public inbox for binutils@sourceware.org
 help / color / mirror / Atom feed
* [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
@ 2020-05-25 18:28 H.J. Lu
  2020-05-26 17:45 ` Fangrui Song
       [not found] ` <CAN30aBHV0wxmp0NvLFeyH1Yoed64UOJ0B74ejQgwrQNY-d93qg@mail.gmail.com>
  0 siblings, 2 replies; 6+ messages in thread
From: H.J. Lu @ 2020-05-25 18:28 UTC (permalink / raw)
  To: binutils

include/elf/common.h has

 #define ET_EXEC         2       /* Executable file */
 #define ET_DYN          3       /* Shared object file */

These predate PIE:

https://groups.google.com/forum/#!topic/generic-abi/mBKlSNldFW4

Updated comments to

 #define ET_EXEC         2       /* Position-dependent executable file */
 #define ET_DYN          3       /* Position-independent executable or
                                    shared object file */

	* elf/common.h: Update comments for ET_EXEC and ET_DYN.
---
 include/ChangeLog    | 4 ++++
 include/elf/common.h | 5 +++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/ChangeLog b/include/ChangeLog
index c309780544..53f50e513f 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,7 @@
+2020-05-25  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* elf/common.h: Update comments for ET_EXEC and ET_DYN.
+
 2020-05-20  Nelson Chu  <nelson.chu@sifive.com>
 
 	* opcode/riscv.h: Include "bfd.h" to support bfd_boolean.
diff --git a/include/elf/common.h b/include/elf/common.h
index 26e6fbc8e6..4d94c4fd5b 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -91,8 +91,9 @@
 
 #define ET_NONE		0	/* No file type */
 #define ET_REL		1	/* Relocatable file */
-#define ET_EXEC		2	/* Executable file */
-#define ET_DYN		3	/* Shared object file */
+#define ET_EXEC		2	/* Position-dependent executable file */
+#define ET_DYN		3	/* Position-independent executable or
+				   shared object file */
 #define ET_CORE		4	/* Core file */
 #define ET_LOOS		0xFE00	/* Operating system-specific */
 #define ET_HIOS		0xFEFF	/* Operating system-specific */
-- 
2.26.2


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
  2020-05-25 18:28 [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN H.J. Lu
@ 2020-05-26 17:45 ` Fangrui Song
       [not found] ` <CAN30aBHV0wxmp0NvLFeyH1Yoed64UOJ0B74ejQgwrQNY-d93qg@mail.gmail.com>
  1 sibling, 0 replies; 6+ messages in thread
From: Fangrui Song @ 2020-05-26 17:45 UTC (permalink / raw)
  To: H.J. Lu; +Cc: binutils

Looks good. Ali in the generic-abi proposed a more generic form:

#define ET_EXEC 2 /* Position-dependent object */
#define ET_DYN 3 /* Position-independent object */


I just filed https://sourceware.org/bugzilla/show_bug.cgi?id=26047 We
may consider disallowing ET_EXEC as linker input.
Happy to know if there are legitimate cases, though.

On Mon, May 25, 2020 at 11:28 AM H.J. Lu via Binutils
<binutils@sourceware.org> wrote:
>
> include/elf/common.h has
>
>  #define ET_EXEC         2       /* Executable file */
>  #define ET_DYN          3       /* Shared object file */
>
> These predate PIE:
>
> https://groups.google.com/forum/#!topic/generic-abi/mBKlSNldFW4
>
> Updated comments to
>
>  #define ET_EXEC         2       /* Position-dependent executable file */
>  #define ET_DYN          3       /* Position-independent executable or
>                                     shared object file */
>
>         * elf/common.h: Update comments for ET_EXEC and ET_DYN.
> ---
>  include/ChangeLog    | 4 ++++
>  include/elf/common.h | 5 +++--
>  2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/ChangeLog b/include/ChangeLog
> index c309780544..53f50e513f 100644
> --- a/include/ChangeLog
> +++ b/include/ChangeLog
> @@ -1,3 +1,7 @@
> +2020-05-25  H.J. Lu  <hongjiu.lu@intel.com>
> +
> +       * elf/common.h: Update comments for ET_EXEC and ET_DYN.
> +
>  2020-05-20  Nelson Chu  <nelson.chu@sifive.com>
>
>         * opcode/riscv.h: Include "bfd.h" to support bfd_boolean.
> diff --git a/include/elf/common.h b/include/elf/common.h
> index 26e6fbc8e6..4d94c4fd5b 100644
> --- a/include/elf/common.h
> +++ b/include/elf/common.h
> @@ -91,8 +91,9 @@
>
>  #define ET_NONE                0       /* No file type */
>  #define ET_REL         1       /* Relocatable file */
> -#define ET_EXEC                2       /* Executable file */
> -#define ET_DYN         3       /* Shared object file */
> +#define ET_EXEC                2       /* Position-dependent executable file */
> +#define ET_DYN         3       /* Position-independent executable or
> +                                  shared object file */
>  #define ET_CORE                4       /* Core file */
>  #define ET_LOOS                0xFE00  /* Operating system-specific */
>  #define ET_HIOS                0xFEFF  /* Operating system-specific */
> --
> 2.26.2
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
       [not found] ` <CAN30aBHV0wxmp0NvLFeyH1Yoed64UOJ0B74ejQgwrQNY-d93qg@mail.gmail.com>
@ 2020-05-30  0:59   ` Fangrui Song
       [not found]   ` <MWHPR12MB14566C7EDEE9DC0828E00DA2CB8C0@MWHPR12MB1456.namprd12.prod.outlook.com>
  1 sibling, 0 replies; 6+ messages in thread
From: Fangrui Song @ 2020-05-30  0:59 UTC (permalink / raw)
  To: Alan Modra; +Cc: binutils, H.J. Lu

