[PATCH 1/2] objtool: Rename elf_open to prevent conflict with libelf from elftoolchain

[PATCH 1/2] objtool: Rename elf_open to prevent conflict with libelf from elftoolchain

[Michael Forney]

Signed-off-by: Michael Forney <mforney@mforney.org>
---
 tools/objtool/check.c | 2 +-
 tools/objtool/elf.c   | 2 +-
 tools/objtool/elf.h   | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 172f99195726..6ed46c36c54f 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2407,7 +2407,7 @@ int check(const char *_objname, bool orc)
 
 	objname = _objname;
 
-	file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY);
+	file.elf = elf_open_path(objname, orc ? O_RDWR : O_RDONLY);
 	if (!file.elf)
 		return 1;
 
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index e99e1be19ad9..4116f564a0b0 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -401,7 +401,7 @@ static int read_relas(struct elf *elf)
 	return 0;
 }
 
-struct elf *elf_open(const char *name, int flags)
+struct elf *elf_open_path(const char *name, int flags)
 {
 	struct elf *elf;
 	Elf_Cmd cmd;
diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h
index e44ca5d51871..c59100d243ac 100644
--- a/tools/objtool/elf.h
+++ b/tools/objtool/elf.h
@@ -74,7 +74,7 @@ struct elf {
 };
 
 
-struct elf *elf_open(const char *name, int flags);
+struct elf *elf_open_path(const char *name, int flags);
 struct section *find_section_by_name(struct elf *elf, const char *name);
 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
 struct symbol *find_symbol_by_name(struct elf *elf, const char *name);
-- 
2.20.1

[PATCH 2/2] objtool: Use Elf_Scn typedef instead of assuming tag name

[Michael Forney]

The libelf implementation might use a different tag name, and the
Elf_Scn typedef is already used throughout the rest of objtool.

Signed-off-by: Michael Forney <mforney@mforney.org>
---
 tools/objtool/elf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4116f564a0b0..a4258d80d4ce 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -463,7 +463,7 @@ struct section *elf_create_section(struct elf *elf, const char *name,
 {
 	struct section *sec, *shstrtab;
 	size_t size = entsize * nr;
-	struct Elf_Scn *s;
+	Elf_Scn *s;
 	Elf_Data *data;
 
 	sec = malloc(sizeof(*sec));
-- 
2.20.1

Re: [PATCH 1/2] objtool: Rename elf_open to prevent conflict with libelf from elftoolchain

[Josh Poimboeuf]

On Sun, Jun 16, 2019 at 04:14:59PM -0700, Michael Forney wrote:
> Signed-off-by: Michael Forney <mforney@mforney.org>
> ---
>  tools/objtool/check.c | 2 +-
>  tools/objtool/elf.c   | 2 +-
>  tools/objtool/elf.h   | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)

Sorry for the delay, I was out for a bit and I'm still trying to get
caught back up on email.

These patches look fine.  I'll try to send them on to the -tip tree
shortly.

Just curious, have you done much testing with the elftoolchain version
of libelf and objtool?  So far objtool has only been successfully used
with the elfutils version, so I'm just curious how compatible your
libelf is with the elfutils version.

-- 
Josh

Re: [PATCH 1/2] objtool: Rename elf_open to prevent conflict with libelf from elftoolchain

[Michael Forney]

On 2019-06-27, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Sun, Jun 16, 2019 at 04:14:59PM -0700, Michael Forney wrote:
>> Signed-off-by: Michael Forney <mforney@mforney.org>
>> ---
>>  tools/objtool/check.c | 2 +-
>>  tools/objtool/elf.c   | 2 +-
>>  tools/objtool/elf.h   | 2 +-
>>  3 files changed, 3 insertions(+), 3 deletions(-)
>
> Sorry for the delay, I was out for a bit and I'm still trying to get
> caught back up on email.

No worries :)

> These patches look fine.  I'll try to send them on to the -tip tree
> shortly.

Thanks!

> Just curious, have you done much testing with the elftoolchain version
> of libelf and objtool?  So far objtool has only been successfully used
> with the elfutils version, so I'm just curious how compatible your
> libelf is with the elfutils version.

I'm not affiliated with elftoolchain, I am just trying it out on my
system as an alternative to elfutils libelf for its clean codebase
that doesn't use many GNU C extensions.

I've done some basic testing to make sure that the .o files after
being processed with `objtool generate --no-fp --retpoline` match
between elfutils and elftoolchain. I noticed two differences, one of
which was due to a bug in elftoolchain that has since been fixed, and
the other is with the offset of SHT_NOBITS section after rewriting[0],
which I think doesn't matter.

[0] https://sourceforge.net/p/elftoolchain/tickets/571/

Re: [PATCH 1/2] objtool: Rename elf_open to prevent conflict with libelf from elftoolchain

[Josh Poimboeuf]

On Thu, Jun 27, 2019 at 05:52:53PM -0700, Michael Forney wrote:
> On 2019-06-27, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> > On Sun, Jun 16, 2019 at 04:14:59PM -0700, Michael Forney wrote:
> >> Signed-off-by: Michael Forney <mforney@mforney.org>
> >> ---
> >>  tools/objtool/check.c | 2 +-
> >>  tools/objtool/elf.c   | 2 +-
> >>  tools/objtool/elf.h   | 2 +-
> >>  3 files changed, 3 insertions(+), 3 deletions(-)
> >
> > Sorry for the delay, I was out for a bit and I'm still trying to get
> > caught back up on email.
> 
> No worries :)
> 
> > These patches look fine.  I'll try to send them on to the -tip tree
> > shortly.
> 
> Thanks!
> 
> > Just curious, have you done much testing with the elftoolchain version
> > of libelf and objtool?  So far objtool has only been successfully used
> > with the elfutils version, so I'm just curious how compatible your
> > libelf is with the elfutils version.
> 
> I'm not affiliated with elftoolchain, I am just trying it out on my
> system as an alternative to elfutils libelf for its clean codebase
> that doesn't use many GNU C extensions.
> 
> I've done some basic testing to make sure that the .o files after
> being processed with `objtool generate --no-fp --retpoline` match
> between elfutils and elftoolchain. I noticed two differences, one of
> which was due to a bug in elftoolchain that has since been fixed, and
> the other is with the offset of SHT_NOBITS section after rewriting[0],
> which I think doesn't matter.

Awesome, that gives me a lot more confidence.  Thanks!

-- 
Josh