On 04/18/2014 01:02 PM, Mark Wielaard wrote:
On Tue, 2014-04-15 at 14:49 +0200, Florian Weimer wrote:
+2014-04-15 Florian Weimer <[email protected]>
+
+ * dwelf_dwarf_gnu_debugaltlink.c: New file.
+ * Makefile.am (libdwelf_a_SOURCES): Add it.
+ * libdwelf.h (dwelf_dwarf_gnu_debugaltlink): Declare new function.
+ * libdwelfP.h (dwelf_dwarf_gnu_debugaltlink): Add internal
+ declaration.
The code looks fine. But I still like the "tri-state" return more to
indicate why/how things went. Precisely because then you don't have to
do:
+ Elf_Data *data = dwarf->sectiondata[IDX_gnu_debugaltlink];
+ if (data == NULL)
+ {
+ /* Missing data is not actually an error. */
+ __libdw_seterrno (0);
+ return NULL;
+ }
[...]
+/* Returns the name of the alternate debug information file from the
+ .gnu_debugaltlink section if found in the ELF. On success, writes
+ a pointer to the build ID to *BUILD_IDP, and its length to
+ *BUILD_ID_LENP. Returns NULL if the ELF file didn't have a
+ .gnu_debuglink section (and sets the dwarf_errcode error code to
+ 0), had malformed data in the section or some other error occured.
+ The returned pointers are valid while the ELF handle is valid. */
+extern const char *dwelf_dwarf_gnu_debugaltlink (Dwarf *dwarf,
+ const void **build_idp,
+ size_t *build_id_lenp);
I'm not sure if this addresses this completely addresses the issue. A
return value of 0 could mean "no debugaltlink data" or "the build ID has
zero length".
I don't like setting the error code to zero, but as far as I can tell,
the error codes are not exposed, and a caller would have to resort to
string comparisons to check if it's the expected "missing section"
error, or something about lack of resources or malformed input data.
+2014-04-15 Florian Weimer <[email protected]>
+
+ * debugaltlink.c, run-debugaltlink.sh: New files.
+ * Makefile.am (check_PROGRAMS): Add debugaltlink.
+ (TESTS): Add run-debugaltlink.sh.
+ (debugaltlink_LDADD): New variable.
Thanks for adding the testcase. run-debugaltlink.sh should also be added
to EXTRA_DIST (I also forgot that in my dwelf_elf_gnu_debuglink patch
(fixed on the mjw/dwelf branch).
Can't we handle this in a better way with make variables, so that the
file needs to be listed in just one place?
Anyway, I've fixed it in my copy.
--
Florian Weimer / Red Hat Product Security Team
