[dpdk-dev] [RFC 1/6] process-info: introduce process-info library

[Ciara Power <ciara.power@intel.com>]

From: Bruce Richardson <bruce.richardson@intel.com>

This patch introduces the process_info library. The library does socket
and connection management on a local unix socket, and allows the calling
of callback functions on receipt of a message from a connected client.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: Ciara Power <ciara.power@intel.com>

---
The library is not yet initialised to run, this will come in a later
patch integrating with the EAL library.
---
 config/common_base                            |   5 +
 lib/Makefile                                  |   1 +
 lib/librte_process_info/Makefile              |  26 ++
 lib/librte_process_info/meson.build           |   8 +
 lib/librte_process_info/process_info.c        | 231 ++++++++++++++++++
 lib/librte_process_info/rte_process_info.h    |  25 ++
 .../rte_process_info_version.map              |   6 +
 lib/meson.build                               |   1 +
 mk/rte.app.mk                                 |   1 +
 9 files changed, 304 insertions(+)
 create mode 100644 lib/librte_process_info/Makefile
 create mode 100644 lib/librte_process_info/meson.build
 create mode 100644 lib/librte_process_info/process_info.c
 create mode 100644 lib/librte_process_info/rte_process_info.h
 create mode 100644 lib/librte_process_info/rte_process_info_version.map

diff --git a/config/common_base b/config/common_base
index 7dec7ed45..5f49b934f 100644
--- a/config/common_base
+++ b/config/common_base
@@ -1093,3 +1093,8 @@ CONFIG_RTE_APP_CRYPTO_PERF=y
 # Compile the eventdev application
 #
 CONFIG_RTE_APP_EVENTDEV=y
+
+#
+# Compile the process_info library
+#
+CONFIG_RTE_LIBRTE_PROCESS_INFO=y
diff --git a/lib/Makefile b/lib/Makefile
index 46b91ae1a..466cd04ef 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -4,6 +4,7 @@
 include $(RTE_SDK)/mk/rte.vars.mk
 
