openharmony/third_party_elfutils
1
0
Fork 0
mirror of https://github.com/openharmony/third_party_elfutils.git synced 2026-07-01 06:41:51 -04:00
Code Issues Packages Projects Releases Wiki Activity

libdwelf: Make dwelf_elf_begin return NULL only when there is an error.

Browse Source 
dwelf_elf_begin was slightly different from elf_begin in case the file
turned out to not be an ELF file. elf_begin would return an Elf handle
with ELF_K_NONE. But dwelf_elf_begin would return NULL. This made it
impossible to tell the difference between a file or decompression error
and a (decompressed) file not being an ELF file.

Since dwelf_elf_begin could still return different kinds of ELF files
(ELF_K_ELF or ELF_K_AR - and theoretically ELF_K_COFF) this was not
really useful anyway. So make it so that dwelf_elf_begin always returns
an Elf handle unless there was a real error reading or decompressing
the file. Otherwise return NULL to make clear there was a real error.

Make sure that the decompression function returns DWFL_E_BADELF only
when the file isn't compressed. In which case the Elf handle won't
be replaced and can be returned (as ELF_K_NONE).

Add a new version to dwelf_elf_begin so programs can rely on it
returning NULL only for real errors.

Signed-off-by: Mark Wielaard <mark@klomp.org>
This commit is contained in:
Mark Wielaard
2019-08-12 00:43:22 +02:00
parent d37f6ea7e3
commit 7ea82243ec
8 changed files with 45 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
libdwelf/ChangeLog
+6
View File
@@ -1,3 +1,9 @@
2019-08-12 Mark Wielaard <mark@klomp.org>
* libdwelf.h (dwelf_elf_begin): Update documentation.
* dwelf_elf_begin.c (dwelf_elf_begin): Don't suppress ELF_K_NONE.
Mark old and new version.
2019-06-28 Mark Wielaard <mark@klomp.org>
* Makefile.am (libdwelf_a_SOURCES): Add dwelf_elf_e_machine_string.c.
libdwelf/dwelf_elf_begin.c
+7 -5
View File
@@ -41,13 +41,13 @@ dwelf_elf_begin (int fd)
{
Elf *elf = NULL;
Dwfl_Error e = __libdw_open_elf (fd, &elf);
if (elf != NULL && elf_kind (elf) != ELF_K_NONE)
if (e == DWFL_E_NOERROR)
return elf;
/* Elf wasn't usable. Make sure there is a proper elf error message. */
if (elf != NULL)
elf_end (elf);
/* Elf wasn't usable. Make sure there is a proper elf error
message. This is probably not the real error, because there is
no good way to propagate errnos or decompression errors, but
better than nothing. */
if (e != DWFL_E_LIBELF)
{
@@ -60,3 +60,5 @@ dwelf_elf_begin (int fd)
return NULL;
}
OLD_VERSION (dwelf_elf_begin, ELFUTILS_0.175)
NEW_VERSION (dwelf_elf_begin, ELFUTILS_0.177)
libdwelf/libdwelf.h
+6 -3
View File
@@ -128,9 +128,12 @@ extern void dwelf_strtab_free (Dwelf_Strtab *st)
/* Creates a read-only Elf handle from the given file handle. The
file may be compressed and/or contain a linux kernel image header,
in which case it is eagerly decompressed in full and the Elf handle
is created as if created with elf_memory (). On error NULL is
returned. The Elf handle should be closed with elf_end (). The
file handle will not be closed. Does not return ELF_K_NONE handles. */
is created as if created with elf_memory (). On decompression or
file errors NULL is returned (and elf_errno will be set). If there
was no error, but the file is not an ELF file, then an ELF_K_NONE
Elf handle is returned (just like with elf_begin). The Elf handle
should be closed with elf_end (). The file handle will not be
closed. */
extern Elf *dwelf_elf_begin (int fd);
/* Returns a human readable string for the given ELF header e_machine