RE: [PATCH][PR threads/15824] when get threads name failed from info threads with linux kernel version earlier than 2.6.33

Will Huang
2013-08-19T02:52:46Z

Thanks Yao,
Ok, switch to mainline. Patch is updated, please review it again. Thanks.

diff -ruN ./gdb.org/ChangeLog ./gdb/ChangeLog
--- ./gdb.org/ChangeLog 2013-08-16 12:30:22.000000000 +0800
+++ ./gdb/ChangeLog 2013-08-19 09:39:32.000000000 +0800
@@ -1,3 +1,11 @@
+2013-08-14 Will Huang <will.huang@aliyun-inc.com>
+
+ PR threads/15824
+ * linux-nat.c (linux_nat_thread_name): Add get thread name from
+ procfs "/proc/$pid/task/$tid/status".
+ * commo/linux-procfs.c (linux_proc_get_thread_name): New.
+ (linux_proc_get_string): New.
+
2013-08-15 Kevin Buettner <kevinb@redhat.com>

* rl78-tdep.c (RL78_RAW_PC_REGNUM): New enum.
diff -ruN ./gdb.org/common/linux-procfs.c ./gdb/common/linux-procfs.c
--- ./gdb.org/common/linux-procfs.c 2013-04-23 00:46:15.000000000 +0800
+++ ./gdb/common/linux-procfs.c 2013-08-19 10:32:55.000000000 +0800
@@ -56,6 +56,57 @@
return retval;
}

+
+/* Return the string length of FILED /proc/LWPID/task/TID/status.
+ Return -1 if not found. */
+
+static int
+linux_proc_get_string (pid_t lwpid, pid_t tid, char *target,
+ size_t t_size, const char *field)
+{
+ size_t field_len = strlen (field);
+ FILE *status_file;
+ char buf[100];
+ int retval = -1;
+
+ if (tid > 0)
+ xsnprintf (buf, sizeof (buf), "/proc/%d/task/%d/status",
+ (int) lwpid, (int) tid);
+ else
+ {
+ /*if TID is zero, ingnore it */
+ xsnprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
+ }
+
+ status_file = gdb_fopen_cloexec (buf, "r");
+ if (status_file == NULL)
+ {
+ warning (_("unable to open /proc file '%s'"), buf);
+ return -1;
+ }
+
+ while (fgets (buf, sizeof (buf), status_file))
+ if (strncmp (buf, field, field_len) == 0 && buf[field_len] == ':')
+ {
+ size_t pos = field_len + 1;
+
+ while ((buf[pos] == ' ' || buf[pos] == '\t')
+ && (pos < sizeof (buf) - 1))
+ pos++;
+
+ strncpy (target, &buf[pos], t_size);
+ target[t_size - 1] = '\0';
+ retval = strlen (target);
+ if (retval > 0 && target[retval - 1] == '\n')
+ target[retval - 1] = '\0';
+
+ break;
+ }
+
+ fclose (status_file);
+ return retval;
+}
+
/* Return the TGID of LWPID from /proc/pid/status. Returns -1 if not
found. */

@@ -119,3 +170,13 @@
{
return linux_proc_pid_has_state (pid, "Z (zombie)");
}
+
+/* Save the name of thread PID/TID into buffer NAME. SIZE is the size
+ of buffer NAME. Return the length of the name if success,
+ otherwise return -1. */
+
+int
+linux_proc_get_thread_name (pid_t pid, pid_t tid, char *name, size_t size)
+{
+ return linux_proc_get_string (pid, tid, name, size, "Name");
+}
diff -ruN ./gdb.org/common/linux-procfs.h ./gdb/common/linux-procfs.h
--- ./gdb.org/common/linux-procfs.h 2013-01-01 14:32:54.000000000 +0800
+++ ./gdb/common/linux-procfs.h 2013-08-19 10:32:57.000000000 +0800
@@ -40,4 +40,10 @@

extern int linux_proc_pid_is_zombie (pid_t pid);

+/* Save the name of thread PID/TID into buffer NAME. SIZE is the size
+ of buffer NAME. Return the length of the name if success,
+ otherwise return -1. */
+
+extern int linux_proc_get_thread_name (pid_t pid, pid_t tid,
+ char *name, size_t size);
#endif /* COMMON_LINUX_PROCFS_H */
diff -ruN ./gdb.org/linux-nat.c ./gdb/linux-nat.c
--- ./gdb.org/linux-nat.c 2013-07-01 19:28:30.000000000 +0800
+++ ./gdb/linux-nat.c 2013-08-19 09:45:34.000000000 +0800
@@ -4291,6 +4291,17 @@
fclose (comm_file);
}

