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-rw-r--r--libdw/ChangeLog6
-rw-r--r--libdw/dwarf_begin_elf.c120
-rw-r--r--libdwfl/ChangeLog8
-rw-r--r--libdwfl/dwfl_module_getdwarf.c121
4 files changed, 135 insertions, 120 deletions
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 49004325..3152239f 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,9 @@
+2014-04-15 Florian Weimer <fweimer@redhat.com>
+
+ * dwarf_begin_elf.c (__check_build_id, try_debugaltlink)
+ (open_debugaltlink): Move to libdwfl.
+ (check_section): Do not locate alternate debuginfo.
+
2014-04-24 Florian Weimer <fweimer@redhat.com>
* libdw.map (ELFUTILS_0.159): Export dwelf_dwarf_gnu_debugaltlink.
diff --git a/libdw/dwarf_begin_elf.c b/libdw/dwarf_begin_elf.c
index 5f69c61c..4c6346ae 100644
--- a/libdw/dwarf_begin_elf.c
+++ b/libdw/dwarf_begin_elf.c
@@ -32,7 +32,6 @@
#endif
#include <assert.h>
-#include <inttypes.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
@@ -72,113 +71,6 @@ static const char dwarf_scnnames[IDX_last][18] =
};
#define ndwarf_scnnames (sizeof (dwarf_scnnames) / sizeof (dwarf_scnnames[0]))
-#ifdef ENABLE_DWZ
-internal_function int
-__check_build_id (Dwarf *dw, const uint8_t *build_id, const size_t id_len)
-{
- if (dw == NULL)
- return -1;
-
- Elf *elf = dw->elf;
- Elf_Scn *scn = elf_nextscn (elf, NULL);
- if (scn == NULL)
- return -1;
-
- do
- {
- GElf_Shdr shdr_mem;
- GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
- if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE)
- {
- size_t pos = 0;
- GElf_Nhdr nhdr;
- size_t name_pos;
- size_t desc_pos;
- Elf_Data *data = elf_getdata (scn, NULL);
- while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos,
- &desc_pos)) > 0)
- if (nhdr.n_type == NT_GNU_BUILD_ID
- && nhdr.n_namesz == sizeof "GNU"
- && ! memcmp (data->d_buf + name_pos, "GNU", sizeof "GNU"))
- return (nhdr.n_descsz == id_len
- && ! memcmp (data->d_buf + desc_pos,
- build_id, id_len)) ? 0 : 1;
- }
- }
- while ((scn = elf_nextscn (elf, scn)) != NULL);
-
- return -1;
-}
-
-/* Try to open an debug alt link by name, checking build_id.
- Marks free_alt on success, return NULL on failure. */
-static Dwarf *
-try_debugaltlink (Dwarf *result, const char *try_name,
- const uint8_t *build_id, const size_t id_len)
-{
- int fd = open (try_name, O_RDONLY);
- if (fd > 0)
- {
- result->alt_dwarf = INTUSE (dwarf_begin) (fd, DWARF_C_READ);
- if (result->alt_dwarf != NULL)
- {
- Elf *elf = result->alt_dwarf->elf;
- if (__check_build_id (result->alt_dwarf, build_id, id_len) == 0
- && elf_cntl (elf, ELF_C_FDREAD) == 0)
- {
- close (fd);
- result->free_alt = 1;
- return result;
- }
- INTUSE (dwarf_end) (result->alt_dwarf);
- }
- close (fd);
- }
- return NULL;
-}
-
-/* For dwz multifile support, ignore if it looks wrong. */
-static Dwarf *
-open_debugaltlink (Dwarf *result, const char *alt_name,
- const uint8_t *build_id, const size_t id_len)
-{
- /* First try the name itself, it is either an absolute path or
- a relative one. Sadly we don't know relative from where at
- this point. */
- if (try_debugaltlink (result, alt_name, build_id, id_len) != NULL)
- return result;
-
- /* Lets try based on the build-id. This is somewhat distro specific,
- we are following the Fedora implementation described at
- https://fedoraproject.org/wiki/Releases/FeatureBuildId#Find_files_by_build_ID
- */
