eal: add telemetry callbacks

EAL now registers commands to provide some basic info from EAL.

Example:
Connecting to /var/run/dpdk/rte/dpdk_telemetry.v2
{"version": "DPDK 20.05.0-rc0", "pid": 72662, "max_output_len": 16384}
--> /
{"/": ["/", "/eal/app_params", "/eal/params", "/ethdev/link_status", \
    "/ethdev/list", "/ethdev/xstats", "/help", "/info", "/rawdev/list", \
    "/rawdev/xstats"]}
--> /eal/app_params
{"/eal/app_params": ["-i"]}
--> /eal/params
{"/eal/params": ["./app/dpdk-testpmd"]}

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: Ciara Power <ciara.power@intel.com>
Reviewed-by: Keith Wiles <keith.wiles@intel.com>

lib/librte_eal/common/eal_common_options.c

@@ -29,6 +29,9 @@
 #include <rte_version.h>
 #include <rte_devargs.h>
 #include <rte_memcpy.h>
+#ifndef RTE_EXEC_ENV_WINDOWS
+#include <rte_telemetry.h>
+#endif
 
 #include "eal_internal_cfg.h"
 #include "eal_options.h"
@@ -139,6 +142,76 @@ static int master_lcore_parsed;
 static int mem_parsed;
 static int core_parsed;
 
+#ifndef RTE_EXEC_ENV_WINDOWS
+static char **eal_args;
+static char **eal_app_args;
+
+#define EAL_PARAM_REQ "/eal/params"
+#define EAL_APP_PARAM_REQ "/eal/app_params"
+
+/* callback handler for telemetry library to report out EAL flags */
+int
+handle_eal_info_request(const char *cmd, const char *params __rte_unused,
+		struct rte_tel_data *d)
+{
+	char **args;
+	int used = 0;
+	int i = 0;
+
+	if (strcmp(cmd, EAL_PARAM_REQ) == 0)
+		args = eal_args;
+	else
+		args = eal_app_args;
+
+	rte_tel_data_start_array(d, RTE_TEL_STRING_VAL);
+	if (args == NULL || args[0] == NULL)
+		return 0;
+
+	for ( ; args[i] != NULL; i++)
+		used = rte_tel_data_add_array_string(d, args[i]);
+	return used;
+}
+
+int
+eal_save_args(int argc, char **argv)
+{
+	int i, j;
+
+	rte_telemetry_register_cmd(EAL_PARAM_REQ, handle_eal_info_request,
+			"Returns EAL commandline parameters used. Takes no parameters");
+	rte_telemetry_register_cmd(EAL_APP_PARAM_REQ, handle_eal_info_request,
+			"Returns app commandline parameters used. Takes no parameters");
+
+	/* clone argv to report out later. We overprovision, but
+	 * this does not waste huge amounts of memory
+	 */
+	eal_args = calloc(argc + 1, sizeof(*eal_args));
+	if (eal_args == NULL)
+		return -1;
+
+	for (i = 0; i < argc; i++) {
+		eal_args[i] = strdup(argv[i]);
+		if (strcmp(argv[i], "--") == 0)
+			break;
+	}
+	eal_args[i++] = NULL; /* always finish with NULL */
+
+	/* allow reporting of any app args we know about too */
+	if (i >= argc)
+		return 0;
+
+	eal_app_args = calloc(argc - i + 1, sizeof(*eal_args));
+	if (eal_app_args == NULL)
+		return -1;
+
+	for (j = 0; i < argc; j++, i++)
+		eal_app_args[j] = strdup(argv[i]);
+	eal_app_args[j] = NULL;
+
+	return 0;
+}
+#endif
+
 static int
 eal_option_device_add(enum rte_devtype type, const char *optarg)
 {

lib/librte_eal/common/eal_options.h

@@ -7,6 +7,8 @@
 
 #include "getopt.h"
 
+struct rte_tel_data;
+
 enum {
 	/* long options mapped to a short option */
 #define OPT_HELP              "help"
@@ -96,5 +98,8 @@ int eal_check_common_options(struct internal_config *internal_cfg);
 void eal_common_usage(void);
 enum rte_proc_type_t eal_proc_type_detect(void);
 int eal_plugins_init(void);
+int eal_save_args(int argc, char **argv);
+int handle_eal_info_request(const char *cmd, const char *params __rte_unused,
+		struct rte_tel_data *d);
 
 #endif /* EAL_OPTIONS_H */

lib/librte_eal/freebsd/eal.c

@@ -717,6 +717,9 @@ rte_eal_init(int argc, char **argv)
 
 	eal_reset_internal_config(&internal_config);
 
+	/* clone argv to report out later in telemetry */
+	eal_save_args(argc, argv);
+
 	/* set log level as early as possible */
 	eal_log_level_parse(argc, argv);
 

lib/librte_eal/linux/eal.c

@@ -984,6 +984,9 @@ rte_eal_init(int argc, char **argv)
 	/* set log level as early as possible */
 	eal_log_level_parse(argc, argv);
 
+	/* clone argv to report out later in telemetry */
+	eal_save_args(argc, argv);
+
 	if (rte_eal_cpu_init() < 0) {
 		rte_eal_init_alert("Cannot detect lcores.");
 		rte_errno = ENOTSUP;