log: syslog driver

Provide a log driver that broadcasts RFC 3164 messages to syslog servers.
rsyslog is one implementation of such a server.

The messages are sent to the local broadcast address 255.255.255.255 on
port 514.

The environment variable log_hostname can be used to provide the HOSTNAME
field for the messages. The optional TIMESTAMP field of RFC 3164 is not
provided.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index d8d420f84f731d0b0dd8f3cd2d4eca3ade269368..0bafe5cabca8aee398479e47228c971a9a585a95 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -654,7 +654,7 @@ LOGGING
 M:     Simon Glass <sjg@chromium.org>
 S:     Maintained
 T:     git https://gitlab.denx.de/u-boot/u-boot.git
-F:     common/log.c
+F:     common/log*
 F:     cmd/log.c
 F:     test/log/log_test.c
 F:     test/py/tests/test_log.py

diff --git a/common/Kconfig b/common/Kconfig
index 40da8fa7a3d9f8445a1a806696f3f5ac061a766d..ee4f748c32b8bf0136e3f90669915e93d217b1e1 100644 (file)
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -775,6 +775,13 @@ config TPL_LOG_CONSOLE
          log message is shown - other details like level, category, file and
          line number are omitted.
 
+config LOG_SYSLOG
+       bool "Log output to syslog server"
+       depends on LOG && NET
+       help
+         Enables a log driver which broadcasts log records via UDP port 514
+         to syslog servers.
+
 config LOG_TEST
        bool "Provide a test for logging"
        depends on LOG && UNIT_TEST

diff --git a/common/Makefile b/common/Makefile
index 702f2396cf466119f47aa218643a4d5dc9d7dd92..d84e10ba99d78df994bc31673070aeda8446de09 100644 (file)
--- a/common/Makefile
+++ b/common/Makefile
@@ -132,6 +132,7 @@ obj-$(CONFIG_DFU_OVER_USB) += dfu.o
 obj-y += command.o
 obj-$(CONFIG_$(SPL_TPL_)LOG) += log.o
 obj-$(CONFIG_$(SPL_TPL_)LOG_CONSOLE) += log_console.o
+obj-$(CONFIG_$(SPL_TPL_)LOG_SYSLOG) += log_syslog.o
 obj-y += s_record.o
 obj-$(CONFIG_CMD_LOADB) += xyzModem.o
 obj-$(CONFIG_$(SPL_TPL_)YMODEM_SUPPORT) += xyzModem.o

diff --git a/common/log_syslog.c b/common/log_syslog.c
new file mode 100644 (file)
index 0000000..5e3e20e
--- /dev/null
+++ b/common/log_syslog.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Log to syslog.
+ *
+ * Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ */
+
+#include <common.h>
+#include <log.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define BUFFER_SIZE 480
+
+static void append(char **buf, char *buf_end, const char *fmt, ...)
+{
+       va_list args;
+       size_t size = buf_end - *buf;
+
+       va_start(args, fmt);
+       vsnprintf(*buf, size, fmt, args);
+       va_end(args);
+       *buf += strlen(*buf);
+}
+
+static int log_syslog_emit(struct log_device *ldev, struct log_rec *rec)
+{
+       int ret;
+       int fmt = gd->log_fmt;
+       char msg[BUFFER_SIZE];
+       char *msg_end = msg + BUFFER_SIZE;
+       char *ptr = msg;
+       char *iphdr;
+       char *log_msg;
+       int eth_hdr_size;
+       struct in_addr bcast_ip;
+       static int processing_msg;
+       unsigned int log_level;
+       char *log_hostname;
+
+       /* Fend off messages from the network stack while writing a message */
+       if (processing_msg)
+               return 0;
+
+       processing_msg = 1;
+
+       /* Setup packet buffers */
+       net_init();
+       /* Disable hardware and put it into the reset state */
+       eth_halt();
+       /* Set current device according to environment variables */
+       eth_set_current();
+       /* Get hardware ready for send and receive operations */
+       ret = eth_init();
+       if (ret < 0) {
+               eth_halt();
+               goto out;
+       }
+
+       memset(msg, 0, BUFFER_SIZE);
+
+       /* Set ethernet header */
+       eth_hdr_size = net_set_ether((uchar *)ptr, net_bcast_ethaddr, PROT_IP);
+       ptr += eth_hdr_size;
+       iphdr = ptr;
+       ptr += IP_UDP_HDR_SIZE;
+       log_msg = ptr;
+
+       /*
+        * The syslog log levels defined in RFC 5424 match the U-Boot ones up to
+        * level 7 (debug).
+        */
+       log_level = rec->level;
+       if (log_level > 7)
+               log_level = 7;
+       /* Leave high bits as 0 to write a 'kernel message' */
+
+       /* Write log message to buffer */
+       append(&ptr, msg_end, "<%u>", log_level);
+       log_hostname = env_get("log_hostname");
+       if (log_hostname)
+               append(&ptr, msg_end, "%s ", log_hostname);
+       append(&ptr, msg_end, "uboot: ");
+       if (fmt & (1 << LOGF_LEVEL))
+               append(&ptr, msg_end, "%s.",
+                      log_get_level_name(rec->level));
+       if (fmt & (1 << LOGF_CAT))
+               append(&ptr, msg_end, "%s,",
+                      log_get_cat_name(rec->cat));
+       if (fmt & (1 << LOGF_FILE))
+               append(&ptr, msg_end, "%s:", rec->file);
+       if (fmt & (1 << LOGF_LINE))
+               append(&ptr, msg_end, "%d-", rec->line);
+       if (fmt & (1 << LOGF_FUNC))
+               append(&ptr, msg_end, "%s()", rec->func);
+       if (fmt & (1 << LOGF_MSG))
+               append(&ptr, msg_end, "%s%s",
+                      fmt != (1 << LOGF_MSG) ? " " : "", rec->msg);
+       /* Consider trailing 0x00 */
+       ptr++;
+
+       debug("log message: '%s'\n", log_msg);
+
+       /* Broadcast message */
+       bcast_ip.s_addr = 0xFFFFFFFFL;
+       net_set_udp_header((uchar *)iphdr, bcast_ip, 514, 514, ptr - log_msg);
+       net_send_packet((uchar *)msg, ptr - msg);
+
+out:
+       processing_msg = 0;
+       return ret;
+}
+
+LOG_DRIVER(syslog) = {
+       .name   = "syslog",
+       .emit   = log_syslog_emit,
+};

diff --git a/doc/README.log b/doc/README.log
index 19856d43da22e8e59a3c48c008f0a2e61e9e7c37..1057981f452eda35a58f302e034bb742ca9cfb88 100644 (file)
--- a/doc/README.log
+++ b/doc/README.log
@@ -147,7 +147,10 @@ several possible determinations for logging information, all of which can be
 enabled or disabled independently:
 
    console - goes to stdout
+   syslog - broadcast RFC 3164 messages to syslog servers on UDP port 514
 
+The syslog driver sends the value of environmental variable 'log_hostname' as
+HOSTNAME if available.
 
 Log format
 ----------