-#define DEBUG_PREFIX "/usr/lib/debug/.build-id/"
-#define PREFIX_LEN sizeof (DEBUG_PREFIX)
- char id_name[PREFIX_LEN + 1 + id_len * 2 + sizeof ".debug" - 1];
- strcpy (id_name, DEBUG_PREFIX);
- int n = snprintf (&id_name[PREFIX_LEN - 1],
- 4, "%02" PRIx8 "/", (uint8_t) build_id[0]);
- assert (n == 3);
- for (size_t i = 1; i < id_len; ++i)
- {
- n = snprintf (&id_name[PREFIX_LEN - 1 + 3 + (i - 1) * 2],
- 3, "%02" PRIx8, (uint8_t) build_id[i]);
- assert (n == 2);
- }
- strcpy (&id_name[PREFIX_LEN - 1 + 3 + (id_len - 1) * 2],
- ".debug");
-
- if (try_debugaltlink (result, id_name, build_id, id_len))
- return result;
-
- /* Everything failed, mark this Dwarf as not having an alternate,
- but don't fail the load. The user may want to set it by hand
- before usage. */
- result->alt_dwarf = NULL;
- return result;
-}
-#endif /* ENABLE_DWZ */
-
static Dwarf *
check_section (Dwarf *result, GElf_Ehdr *ehdr, Elf_Scn *scn, bool inscngrp)
{
@@ -319,18 +211,6 @@ check_section (Dwarf *result, GElf_Ehdr *ehdr, Elf_Scn *scn, bool inscngrp)
}
#endif
-#ifdef ENABLE_DWZ
- Elf_Data *data = result->sectiondata[IDX_gnu_debugaltlink];
- if (data != NULL && data->d_size != 0)
- {
- const char *alt_name = data->d_buf;
- const void *build_id = memchr (data->d_buf, '\0', data->d_size);
- const int id_len = data->d_size - (build_id - data->d_buf + 1);
- if (alt_name && build_id && id_len > 0)
- return open_debugaltlink (result, alt_name, build_id + 1, id_len);
- }
-#endif /* ENABLE_DWZ */
-
return result;
}
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 5c1ab809..62ea412c 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,11 @@
+2014-04-15 Florian Weimer <fweimer@redhat.com>
+
+ * dwfl_module_getdwarf.c (__check_build_id): Moved from libdw.
+ (try_debugaltlink): Likewise.
+ (open_debugaltlink): Likewise.
+ (load_dw): Locate alternate debug information using
+ dwelf_dwarf_gnu_debugaltlink and call open_debugaltlink.
+
2014-04-11 Mark Wielaard <mjw@redhat.com>
* Makefile.am (AM_CPPFLAGS): Add libdwelf.
diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index f8a7816a..6163ddbe 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -27,12 +27,120 @@
not, see <http://www.gnu.org/licenses/>. */
#include "libdwflP.h"
+#include <inttypes.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include "../libdw/libdwP.h" /* DWARF_E_* values are here. */
#include "../libelf/libelfP.h"
+#ifdef ENABLE_DWZ
+internal_function int
+__check_build_id (Dwarf *dw, const uint8_t *build_id, const size_t id_len)
+{
+ if (dw == NULL)
+ return -1;
+
+ Elf *elf = dw->elf;
+ Elf_Scn *scn = elf_nextscn (elf, NULL);
+ if (scn == NULL)
+ return -1;
+
+ do
+ {
+ GElf_Shdr shdr_mem;
+ GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
+ if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE)
+ {
+ size_t pos = 0;
+ GElf_Nhdr nhdr;
+ size_t name_pos;
+ size_t desc_pos;
+ Elf_Data *data = elf_getdata (scn, NULL);
+ while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos,
+ &desc_pos)) > 0)
+ if (nhdr.n_type == NT_GNU_BUILD_ID
+ && nhdr.n_namesz == sizeof "GNU"
+ && ! memcmp (data->d_buf + name_pos, "GNU", sizeof "GNU"))
+ return (nhdr.n_descsz == id_len
+ && ! memcmp (data->d_buf + desc_pos,
+ build_id, id_len)) ? 0 : 1;
+ }
+ }
+ while ((scn = elf_nextscn (elf, scn)) != NULL);
+
+ return -1;
+}
+
+/* Try to open an debug alt link by name, checking build_id.
