[PATCH] ptrace debug

[Cyrill Gorcunov]

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
 ptrace.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/ptrace.c b/ptrace.c
index 0140918..cdc9c38 100644
--- a/ptrace.c
+++ b/ptrace.c
@@ -36,6 +36,29 @@ int unseize_task(pid_t pid, int st)
 	return ptrace(PTRACE_DETACH, pid, NULL, NULL);
 }
 
+static char *task_comm(pid_t pid)
+{
+	static char comm[32];
+	char path[64];
+	int fd;
+
+	snprintf(path, sizeof(path), "/proc/%d/comm", pid);
+
+	fd = open(path, O_RDONLY);
+	if (fd >= 0) {
+		size_t ret;
+
+		ret = read(fd, comm, sizeof(comm) - 1);
+		if (ret < 0)
+			ret = 1;
+		comm[ret - 1] = '\0';
+		close(fd);
+		return comm;
+	}
+
+	return NULL;
+}
+
 /*
  * This routine seizes task putting it into a special
  * state where we can manipulate the task via ptrace
@@ -71,8 +94,8 @@ int seize_task(pid_t pid, pid_t ppid, pid_t *pgid, pid_t *sid)
 
 	if (ret < 0) {
 		if (ps.state != 'Z') {
-			pr_err("Unseizeable non-zombie %d found, state %c\n",
-					pid, ps.state);
+			pr_err("Unseizeable non-zombie %d (%s) found, state %c\n",
+					pid, task_comm(pid), ps.state);
 			return -1;
 		}
 
-- 
1.8.1.4


--4Ckj6UjgE2iN1+kY--