[v19,14/15] log: add support for systemd journal

Message ID 20240330030429.4630-15-stephen@networkplumber.org (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series Logging unification and improvements |

Checks

Context Check Description
ci/checkpatch warning coding style issues

Commit Message

Stephen Hemminger March 30, 2024, 3 a.m. UTC
  If DPDK application is being run as a systemd service, then
it can use the journal protocol which allows putting more information
in the log such as priority and other information.

The use of journal protocol is automatically detected and
handled.  Rather than having a dependency on libsystemd,
just use the protocol directly as defined in:
	https://systemd.io/JOURNAL_NATIVE_PROTOCOL/

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 doc/guides/prog_guide/log_lib.rst   |  14 ++
 lib/eal/common/eal_common_options.c |  11 ++
 lib/eal/common/eal_options.h        |   2 +
 lib/log/log.c                       |   5 +
 lib/log/log_internal.h              |   3 +
 lib/log/log_journal.c               | 216 ++++++++++++++++++++++++++++
 lib/log/log_private.h               |   4 +
 lib/log/log_stubs.c                 |   6 +
 lib/log/meson.build                 |   5 +
 lib/log/version.map                 |   1 +
 10 files changed, 267 insertions(+)
 create mode 100644 lib/log/log_journal.c
  

Patch

diff --git a/doc/guides/prog_guide/log_lib.rst b/doc/guides/prog_guide/log_lib.rst
index abaedc7212..476dedb097 100644
--- a/doc/guides/prog_guide/log_lib.rst
+++ b/doc/guides/prog_guide/log_lib.rst
@@ -100,6 +100,20 @@  option. There are three possible settings for this option:
 
 If ``--syslog`` option is not specified, then only console (stderr) will be used.
 
+Messages can be redirected to systemd journal which is an enhanced version of syslog with the ``--log-journal`` option.
+
+There are three possible settings for this option:
+
+*auto*
+    If stderr is redirected to journal by ``systemd`` service
+    then use journal socket to instead of stderr for log.
+    This is the default.
+
+*never*
+    Do not try to use journal.
+
+*always*
+    Always try to direct messages to journal socket.
 
 
 Using Logging APIs to Generate Log Messages
diff --git a/lib/eal/common/eal_common_options.c b/lib/eal/common/eal_common_options.c
index 9ca7db04aa..9a82118184 100644
--- a/lib/eal/common/eal_common_options.c
+++ b/lib/eal/common/eal_common_options.c
@@ -74,6 +74,7 @@  eal_long_options[] = {
 	{OPT_IOVA_MODE,	        1, NULL, OPT_IOVA_MODE_NUM        },
 	{OPT_LCORES,            1, NULL, OPT_LCORES_NUM           },
 	{OPT_LOG_LEVEL,         1, NULL, OPT_LOG_LEVEL_NUM        },
+	{OPT_LOG_JOURNAL,	2, NULL, OPT_LOG_JOURNAL_NUM	  },
 	{OPT_LOG_TIMESTAMP,     2, NULL, OPT_LOG_TIMESTAMP_NUM    },
 	{OPT_TRACE,             1, NULL, OPT_TRACE_NUM            },
 	{OPT_TRACE_DIR,         1, NULL, OPT_TRACE_DIR_NUM        },
@@ -1617,6 +1618,7 @@  eal_log_level_parse(int argc, char * const argv[])
 		switch (opt) {
 		case OPT_LOG_LEVEL_NUM:
 		case OPT_SYSLOG_NUM:
+		case OPT_LOG_JOURNAL_NUM:
 		case OPT_LOG_TIMESTAMP_NUM:
 			if (eal_parse_common_option(opt, optarg, internal_conf) < 0)
 				return -1;
@@ -1843,6 +1845,14 @@  eal_parse_common_option(int opt, const char *optarg,
 			return -1;
 		}
 		break;
+
+	case OPT_LOG_JOURNAL_NUM:
+		if (eal_log_journal(optarg) < 0) {
+			EAL_LOG(ERR, "invalid parameters for --"
+				OPT_LOG_JOURNAL);
+			return -1;
+		}
+		break;
 #endif
 
