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Fetch signal information for native FreeBSD processes. 

Use the `pl_siginfo' field in the `struct ptrace_lwpinfo' object returned
by the PT_LWPINFO ptrace() request to supply the current contents of
$_siginfo for each thread.  Note that FreeBSD does not supply a way to
modify the signal information for a thread, so $_siginfo is read-only for
FreeBSD.

To handle 32-bit processes on a 64-bit host, define types for 32-bit
compatible siginfo_t and convert the 64-bit siginfo_t to the 32-bit
equivalent when supplying information for a 32-bit process.

gdb/ChangeLog:

	* fbsd-nat.c [PT_LWPINFO && __LP64__] (union sigval32)
	(struct siginfo32): New.
	[PT_LWPINFO] (fbsd_siginfo_size, fbsd_convert_siginfo): New.
	(fbsd_xfer_partial) [PT_LWPINFO]: Handle TARGET_OBJECT_SIGNAL_INFO
	via ptrace(PT_LWPINFO).
This commit is contained in:
John Baldwin 2017-06-28 09:53:06 -07:00
parent 762c974a09
commit 929edea98d
2 changed files with 170 additions and 0 deletions
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8
gdb/ChangeLog
View File

@ -1,3 +1,11 @@
2017-07-07 John Baldwin <jhb@FreeBSD.org>
* fbsd-nat.c [PT_LWPINFO && __LP64__] (union sigval32)
(struct siginfo32): New.
[PT_LWPINFO] (fbsd_siginfo_size, fbsd_convert_siginfo): New.
(fbsd_xfer_partial) [PT_LWPINFO]: Handle TARGET_OBJECT_SIGNAL_INFO
via ptrace(PT_LWPINFO).
2017-07-07 John Baldwin <jhb@FreeBSD.org>
* fbsd-tdep.c (fbsd_gdbarch_data_handle, struct fbsd_gdbarch_data)

162
gdb/fbsd-nat.c
View File

@ -28,6 +28,7 @@
#include <sys/types.h>
#include <sys/procfs.h>
#include <sys/ptrace.h>
#include <sys/signal.h>
#include <sys/sysctl.h>
#ifdef HAVE_KINFO_GETVMMAP
#include <sys/user.h>
@ -216,6 +217,135 @@ static enum target_xfer_status (*super_xfer_partial) (struct target_ops *ops,
ULONGEST len,
ULONGEST *xfered_len);
#ifdef PT_LWPINFO
/* Return the size of siginfo for the current inferior. */
#ifdef __LP64__
union sigval32 {
int sival_int;
uint32_t sival_ptr;
};
/* This structure matches the naming and layout of `siginfo_t' in
<sys/signal.h>. In particular, the `si_foo' macros defined in that
header can be used with both types to copy fields in the `_reason'
union. */
struct siginfo32
{
int si_signo;
int si_errno;
int si_code;
__pid_t si_pid;
__uid_t si_uid;
int si_status;
uint32_t si_addr;
union sigval32 si_value;
union
{
struct
{
int _trapno;
} _fault;
struct
{
int _timerid;
int _overrun;
} _timer;
struct
{
int _mqd;
} _mesgq;
struct
{
int32_t _band;
} _poll;
struct
{
int32_t __spare1__;
int __spare2__[7];
} __spare__;
} _reason;
};
#endif
static size_t
fbsd_siginfo_size ()
{
#ifdef __LP64__
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If so, use the 32-bit siginfo size. */
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
return sizeof (struct siginfo32);
#endif
return sizeof (siginfo_t);
}
/* Convert a native 64-bit siginfo object to a 32-bit object. Note
that FreeBSD doesn't support writing to $_siginfo, so this only
needs to convert one way. */
static void
fbsd_convert_siginfo (siginfo_t *si)
{
#ifdef __LP64__
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If not, nothing to do. */
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word != 32)
return;
struct siginfo32 si32;
si32.si_signo = si->si_signo;
si32.si_errno = si->si_errno;
si32.si_code = si->si_code;
si32.si_pid = si->si_pid;
si32.si_uid = si->si_uid;
si32.si_status = si->si_status;
si32.si_addr = (uintptr_t) si->si_addr;
/* If sival_ptr is being used instead of sival_int on a big-endian
platform, then sival_int will be zero since it holds the upper
32-bits of the pointer value. */
#if _BYTE_ORDER == _BIG_ENDIAN
if (si->si_value.sival_int == 0)
si32->si_value.sival_ptr = (uintptr_t) si->si_value.sival_ptr;
else
si32.si_value.sival_int = si->si_value.sival_int;
#else
si32.si_value.sival_int = si->si_value.sival_int;
#endif
/* Always copy the spare fields and then possibly overwrite them for
signal-specific or code-specific fields. */
si32._reason.__spare__.__spare1__ = si->_reason.__spare__.__spare1__;
for (int i = 0; i < 7; i++)
si32._reason.__spare__.__spare2__[i] = si->_reason.__spare__.__spare2__[i];
switch (si->si_signo) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
si32.si_trapno = si->si_trapno;
break;
}
switch (si->si_code) {
case SI_TIMER:
si32.si_timerid = si->si_timerid;
si32.si_overrun = si->si_overrun;
break;
case SI_MESGQ:
si32.si_mqd = si->si_mqd;
break;
}
memcpy(si, &si32, sizeof (si32));
#endif
}
#endif
/* Implement the "to_xfer_partial target_ops" method. */
static enum target_xfer_status
@ -228,6 +358,38 @@ fbsd_xfer_partial (struct target_ops *ops, enum target_object object,
switch (object)
{
#ifdef PT_LWPINFO
case TARGET_OBJECT_SIGNAL_INFO:
{
struct ptrace_lwpinfo pl;
size_t siginfo_size;
/* FreeBSD doesn't support writing to $_siginfo. */
if (writebuf != NULL)
return TARGET_XFER_E_IO;
if (inferior_ptid.lwp_p ())
pid = inferior_ptid.lwp ();
siginfo_size = fbsd_siginfo_size ();
if (offset > siginfo_size)
return TARGET_XFER_E_IO;
if (ptrace (PT_LWPINFO, pid, (PTRACE_TYPE_ARG3) &pl, sizeof (pl)) == -1)
return TARGET_XFER_E_IO;
if (!(pl.pl_flags & PL_FLAG_SI))
return TARGET_XFER_E_IO;
fbsd_convert_siginfo (&pl.pl_siginfo);
if (offset + len > siginfo_size)
len = siginfo_size - offset;
memcpy (readbuf, ((gdb_byte *) &pl.pl_siginfo) + offset, len);
*xfered_len = len;
return TARGET_XFER_OK;
}
#endif
case TARGET_OBJECT_AUXV:
{
struct cleanup *cleanup = make_cleanup (null_cleanup, NULL);