[PATCH 7/7] ndctl: cxl: add monitor command to cxl

[Dave Jiang <dave.jiang@intel.com>]

Connect the monitoring functionality to the cxl monitor command. Add basic
functionality to the cxl monitor command where it can be launched as a daemon
and logging can be designated to stdout or a file.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 cxl/builtin.h |    1 +
 cxl/cxl.c     |    1 +
 cxl/monitor.c |   70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/cxl/builtin.h b/cxl/builtin.h
index b28c2213993b..34c5cfb49051 100644
--- a/cxl/builtin.h
+++ b/cxl/builtin.h
@@ -22,4 +22,5 @@ int cmd_create_region(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_enable_region(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_disable_region(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_destroy_region(int argc, const char **argv, struct cxl_ctx *ctx);
+int cmd_monitor(int argc, const char **argv, struct cxl_ctx *ctx);
 #endif /* _CXL_BUILTIN_H_ */
diff --git a/cxl/cxl.c b/cxl/cxl.c
index dd1be7a054a1..3be7026f43d3 100644
--- a/cxl/cxl.c
+++ b/cxl/cxl.c
@@ -76,6 +76,7 @@ static struct cmd_struct commands[] = {
 	{ "enable-region", .c_fn = cmd_enable_region },
 	{ "disable-region", .c_fn = cmd_disable_region },
 	{ "destroy-region", .c_fn = cmd_destroy_region },
+	{ "monitor", .c_fn = cmd_monitor },
 };
 
 int main(int argc, const char **argv)
diff --git a/cxl/monitor.c b/cxl/monitor.c
index e030542a3fe8..e185d15254ec 100644
--- a/cxl/monitor.c
+++ b/cxl/monitor.c
@@ -34,9 +34,12 @@
 const char *systems[] = { "cxl_events", "cxl_aer", NULL };
 
 static struct monitor {
+	const char *log;
 	struct log_ctx ctx;
 	FILE *log_file;
 	bool human;
+	bool verbose;
+	bool daemon;
 } monitor;
 
 static void log_standard(struct log_ctx *ctx, int priority, const char *file,
@@ -163,3 +166,70 @@ epoll_err:
 	free(events);
 	return rc;
 }
+
+int cmd_monitor(int argc, const char **argv, struct cxl_ctx *ctx)
+{
+	const struct option options[] = {
+		OPT_FILENAME('l', "log", &monitor.log,
+				"<file> | standard",
+				"where to output the monitor's notification"),
+		OPT_BOOLEAN('\0', "daemon", &monitor.daemon,
+				"run cxl monitor as a daemon"),
+		OPT_BOOLEAN('u', "human", &monitor.human,
+				"use human friendly output formats"),
+		OPT_BOOLEAN('v', "verbose", &monitor.verbose,
+				"emit extra debug messages to log"),
+		OPT_END(),
+	};
+	const char * const u[] = {
+		"cxl monitor [<options>]",
+		NULL
+	};
+	const char *prefix ="./";
+	int rc = 0, i;
+
+	argc = parse_options_prefix(argc, argv, prefix, options, u, 0);
+	for (i = 0; i < argc; i++)
+		error("unknown parameter \"%s\"\n", argv[i]);
+	if (argc)
+		usage_with_options(u, options);
+
+	log_init(&monitor.ctx, "cxl/monitor", "CXL_MONITOR_LOG");
+	monitor.ctx.log_fn = log_standard;
+
+	if (monitor.verbose)
+		monitor.ctx.log_priority = LOG_DEBUG;
+	else
+		monitor.ctx.log_priority = LOG_INFO;
+
+	if (monitor.log) {
+		if (strncmp(monitor.log, "./", 2) != 0)
+			fix_filename(prefix, (const char **)&monitor.log);
+		if (strncmp(monitor.log, "./standard", 10) == 0) {
+			monitor.ctx.log_fn = log_standard;
+		} else {
+			monitor.log_file = fopen(monitor.log, "a+");
+			if (!monitor.log_file) {
+				rc = -errno;
+				error("open %s failed: %d\n", monitor.log, rc);
+				goto out;
+			}
+			monitor.ctx.log_fn = log_file;
+		}
+	}
+
+	if (monitor.daemon) {
+		if (daemon(0, 0) != 0) {
+			err(&monitor, "daemon start failed\n");
+			goto out;
+		}
+		info(&monitor, "cxl monitor daemon started.\n");
+	}
+
+	rc = monitor_event(ctx);
+
+out:
+	if (monitor.log_file)
+		fclose(monitor.log_file);
+	return rc;
+}