OpenE2K/binutils-gdb
12
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Remove lwp -> pid conversion in linux_nat_xfer_partial

Browse Source 
The linux_nat_xfer_partial does a conversion of inferior_ptid: if it's
an LWP (ptid::lwp != 0), it builds a new ptid with the lwp as
the pid and assigns that temporarily to inferior_ptid.  For example, if
inferior_ptid is:

  { .pid = 1234, .lwp = 1235 }

it will assign this to inferior_ptid for the duration of the call:

  { .pid = 1235, .lwp = 0 }

Instead of doing this, this patch teaches the inf-ptrace implementation
of xfer_partial to deal with ptids representing lwps by using
get_ptrace_pid.

Also, in linux_proc_xfer_spu and linux_proc_xfer_partial, we use ptid_get_lwp
instead of ptid_get_pid.  While not strictly necessary, since the content of
/proc/<pid> and /proc/<lwp> should be the same, it's a bit safer, because:

- some files under /proc/<pid>/ may not work if the <pid> thread is
  running, just like ptrace requires a stopped thread.  The current
  thread's lwp id is more likely to be in the necessary state (stopped).

- if the leader (<pid>) had exited and is thus now zombie, then several
  files under "/proc/<pid>" won't work, while they will if you use
  "/proc/<lwp>".

The testsuite found no regression on native amd64 linux.

gdb/ChangeLog:

	* inf-ptrace.c (inf_ptrace_xfer_partial): Get pid from ptid
	using get_ptrace_pid.
	* linux-nat.c (linux_nat_xfer_partial): Don't set/restore
	inferior_ptid.
	(linux_proc_xfer_partial, linux_proc_xfer_spu): Use lwp of
	inferior_ptid instead of pid.
This commit is contained in:
Simon Marchi 2017-03-22 10:35:07 -04:00 committed by Simon Marchi
parent 11997a83a0
commit b67aeab02c
3 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gdb/ChangeLog
View File

@ -1,3 +1,12 @@
2017-03-22 Simon Marchi <simon.marchi@polymtl.ca>
* inf-ptrace.c (inf_ptrace_xfer_partial): Get pid from ptid
using get_ptrace_pid.
* linux-nat.c (linux_nat_xfer_partial): Don't set/restore
inferior_ptid.
(linux_proc_xfer_partial, linux_proc_xfer_spu): Use lwp of
inferior_ptid instead of pid.
2017-03-22 Yao Qi <yao.qi@linaro.org>
* aarch64-tdep.c: Wrap locally used classes in anonymous

2
gdb/inf-ptrace.c
View File

@ -520,7 +520,7 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
{
pid_t pid = ptid_get_pid (inferior_ptid);
pid_t pid = get_ptrace_pid (inferior_ptid);
switch (object)
{

13
gdb/linux-nat.c
View File

@ -3890,7 +3890,6 @@ linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
{
struct cleanup *old_chain;
enum target_xfer_status xfer;
if (object == TARGET_OBJECT_SIGNAL_INFO)
@ -3903,15 +3902,9 @@ linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
return TARGET_XFER_EOF;
old_chain = save_inferior_ptid ();
if (ptid_lwp_p (inferior_ptid))
inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
offset, len, xfered_len);
do_cleanups (old_chain);
return xfer;
}
@ -4001,8 +3994,8 @@ linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
/* We could keep this file open and cache it - possibly one per
thread. That requires some juggling, but is even faster. */
xsnprintf (filename, sizeof filename, "/proc/%d/mem",
ptid_get_pid (inferior_ptid));
xsnprintf (filename, sizeof filename, "/proc/%ld/mem",
ptid_get_lwp (inferior_ptid));
fd = gdb_open_cloexec (filename, ((readbuf ? O_RDONLY : O_WRONLY)
| O_LARGEFILE), 0);
if (fd == -1)
@ -4095,7 +4088,7 @@ linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
char buf[128];
int fd = 0;
int ret = -1;
int pid = ptid_get_pid (inferior_ptid);
int pid = ptid_get_lwp (inferior_ptid);
if (!annex)
{