On Thu, Mar 12, 2015 at 3:07 PM, Roland McGrath <[email protected]> wrote: > GETREGS/SETREGS works fine everywhere. Just use it unconditionally.
This patch uses PTRACE_GETREGS/PTRACE_SETREGS to update rip. -- H.J.
From 75b3cb18bbc9cbe51142c9ca314c69cb54cb9bba Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <[email protected]> Date: Thu, 12 Mar 2015 12:14:43 -0700 Subject: [PATCH 2/3] Use PTRACE_GETREGS/PTRACE_SETREGS to update rip Use PTRACE_POKEUSER to update rip is unsupported for x32. We should use PTRACE_GETREGS/PTRACE_SETREGS to update rip. --- tests/backtrace.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/tests/backtrace.c b/tests/backtrace.c index ab4110f..05cc0f6 100644 --- a/tests/backtrace.c +++ b/tests/backtrace.c @@ -260,9 +260,13 @@ prepare_thread (pid_t pid2 __attribute__ ((unused)), abort (); #else /* x86_64 */ long l; + struct user_regs_struct user_regs; errno = 0; - l = ptrace (PTRACE_POKEUSER, pid2, - (void *) (intptr_t) offsetof (struct user_regs_struct, rip), jmp); + l = ptrace (PTRACE_GETREGS, pid2, 0, (intptr_t) &user_regs); + assert_perror (errno); + assert (l == 0); + user_regs.rip = (intptr_t) jmp; + l = ptrace (PTRACE_SETREGS, pid2, 0, (intptr_t) &user_regs); assert_perror (errno); assert (l == 0); l = ptrace (PTRACE_CONT, pid2, NULL, (void *) (intptr_t) SIGUSR2); @@ -381,7 +385,7 @@ exec_dump (const char *exec) #ifndef __x86_64__ is_x86_64_native = false; #else /* __x86_64__ */ - is_x86_64_native = ehdr->e_ident[EI_CLASS] == ELFCLASS64; + is_x86_64_native = ehdr->e_machine == EM_X86_64; #endif /* __x86_64__ */ void (*jmp) (void) = 0; if (is_x86_64_native) -- 1.9.3
