Re: [RFA] handle android bionic ptrace in gdbserver.

Thiago Jung Bauermann
2012-03-30T20:29:23Z

On Thu, 2012-03-29 at 17:42 +0100, Pedro Alves wrote:
> On 03/28/2012 01:26 AM, Thiago Jung Bauermann wrote:
> > Good catch, that's what happened indeed. I don't know what would be the
> > correct fix. I changed the types of the variables that are passed to
> > ptrace from int to long. At least it hurts the eyes less than two casts
>
> > in a row.
>
> :-)
>
> Honestly, I'd prefer the double cast, in order to leave the ptrace arg
> type intricacy closest the the ptrace call as possible, instead of that care
> being spread and diluted about. It's also what other places in the code
> base already do (both gdb and gdbserver).

Makes sense. I'm still wondering why the current code works on 64 bit
Linux platforms though.

Updated patch follows.

--
[]'s
Thiago Jung Bauermann
Linaro Toolchain Working Group

2012-03-30 Thiago Jung Bauermann <thiago.bauermann@linaro.org>

* linux-low.h (PTRACE_ARG3_TYPE): Move macro from linux-low.c.
(PTRACE_ARG4_TYPE): Likewise.
(PTRACE_XFER_TYPE): Likewise.
* linux-arm-low.c (arm_prepare_to_resume): Cast third argument of
ptrace to PTRACE_ARG3_TYPE.
* linux-low.c (PTRACE_ARG3_TYPE): Move macro to linux-low.h.
(PTRACE_ARG4_TYPE): Likewise.
(PTRACE_XFER_TYPE): Likewise.
(linux_detach_one_lwp): Cast fourth argument of
ptrace to long then PTRACE_ARG4_TYPE.
(regsets_fetch_inferior_registers): Cast third argument of
ptrace to long then PTRACE_ARG3_TYPE.
(regsets_store_inferior_registers): Likewise.

diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index bf1792b..c4d2000 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -709,13 +709,15 @@ arm_prepare_to_resume (struct lwp_info *lwp)
errno = 0;

if (arm_hwbp_control_is_enabled (proc_info->bpts[i].control))
- if (ptrace (PTRACE_SETHBPREGS, pid, ((i << 1) + 1),
- &proc_info->bpts[i].address) < 0)
+ if (ptrace (PTRACE_SETHBPREGS, pid,
+ (PTRACE_ARG3_TYPE) ((i << 1) + 1),
+ &proc_info->bpts[i].address) < 0)
perror_with_name ("Unexpected error setting breakpoint address");

if (arm_hwbp_control_is_initialized (proc_info->bpts[i].control))
- if (ptrace (PTRACE_SETHBPREGS, pid, ((i << 1) + 2),
- &proc_info->bpts[i].control) < 0)
+ if (ptrace (PTRACE_SETHBPREGS, pid,
+ (PTRACE_ARG3_TYPE) ((i << 1) + 2),
+ &proc_info->bpts[i].control) < 0)
perror_with_name ("Unexpected error setting breakpoint");

lwp_info->bpts_changed[i] = 0;
@@ -727,13 +729,15 @@ arm_prepare_to_resume (struct lwp_info *lwp)
errno = 0;

if (arm_hwbp_control_is_enabled (proc_info->wpts[i].control))
- if (ptrace (PTRACE_SETHBPREGS, pid, -((i << 1) + 1),
- &proc_info->wpts[i].address) < 0)
+ if (ptrace (PTRACE_SETHBPREGS, pid,
+ (PTRACE_ARG3_TYPE) -((i << 1) + 1),
+ &proc_info->wpts[i].address) < 0)
perror_with_name ("Unexpected error setting watchpoint address");

if (arm_hwbp_control_is_initialized (proc_info->wpts[i].control))
- if (ptrace (PTRACE_SETHBPREGS, pid, -((i << 1) + 2),
- &proc_info->wpts[i].control) < 0)
+ if (ptrace (PTRACE_SETHBPREGS, pid,
+ (PTRACE_ARG3_TYPE) -((i << 1) + 2),
+ &proc_info->wpts[i].control) < 0)
perror_with_name ("Unexpected error setting watchpoint");

lwp_info->wpts_changed[i] = 0;
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 043451d..51f6801 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -241,10 +241,6 @@ struct pending_signals
struct pending_signals *prev;
};

-#define PTRACE_ARG3_TYPE void *
-#define PTRACE_ARG4_TYPE void *
-#define PTRACE_XFER_TYPE long
-
#ifdef HAVE_LINUX_REGSETS
static char *disabled_regsets;
static int num_regsets;
@@ -1151,7 +1147,8 @@ linux_detach_one_lwp (struct inferior_list_entry *entry, void *args)
/* Finally, let it resume. */
if (the_low_target.prepare_to_resume != NULL)
the_low_target.prepare_to_resume (lwp);
- if (ptrace (PTRACE_DETACH, lwpid_of (lwp), 0, sig) < 0)
+ if (ptrace (PTRACE_DETACH, lwpid_of (lwp), 0,
+ (PTRACE_ARG4_TYPE) (long) sig) < 0)
error (_("Can't detach %s: %s"),
target_pid_to_str (ptid_of (lwp)),
strerror (errno));
@@ -3991,7 +3988,8 @@ regsets_fetch_inferior_registers (struct regcache *regcache)
data = buf;

#ifndef __sparc__
- res = ptrace (regset->get_request, pid, nt_type, data);
+ res = ptrace (regset->get_request, pid,
+ (PTRACE_ARG3_TYPE) (long) nt_type, data);
#else
res = ptrace (regset->get_request, pid, data, nt_type);
#endif
@@ -4064,7 +4062,8 @@ regsets_store_inferior_registers (struct regcache *regcache)
data = buf;

#ifndef __sparc__
- res = ptrace (regset->get_request, pid, nt_type, data);
+ res = ptrace (regset->get_request, pid,
+ (PTRACE_ARG3_TYPE) (long) nt_type, data);
#else
res = ptrace (regset->get_request, pid, data, nt_type);
#endif
@@ -4076,7 +4075,8 @@ regsets_store_inferior_registers (struct regcache *regcache)

/* Only now do we write the register set. */
#ifndef __sparc__
- res = ptrace (regset->set_request, pid, nt_type, data);
+ res = ptrace (regset->set_request, pid,
+ (PTRACE_ARG3_TYPE) (long) nt_type, data);
#else
res = ptrace (regset->set_request, pid, data, nt_type);
#endif
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 07eda12..de4d1fa 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -24,6 +24,10 @@

#include "gdb_proc_service.h"

+#define PTRACE_ARG3_TYPE void *
+#define PTRACE_ARG4_TYPE void *
+#define PTRACE_XFER_TYPE long
+
#ifdef HAVE_LINUX_REGSETS
typedef void (*regset_fill_func) (struct regcache *, void *);
typedef void (*regset_store_func) (struct regcache *, const void *);