Does https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d871d478061f10b0879c688e2fa941407e9137aa
start to set DF_1_PIE on non-Solaris platforms (e.g. Linux) as well?

I guess previous versions of binutils don't set the flag.

This flag makes sense to me, because it makes the distinction of
executable/shared object for ET_DYN.

On Tue, May 26, 2020 at 10:45 AM Fangrui Song <i@maskray.me> wrote:
>
> Looks good. Ali in the generic-abi proposed a more generic form:
>
> #define ET_EXEC 2 /* Position-dependent object */
> #define ET_DYN 3 /* Position-independent object */
>
>
> I just filed https://sourceware.org/bugzilla/show_bug.cgi?id=26047 We
> may consider disallowing ET_EXEC as linker input.
> Happy to know if there are legitimate cases, though.
>
> On Mon, May 25, 2020 at 11:28 AM H.J. Lu via Binutils
> <binutils@sourceware.org> wrote:
> >
> > include/elf/common.h has
> >
> >  #define ET_EXEC         2       /* Executable file */
> >  #define ET_DYN          3       /* Shared object file */
> >
> > These predate PIE:
> >
> > https://groups.google.com/forum/#!topic/generic-abi/mBKlSNldFW4
> >
> > Updated comments to
> >
> >  #define ET_EXEC         2       /* Position-dependent executable file */
> >  #define ET_DYN          3       /* Position-independent executable or
> >                                     shared object file */
> >
> >         * elf/common.h: Update comments for ET_EXEC and ET_DYN.
> > ---
> >  include/ChangeLog    | 4 ++++
> >  include/elf/common.h | 5 +++--
> >  2 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/ChangeLog b/include/ChangeLog
> > index c309780544..53f50e513f 100644
> > --- a/include/ChangeLog
> > +++ b/include/ChangeLog
> > @@ -1,3 +1,7 @@
> > +2020-05-25  H.J. Lu  <hongjiu.lu@intel.com>
> > +
> > +       * elf/common.h: Update comments for ET_EXEC and ET_DYN.
> > +
> >  2020-05-20  Nelson Chu  <nelson.chu@sifive.com>
> >
> >         * opcode/riscv.h: Include "bfd.h" to support bfd_boolean.
> > diff --git a/include/elf/common.h b/include/elf/common.h
> > index 26e6fbc8e6..4d94c4fd5b 100644
> > --- a/include/elf/common.h
> > +++ b/include/elf/common.h
> > @@ -91,8 +91,9 @@
> >
> >  #define ET_NONE                0       /* No file type */
> >  #define ET_REL         1       /* Relocatable file */
> > -#define ET_EXEC                2       /* Executable file */
> > -#define ET_DYN         3       /* Shared object file */
> > +#define ET_EXEC                2       /* Position-dependent executable file */
> > +#define ET_DYN         3       /* Position-independent executable or
> > +                                  shared object file */
> >  #define ET_CORE                4       /* Core file */
> >  #define ET_LOOS                0xFE00  /* Operating system-specific */
> >  #define ET_HIOS                0xFEFF  /* Operating system-specific */
> > --
> > 2.26.2
> >

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
       [not found]   ` <MWHPR12MB14566C7EDEE9DC0828E00DA2CB8C0@MWHPR12MB1456.namprd12.prod.outlook.com>
@ 2020-05-30  1:10     ` H.J. Lu
  2020-05-30 17:17       ` Fangrui Song
  2020-05-30 20:13       ` Pedro Alves
  0 siblings, 2 replies; 6+ messages in thread
From: H.J. Lu @ 2020-05-30  1:10 UTC (permalink / raw)
  To: Fangrui Song; +Cc: Alan Modra, Binutils

On Fri, May 29, 2020 at 6:06 PM Fangrui Song <i@maskray.me> wrote:
>
> Does https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d871d478061f10b0879c688e2fa941407e9137aa
> start to set DF_1_PIE on non-Solaris platforms (e.g. Linux) as well?

