[PATCH 23/23] /proc/PID/syscall

Roland McGrath
2008-07-17T07:37:42Z

This adds /proc/PID/syscall and /proc/PID/task/TID/syscall magic files.
These use task_current_syscall() to show the task's current system call
number and argument registers, stack pointer and PC. For a task blocked
but not in a syscall, the file shows "-1" in place of the syscall number,
followed by only the SP and PC. For a task that's not blocked, it shows
"running".

Signed-off-by: Roland McGrath <roland@redhat.com>
---
fs/proc/base.c | 26 ++++++++++++++++++++++++++
1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6f21daa..6c950c7 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -509,6 +509,26 @@ static int proc_pid_limits(struct task_struct *task, char *buffer)
return count;
}

+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+static int proc_pid_syscall(struct task_struct *task, char *buffer)
+{
+ long nr;
+ unsigned long args[6], sp, pc;
+
+ if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
+ return sprintf(buffer, "running\n");
+
+ if (nr < 0)
+ return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
+
+ return sprintf(buffer,
+ "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+ nr,
+ args[0], args[1], args[2], args[3], args[4], args[5],
+ sp, pc);
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
+
/************************************************************************/
/* Here the fs part begins */
/************************************************************************/
@@ -2425,6 +2445,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+ INF("syscall", S_IRUSR, pid_syscall),
+#endif
INF("cmdline", S_IRUGO, pid_cmdline),
ONE("stat", S_IRUGO, tgid_stat),
ONE("statm", S_IRUGO, pid_statm),
@@ -2757,6 +2780,9 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+ INF("syscall", S_IRUSR, pid_syscall),
+#endif
INF("cmdline", S_IRUGO, pid_cmdline),
ONE("stat", S_IRUGO, tid_stat),
ONE("statm", S_IRUGO, pid_statm),