[Ltrace-devel] 3 patches for ltrace - fixes "armhf" target

[Sedat Dilek]

Did you try latest Git of ltrace on ARM arch?

- Sedat -

http://anonscm.debian.org/gitweb/?p=collab-maint/ltrace.git;a=summary

On Wed, Mar 6, 2013 at 4:47 PM, Greg Alexander <ltracedeb at galexander.org> wrote:
> Hi all -
>
> Thanks for work on ltrace, it is fabulous.
>
> I am using Debian on armhf, and I built ltrace from
> ltrace_0.5.3.orig.tar.gz that I downloaded from the Debian pool.
> I found a few problems on this target, and corrected them.  The patches
> aren't long so I'm just going to append them at the bottom of this email,
> but let me know if I should have done something different.
>
> First patch corrects a build problem, header files were included in the
> wrong order, so just use "common.h" instead.
>
> Second patch corrects syscall tracing.  For whatever reason, my EABI
> syscalls calls are using the ARM-Thumb encoding of the SWI/SVC
> instruction, so I just added a condition for that.
>
> Third patch provides fallback behavior if PTRACE_SINGLESTEP is
> unavailable.  There is a #if to check for __sparc__ or __ia64__ to avoid
> PTRACE_SINGLESTEP, and I left that alone, but probably it should go away
> too.  My patch tries PTRACE_SINGLESTEP, but if -1 is returned then it
> falls back to the same behavior as on sparc/ia64.  I think that is a
> better solution than adding __arm__ to the #if, because if the kernel
> does change to support PTRACE_SINGLESTEP here, it will not be any more
> work for ltrace to support it.
>
> Thank you!
> - Greg
>
>
> --- ltrace-0.5.3.orig/sysdeps/linux-gnu/arm/breakpoint.c        2009-07-25 11:13:02.000000000 -0400
> +++ ltrace-0.5.3/sysdeps/linux-gnu/arm/breakpoint.c     2013-03-06 09:21:41.803584766 -0500
> @@ -25,9 +25,7 @@
>  #include <sys/ptrace.h>
>  #include "config.h"
>  #include "arch.h"
> -#include "options.h"
> -#include "output.h"
> -#include "debug.h"
> +#include "common.h"
>
>  void
>  arch_enable_breakpoint(pid_t pid, Breakpoint *sbp) {
> --- ltrace-0.5.3.orig/sysdeps/linux-gnu/arm/trace.c     2009-07-25 11:13:02.000000000 -0400
> +++ ltrace-0.5.3/sysdeps/linux-gnu/arm/trace.c  2013-03-06 09:41:38.078585339 -0500
> @@ -52,6 +52,9 @@
>                 if (insn == 0xef000000 || insn == 0x0f000000) {
>                         /* EABI syscall */
>                         *sysnum = ptrace(PTRACE_PEEKUSER, proc->pid, off_r7, 0);
> +               } else if ((insn & 0xffff0000) == 0xdf000000) {
> +                       /* EABI syscall "encoding T1" (thumb) */
> +                       *sysnum = ptrace(PTRACE_PEEKUSER, proc->pid, off_r7, 0);
>                 } else if ((insn & 0xfff00000) == 0xef900000) {
>                         /* old ABI syscall */
>                         *sysnum = insn & 0xfffff;
> --- ltrace-0.5.3.orig/sysdeps/linux-gnu/trace.c 2009-07-25 11:13:02.000000000 -0400
> +++ ltrace-0.5.3/sysdeps/linux-gnu/trace.c      2013-03-06 10:26:15.368586617 -0500
> @@ -122,7 +122,10 @@
>  #if defined __sparc__  || defined __ia64___
>                 ptrace(PTRACE_SYSCALL, pid, 0, signum);
>  #else
> -               ptrace(PTRACE_SINGLESTEP, pid, 0, signum);
> +               if (ptrace(PTRACE_SINGLESTEP, pid, 0, signum) == -1) {
> +                       ptrace(PTRACE_SYSCALL, pid, 0, signum);
> +               }
> +
>  #endif
>         } else {
>                 ptrace(PTRACE_SYSCALL, pid, 0, signum);
> @@ -158,7 +161,9 @@
>                 /* we don't want to singlestep here */
>                 continue_process(proc->pid);
>  #else
> -               ptrace(PTRACE_SINGLESTEP, proc->pid, 0, 0);
> +               if (ptrace(PTRACE_SINGLESTEP, proc->pid, 0, 0) == -1) {
> +                       continue_process(proc->pid);
> +               }
>  #endif
>         }
>  }
>
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