[PATCH] Allow gdb to find debug symbols file by build-id for PE file format also

Jon Turney
2015-06-10T14:26:49Z

This promotes BFD's struct elf_build_id to the generic struct bfd_build_id,
populated when an ELF or PE BFD is read.

gdb is updated to use that, and to use the build-id to find symbols for PE files
also.

There is currently no generic way to extract the build-id from an object file,
perhaps an option to objdump to do this might make sense?

On x86_64-pc-cygwin, gdb's sepdebug.exp changes:

-# of unsupported tests 1
+# of expected passes 90

I don't seem to get consistent testsuite runs on i686-linux-gnu, but there
don't appear to be any regressions.

bfd/ChangeLog:

2015-06-10 Jon Turney <jon.turney@dronecode.org.uk>

* elf-bfd.h : Remove struct elf_build_id.
* bfd.c : Add struct bfd_build_id.
* bfd-in2.h: Regenerate.
* elf.c (elfobj_grok_gnu_build_id): Update to use bfd_build_id.
* libpei.h: Add protoype and macros for
bfd_XXi_slurp_codeview_record.
* peXXigen.c (_bfd_XXi_slurp_codeview_record): Make public
* peicode.h (pe_bfd_read_buildid): Add.
(pe_bfd_object_p): Use pe_bfd_read_buildid().

gdb/ChangeLog:

2015-06-10 Jon Turney <jon.turney@dronecode.org.uk>

* build-id.c: Don't include elf-bfd.h.
(build_id_bfd_get): Use bfd_build_id.
(build_id_verify): Ditto.
* build-id.h: Ditto.
(find_separate_debug_file_by_buildid): Ditto.
* python/py-objfile.c: Don't include elf-bfd.h.
(objfpy_get_build_id) Use bfd_build_id.
(objfpy_build_id_matches, objfpy_lookup_objfile_by_build_id): Ditto.
* coffread.c: Include build-id.h.
(coff_symfile_read): Try find_separate_debug_file_by_buildid.

gdb/doc/ChangeLog:

2015-06-10 Jon Turney <jon.turney@dronecode.org.uk>

* gdb.texinfo (Separate Debug Files): Document that PE is also
supported.

gdb/testsuite/ChangeLog:

2015-06-10 Jon Turney <jon.turney@dronecode.org.uk>

* gdb.base/sepdebug.exp: Add EXEEXT where needed.
* lib/gdb.exp (get_build_id): Teach how to extract build-id from a
PE file.
* lib/future.exp (gdb_find_objdump): Add gdb_find_objdump.

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
---
bfd/ChangeLog | 12 +++++
bfd/bfd-in2.h | 9 ++++
bfd/bfd.c | 9 ++++
bfd/elf-bfd.h | 10 ----
bfd/elf.c | 12 ++---
bfd/libpei.h | 4 ++
bfd/peXXigen.c | 2 +-
bfd/peicode.h | 100 ++++++++++++++++++++++++++++++++++--
gdb/ChangeLog | 13 +++++
gdb/build-id.c | 21 ++++----
gdb/build-id.h | 2 +-
gdb/coffread.c | 6 ++-
gdb/doc/ChangeLog | 5 ++
gdb/doc/gdb.texinfo | 2 +-
gdb/python/py-objfile.c | 7 ++-
gdb/testsuite/ChangeLog | 7 +++
gdb/testsuite/gdb.base/sepdebug.exp | 12 ++---
gdb/testsuite/lib/future.exp | 11 ++++
gdb/testsuite/lib/gdb.exp | 53 +++++++++++--------
19 files changed, 231 insertions(+), 66 deletions(-)

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 09331bd..c98e4bd 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -6322,6 +6322,12 @@ enum bfd_plugin_format
bfd_plugin_no = 2
};

+struct bfd_build_id
+ {
+ size_t size;
+ bfd_byte data[1];
+ };
+
struct bfd
{
/* The filename the application opened the BFD with. */
@@ -6606,6 +6612,9 @@ struct bfd
struct objalloc *, but we use void * to avoid requiring the inclusion
of objalloc.h. */
void *memory;
+
+ /* For input BFDs, the build ID, if the object has one. */
+ const struct bfd_build_id *build_id;
};

