @@ -1218,7 +1240,7 @@ linux_core_info_proc_mappings (struct gdbarch *gdbarch, const char *args)
> > }
> > },
> > [=] (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs,
> > - const char *filename)
> > + const char *filename, const bfd_build_id *build_id)
> > {
> > if (gdbarch_addr_bit (gdbarch) == 32)
> > printf_filtered ("\t%10s %10s %10s %10s %s\n",
> > diff --git a/gdb/progspace.c b/gdb/progspace.c
> > index 7080bf8ee27..8b7b949d959 100644
> > --- a/gdb/progspace.c
> > +++ b/gdb/progspace.c
> > @@ -17,6 +17,7 @@
> > You should have received a copy of the GNU General Public License
> > along with this program. If not, see <http://www.gnu.org/licenses/>. */
> >
> > +#include "build-id.h"
> > #include "defs.h"
> > #include "gdbcmd.h"
> > #include "objfiles.h"
> > @@ -358,6 +359,37 @@ print_program_space (struct ui_out *uiout, int requested)
> > }
> > }
> >
> > +/* See progspace.h. */
> > +
> > +void
> > +program_space::set_cbfd_soname_build_id (std::string soname,
> > + const bfd_build_id *build_id)
> > +{
> > + cbfd_soname_to_build_id[std::move (soname)] = build_id_to_string (build_id);
> > +}
> > +
> > +/* See progspace.h. */
> > +
> > +const char *
> > +program_space::get_cbfd_soname_build_id (const char *soname)
> > +{
> > + gdb_assert (soname);
> > +
> > + auto it = cbfd_soname_to_build_id.find (basename (soname));
> > + if (it == cbfd_soname_to_build_id.end ())
> > + return nullptr;
> > +
> > + return it->second.c_str ();
> > +}
> > +
> > +/* See progspace.h. */
> > +
> > +void
> > +program_space::clear_cbfd_soname_build_ids ()
> > +{
> > + cbfd_soname_to_build_id.clear ();
> > +}
> > +
> > /* Boolean test for an already-known program space id. */
> >
> > static int
> > diff --git a/gdb/progspace.h b/gdb/progspace.h
> > index fb348ca7539..b42b3ffc4f1 100644
> > --- a/gdb/progspace.h
> > +++ b/gdb/progspace.h
> > @@ -30,6 +30,7 @@
> > #include "gdbsupport/safe-iterator.h"
> > #include <list>
> > #include <vector>
> > +#include <unordered_map>
> >
> > struct target_ops;
> > struct bfd;
> > @@ -324,6 +325,19 @@ struct program_space
> > /* Binary file diddling handle for the core file. */
> > gdb_bfd_ref_ptr cbfd;
> >
> > + /* Associate a core file SONAME with BUILD_ID so that it can be retrieved
> > + with get_cbfd_soname_build_id. */
> > + void set_cbfd_soname_build_id (std::string soname,
> > + const bfd_build_id *build_id);
> > +
> > + /* If a core file SONAME had a build-id associated with it by a previous
> > + call to set_cbfd_soname_build_id then return the build-id as a
> > + NULL-terminated hex string. */
> > + const char *get_cbfd_soname_build_id (const char *soname);
> > +
> > + /* Clear all core file soname to build-id mappings. */
> > + void clear_cbfd_soname_build_ids ();
> > +
> > /* The address space attached to this program space. More than one
> > program space may be bound to the same address space. In the
> > traditional unix-like debugging scenario, this will usually
> > @@ -378,6 +392,9 @@ struct program_space
> > /* The set of target sections matching the sections mapped into
> > this program space. Managed by both exec_ops and solib.c. */
> > target_section_table m_target_sections;
> > +
> > + /* Mapping of a core file's library sonames to their respective build-ids. */
> > + std::unordered_map<std::string, std::string> cbfd_soname_to_build_id;
> > };
> >
> > /* An address space. It is used for comparing if
> > diff --git a/gdb/solib.c b/gdb/solib.c
