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Re: [PATCH][PR threads/15824] when get threads name failed from info threads with linux kernel version earlier than 2.6.33
- From: Yao Qi <yao at codesourcery dot com>
- To: Will Huang <will dot huang at aliyun-inc dot com>
- Cc: <gdb-patches at sourceware dot org>
- Date: Fri, 16 Aug 2013 10:25:30 +0800
- Subject: Re: [PATCH][PR threads/15824] when get threads name failed from info threads with linux kernel version earlier than 2.6.33
- References: <00b201ce98a6$7cf69150$76e3b3f0$ at huang@aliyun-inc.com>
Hi Will,
I am not the 'right' person to review this patch, however, I find some
thing obviously incorrect. I point them out here.
On 08/14/2013 12:26 PM, Will Huang wrote:
diff -ruN ./gdb.org/ChangeLog ./gdb/ChangeLog
--- ./gdb.org/ChangeLog 2013-04-26 19:43:30.000000000 +0800
+++ ./gdb/ChangeLog 2013-08-14 11:09:08.000000000 +0800
@@ -1,3 +1,11 @@
+2013-08-14 Will Huang<will.huang@aliyun-inc.com>
+
+ PR threads/15824
Each line should be prefixed with 'TAB' instead of 8 spaces.
+ * 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.
+ * commo/linux-procfs.c (linux_proc_get_string): New.
^^^^^^^^^^^^^^^^^^^^^^^ Duplicated.
Only have to mention the same file once.
+
2013-04-26 Joel Brobecker<brobecker@adacore.com>
* NEWS: Change "since GDB 7.5" into "in GDB 7.6".
diff -ruN ./gdb.org/common/linux-procfs.c ./gdb/common/linux-procfs.c
--- ./gdb.org/common/linux-procfs.c 2013-01-01 14:32:54.000000000 +0800
+++ ./gdb/common/linux-procfs.c 2013-08-12 16:51:33.000000000 +0800
@@ -55,6 +55,51 @@
return retval;
}
+/* Return the string length of Name from/proc/$pid/task/$tid/status.
Space after "from" is needed.
s/Name/FIELD
s/$pid/LWPID
s/$tid/TID
+ Returns -1 if not found. */
s/Returns/Return
+
+static int
+linux_proc_get_string (pid_t lwpid, pid_t tid,
+ char *target, size_t t_size, const char *field)
"char *target" should go to the previous line.
+{
+ size_t field_len = strlen (field);
+ FILE *status_file;
+ char buf[100];
+ int retval = -1;
+
+ if (tid > 0)
+ snprintf (buf, sizeof (buf),
+ "/proc/%d/task/%d/status", (int) lwpid, (int) tid);
Use xsnprintf, and the indentation looks wrong.
+ else
+ snprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
+
Likewise. Is it a dead path? Can 'tid' be negative?
+ status_file = fopen (buf, "r");
Use gdb_fopen_cloexec?
+ 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))
Your mailer wrap this line...
+ 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. */
@@ -118,3 +163,11 @@
{
return linux_proc_pid_has_state (pid, "Z (zombie)");
}
+
+/*Get thread name identified by PID & TID*/
I am not good at comments either, but I suggest
/* 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 2013-08-12 16:50:39.000000000 +0800
@@ -40,4 +40,10 @@
extern int linux_proc_pid_is_zombie (pid_t pid);
+/* Return -1 if thread Name of tid didn't found;
Comments should be updated as what I suggested above...
+ "char *name" for thread name (need be allocated by caller). */
+
+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 2013-02-13 22:59:49.000000000 +0800
+++ ./gdb/linux-nat.c 2013-08-12 16:47:26.000000000 +0800
@@ -4294,6 +4294,14 @@
fclose (comm_file);
}
+ else
+ {
+ static char comm[COMM_LEN + 1];
+ int size = linux_proc_get_thread_name (pid, lwp, comm, COMM_LEN+1);
A blank line is needed. Space is needed before and after "+".
The type of pid is int and type of lwp is long, but the types of
parameters of linux_proc_get_thread_name are pid_t and pid_t. It is
inconsistent.
--
Yao (éå)