From b67aeab02c05fdd654f132a550dd4f196cb1f6d3 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Wed, 22 Mar 2017 10:35:07 -0400 Subject: [PATCH] Remove lwp -> pid conversion in linux_nat_xfer_partial 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/ and /proc/ should be the same, it's a bit safer, because: - some files under /proc// may not work if the 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 () had exited and is thus now zombie, then several files under "/proc/" won't work, while they will if you use "/proc/". 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. --- gdb/ChangeLog | 9 +++++++++ gdb/inf-ptrace.c | 2 +- gdb/linux-nat.c | 13 +++---------- 3 files changed, 13 insertions(+), 11 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a621048..8bb9e21 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2017-03-22 Simon Marchi + + * 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 * aarch64-tdep.c: Wrap locally used classes in anonymous diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c index 61d2426..f912d28 100644 --- a/gdb/inf-ptrace.c +++ b/gdb/inf-ptrace.c @@ -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) { diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 73ef2d4..dff0da5 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -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) { -- 2.7.4