[v4,5/6] test: log: test syslog logging driver

diff --git a/test/log/Makefile b/test/log/Makefile
index 98178f5e2b..4c92550f6e 100644
--- a/test/log/Makefile
+++ b/test/log/Makefile
@@ -8,6 +8,10 @@  ifdef CONFIG_UT_LOG

 obj-y += test-main.o

+ifdef CONFIG_SANDBOX
+obj-$(CONFIG_LOG_SYSLOG) += syslog_test.o
+endif
+
 ifndef CONFIG_LOG
 obj-$(CONFIG_CONSOLE_RECORD) += nolog_test.o
 endif
diff --git a/test/log/syslog_test.c b/test/log/syslog_test.c
new file mode 100644
index 0000000000..6ca5760eac
--- /dev/null
+++ b/test/log/syslog_test.c
@@ -0,0 +1,280 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk at gmx.de>
+ *
+ * Logging function tests for CONFIG_LOG_SYSLOG=y.
+ *
+ * Invoke the test with: ./u-boot -d arch/sandbox/dts/test.dtb
+ */
+
+/* Override CONFIG_LOG_MAX_LEVEL */
+#define LOG_DEBUG
+
+#include <common.h>
+#include <dm/device.h>
+#include <hexdump.h>
+#include <test/log.h>
+#include <test/test.h>
+#include <test/suites.h>
+#include <test/ut.h>
+#include <asm/eth.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * struct sb_log_env - private data for sandbox ethernet driver
+ *
+ * This structure is used for the private data of the sandbox ethernet
+ * driver.
+ *
+ * @expected:	string expected to be written by the syslog driver
+ * @uts:	unit test state
+ */
+struct sb_log_env {
+	const char *expected;
+	struct unit_test_state *uts;
+};
+
+/**
+ * sb_log_tx_handler() - transmit callback function
+ *
+ * This callback function is invoked when a network package is sent using the
+ * sandbox Ethernet driver. The private data of the driver holds a sb_log_env
+ * structure with the unit test state and the expected UDP payload.
+ *
+ * The following checks are executed:
+ *
+ * * the Ethernet packet indicates a IP broadcast message
+ * * the IP header is for a local UDP broadcast message to port 514
+ * * the UDP payload matches the expected string
+ *
+ * After testing the pointer to the expected string is set to NULL to signal
+ * that the callback function has been called.
+ *
+ * @dev:	sandbox ethernet device
+ * @packet:	Ethernet packet
+ * @len:	length of Ethernet packet
+ * Return:	0 = success
+ */
+static int sb_log_tx_handler(struct udevice *dev, void *packet,
+			     unsigned int len)
+{
+	struct eth_sandbox_priv *priv = dev_get_priv(dev);
+	struct sb_log_env *env = priv->priv;
+	/* uts is updated by the ut_assert* macros */
+	struct unit_test_state *uts = env->uts;
+	char *buf = packet;
+	struct ethernet_hdr *eth_hdr = packet;
+	struct ip_udp_hdr *ip_udp_hdr;
+
+	/* Check Ethernet header */
+	ut_asserteq_mem(&eth_hdr->et_dest, net_bcast_ethaddr, ARP_HLEN);
+	ut_asserteq(ntohs(eth_hdr->et_protlen), PROT_IP);
+
+	/* Check IP header */
+	buf += sizeof(struct ethernet_hdr);
+	ip_udp_hdr = (struct ip_udp_hdr *)buf;
+	ut_asserteq(ip_udp_hdr->ip_p, IPPROTO_UDP);
+	ut_asserteq(ip_udp_hdr->ip_dst.s_addr, 0xffffffff);
+	ut_asserteq(ntohs(ip_udp_hdr->udp_dst), 514);
+	ut_asserteq(UDP_HDR_SIZE + strlen(env->expected) + 1,
+		    ntohs(ip_udp_hdr->udp_len));
+
+	/* Check payload */
+	buf += sizeof(struct ip_udp_hdr);
+	ut_asserteq_mem(env->expected, buf,
+			ntohs(ip_udp_hdr->udp_len) - UDP_HDR_SIZE);
+
+	/* Signal that the callback function has been executed */
+	env->expected = NULL;
+
+	return 0;
+}
+
+/**
+ * syslog_test_log_err() - test log_err() function
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_err(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_INFO;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<3>sandbox uboot: syslog_test_log_err() "
+		       "testing log_err\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_err("testing %s\n", "log_err");
+	/* Check that the callback function was called */
+	sandbox_eth_set_tx_handler(0, NULL);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_err);
+
+/**
+ * syslog_test_log_warning() - test log_warning() function
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_warning(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_INFO;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<4>sandbox uboot: syslog_test_log_warning() "
+		       "testing log_warning\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_warning("testing %s\n", "log_warning");
+	sandbox_eth_set_tx_handler(0, NULL);
+	/* Check that the callback function was called */
+	ut_assertnull(env.expected);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_warning);
+
+/**
+ * syslog_test_log_notice() - test log_notice() function
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_notice(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_INFO;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<5>sandbox uboot: syslog_test_log_notice() "
+		       "testing log_notice\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_notice("testing %s\n", "log_notice");
+	sandbox_eth_set_tx_handler(0, NULL);
+	/* Check that the callback function was called */
+	ut_assertnull(env.expected);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_notice);
+
+/**
+ * syslog_test_log_info() - test log_info() function
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_info(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_INFO;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<6>sandbox uboot: syslog_test_log_info() "
+		       "testing log_info\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_info("testing %s\n", "log_info");
+	sandbox_eth_set_tx_handler(0, NULL);
+	/* Check that the callback function was called */
+	ut_assertnull(env.expected);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_info);
+
+/**
+ * syslog_test_log_debug() - test log_debug() function
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_debug(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_DEBUG;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<7>sandbox uboot: syslog_test_log_debug() "
+		       "testing log_debug\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_debug("testing %s\n", "log_debug");
+	sandbox_eth_set_tx_handler(0, NULL);
+	/* Check that the callback function was called */
+	ut_assertnull(env.expected);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_debug);
+
+/**
+ * syslog_test_log_nodebug() - test logging level filter
+ *
+ * Verify that log_debug() does not lead to a log message if the logging level
+ * is set to LOGL_INFO.
+ *
+ * @uts:	unit test state
+ * Return:	0 = success
+ */
+static int syslog_test_log_nodebug(struct unit_test_state *uts)
+{
+	int old_log_level = gd->default_log_level;
+	struct sb_log_env env;
+
+	gd->log_fmt = LOGF_DEFAULT;
+	gd->default_log_level = LOGL_INFO;
+	env_set("ethact", "eth at 10002000");
+	env_set("log_hostname", "sandbox");
+	env.expected = "<7>sandbox uboot: syslog_test_log_nodebug() "
+		       "testing log_debug\n";
+	env.uts = uts;
+	sandbox_eth_set_tx_handler(0, sb_log_tx_handler);
+	/* Used by ut_assert macros in the tx_handler */
+	sandbox_eth_set_priv(0, &env);
+	log_debug("testing %s\n", "log_debug");
+	sandbox_eth_set_tx_handler(0, NULL);
+	/* Check that the callback function was not called */
+	ut_assertnonnull(env.expected);
+	gd->default_log_level = old_log_level;
+
+	return 0;
+}
+LOG_TEST(syslog_test_log_nodebug);