From: Omar Sandoval <osan...@fb.com>
dwfl_addrmodule matches a module if the address lies within low_addr and
high_addr. This is incorrect for relocatable files, particularly kernel
modules: sections of different modules can be intermingled within the
same range of addresses. Instead, we should index each section
independently.
Signed-off-by: Omar Sandoval <osan...@fb.com>
---
libdwfl/ChangeLog | 6 ++++++
libdwfl/derelocate.c | 24 ++++++------------------
libdwfl/dwfl_addrmodule.c | 25 +++++++++++++++++++++----
libdwfl/libdwflP.h | 17 +++++++++++++++++
4 files changed, 50 insertions(+), 22 deletions(-)
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 8dc20961..d55aeb47 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -4,6 +4,8 @@
(Dwfl_Module): Remove coalescing state.
Rename lookup_tail_ndx to next_segndx.
Rename segment member to lookup.
+ (struct dwfl_relocation): Move from derelocate.c
+ (__libdwfl_cache_sections): Add.
(Dwfl): Replace module lookup table with new definition.
* relocate.c (__libdwfl_relocate_value): Return
DWFL_E_NOT_LOADED if section is not loaded.
@@ -14,6 +16,7 @@
(dwfl_addrsegment): Use dwfl_addrmodule to get module.
* libdwfl.h (dwfl_report_segment): Document that IDENT is now ignored.
* dwfl_addrmodule.c: Add new module lookup table implementation.
+ Index sections for relocatable files instead of full address range.
(dwfl_addrmodule): Use new module lookup table instead of
dwfl_addrsegment.
* dwfl_getmodules.c (dwfl_getmodules): Use new module lookup table.
@@ -21,6 +24,9 @@
(use): Likewise.
* link_map.c: Use dwfl_addrmodule instead of dwfl_addrsegment when
segment index is not needed.
+ * derelocate.c (struct dwfl_relocation): Move to libdwflP.h.
+ (cache_sections): Rename to __libdwfl_cache_sections and make
+ non-static.
2019-12-05 Mark Wielaard <m...@klomp.org>
diff --git a/libdwfl/derelocate.c b/libdwfl/derelocate.c
index 2f80b20f..238aa6e2 100644
--- a/libdwfl/derelocate.c
+++ b/libdwfl/derelocate.c
@@ -32,19 +32,6 @@
#include "libdwflP.h"
-struct dwfl_relocation
-{
- size_t count;
- struct
- {
- Elf_Scn *scn;
- Elf_Scn *relocs;
- const char *name;
- GElf_Addr start, end;
- } refs[0];
-};
-
-
struct secref
{
struct secref *next;
@@ -76,8 +63,9 @@ compare_secrefs (const void *a, const void *b)
return elf_ndxscn ((*p1)->scn) - elf_ndxscn ((*p2)->scn);
}
-static int
-cache_sections (Dwfl_Module *mod)
+int
+internal_function
+__libdwfl_cache_sections (Dwfl_Module *mod)
{
if (likely (mod->reloc_info != NULL))
return mod->reloc_info->count;
@@ -242,7 +230,7 @@ dwfl_module_relocations (Dwfl_Module *mod)
switch (mod->e_type)
{
case ET_REL:
- return cache_sections (mod);
+ return __libdwfl_cache_sections (mod);
case ET_DYN:
return 1;
@@ -278,7 +266,7 @@ dwfl_module_relocation_info (Dwfl_Module *mod, unsigned int
idx,
return NULL;
}
- if (cache_sections (mod) < 0)
+ if (__libdwfl_cache_sections (mod) < 0)
return NULL;
struct dwfl_relocation *sections = mod->reloc_info;
@@ -330,7 +318,7 @@ check_module (Dwfl_Module *mod)
static int
find_section (Dwfl_Module *mod, Dwarf_Addr *addr)
{
- if (cache_sections (mod) < 0)
+ if (__libdwfl_cache_sections (mod) < 0)
return -1;
struct dwfl_relocation *sections = mod->reloc_info;
diff --git a/libdwfl/dwfl_addrmodule.c b/libdwfl/dwfl_addrmodule.c
index 21db4883..1eb45317 100644
--- a/libdwfl/dwfl_addrmodule.c
+++ b/libdwfl/dwfl_addrmodule.c
@@ -74,10 +74,27 @@ create_lookup_module (Dwfl *dwfl)
for (Dwfl_Module *mod = dwfl->modulelist; mod != NULL; mod = mod->next)
if (! mod->gc)
{
- GElf_Addr start = __libdwfl_segment_start(dwfl, mod->low_addr);
- GElf_Addr end = __libdwfl_segment_end(dwfl, mod->high_addr);
- if (append_lookup_module(dwfl, mod, start, end))
- return true;
+ Dwarf_Addr bias;
+ if (mod->dwfl->callbacks->find_elf
+ && dwfl_module_getdwarf(mod, &bias)
+ && mod->e_type == ET_REL)
+ {
+ if (__libdwfl_cache_sections (mod) < 0)
+ return true;
+
+ struct dwfl_relocation *sections = mod->reloc_info;
+ for (size_t i = 0; i < sections->count; i++)
+ if (append_lookup_module(dwfl, mod, sections->refs[i].start,
+ sections->refs[i].end))
+ return true;
+ }
+ else
+ {
+ GElf_Addr start = __libdwfl_segment_start(dwfl, mod->low_addr);
+ GElf_Addr end = __libdwfl_segment_end(dwfl, mod->high_addr);
+ if (append_lookup_module(dwfl, mod, start, end))
+ return true;
+ }
}
qsort (dwfl->lookup_module, dwfl->lookup_module_elts,
diff --git a/libdwfl/libdwflP.h b/libdwfl/libdwflP.h
index 6661cc4c..2589eb66 100644
--- a/libdwfl/libdwflP.h
+++ b/libdwfl/libdwflP.h
@@ -169,6 +169,18 @@ struct dwfl_file
GElf_Addr address_sync;
};
+struct dwfl_relocation
+{
+ size_t count;
+ struct
+ {
+ Elf_Scn *scn;
+ Elf_Scn *relocs;
+ const char *name;
+ GElf_Addr start, end;
+ } refs[0];
+};
+
struct Dwfl_Module
{
Dwfl *dwfl;
@@ -486,6 +498,11 @@ extern void __libdwfl_getelf (Dwfl_Module *mod)
internal_function;
extern Dwfl_Error __libdwfl_relocate (Dwfl_Module *mod, Elf *file, bool debug)
internal_function;
+/* Cache SHF_ALLOC sections in MOD->reloc_info. Returns the number of sections
+ on success or -1 on error. */
+extern int __libdwfl_cache_sections (Dwfl_Module *mod)
+ internal_function;
+
/* Find the section index in mod->main.elf that contains the given
*ADDR. Adjusts *ADDR to be section relative on success, returns
SHN_UNDEF on failure. */
--
2.24.0