/* See note beside bfd_set_section_userdata. */
diff --git a/bfd/bfd.c b/bfd/bfd.c
index ab410cb..e60f358 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -51,6 +51,12 @@ CODE_FRAGMENT
. bfd_plugin_no = 2
. };
.
+.struct bfd_build_id
+. {
+. size_t size;
+. bfd_byte data[1];
+. };
+.
.struct bfd
.{
. {* The filename the application opened the BFD with. *}
@@ -335,6 +341,9 @@ CODE_FRAGMENT
. struct objalloc *, but we use void * to avoid requiring the inclusion
. of objalloc.h. *}
. void *memory;
+.
+. {* For input BFDs, the build ID, if the object has one. *}
+. const struct bfd_build_id *build_id;
.};
.
.{* See note beside bfd_set_section_userdata. *}
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 9807fe7..1127b7e 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -1563,13 +1563,6 @@ struct sdt_note
bfd_byte data[1];
};

-/* NT_GNU_BUILD_ID note type info for input BFDs. */
-struct elf_build_id
-{
- size_t size;
- bfd_byte data[1];
-};
-
/* tdata information grabbed from an elf core file. */
struct core_elf_obj_tdata
{
@@ -1704,9 +1697,6 @@ struct elf_obj_tdata
obj_attribute known_obj_attributes[2][NUM_KNOWN_OBJ_ATTRIBUTES];
obj_attribute_list *other_obj_attributes[2];

- /* NT_GNU_BUILD_ID note type. */
- struct elf_build_id *build_id;
-
/* Linked-list containing information about every Systemtap section
found in the object file. Each section corresponds to one entry
in the list. */
diff --git a/bfd/elf.c b/bfd/elf.c
index 619a640..47638f4 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -9116,18 +9116,18 @@ elfcore_grok_note (bfd *abfd, Elf_Internal_Note *note)
static bfd_boolean
elfobj_grok_gnu_build_id (bfd *abfd, Elf_Internal_Note *note)
{
- struct elf_obj_tdata *t;
+ struct bfd_build_id* build_id;

if (note->descsz == 0)
return FALSE;

- t = elf_tdata (abfd);
- t->build_id = bfd_alloc (abfd, sizeof (*t->build_id) - 1 + note->descsz);
- if (t->build_id == NULL)
+ build_id = bfd_alloc (abfd, sizeof (struct bfd_build_id) - 1 + note->descsz);
+ if (build_id == NULL)
return FALSE;

- t->build_id->size = note->descsz;
- memcpy (t->build_id->data, note->descdata, note->descsz);
+ build_id->size = note->descsz;
+ memcpy (build_id->data, note->descdata, note->descsz);
+ abfd->build_id = build_id;

return TRUE;
}
diff --git a/bfd/libpei.h b/bfd/libpei.h
index d19a3b2..a6f3da0 100644
--- a/bfd/libpei.h
+++ b/bfd/libpei.h
@@ -238,6 +238,7 @@
#define _bfd_XXi_swap_debugdir_in _bfd_pex64i_swap_debugdir_in
#define _bfd_XXi_swap_debugdir_out _bfd_pex64i_swap_debugdir_out
#define _bfd_XXi_write_codeview_record _bfd_pex64i_write_codeview_record
+#define _bfd_XXi_slurp_codeview_record _bfd_pex64i_slurp_codeview_record

#elif defined COFF_WITH_pep

@@ -272,6 +273,7 @@
#define _bfd_XXi_swap_debugdir_in _bfd_pepi_swap_debugdir_in
#define _bfd_XXi_swap_debugdir_out _bfd_pepi_swap_debugdir_out
#define _bfd_XXi_write_codeview_record _bfd_pepi_write_codeview_record
+#define _bfd_XXi_slurp_codeview_record _bfd_pepi_slurp_codeview_record

