[dpdk-dev] [PATCH v10 01/12] eal: add option register infrastructure

[Harry van Haaren <harry.van.haaren@intel.com>]

From: Kevin Laatz <kevin.laatz@intel.com>

This commit adds infrastructure to EAL that allows an application to
register it's init function with EAL. This allows libraries to be
initialized at the end of EAL init.

This infrastructure allows libraries that depend on EAL to be initialized
as part of EAL init, removing circular dependency issues.

Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 lib/librte_eal/bsdapp/eal/Makefile         |  1 +
 lib/librte_eal/bsdapp/eal/eal.c            | 14 ++++-
 lib/librte_eal/common/Makefile             |  1 +
 lib/librte_eal/common/eal_private.h        | 21 ++++++++
 lib/librte_eal/common/include/rte_option.h | 63 ++++++++++++++++++++++
 lib/librte_eal/common/meson.build          |  2 +
 lib/librte_eal/common/rte_option.c         | 54 +++++++++++++++++++
 lib/librte_eal/linuxapp/eal/Makefile       |  1 +
 lib/librte_eal/linuxapp/eal/eal.c          | 14 ++++-
 lib/librte_eal/rte_eal_version.map         |  1 +
 10 files changed, 170 insertions(+), 2 deletions(-)
 create mode 100644 lib/librte_eal/common/include/rte_option.h
 create mode 100644 lib/librte_eal/common/rte_option.c

diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
index d19f53c1e..bfeddaadc 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -67,6 +67,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += malloc_elem.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += malloc_heap.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += malloc_mp.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += rte_keepalive.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += rte_option.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += rte_service.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += rte_reciprocal.c
 
diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index f94c5c5f4..11cbda964 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -42,6 +42,7 @@
 #include <rte_devargs.h>
 #include <rte_version.h>
 #include <rte_vfio.h>
+#include <rte_option.h>
 #include <rte_atomic.h>
 #include <malloc_heap.h>
 
@@ -414,12 +415,20 @@ eal_parse_args(int argc, char **argv)
 	argvopt = argv;
 	optind = 1;
 	optreset = 1;
+	opterr = 0;
 
 	while ((opt = getopt_long(argc, argvopt, eal_short_options,
 				  eal_long_options, &option_index)) != EOF) {
 
-		/* getopt is not happy, stop right now */
+		/*
+		 * getopt didn't recognise the option, lets parse the
+		 * registered options to see if the flag is valid
+		 */
 		if (opt == '?') {
+			ret = rte_option_parse(argv[optind-1]);
+			if (ret == 0)
+				continue;
+
 			eal_usage(prgname);
 			ret = -1;
 			goto out;
@@ -791,6 +800,9 @@ rte_eal_init(int argc, char **argv)
 
 	rte_eal_mcfg_complete();
 
+	/* Call each registered callback, if enabled */
+	rte_option_init();
+
 	return fctret;
 }
 
diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile
index cca68826f..87d8c455d 100644
--- a/lib/librte_eal/common/Makefile
+++ b/lib/librte_eal/common/Makefile
@@ -12,6 +12,7 @@ INC += rte_tailq.h rte_interrupts.h rte_alarm.h
 INC += rte_string_fns.h rte_version.h
 INC += rte_eal_memconfig.h rte_malloc_heap.h
 INC += rte_hexdump.h rte_devargs.h rte_bus.h rte_dev.h rte_class.h
+INC += rte_option.h
 INC += rte_pci_dev_feature_defs.h rte_pci_dev_features.h
 INC += rte_malloc.h rte_keepalive.h rte_time.h
 INC += rte_service.h rte_service_component.h
diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index b189d675d..442c6dc48 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -349,4 +349,25 @@ dev_sigbus_handler_register(void);
 int
 dev_sigbus_handler_unregister(void);
 
