[LEDE-DEV] [PATCH ubox] Fix logger starvation and Add feature log priority filtering

[Ron Brash]

Hello all,

We had an issue with a customer's recent deployment and needed to
perform the following:
* Add a syslog filtering functionality into the logger
* Fix a condition where ubox's logd would continue running, but needed
to be restarted after it stopped responding after several hours (or
after a large number of logs were sent to it)

The inline patch is following the signature.

Ron Brash
CTO  & Co-founder of Atlants Embedded Inc.
www.atlantsembedded.com
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Fix for silent logging error:
* There was a condition on a custom at91 board where the
logreader/logd would starve

Add functionality to add priority parsing into the log daemon
* Previously had no way to do this with a customer's setup
---
 log/logd.c    | 14 +++++++++++++-
 log/logread.c | 27 +++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/log/logd.c b/log/logd.c
index 07aee2b..a60cb8f 100644
--- a/log/logd.c
+++ b/log/logd.c
@@ -27,6 +27,7 @@
 #include "syslog.h"

 int debug = 0;
+int priority = 7;
 static struct blob_buf b;
 static struct ubus_auto_conn conn;
 static LIST_HEAD(clients);
@@ -182,6 +183,9 @@ ubus_notify_log(struct log_head *l)
  if (list_empty(&clients))
  return;

+ if((l->priority & 7) > priority) {
+ return; // skip if greater (logger level filtering)
+ }
  blob_buf_init(&b, 0);
  blobmsg_add_string(&b, "msg", l->data);
  blobmsg_add_u32(&b, "id", l->id);
@@ -214,13 +218,21 @@ main(int argc, char **argv)
  int ch, log_size = 16;

  signal(SIGPIPE, SIG_IGN);
- while ((ch = getopt(argc, argv, "S:")) != -1) {
+ while ((ch = getopt(argc, argv, "P:S:")) != -1) {
  switch (ch) {
  case 'S':
  log_size = atoi(optarg);
  if (log_size < 1)
  log_size = 16;
  break;
+ case 'P':
+ priority = atoi(optarg);
+ if (priority < 0)
+ priority = 0;
+ else if(priority > 7) {
+ priority = 7; // bounds check
+ }
+ break;
  }
  }
  log_size *= 1024;
diff --git a/log/logread.c b/log/logread.c
index edac1d9..2032819 100644
--- a/log/logread.c
+++ b/log/logread.c
@@ -230,8 +230,10 @@ static void logread_fd_data_cb(struct ustream *s,
int bytes)
  break;

  cur_len = blob_len(a) + sizeof(*a);
- if (len < cur_len)
+ if (len < cur_len) {
+ ustream_consume(s, len);
  break;
+ }

  log_notify(a);
  ustream_consume(s, cur_len);
@@ -240,14 +242,28 @@ static void logread_fd_data_cb(struct ustream
*s, int bytes)
  uloop_end();
 }

+static void notify_fd_remove_cb();
+
 static void logread_fd_cb(struct ubus_request *req, int fd)
 {
  static struct ustream_fd test_fd;
-
+ uloop_register_notify_fd_remove(fd, notify_fd_remove_cb);
  test_fd.stream.notify_read = logread_fd_data_cb;
  ustream_fd_init(&test_fd, fd);
 }

+struct ubus_context *context;
+uint32_t ctx_id;
+struct blob_buf * bb;
+struct ubus_request request;
+
+static void notify_fd_remove_cb() {
+ ubus_lookup_id(context, "log", &ctx_id);
+ ubus_invoke_async(context, ctx_id, "read", bb->head, &request);
+ request.fd_cb = logread_fd_cb;
+ ubus_complete_request_async(context, &request);
+}
+
 int main(int argc, char **argv)
 {
  static struct ubus_request req;
@@ -361,11 +377,14 @@ int main(int argc, char **argv)
  } else {
  sender.fd = STDOUT_FILENO;
  }
-
+
+ context = ctx;
+ bb = &b;
+
  ubus_invoke_async(ctx, id, "read", b.head, &req);
  req.fd_cb = logread_fd_cb;
  ubus_complete_request_async(ctx, &req);
-
+
  uloop_run();
  ubus_free(ctx);
  uloop_done();
--