 	case OPT_LOG_LEVEL_NUM:
@@ -2223,6 +2233,7 @@  eal_common_usage(void)
 	       "  --"OPT_PROC_TYPE"         Type of this process (primary|secondary|auto)\n"
 #ifndef RTE_EXEC_ENV_WINDOWS
 	       "  --"OPT_SYSLOG"[=<when>]   Enable use of syslog\n"
+	       "  --"OPT_LOG_JOURNAL"[=<when>]  Enable use of systemd journal\n"
 #endif
 	       "  --"OPT_LOG_LEVEL"=<level> Set global log level\n"
 	       "  --"OPT_LOG_LEVEL"=<type-match>:<level>\n"
diff --git a/lib/eal/common/eal_options.h b/lib/eal/common/eal_options.h
index e24c9eca53..c5a1c70288 100644
--- a/lib/eal/common/eal_options.h
+++ b/lib/eal/common/eal_options.h
@@ -35,6 +35,8 @@  enum {
 	OPT_LCORES_NUM,
 #define OPT_LOG_LEVEL         "log-level"
 	OPT_LOG_LEVEL_NUM,
+#define OPT_LOG_JOURNAL       "log-journal"
+	OPT_LOG_JOURNAL_NUM,
 #define OPT_LOG_TIMESTAMP     "log-timestamp"
 	OPT_LOG_TIMESTAMP_NUM,
 #define OPT_TRACE             "trace"
diff --git a/lib/log/log.c b/lib/log/log.c
index ddb8400d73..d97bde984e 100644
--- a/lib/log/log.c
+++ b/lib/log/log.c
@@ -515,6 +515,11 @@  eal_log_init(const char *id)
 #else
 	bool is_terminal = isatty(STDERR_FILENO);
 
+#ifdef RTE_EXEC_ENV_LINUX
+	if (log_journal_enabled(id))
+		rte_logs.print_func = journal_print;
+	else
+#endif
 	if (log_syslog_enabled(is_terminal))
 		log_syslog_open(id, is_terminal);
 	else
diff --git a/lib/log/log_internal.h b/lib/log/log_internal.h
index 7c7d44eed2..82fdc21ac2 100644
--- a/lib/log/log_internal.h
+++ b/lib/log/log_internal.h
@@ -29,6 +29,9 @@  int eal_log_save_pattern(const char *pattern, uint32_t level);
 __rte_internal
 int eal_log_syslog(const char *name);
 
