Add coredump feature and print PC

package/luci/files/luci/i18n/smartdns.zh-cn.po

@@ -16,6 +16,12 @@ msgstr "SmartDNS是一个本地高性能DNS服务器，支持避免域名污染
 msgid "Custom Settings"
 msgstr "自定义设置"
 
+msgid "Generate Coredump"
+msgstr "生成coredump"
+
+msgid "Generate Coredump file when smartdns crash, coredump file is located at /tmp/smartdns.xxx.core."
+msgstr "当smartdns异常时生成coredump文件，coredump文件在/tmp/smartdns.xxx.core."
+
 msgid "Server Name"
 msgstr "服务器名称"
 

package/luci/files/luci/model/cbi/smartdns/smartdns.lua

@@ -103,6 +103,13 @@ function custom.write(self, section, value)
 	nixio.fs.writefile("/etc/smartdns/custom.conf", value)
 end
 
+o = s:taboption("custom", Flag, "coredump", translate("Generate Coredump"), translate("Generate Coredump file when smartdns crash, coredump file is located at /tmp/smartdns.xxx.core."))
+o.rmempty     = false
+o.default     = o.disabled
+o.cfgvalue    = function(...)
+    return Flag.cfgvalue(...) or "0"
+end
+
 -- Upstream servers
 s = m:section(TypedSection, "server", translate("Upstream Servers"), translate("Upstream Servers, support UDP, TCP protocol. " ..
 	"Please configure multiple DNS servers, including multiple foreign DNS servers."))

package/openwrt/files/etc/init.d/smartdns

@@ -174,6 +174,11 @@ start_service() {
 		conf_append "server-name" "$server_name"	
 	fi
 
+	config_get "coredump" "$section" "coredump" "0"
+	if [ "$coredump" = "1" ]; then
+		COREDUMP="1"
+	fi
+
 	config_get "port" "$section" "port" "6053"
 	config_get "ipv6_server" "$section" "ipv6_server" "1"
 	config_get "tcp_server" "$section" "tcp_server" "1"

src/dns_client.c

@@ -927,7 +927,7 @@ static int _dns_client_process_udp(struct dns_server_info *server_info, struct e
 		}
 	}
 
-	tlog(TLOG_DEBUG, "recv udp, from %s, ttl: %d", gethost_by_addr(from_host, (struct sockaddr *)&from, from_len), ttl);
+	tlog(TLOG_DEBUG, "recv udp, from %s, len: %d, ttl: %d", gethost_by_addr(from_host, (struct sockaddr *)&from, from_len), len, ttl);
 
 	if ((ttl != server_info->ttl) && (server_info->ttl > 0) && (server_info->result_flag & DNSSERVER_FLAG_CHECK_TTL)) {
 		/* tlog(TLOG_DEBUG, "TTL mismatch, from:%d, local %d, discard result", ttl, server_info->ttl); */

src/smartdns.c

@@ -39,6 +39,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <ucontext.h>
 
 #define RESOLVE_FILE "/etc/resolv.conf"
 #define MAX_LINE_LEN 1024
@@ -297,10 +298,24 @@ void sig_exit(int signo)
 	dns_server_stop();
 }
 
-void sig_error_exit(int signo, siginfo_t *siginfo, void *context)
+void sig_error_exit(int signo, siginfo_t *siginfo, void *ct)
 {
-	tlog(TLOG_ERROR, "process exit with signal %d, code = %d, errno = %d, pid = %d, self = %d, addr = %p\n", signo, siginfo->si_code, siginfo->si_errno,
+	unsigned long PC = 0;
-		 siginfo->si_pid, getpid(), siginfo->si_addr);
+	ucontext_t *context = ct;
+#if defined(__i386__)
+		int *pgregs = (int*)(&(context->uc_mcontext.gregs));
+		PC = pgregs[REG_EIP];
+#elif defined(__x86_64__) 
+		int *pgregs = (int*)(&(context->uc_mcontext.gregs));
+		PC = pgregs[REG_RIP];
+#elif defined(__aarch64__) || defined(__arm__)
+		PC = context->uc_mcontext.arm_pc;
+#elif defined(__mips__)
+		PC = context->uc_mcontext.pc;
+#endif
+	tlog(TLOG_ERROR, "process exit with signal %d, code = %d, errno = %d, pid = %d, self = %d, pc = %#lx, addr = %#lx\n", signo, siginfo->si_code, siginfo->si_errno,
+		 siginfo->si_pid, getpid(), PC, (unsigned long)siginfo->si_addr);
+
 	sleep(1);
 	_exit(0);
 }