+ Marks free_alt on success, return NULL on failure. */
+static Dwarf *
+try_debugaltlink (Dwarf *result, const char *try_name,
+ const uint8_t *build_id, const size_t id_len)
+{
+ int fd = open (try_name, O_RDONLY);
+ if (fd > 0)
+ {
+ Dwarf *alt_dwarf = INTUSE (dwarf_begin) (fd, DWARF_C_READ);
+ if (alt_dwarf != NULL)
+ {
+ Elf *elf = alt_dwarf->elf;
+ if (__check_build_id (alt_dwarf, build_id, id_len) == 0
+ && elf_cntl (elf, ELF_C_FDREAD) == 0)
+ {
+ close (fd);
+ INTUSE (dwarf_setalt) (result, alt_dwarf);
+ result->free_alt = true;
+ return result;
+ }
+ INTUSE (dwarf_end) (result->alt_dwarf);
+ }
+ close (fd);
+ }
+ return NULL;
+}
+
+/* For dwz multifile support, ignore if it looks wrong. */
+static Dwarf *
+open_debugaltlink (Dwarf *result, const char *alt_name,
+ const uint8_t *build_id, const size_t id_len)
+{
+ /* First try the name itself, it is either an absolute path or
+ a relative one. Sadly we don't know relative from where at
+ this point. */
+ if (try_debugaltlink (result, alt_name, build_id, id_len) != NULL)
+ return result;
+
+ /* Lets try based on the build-id. This is somewhat distro specific,
+ we are following the Fedora implementation described at
+ https://fedoraproject.org/wiki/Releases/FeatureBuildId#Find_files_by_build_ID
+ */
+#define DEBUG_PREFIX "/usr/lib/debug/.build-id/"
+#define PREFIX_LEN sizeof (DEBUG_PREFIX)
+ char id_name[PREFIX_LEN + 1 + id_len * 2 + sizeof ".debug" - 1];
+ strcpy (id_name, DEBUG_PREFIX);
+ int n = snprintf (&id_name[PREFIX_LEN - 1],
+ 4, "%02" PRIx8 "/", (uint8_t) build_id[0]);
+ assert (n == 3);
+ for (size_t i = 1; i < id_len; ++i)
+ {
+ n = snprintf (&id_name[PREFIX_LEN - 1 + 3 + (i - 1) * 2],
+ 3, "%02" PRIx8, (uint8_t) build_id[i]);
+ assert (n == 2);
+ }
+ strcpy (&id_name[PREFIX_LEN - 1 + 3 + (id_len - 1) * 2],
+ ".debug");
+
+ if (try_debugaltlink (result, id_name, build_id, id_len))
+ return result;
+
+ /* Everything failed, mark this Dwarf as not having an alternate,
+ but don't fail the load. The user may want to set it by hand
+ before usage. */
+ result->alt_dwarf = NULL;
+ return result;
+}
+#endif /* ENABLE_DWZ */
/* Open libelf FILE->fd and compute the load base of ELF as loaded in MOD.
When we return success, FILE->elf and FILE->vaddr are set up. */
@@ -1122,6 +1230,19 @@ load_dw (Dwfl_Module *mod, struct dwfl_file *debugfile)
return err == DWARF_E_NO_DWARF ? DWFL_E_NO_DWARF : DWFL_E (LIBDW, err);
}
+#ifdef ENABLE_DWZ
+ /* For dwz multifile support, ignore if it looks wrong. */
+ {
+ const void *build_id;
+ const char *alt_name;
+ size_t id_len = INTUSE (dwelf_dwarf_gnu_debugaltlink) (mod->dw,
+ &alt_name,
+ &build_id);
+ if (id_len > 0)
+ open_debugaltlink (mod->dw, alt_name, build_id, id_len);
+ }
+#endif /* ENABLE_DWZ */
+
/* Until we have iterated through all CU's, we might do lazy lookups. */
mod->lazycu = 1;