+__rte_internal
+int eal_log_journal(const char *opt);
+
 /*
  * Convert log level to string.
  */
diff --git a/lib/log/log_journal.c b/lib/log/log_journal.c
new file mode 100644
index 0000000000..f7b5aafc9d
--- /dev/null
+++ b/lib/log/log_journal.c
@@ -0,0 +1,216 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include <rte_common.h>
+#include <rte_log.h>
+
+#include "log_internal.h"
+#include "log_private.h"
+
+static enum {
+	LOG_JOURNAL_NEVER = 0,	/* do not use journal */
+	LOG_JOURNAL_AUTO,	/* use if stderr is set to journal */
+	LOG_JOURNAL_ALWAYS,	/* always try to use journal */
+} log_journal_opt = LOG_JOURNAL_AUTO;
+
+static int log_journal_fd = -1;
+
+int
+eal_log_journal(const char *str)
+{
+	if (str == NULL || strcmp(str, "auto") == 0)
+		log_journal_opt = LOG_JOURNAL_AUTO;
+	else if (strcmp(str, "always") == 0)
+		log_journal_opt = LOG_JOURNAL_ALWAYS;
+	else if (strcmp(str, "never") == 0)
+		log_journal_opt = LOG_JOURNAL_NEVER;
+	else
+		return -1;
+	return 0;
+}
+
+/*
+ * send structured message using journal protocol
+ * See: https://systemd.io/JOURNAL_NATIVE_PROTOCOL/
+ */
+static int
+journal_send(uint32_t level, const char *buf, size_t len)
+{
+	struct iovec iov[3];
+	const unsigned int niov = RTE_DIM(iov);
+	char msg[] = "MESSAGE=";
+	char pbuf[16];	/* "PRIORITY=N\n" */
+
+	iov[0].iov_base = msg;
+	iov[0].iov_len = strlen(msg);
+
+	iov[1].iov_base = (char *)(uintptr_t)buf;
+	iov[1].iov_len = len;
+
+	/* priority value between 0 ("emerg") and 7 ("debug") */
+	iov[2].iov_base = pbuf;
+	iov[2].iov_len = snprintf(pbuf, sizeof(pbuf),
+				  "PRIORITY=%i\n", level - 1);
+
+	return writev(log_journal_fd, iov, niov);
+}
+
+int
+journal_print(FILE *f __rte_unused, uint32_t level,
+	      const char *format, va_list ap)
+{
+	char *buf = NULL;
+	size_t len;
+	int ret;
+
+	len = vasprintf(&buf, format, ap);
+	if (len == 0)
+		return 0;
+
+	/* check that message ends with newline, if not add one */
+	if (buf[len - 1] != '\n') {
+		char *nbuf;
+
+		nbuf = realloc(buf, len + 1);
+		if (nbuf == NULL) {
+			free(buf);
+			return 0;
+		}
+		buf = nbuf;
+		buf[len++] = '\n';
+	}
+
+	ret = journal_send(level, buf, len);
+	free(buf);
+	return ret;
+}
+
+/* wrapper for log stream to put messages into journal */
+static ssize_t
+journal_log_write(__rte_unused void *c, const char *buf, size_t size)
+{
+	return journal_send(rte_log_cur_msg_loglevel(), buf, size);
+}
+
+static int
+journal_log_close(__rte_unused void *c)
+{
+	close(log_journal_fd);
+	log_journal_fd = -1;
+	return 0;
+}
+
+static cookie_io_functions_t journal_log_func = {
+	.write = journal_log_write,
+	.close = journal_log_close,
+};
+
+/*
+ * Check if stderr is going to system journal.
+ * This is the documented way to handle systemd journal
+ *
+ * See: https://systemd.io/JOURNAL_NATIVE_PROTOCOL/
+ *
+ */
+static bool
+is_journal(int fd)
+{
+	char *jenv, *endp = NULL;
+	struct stat st;
+	unsigned long dev, ino;
+
+	jenv = getenv("JOURNAL_STREAM");
+	if (jenv == NULL)
+		return false;
+
+	if (fstat(fd, &st) < 0)
+		return false;
+
+	/* systemd sets colon-separated list of device and inode number */
+	dev = strtoul(jenv, &endp, 10);
+	if (endp == NULL || *endp != ':')
+		return false;	/* missing colon */
+
+	ino = strtoul(endp + 1, NULL, 10);
+
+	return dev == st.st_dev && ino == st.st_ino;
+}
+
+/* Connect to systemd's journal service */
+static int
+open_journal(void)
+{
+	struct sockaddr_un sun = {
+		.sun_family = AF_UNIX,
+		.sun_path = "/run/systemd/journal/socket",
+	};
+	int s;
+
+	s = socket(AF_UNIX, SOCK_DGRAM, 0);
+	if (s < 0) {
+		perror("socket");
+		return -1;
+	}
+
+	if (connect(s, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
+		perror("connect");
+		close(s);
+		return -1;
+	}
+
+	return s;
+}
+
+bool log_journal_enabled(const char *id)
+{
+	FILE *log_stream;
+	char *syslog_id = NULL;
+	ssize_t len;
+
+	if (log_journal_opt == LOG_JOURNAL_NEVER)
+		return false;
+
+	if (log_journal_opt == LOG_JOURNAL_AUTO &&
+	    !is_journal(STDERR_FILENO))
+		return false;
+
+	log_journal_fd = open_journal();
+	if (log_journal_fd < 0)
+		return false;
+
+	/* Send identifier as first message */
+	len = asprintf(&syslog_id, "SYSLOG_IDENTIFIER=%s\nSYSLOG_PID=%u",
+		       id, getpid());
+	if (len == 0)
+		goto error;
+
+	if (write(log_journal_fd, syslog_id, len) != len) {
+		perror("write");
+		goto error;
+	}
+
+	free(syslog_id);
+
+	/* redirect other log messages to journal */
+	log_stream = fopencookie(NULL, "w", journal_log_func);
+	if (log_stream != NULL) {
+		rte_openlog_stream(log_stream);
+		return true;
+	}
+
+error:
+	free(syslog_id);
+	close(log_journal_fd);
+	log_journal_fd = -1;
+	return false;
+}
diff --git a/lib/log/log_private.h b/lib/log/log_private.h
index 0e7d10ffca..988579fc08 100644
--- a/lib/log/log_private.h
+++ b/lib/log/log_private.h
@@ -18,5 +18,9 @@  int log_print_with_timestamp(FILE *f, uint32_t level, const char *format, va_lis
 bool log_syslog_enabled(bool is_tty);
 void log_syslog_open(const char *id, bool is_terminal);
 
+bool log_journal_enabled(const char *id);
+
+__rte_format_printf(3, 0)
+int journal_print(FILE *f, uint32_t level, const char *format, va_list ap);
 
 #endif /* LOG_PRIVATE_H */
diff --git a/lib/log/log_stubs.c b/lib/log/log_stubs.c
index cb34217af8..803a6e9f6b 100644
--- a/lib/log/log_stubs.c
+++ b/lib/log/log_stubs.c
@@ -26,3 +26,9 @@  eal_log_syslog(const char *str __rte_unused)
 {
 	return -1;
 }
+
+int
+eal_log_journal(const char *str __rte_unused)
+{
+	return -1;
+}
diff --git a/lib/log/meson.build b/lib/log/meson.build
index 37507299e7..5b9be7f6f1 100644
--- a/lib/log/meson.build
+++ b/lib/log/meson.build
@@ -7,10 +7,15 @@  sources = files(
         'log_timestamp.c',
 )
 
+if is_linux
+    sources += files('log_journal.c')
+endif
+
 if is_windows
 	sources += files('log_stubs.c')
 else
 	sources += files('log_syslog.c')
 endif
 
+
 headers = files('rte_log.h')
diff --git a/lib/log/version.map b/lib/log/version.map
index 14d6681a5f..7af97ece43 100644
--- a/lib/log/version.map
+++ b/lib/log/version.map
@@ -26,6 +26,7 @@  INTERNAL {
 	global:
 
 	eal_log_init;
+	eal_log_journal;
 	eal_log_level2str;
 	eal_log_save_pattern;
 	eal_log_save_regexp;