 DIRS-$(CONFIG_RTE_LIBRTE_KVARGS) += librte_kvargs
+DIRS-$(CONFIG_RTE_LIBRTE_PROCESS_INFO) += librte_process_info
 DIRS-$(CONFIG_RTE_LIBRTE_EAL) += librte_eal
 DEPDIRS-librte_eal := librte_kvargs
 DIRS-$(CONFIG_RTE_LIBRTE_PCI) += librte_pci
diff --git a/lib/librte_process_info/Makefile b/lib/librte_process_info/Makefile
new file mode 100644
index 000000000..67b9a9f20
--- /dev/null
+++ b/lib/librte_process_info/Makefile
@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright 2019 Intel Corporation
+
+include $(RTE_SDK)/mk/rte.vars.mk
+
+# library name
+LIB = librte_process_info.a
+
+CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
+CFLAGS += -I$(RTE_SDK)/lib/librte_eal/common/include
+CFLAGS += -I$(RTE_SDK)/lib/librte_eal/common/include/arch/$(ARCH_DIR)/
+CFLAGS += -pthread
+LDLIBS += -pthread
+
+EXPORT_MAP := rte_process_info_version.map
+
+LIBABIVER := 1
+
+# all source are stored in SRCS-y
+SRCS-$(CONFIG_RTE_LIBRTE_KVARGS) := process_info.c
+
+# install includes
+INCS := rte_process_info.h
+SYMLINK-y-include := $(INCS)
+
+include $(RTE_SDK)/mk/rte.lib.mk
diff --git a/lib/librte_process_info/meson.build b/lib/librte_process_info/meson.build
new file mode 100644
index 000000000..42850e816
--- /dev/null
+++ b/lib/librte_process_info/meson.build
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2019 Intel Corporation
+
+includes = [global_inc]
+includes += include_directories('../librte_eal/common/include/arch/' + arch_subdir)
+
+sources = files('process_info.c')
+headers = files('rte_process_info.h')
diff --git a/lib/librte_process_info/process_info.c b/lib/librte_process_info/process_info.c
new file mode 100644
index 000000000..3959e24fa
--- /dev/null
+++ b/lib/librte_process_info/process_info.c
@@ -0,0 +1,231 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2019 Intel Corporation
+ */
+
+#include <unistd.h>
+#include <pthread.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <dlfcn.h>
+
+#include <rte_string_fns.h>
+#include <rte_common.h>
+#include <rte_spinlock.h>
+
+#include "rte_process_info.h"
+
+#define MAX_CMD_LEN 56
+
+static int
+list_commands(const char *cmd __rte_unused, const char *params __rte_unused,
+		char *buffer, int buf_len);
+
+struct cmd_callback {
+	char cmd[MAX_CMD_LEN];
+	process_info_cb fn;
+};
+
+static int sock = -1;
+static struct sockaddr_un sun;
+static char process_info_log_error[1024];
+static struct cmd_callback callbacks[PROCESS_INFO_MAX_CALLBACKS] = {
+		{ .cmd = "/", .fn = list_commands },
+};
+static int num_callbacks = 1;
+static rte_spinlock_t callback_sl = RTE_SPINLOCK_INITIALIZER;
+
+/* we won't link against libbsd, so just always use DPDKs-specific version */
+#ifndef strlcpy
+#define strlcpy rte_strlcpy
+#endif
+
+int
+rte_process_info_register(const char *cmd, process_info_cb fn)
+{
+	int i = 0;
+
+	if (strlen(cmd) >= MAX_CMD_LEN || fn == NULL)
+		return -EINVAL;
+	if (num_callbacks >= PROCESS_INFO_MAX_CALLBACKS)
+		return -ENOENT;
+	if (cmd[0] != '/')
+		return -EINVAL;
+
+	rte_spinlock_lock(&callback_sl);
+	while (i < num_callbacks && strcmp(cmd, callbacks[i].cmd) > 0)
+		i++;
+	if (i != num_callbacks)
+		memmove(callbacks + i + 1, callbacks + i,
+			sizeof(struct cmd_callback) * (num_callbacks - i));
+
+	strlcpy(callbacks[i].cmd, cmd, MAX_CMD_LEN);
+	callbacks[i].fn = fn;
+	num_callbacks++;
+	rte_spinlock_unlock(&callback_sl);
+
+	return 0;
+}
+
+static int
+list_commands(const char *cmd __rte_unused, const char *params __rte_unused,
+		char *buffer, int buf_len)
+{
+	int i, used = 0;
+
+	used += strlcpy(buffer, "[", buf_len);
+	for (i = 0; i < num_callbacks; i++)
+		used += snprintf(buffer + used, buf_len - used, "\"%s\",",
+				callbacks[i].cmd);
+	buffer[used - 1] = ']';
+	return used;
+}
+
+static void
+perform_command(process_info_cb fn, const char *cmd, const char *param, int s)
+{
+	char out_buf[1024 * 12];
+
+	int used = snprintf(out_buf,
+			sizeof(out_buf), "{\"%s\":", cmd);
+	int ret = fn(cmd, param, out_buf + used, sizeof(out_buf) - used);
+	if (ret < 0) {
+		used += strlcpy(out_buf + used, "null}\n",
+				sizeof(out_buf) - used);
+		if (write(s, out_buf, used) < 0)
+			perror("Error writing to socket");
+		return;
+	}
+	used += ret;
+	used += strlcpy(out_buf + used, "}\n", sizeof(out_buf) - used);
+	if (write(s, out_buf, used) < 0)
+		perror("Error writing to socket");
+}
+
+static int
+unknown_command(const char *cmd __rte_unused, const char *params __rte_unused,
+		char *buffer, int buf_len)
+{
+	return snprintf(buffer, buf_len, "null");
+}
+
+static void *
+client_handler(void *sock_id)
+{
+	int s = (int)(uintptr_t)sock_id;
+	char buffer[1024];
+
+	/* receive data is not null terminated */
+	int bytes = read(s, buffer, sizeof(buffer));
+	buffer[bytes] = 0;
+
+	while (bytes > 0) {
+		const char *cmd = strtok(buffer, ",");
+		const char *param = strtok(NULL, ",");