#else /* !COFF_WITH_pep */

@@ -306,6 +308,7 @@
#define _bfd_XXi_swap_debugdir_in _bfd_pei_swap_debugdir_in
#define _bfd_XXi_swap_debugdir_out _bfd_pei_swap_debugdir_out
#define _bfd_XXi_write_codeview_record _bfd_pei_write_codeview_record
+#define _bfd_XXi_slurp_codeview_record _bfd_pei_slurp_codeview_record

#endif /* !COFF_WITH_pep */

@@ -351,6 +354,7 @@ bfd_boolean _bfd_XXi_final_link_postscript (bfd *, struct coff_final_link_info *
void _bfd_XXi_swap_debugdir_in (bfd *, void *, void *);
unsigned _bfd_XXi_swap_debugdir_out (bfd *, void *, void *);
unsigned _bfd_XXi_write_codeview_record (bfd *, file_ptr, CODEVIEW_INFO *);
+CODEVIEW_INFO * _bfd_XXi_slurp_codeview_record (bfd * abfd, file_ptr where, unsigned long length, CODEVIEW_INFO *cvinfo);

/* The following are needed only for ONE of pe or pei, but don't
otherwise vary; peicode.h fixes up ifdefs but we provide the
diff --git a/bfd/peXXigen.c b/bfd/peXXigen.c
index c897c64..d209b50 100644
--- a/bfd/peXXigen.c
+++ b/bfd/peXXigen.c
@@ -1140,7 +1140,7 @@ _bfd_XXi_swap_debugdir_out (bfd * abfd, void * inp, void * extp)
return sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
}

-static CODEVIEW_INFO *
+CODEVIEW_INFO *
_bfd_XXi_slurp_codeview_record (bfd * abfd, file_ptr where, unsigned long length, CODEVIEW_INFO *cvinfo)
{
char buffer[256+1];
diff --git a/bfd/peicode.h b/bfd/peicode.h
index 200ef5e..06bcaa9 100644
--- a/bfd/peicode.h
+++ b/bfd/peicode.h
@@ -1255,6 +1255,87 @@ pe_ILF_object_p (bfd * abfd)
return abfd->xvec;
}

+static void
+pe_bfd_read_buildid(bfd *abfd)
+{
+ pe_data_type *pe = pe_data (abfd);
+ struct internal_extra_pe_aouthdr *extra = &pe->pe_opthdr;
+ asection *section;
+ bfd_byte *data = 0;
+ bfd_size_type dataoff;
+ unsigned int i;
+
+ bfd_vma addr = extra->DataDirectory[PE_DEBUG_DATA].VirtualAddress;
+ bfd_size_type size = extra->DataDirectory[PE_DEBUG_DATA].Size;
+
+ if (size == 0)
+ return;
+
+ addr += extra->ImageBase;
+
+ /* Search for the section containing the DebugDirectory */
+ for (section = abfd->sections; section != NULL; section = section->next)
+ {
+ if ((addr >= section->vma) && (addr < (section->vma + section->size)))
+ break;
+ }
+
+ if (section == NULL)
+ {
+ return;
+ }
+ else if (!(section->flags & SEC_HAS_CONTENTS))
+ {
+ return;
+ }
+
+ dataoff = addr - section->vma;
+
+ /* Read the whole section. */
+ if (!bfd_malloc_and_get_section (abfd, section, &data))
+ {
+ if (data != NULL)
+ free (data);
+ return;
+ }
+
+ /* Search for a CodeView entry in the DebugDirectory */
+ for (i = 0; i < size / sizeof (struct external_IMAGE_DEBUG_DIRECTORY); i++)
+ {
+ struct external_IMAGE_DEBUG_DIRECTORY *ext
+ = &((struct external_IMAGE_DEBUG_DIRECTORY *)(data + dataoff))[i];
+ struct internal_IMAGE_DEBUG_DIRECTORY idd;
+
+ _bfd_XXi_swap_debugdir_in (abfd, ext, &idd);
+
+ if (idd.Type == PE_IMAGE_DEBUG_TYPE_CODEVIEW)
+ {
+ char buffer[256 + 1];
+ CODEVIEW_INFO *cvinfo = (CODEVIEW_INFO *) buffer;
+
+ /*
+ The debug entry doesn't have to have to be in a section, in which
+ case AddressOfRawData is 0, so always use PointerToRawData.
+ */
+ if (_bfd_XXi_slurp_codeview_record (abfd,
+ (file_ptr) idd.PointerToRawData,
+ idd.SizeOfData, cvinfo))
+ {
+ struct bfd_build_id* build_id = bfd_alloc(abfd,
+ sizeof(struct bfd_build_id) + cvinfo->SignatureLength);
+ if (build_id)
+ {
+ build_id->size = cvinfo->SignatureLength;
+ memcpy(build_id->data, cvinfo->Signature,
+ cvinfo->SignatureLength);
+ abfd->build_id = build_id;
+ }
+ }
+ break;
+ }
+ }
+}
+
static const bfd_target *
pe_bfd_object_p (bfd * abfd)
{
@@ -1265,6 +1346,7 @@ pe_bfd_object_p (bfd * abfd)
struct internal_aouthdr internal_a;
file_ptr opt_hdr_size;
file_ptr offset;
+ const bfd_target *result;