+/**
+ * Check if the option is registered.
+ *
+ * @param option
+ *  The option to be parsed.
+ *
+ * @return
+ *  0 on success
+ * @return
+ *  -1 on fail
+ */
+int
+rte_option_parse(const char *opt);
+
+/**
+ * Iterate through the registered options and execute the associated
+ * callback if enabled.
+ */
+void
+rte_option_init(void);
+
 #endif /* _EAL_PRIVATE_H_ */
diff --git a/lib/librte_eal/common/include/rte_option.h b/lib/librte_eal/common/include/rte_option.h
new file mode 100644
index 000000000..8957b970c
--- /dev/null
+++ b/lib/librte_eal/common/include/rte_option.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Intel Corporation.
+ */
+
+#ifndef __INCLUDE_RTE_OPTION_H__
+#define __INCLUDE_RTE_OPTION_H__
+
+/**
+ * @file
+ *
+ * This API offers the ability to register options to the EAL command line and
+ * map those options to functions that will be executed at the end of EAL
+ * initialization. These options will be available as part of the EAL command
+ * line of applications and are dynamically managed.
+ *
+ * This is used primarily by DPDK libraries offering command line options.
+ * Currently, this API is limited to registering options without argument.
+ *
+ * The register API can be used to resolve circular dependency issues
+ * between EAL and the library. The library uses EAL, but is also initialized
+ * by EAL. Hence, EAL depends on the init function of the library. The API
+ * introduced in rte_option allows us to register the library init with EAL
+ * (passing a function pointer) and avoid the circular dependency.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef int (*rte_option_cb)(void);
+
+/*
+ * Structure describing the EAL command line option being registered.
+ */
+struct rte_option {
+	TAILQ_ENTRY(rte_option) next; /**< Next entry in the list. */
+	char *opt_str;             /**< The option name. */
+	rte_option_cb cb;          /**< Function called when option is used. */
+	int enabled;               /**< Set when the option is used. */
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Register an option to the EAL command line.
+ * When recognized, the associated function will be executed at the end of EAL
+ * initialization.
+ *
+ * The associated structure must be available the whole time this option is
+ * registered (i.e. not stack memory).
+ *
+ * @param opt
+ *  Structure describing the option to parse.
+ */
+void __rte_experimental
+rte_option_register(struct rte_option *opt);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/lib/librte_eal/common/meson.build b/lib/librte_eal/common/meson.build
index 04c414356..2a10d57d8 100644
--- a/lib/librte_eal/common/meson.build
+++ b/lib/librte_eal/common/meson.build
@@ -34,6 +34,7 @@ common_sources = files(
 	'malloc_mp.c',
 	'rte_keepalive.c',
 	'rte_malloc.c',
+	'rte_option.c',
 	'rte_reciprocal.c',
 	'rte_service.c'
 )
@@ -71,6 +72,7 @@ common_headers = files(
 	'include/rte_malloc_heap.h',
 	'include/rte_memory.h',
 	'include/rte_memzone.h',
+	'include/rte_option.h',
 	'include/rte_pci_dev_feature_defs.h',
 	'include/rte_pci_dev_features.h',
 	'include/rte_per_lcore.h',
diff --git a/lib/librte_eal/common/rte_option.c b/lib/librte_eal/common/rte_option.c
new file mode 100644
index 000000000..02d59a869
--- /dev/null
+++ b/lib/librte_eal/common/rte_option.c
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Intel Corporation.
+ */
+
+#include <unistd.h>
+#include <string.h>
+
+#include <rte_eal.h>
+#include <rte_option.h>
+
+#include "eal_private.h"
+
+TAILQ_HEAD(rte_option_list, rte_option);
+
+struct rte_option_list rte_option_list =
+	TAILQ_HEAD_INITIALIZER(rte_option_list);
+
+static struct rte_option *option;
+
+int
+rte_option_parse(const char *opt)
+{
+	/* Check if the option is registered */
+	TAILQ_FOREACH(option, &rte_option_list, next) {
+		if (strcmp(opt, option->opt_str) == 0) {
+			option->enabled = 1;
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+void __rte_experimental
+rte_option_register(struct rte_option *opt)
+{
+	TAILQ_FOREACH(option, &rte_option_list, next) {
+		if (strcmp(opt->opt_str, option->opt_str) == 0)
+			RTE_LOG(INFO, EAL, "Option %s has already been registered.",
+					opt->opt_str);
+			return;
+	}
+
+	TAILQ_INSERT_HEAD(&rte_option_list, opt, next);
+}
+
+void
+rte_option_init(void)
+{
+	TAILQ_FOREACH(option, &rte_option_list, next) {
+		if (option->enabled)
+			option->cb();
+	}
+}
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index 728088594..51deb5797 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -75,6 +75,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += malloc_elem.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += malloc_heap.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += malloc_mp.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += rte_keepalive.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += rte_option.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += rte_service.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += rte_reciprocal.c
 
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 76536bae2..930070e43 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -48,6 +48,7 @@
 #include <rte_atomic.h>
 #include <malloc_heap.h>
 #include <rte_vfio.h>
+#include <rte_option.h>
 
 #include "eal_private.h"
 #include "eal_thread.h"
@@ -600,12 +601,20 @@ eal_parse_args(int argc, char **argv)
 
 	argvopt = argv;
 	optind = 1;
+	opterr = 0;
 
 	while ((opt = getopt_long(argc, argvopt, eal_short_options,
 				  eal_long_options, &option_index)) != EOF) {
 
-		/* getopt is not happy, stop right now */
+		/*
+		 * getopt didn't recognise the option, lets parse the
+		 * registered options to see if the flag is valid
+		 */
 		if (opt == '?') {
+			ret = rte_option_parse(argv[optind-1]);
+			if (ret == 0)
+				continue;
+
 			eal_usage(prgname);
 			ret = -1;
 			goto out;
@@ -1080,6 +1089,9 @@ rte_eal_init(int argc, char **argv)
 
 	rte_eal_mcfg_complete();
 
+	/* Call each registered callback, if enabled */
+	rte_option_init();
+
 	return fctret;
 }
 
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index f4a2b38fd..5b6d91ffd 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -350,6 +350,7 @@ EXPERIMENTAL {
 	rte_mp_request_sync;
 	rte_mp_request_async;
 	rte_mp_sendmsg;
+	rte_option_register;
 	rte_service_lcore_attr_get;
 	rte_service_lcore_attr_reset_all;
 	rte_service_may_be_active;
-- 
2.17.1