+		process_info_cb fn = unknown_command;
+		int i;
+
+		rte_spinlock_lock(&callback_sl);
+		for (i = 0; i < num_callbacks; i++)
+			if (strcmp(cmd, callbacks[i].cmd) == 0) {
+				fn = callbacks[i].fn;
+				break;
+			}
+
+		rte_spinlock_unlock(&callback_sl);
+		perform_command(fn, cmd, param, s);
+
+		bytes = read(s, buffer, sizeof(buffer));
+		buffer[bytes] = 0;
+	}
+	close(s);
+	return NULL;
+}
+
+static void *
+socket_listener(void *unused __rte_unused)
+{
+	while (1) {
+		pthread_t th;
+		int s = accept(sock, NULL, NULL);
+		if (s < 0) {
+			snprintf(process_info_log_error,
+					sizeof(process_info_log_error),
+					"Error with accept, process_info thread"
+					" quitting\n");
+			return NULL;
+		}
+		pthread_create(&th, NULL, client_handler, (void *)(uintptr_t)s);
+		pthread_detach(th);
+	}
+	return NULL;
+}
+
+static inline char *
+get_socket_path(const char *runtime_dir)
+{
+	static char path[PATH_MAX];
+
+	if (strlen(runtime_dir) == 0)
+		snprintf(path, sizeof(path), "/tmp/dpdk_process_info.%d",
+				getpid());
+	else
+		snprintf(path, sizeof(path), "%s/process_info.%d",
+				runtime_dir, getpid());
+	return path;
+}
+
+static void
+unlink_socket(void)
+{
+	if (sun.sun_path[0])
+		unlink(sun.sun_path);
+}
+
+int
+rte_process_info_init(const char *runtime_dir, const char **err_str)
+{
+	pthread_t t;
+
+	sock = socket(AF_UNIX, SOCK_SEQPACKET, 0);
+	if (sock < 0) {
+		snprintf(process_info_log_error, sizeof(process_info_log_error),
+				"Error with socket creation, %s",
+				strerror(errno));
+		*err_str = process_info_log_error;
+		return -1;
+	}
+
+	sun.sun_family = AF_UNIX;
+	if (strlcpy(sun.sun_path, get_socket_path(runtime_dir),
+			sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
+		snprintf(process_info_log_error, sizeof(process_info_log_error),
+				"Error with socket binding, path too long");
+		goto error;
+	}
+	if (bind(sock, (void *)&sun, sizeof(sun)) < 0) {
+		snprintf(process_info_log_error, sizeof(process_info_log_error),
+				"Error binding socket: %s",
+				strerror(errno));
+		sun.sun_path[0] = 0;
+		goto error;
+	}
+
+	if (listen(sock, 1) < 0) {
+		snprintf(process_info_log_error, sizeof(process_info_log_error),
+				"Error calling listen for socket: %s",
+				strerror(errno));
+		goto error;
+	}
+
+	pthread_create(&t, NULL, socket_listener, NULL);
+	atexit(unlink_socket);
+
+	return 0;
+
+error:
+	close(sock);
+	unlink_socket();
+	sock = -1;
+	*err_str = process_info_log_error;
+	return -1;
+}
diff --git a/lib/librte_process_info/rte_process_info.h b/lib/librte_process_info/rte_process_info.h
new file mode 100644
index 000000000..d8d86ef57
--- /dev/null
+++ b/lib/librte_process_info/rte_process_info.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2019 Intel Corporation
+ */
+
+#ifndef _RTE_PROCESS_INFO_H_
+#define _RTE_PROCESS_INFO_H_
+
+#include <stdint.h>
+#include <rte_compat.h>
+
+#define PROCESS_INFO_MAX_CALLBACKS 64
+
+/* callback returns json data in buffer, up to buf_len long.
+ * returns length of buffer used on success, negative on error.
+ */
+typedef int (*process_info_cb)(const char *cmd, const char *params,
+		char *buffer, int buf_len);
+
+__rte_experimental
+int rte_process_info_register(const char *cmd, process_info_cb fn);
+
+__rte_experimental
+int rte_process_info_init(const char *runtime_dir, const char **err_str);
+
+#endif
diff --git a/lib/librte_process_info/rte_process_info_version.map b/lib/librte_process_info/rte_process_info_version.map
new file mode 100644
index 000000000..7e6f68d5a
--- /dev/null
+++ b/lib/librte_process_info/rte_process_info_version.map
@@ -0,0 +1,6 @@
+EXPERIMENTAL {
+	global:
+		rte_process_info_init;
+		rte_process_info_register;
+	local: *;
+};
diff --git a/lib/meson.build b/lib/meson.build
index 6ceb5e756..fe11a02c8 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -10,6 +10,7 @@
 # core libs which are widely reused, so their deps are kept to a minimum.
 libraries = [
 	'kvargs', # eal depends on kvargs
+	'process_info', # basic info querying capability about dpdk processes
 	'eal', # everything depends on eal
 	'ring', 'mempool', 'mbuf', 'net', 'meter', 'ethdev', 'pci', # core
 	'cmdline',
diff --git a/mk/rte.app.mk b/mk/rte.app.mk
index 05ea034b9..3c61cbb67 100644
--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk
@@ -77,6 +77,7 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_HASH)           += -lrte_hash
 _LDLIBS-$(CONFIG_RTE_LIBRTE_MEMBER)         += -lrte_member
 _LDLIBS-$(CONFIG_RTE_LIBRTE_VHOST)          += -lrte_vhost
 _LDLIBS-$(CONFIG_RTE_LIBRTE_KVARGS)         += -lrte_kvargs
+_LDLIBS-$(CONFIG_RTE_LIBRTE_PROCESS_INFO)   += -lrte_process_info
 _LDLIBS-$(CONFIG_RTE_LIBRTE_MBUF)           += -lrte_mbuf
 _LDLIBS-$(CONFIG_RTE_LIBRTE_NET)            += -lrte_net
 _LDLIBS-$(CONFIG_RTE_LIBRTE_ETHER)          += -lrte_ethdev
-- 
2.17.1