/* Detect if this a Microsoft Import Library Format element. */
/* First read the beginning of the header. */
@@ -1358,10 +1440,20 @@ pe_bfd_object_p (bfd * abfd)
return NULL;
}

- return coff_real_object_p (abfd, internal_f.f_nscns, &internal_f,
- (opt_hdr_size != 0
- ? &internal_a
- : (struct internal_aouthdr *) NULL));
+
+ result = coff_real_object_p (abfd, internal_f.f_nscns, &internal_f,
+ (opt_hdr_size != 0
+ ? &internal_a
+ : (struct internal_aouthdr *) NULL));
+
+
+ if (result)
+ {
+ /* Now the whole header has been processed, see if there is a build-id */
+ pe_bfd_read_buildid(abfd);
+ }
+
+ return result;
}

#define coff_object_p pe_bfd_object_p
diff --git a/gdb/build-id.c b/gdb/build-id.c
index 8f7bbb4..ebf9f45 100644
--- a/gdb/build-id.c
+++ b/gdb/build-id.c
@@ -19,7 +19,6 @@

#include "defs.h"
#include "bfd.h"
-#include "elf-bfd.h"
#include "gdb_bfd.h"
#include "build-id.h"
#include "gdb_vecs.h"
@@ -30,19 +29,17 @@

/* See build-id.h. */

-const struct elf_build_id *
+const struct bfd_build_id *
build_id_bfd_get (bfd *abfd)
{
- if (!bfd_check_format (abfd, bfd_object)
- || bfd_get_flavour (abfd) != bfd_target_elf_flavour
- /* Although this is ELF_specific, it is safe to do in generic
- code because it does not rely on any ELF-specific symbols at
- link time, and if the ELF code is not available in BFD, then
- ABFD will not have the ELF flavour. */
- || elf_tdata (abfd)->build_id == NULL)
+ if (!bfd_check_format (abfd, bfd_object))
return NULL;

- return elf_tdata (abfd)->build_id;
+ if (abfd->build_id != NULL)
+ return abfd->build_id;
+
+ /* No build-id */
+ return NULL;
}

/* See build-id.h. */
@@ -50,7 +47,7 @@ build_id_bfd_get (bfd *abfd)
int
build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check)
{
- const struct elf_build_id *found;
+ const struct bfd_build_id *found;
int retval = 0;

found = build_id_bfd_get (abfd);
@@ -139,7 +136,7 @@ build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id)
char *
find_separate_debug_file_by_buildid (struct objfile *objfile)
{
- const struct elf_build_id *build_id;
+ const struct bfd_build_id *build_id;

build_id = build_id_bfd_get (objfile->obfd);
if (build_id != NULL)
diff --git a/gdb/build-id.h b/gdb/build-id.h
index f77dda2..bea761b 100644
--- a/gdb/build-id.h
+++ b/gdb/build-id.h
@@ -22,7 +22,7 @@

/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */

-extern const struct elf_build_id *build_id_bfd_get (bfd *abfd);
+extern const struct bfd_build_id *build_id_bfd_get (bfd *abfd);

