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* i386obsd-tdep.c (i386obsd_sigreturn_offset): New variable.

Browse source 
(i386obsd_sigtramp_p): Deal with an arbitrary number of possible
offsets.
(i386obsd_aout_supply_regset): Avoid bogus cast.
This commit is contained in:
Mark Kettenis 2005-07-26 20:02:55 +00:00
parent 9cd9699237
commit 3ed8524757
2 changed files with 37 additions and 18 deletions
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7
gdb/ChangeLog
View file

@ -1,3 +1,10 @@
2005-07-26 Mark Kettenis <kettenis@gnu.org>
* i386obsd-tdep.c (i386obsd_sigreturn_offset): New variable.
(i386obsd_sigtramp_p): Deal with an arbitrary number of possible
offsets.
(i386obsd_aout_supply_regset): Avoid bogus cast.
2005-07-25 Mark Kettenis <kettenis@gnu.org>
* inf-ptrace.c [PT_GET_PROCESS_STATE] (inf_ptrace_follow_fork):

48
gdb/i386obsd-tdep.c
View file

@ -45,13 +45,25 @@
/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
in virtual memory. The randomness makes it somewhat tricky to
detect it, but fortunately we can rely on the fact that the start
of the sigtramp routine is page-aligned. By the way, the mapping
is read-only, so you cannot place a breakpoint in the signal
trampoline. */
of the sigtramp routine is page-aligned. We recognize the
trampoline by looking for the code that invokes the sigreturn
system call. The offset where we can find that code varies from
release to release.
By the way, the mapping mentioned above is read-only, so you cannot
place a breakpoint in the signal trampoline. */
/* Default page size. */
static const int i386obsd_page_size = 4096;
/* Offset for sigreturn(2). */
static const int i386obsd_sigreturn_offset[] = {
0x0a, /* OpenBSD 3.2 */
0x14, /* OpenBSD 3.6 */
0x3a, /* OpenBSD 3.8 */
-1
};
/* Return whether the frame preceding NEXT_FRAME corresponds to an
OpenBSD sigtramp routine. */
@ -60,6 +72,7 @@ i386obsd_sigtramp_p (struct frame_info *next_frame)
{
CORE_ADDR pc = frame_pc_unwind (next_frame);
CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1));
/* The call sequence invoking sigreturn(2). */
const gdb_byte sigreturn[] =
{
0xb8,
@ -67,6 +80,7 @@ i386obsd_sigtramp_p (struct frame_info *next_frame)
0xcd, 0x80 /* int $0x80 */
};
size_t buflen = sizeof sigreturn;
const int *offset;
gdb_byte *buf;
char *name;
@ -84,21 +98,18 @@ i386obsd_sigtramp_p (struct frame_info *next_frame)
/* Allocate buffer. */
buf = alloca (buflen);
/* If we can't read the instructions at START_PC, return zero. */
if (!safe_frame_unwind_memory (next_frame, start_pc + 0x0a, buf, buflen))
return 0;
/* Loop over all offsets. */
for (offset = i386obsd_sigreturn_offset; *offset != -1; offset++)
{
/* If we can't read the instructions, return zero. */
if (!safe_frame_unwind_memory (next_frame, start_pc + *offset,
buf, buflen))
return 0;
/* Check for sigreturn(2). */
if (memcmp (buf, sigreturn, buflen) == 0)
return 1;
/* If we can't read the instructions at START_PC, return zero. */
if (!safe_frame_unwind_memory (next_frame, start_pc + 0x14, buf, buflen))
return 0;
/* Check for sigreturn(2) (again). */
if (memcmp (buf, sigreturn, buflen) == 0)
return 1;
/* Check for sigreturn(2). */
if (memcmp (buf, sigreturn, buflen) == 0)
return 1;
}
return 0;
}
@ -133,11 +144,12 @@ i386obsd_aout_supply_regset (const struct regset *regset,
const void *regs, size_t len)
{
const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);
const gdb_byte *gregs = regs;
gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE);
i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset);
i387_supply_fsave (regcache, regnum, gregs + tdep->sizeof_gregset);
}
static const struct regset *