+ else
+ {
+ static char comm[COMM_LEN + 1];
+ int size = linux_proc_get_thread_name ((pid_t) pid, (pid_t) lwp,
+ comm, COMM_LEN + 1);
+
+ if (size > 0)
+ result = comm;
+
+ }
+
#undef COMM_LEN
#undef FORMAT

diff -ruN ./gdb.org/testsuite/ChangeLog ./gdb/testsuite/ChangeLog
--- ./gdb.org/testsuite/ChangeLog 2013-08-17 01:44:21.000000000 +0800
+++ ./gdb/testsuite/ChangeLog 2013-08-19 09:46:08.000000000 +0800
@@ -1,3 +1,9 @@
+2013-08-14 Will Huang <will.huang@aliyun-inc.com>
+
+ PR threads/15824
+ * gdb.threads/manythreads.exp: Add test for get thread
+ original name.
+
2013-08-16 Doug Evans <dje@google.com>

* lib/prelink-support.exp (prelink_yes): Flag test as unsupported if
diff -ruN ./gdb.org/testsuite/gdb.threads/manythreads.exp ./gdb/testsuite/gdb.threads/manythreads.exp
--- ./gdb.org/testsuite/gdb.threads/manythreads.exp 2013-01-01 14:41:27.000000000 +0800
+++ ./gdb/testsuite/gdb.threads/manythreads.exp 2013-08-19 09:47:10.000000000 +0800
@@ -93,6 +93,7 @@
}
}

+gdb_test "info threads" ".*manythreads.*" "check thread original name"
gdb_test_no_output "thread name zardoz" "give a name to the thread"
gdb_test "info threads" ".*zardoz.*" "check thread name"

Thanks,
Will.huang

> -----Original Message-----
> From: Yao Qi [mailto:yao@codesourcery.com]
> Sent: Friday, August 16, 2013 7:29 PM
> To: Will Huang
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH][PR threads/15824] when get threads name failed from info
> threads with linux kernel version earlier than 2.6.33
>
> On 08/16/2013 06:22 PM, Will Huang wrote:
> > Sorry for mistakes. There is no gdb_fopen_cloexec in gdb-7.6. Except that
> all comments are accepted.
> >
>
> Are you proposing a patch for GDB 7.6 tree only? This problem exists on
> mainline too. We post patch for mainline, and backport the patch to internal
> tree or older tree.
>
> > +
> > +static int
> > +linux_proc_get_string (pid_t lwpid, pid_t tid, char *target,
> > + size_t t_size, const char *field) {
> > + size_t field_len = strlen (field);
> > + FILE *status_file;
> > + char buf[100];
> > + int retval = -1;
> > +
> > + if (tid > 0)
> > + xsnprintf (buf, sizeof (buf), "/proc/%d/task/%d/status",
> > + (int) lwpid, (int) tid); else {
> > + /*if TID is zero, ingnore it*/
>
> /* If TID is zero, ignore it. */
>
> > + xsnprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
> > + }
> > +
> > + status_file = fopen (buf, "r");
> > + if (status_file == NULL)
> > + {
> > + warning (_("unable to open /proc file '%s'"), buf);
> > + return -1;
> > + }
> > +
> > + while (fgets (buf, sizeof (buf), status_file))
> > + if (strncmp (buf, field, field_len) == 0 && buf[field_len] == ':')
> > + {
> > + size_t pos = field_len + 1;
>
> Blank line is needed here.
>
> > diff -ruN ./gdb.org/linux-nat.c ./gdb/linux-nat.c
> > --- ./gdb.org/linux-nat.c 2013-02-13 22:59:49.000000000 +0800
> > +++ ./gdb/linux-nat.c 2013-08-16 17:55:19.000000000 +0800
> > @@ -4294,6 +4294,15 @@
> >
> > fclose (comm_file);
> > }
> > + else
> > + {
> > + static char comm[COMM_LEN + 1];
> > + int size = linux_proc_get_thread_name ((pid_t) pid, (pid_t)
> > + lwp, comm, COMM_LEN + 1);
>
> This line is too long.
>
> Otherwise, I don't have comments to this patch.
>
> --
> Yao (齐尧)