/* Return true if ABFD has NT_GNU_BUILD_ID matching the CHECK value.
Otherwise, issue a warning and return false. */
diff --git a/gdb/coffread.c b/gdb/coffread.c
index 3b5a968..7722cdb 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -41,6 +41,7 @@
#include "coff-pe-read.h"

#include "psymtab.h"
+#include "build-id.h"

extern void _initialize_coffread (void);

@@ -738,7 +739,10 @@ coff_symfile_read (struct objfile *objfile, int symfile_flags)
{
char *debugfile;

- debugfile = find_separate_debug_file_by_debuglink (objfile);
+ debugfile = find_separate_debug_file_by_buildid (objfile);
+
+ if (debugfile == NULL)
+ debugfile = find_separate_debug_file_by_debuglink (objfile);
make_cleanup (xfree, debugfile);

if (debugfile)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 9e9138b..9d9685f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18170,7 +18170,7 @@ the executable and the debug file came from the same build.
@item
The executable contains a @dfn{build ID}, a unique bit string that is
also present in the corresponding debug info file. (This is supported
-only on some operating systems, notably those which use the ELF format
+only on some operating systems, when using the ELF or PE file formats
for binary files and the @sc{gnu} Binutils.) For more details about
this feature, see the description of the @option{--build-id}
command-line option in @ref{Options, , Command Line Options, ld.info,
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index c9528c3..5dc9ae6 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -23,7 +23,6 @@
#include "objfiles.h"
#include "language.h"
#include "build-id.h"
-#include "elf-bfd.h"
#include "symtab.h"

typedef struct
@@ -134,7 +133,7 @@ objfpy_get_build_id (PyObject *self, void *closure)
{
objfile_object *obj = (objfile_object *) self;
struct objfile *objfile = obj->objfile;
- const struct elf_build_id *build_id = NULL;
+ const struct bfd_build_id *build_id = NULL;

OBJFPY_REQUIRE_VALID (obj);

@@ -484,7 +483,7 @@ objfpy_build_id_ok (const char *string)
It is assumed that objfpy_build_id_ok (string) returns TRUE. */

static int
-objfpy_build_id_matches (const struct elf_build_id *build_id,
+objfpy_build_id_matches (const struct bfd_build_id *build_id,
const char *string)
{
size_t i;
@@ -542,7 +541,7 @@ objfpy_lookup_objfile_by_build_id (const char *build_id)

ALL_OBJFILES (objfile)
{
- const struct elf_build_id *obfd_build_id;
+ const struct bfd_build_id *obfd_build_id;

if (objfile->obfd == NULL)
continue;
diff --git a/gdb/testsuite/gdb.base/sepdebug.exp b/gdb/testsuite/gdb.base/sepdebug.exp
index 3194377..c363be4 100644
--- a/gdb/testsuite/gdb.base/sepdebug.exp
+++ b/gdb/testsuite/gdb.base/sepdebug.exp
@@ -42,7 +42,7 @@ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {deb
# the name of a debuginfo only file. This file will be stored in the
# gdb.base/ subdirectory.

-if [gdb_gnu_strip_debug $binfile] {
+if [gdb_gnu_strip_debug $binfile$EXEEXT] {
# check that you have a recent version of strip and objcopy installed
unsupported "cannot produce separate debug info files"
return -1
@@ -60,7 +60,7 @@ set new_name [standard_output_file ${testfile}${EXEEXT}]
remote_exec build "rm -rf [file dirname $new_name]"

remote_exec build "mkdir [file dirname $new_name]"
-remote_exec build "ln -s ${binfile} $new_name"
+remote_exec build "ln -s ${binfile}${EXEEXT} $new_name"
clean_restart ${testfile}${EXEEXT}
if { $gdb_file_cmd_debug_info != "debug" } then {
fail "No debug information found."
@@ -716,10 +716,10 @@ proc test_different_dir {type test_different_dir xfail} {
# the "set debug-file-directory" command.