> > index e30affbb7e7..1b99c8ab985 100644
> > --- a/gdb/solib.c
> > +++ b/gdb/solib.c
> > @@ -23,6 +23,7 @@
> > #include <fcntl.h>
> > #include "symtab.h"
> > #include "bfd.h"
> > +#include "build-id.h"
> > #include "symfile.h"
> > #include "objfiles.h"
> > #include "gdbcore.h"
> > @@ -1585,6 +1586,40 @@ gdb_bfd_scan_elf_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr,
> > return 0;
> > }
> >
> > +/* See solib.h. */
> > +
> > +gdb::optional<std::string>
> > +gdb_bfd_read_elf_soname (struct bfd *bfd)
> > +{
> > + gdb_assert (bfd != nullptr);
> > +
> > + gdb_bfd_ref_ptr abfd = gdb_bfd_open (bfd->filename, gnutarget);
> > +
> > + if (abfd == nullptr)
> > + return {};
> > +
> > + /* Check that bfd is an ET_DYN ELF file. */
> > + bfd_check_format (abfd.get (), bfd_object);
> > + if (!(bfd_get_file_flags (abfd.get ()) & DYNAMIC))
> > + return {};
> > +
> > + /* Determine soname of shared library. If found map soname to build-id. */
> > + CORE_ADDR idx;
> > + if (!gdb_bfd_scan_elf_dyntag (DT_SONAME, abfd.get (), &idx, nullptr))
> > + return {};
> > +
> > + struct bfd_section *dynstr = bfd_get_section_by_name (abfd.get (), ".dynstr");
> > + if (dynstr == nullptr || bfd_section_size (dynstr) <= idx)
> > + return {};
> > +
> > + /* Read the soname from the string table. */
> > + gdb::byte_vector dynstr_buf;
> > + if (!gdb_bfd_get_full_section_contents (abfd.get (), dynstr, &dynstr_buf))
> > + return {};
> > +
> > + return std::string ((const char *)dynstr_buf.data () + idx);
> > +}
> > +
> > /* Lookup the value for a specific symbol from symbol table. Look up symbol
> > from ABFD. MATCH_SYM is a callback function to determine whether to pick
> > up a symbol. DATA is the input of this callback function. Return NULL
> > diff --git a/gdb/solib.h b/gdb/solib.h
> > index c50f74e06bf..51cc047463f 100644
> > --- a/gdb/solib.h
> > +++ b/gdb/solib.h
> > @@ -118,6 +118,11 @@ extern CORE_ADDR gdb_bfd_lookup_symbol_from_symtab (bfd *abfd,
> > extern int gdb_bfd_scan_elf_dyntag (const int desired_dyntag, bfd *abfd,
> > CORE_ADDR *ptr, CORE_ADDR *ptr_addr);
> >
> > +/* If BFD is an ELF shared object then attempt to return the string
> > + referred to by its DT_SONAME tag. */
> > +
> > +extern gdb::optional<std::string> gdb_bfd_read_elf_soname (struct bfd *bfd);
> > +
> > /* Enable or disable optional solib event breakpoints as appropriate. */
> >
> > extern void update_solib_breakpoints (void);
> > --
> > 2.31.1
> >
next prev parent reply other threads:[~2021-10-18 23:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 4:24 [PATCH v3 0/3] Add debuginfod core file support Aaron Merey
2021-08-12 4:24 ` [PATCH 1/3] gdb/solib: Refactor scan_dyntag Aaron Merey
2021-08-17 13:28 ` Simon Marchi
2021-08-19 2:30 ` Aaron Merey
2021-08-12 4:24 ` [PATCH 2/3] gdb: Add soname to build-id mapping for corefiles Aaron Merey
2021-08-15 14:51 ` Lancelot SIX
2021-08-17 13:58 ` Simon Marchi
2021-08-19 2:22 ` Aaron Merey
2021-09-29 1:12 ` Aaron Merey
2021-10-18 23:06 ` Aaron Merey [this message]
2021-11-03 18:12 ` [PING**3][PATCH " Aaron Merey
2021-11-04 1:32 ` [PATCH " Simon Marchi
2021-08-12 4:24 ` [PATCH 3/3] PR gdb/27570: missing support for debuginfod in core_target::build_file_mappings Aaron Merey
2021-09-29 1:13 ` Aaron Merey
2021-10-18 23:05 ` [PING**2][PATCH " Aaron Merey
2021-11-03 18:11 ` [PING**3][PATCH " Aaron Merey
2021-11-04 1:37 ` [PATCH " Simon Marchi
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