[hjl@gnu-cfl-2 x86-gcc]$ readelf -h /bin/ld | grep Type
  Type:                              DYN (Shared object file)
[hjl@gnu-cfl-2 x86-gcc]$ readelf -d /bin/ld | grep PIE
 0x000000006ffffffb (FLAGS_1)            Flags: NOW PIE
[hjl@gnu-cfl-2 x86-gcc]$

-- 
H.J.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
  2020-05-30  1:10     ` H.J. Lu
@ 2020-05-30 17:17       ` Fangrui Song
  2020-05-30 20:13       ` Pedro Alves
  1 sibling, 0 replies; 6+ messages in thread
From: Fangrui Song @ 2020-05-30 17:17 UTC (permalink / raw)
  To: H.J. Lu; +Cc: Alan Modra, Binutils

I saw https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/testsuite/ld-elf/pie.d;h=d68b962ca328a981dda980848b794ffd639780df;hb=5fe2850dd96483f176858fd75c098313d5b20bc2
It is a deliberate choice on non-Solaris platforms.

On Fri, May 29, 2020 at 6:10 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, May 29, 2020 at 6:06 PM Fangrui Song <i@maskray.me> wrote:
> >
> > Does https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d871d478061f10b0879c688e2fa941407e9137aa
> > start to set DF_1_PIE on non-Solaris platforms (e.g. Linux) as well?
>
> [hjl@gnu-cfl-2 x86-gcc]$ readelf -h /bin/ld | grep Type
>   Type:                              DYN (Shared object file)
> [hjl@gnu-cfl-2 x86-gcc]$ readelf -d /bin/ld | grep PIE
>  0x000000006ffffffb (FLAGS_1)            Flags: NOW PIE
> [hjl@gnu-cfl-2 x86-gcc]$
>
> --
> H.J.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN
  2020-05-30  1:10     ` H.J. Lu
  2020-05-30 17:17       ` Fangrui Song
@ 2020-05-30 20:13       ` Pedro Alves
  1 sibling, 0 replies; 6+ messages in thread
From: Pedro Alves @ 2020-05-30 20:13 UTC (permalink / raw)
  To: H.J. Lu, Fangrui Song; +Cc: Binutils

On 5/30/20 2:10 AM, H.J. Lu via Binutils wrote:
> On Fri, May 29, 2020 at 6:06 PM Fangrui Song <i@maskray.me> wrote:
>>
>> Does https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d871d478061f10b0879c688e2fa941407e9137aa
>> start to set DF_1_PIE on non-Solaris platforms (e.g. Linux) as well?
> 
> [hjl@gnu-cfl-2 x86-gcc]$ readelf -h /bin/ld | grep Type
>   Type:                              DYN (Shared object file)
> [hjl@gnu-cfl-2 x86-gcc]$ readelf -d /bin/ld | grep PIE
>  0x000000006ffffffb (FLAGS_1)            Flags: NOW PIE
> [hjl@gnu-cfl-2 x86-gcc]$
> 

Gold doesn't set it though: https://sourceware.org/bugzilla/show_bug.cgi?id=26039

Thanks,
Pedro Alves


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-05-30 20:13 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-25 18:28 [PATCH] ELF: Updated comments for ET_EXEC and ET_DYN H.J. Lu
2020-05-26 17:45 ` Fangrui Song
     [not found] ` <CAN30aBHV0wxmp0NvLFeyH1Yoed64UOJ0B74ejQgwrQNY-d93qg@mail.gmail.com>
2020-05-30  0:59   ` Fangrui Song
     [not found]   ` <MWHPR12MB14566C7EDEE9DC0828E00DA2CB8C0@MWHPR12MB1456.namprd12.prod.outlook.com>
2020-05-30  1:10     ` H.J. Lu
2020-05-30 17:17       ` Fangrui Song
2020-05-30 20:13       ` Pedro Alves

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).