set different_dir [standard_output_file ${testfile}.dir]
-set debugfile "${different_dir}/[standard_output_file ${testfile}.debug]"
+set debugfile "${different_dir}/[standard_output_file ${testfile}${EXEEXT}.debug]"
remote_exec build "rm -rf $different_dir"
remote_exec build "mkdir -p [file dirname $debugfile]"
-remote_exec build "mv -f [standard_output_file ${testfile}.debug] $debugfile"
+remote_exec build "mv -f [standard_output_file ${testfile}${EXEEXT}.debug] $debugfile"

test_different_dir debuglink $different_dir 0

@@ -727,7 +727,7 @@ test_different_dir debuglink $different_dir 0
# Test CRC mismatch is reported.

if {[build_executable sepdebug.exp sepdebug2 sepdebug2.c debug] != -1
- && ![gdb_gnu_strip_debug [standard_output_file sepdebug2]]} {
+ && ![gdb_gnu_strip_debug [standard_output_file sepdebug2]$EXEEXT]} {

remote_exec build "cp ${debugfile} [standard_output_file sepdebug2.debug]"

@@ -743,7 +743,7 @@ if {[build_executable sepdebug.exp sepdebug2 sepdebug2.c debug] != -1

# NT_GNU_BUILD_ID / .note.gnu.build-id test:

-set build_id_debug_filename [build_id_debug_filename_get $binfile]
+set build_id_debug_filename [build_id_debug_filename_get $binfile$EXEEXT]
if ![string compare $build_id_debug_filename ""] then {
unsupported "build-id is not supported by the compiler"

diff --git a/gdb/testsuite/lib/future.exp b/gdb/testsuite/lib/future.exp
index 2fb635b..a27e120 100644
--- a/gdb/testsuite/lib/future.exp
+++ b/gdb/testsuite/lib/future.exp
@@ -104,6 +104,17 @@ proc gdb_find_objcopy {} {
return $objcopy
}

+# find target objdump
+proc gdb_find_objdump {} {
+ global OBJDUMP_FOR_TARGET
+ if [info exists OBJDUMP_FOR_TARGET] {
+ set objdump $OBJDUMP_FOR_TARGET
+ } else {
+ set objdump [transform objdump]
+ }
+ return $objdump
+}
+
proc gdb_find_readelf {} {
global READELF_FOR_TARGET
if [info exists READELF_FOR_TARGET] {
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 41797e7..21a4638 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -4539,28 +4539,41 @@ gdb_caching_proc gdb_has_argv0 {
# Returns "" if there is none.

proc get_build_id { filename } {
- set tmp [standard_output_file "${filename}-tmp"]
- set objcopy_program [gdb_find_objcopy]
-
- set result [catch "exec $objcopy_program -j .note.gnu.build-id -O binary $filename $tmp" output]
- verbose "result is $result"
- verbose "output is $output"
- if {$result == 1} {
- return ""
+ if { ([istarget "*-*-mingw*"]
+ || [istarget *-*-cygwin*]) } {
+ set objdump_program [gdb_find_objdump]
+ set result [catch {set data [exec $objdump_program -p $filename | grep signature | cut "-d " -f4]} output]
+ verbose "result is $result"
+ verbose "output is $output"
+ if {$result == 1} {
+ return ""
+ }
+ return $data
}
- set fi [open $tmp]
- fconfigure $fi -translation binary
- # Skip the NOTE header.
- read $fi 16
- set data [read $fi]
- close $fi
- file delete $tmp
- if ![string compare $data ""] then {
- return ""
+ else
+ {
+ set tmp [standard_output_file "${filename}-tmp"]
+ set objcopy_program [gdb_find_objcopy]
+ set result [catch "exec $objcopy_program -j .note.gnu.build-id -O binary $filename $tmp" output]
+ verbose "result is $result"
+ verbose "output is $output"
+ if {$result == 1} {
+ return ""
+ }
+ set fi [open $tmp]
+ fconfigure $fi -translation binary
+ # Skip the NOTE header.
+ read $fi 16
+ set data [read $fi]
+ close $fi
+ file delete $tmp
+ if ![string compare $data ""] then {
+ return ""
+ }
+ # Convert it to hex.
+ binary scan $data H* data
+ return $data
}
- # Convert it to hex.
- binary scan $data H* data
- return $data
}

# Return the build-id hex string (usually 160 bits as 40 hex characters)
--
2.1.4