Port phonebook feature from dosbox-staging

e905a6bd5d

create a phoneboox-<version>.txt file with the layout:
<number> <host:port>

When you dial the number, it will actually connect to the specified host. This is needed
as not all programs allow to enter a hostname or IP address.

It also adds a new property to the config file in the [serial] section named phonebookfile=

include/support.h

@@ -80,4 +80,33 @@ static inline bool is_power_of_2(Bitu val) {
 	 * For more info see https://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2*/
 }
 
+/// Copy a string into C array
+///
+/// This function copies string pointed by src to fixed-size buffer dst.
+/// At most N bytes from src are copied, where N is size of dst.
+/// If exactly N bytes are copied, then terminating null byte is put
+/// into buffer, thus buffer overrun is prevented.
+///
+/// Function returns pointer to buffer to be compatible with std::strcpy.
+///
+/// Usage:
+///
+///     char buffer[2];
+///     safe_strcpy(buffer, "abc");
+///     // buffer is filled with "a"
+
+template<size_t N>
+char * safe_strcpy(char (& dst)[N], const char * src) noexcept {
+        snprintf(dst, N, "%s", src);
+        return & dst[0];
+}
+
+template<size_t N>
+char * safe_strcat(char (& dst)[N], const char * src) noexcept {
+        strncat(dst, src, N - strnlen(dst, N) - 1);
+        return & dst[0];
+}
+
+#define safe_strncpy(a,b,n) do { strncpy((a),(b),(n)-1); (a)[(n)-1] = 0; } while (0)
+
 #endif

src/dosbox.cpp

@@ -2796,6 +2796,9 @@ void DOSBOX_SetupConfigSections(void) {
     Pmulti_remain->GetSection()->Add_string("parameters",Property::Changeable::WhenIdle,"");
     Pmulti_remain->Set_help("see serial1");
 
+    Pstring = secprop->Add_path("phonebookfile", Property::Changeable::OnlyAtStart, "phonebook-" VERSION ".txt");
+    Pstring->Set_help("File used to map fake phone numbers to addresses.");
+
     // printer redirection parameters
     secprop = control->AddSection_prop("printer", &Null_Init);
     Pbool = secprop->Add_bool("printer", Property::Changeable::WhenIdle, true);

src/hardware/serialport/serialport.cpp

@@ -1337,6 +1337,11 @@ public:
         //       COM1 is a 8251 UART, while COM2 and higher if they exist are 8250/16xxx UARTs
         if (IS_PC98_ARCH) return;
 
+#if C_MODEM
+                const Prop_path *pbFilename = section->Get_path("phonebookfile");
+		MODEM_ReadPhonebook(pbFilename->realpath);
+#endif
+                
 		char s_property[] = "serialx"; 
 		for(Bit8u i = 0; i < 4; i++) {
 			// get the configuration property

src/hardware/serialport/softmodem.h

@@ -50,6 +50,8 @@ enum ResTypes {
 #define TEL_CLIENT 0
 #define TEL_SERVER 1
 
+bool MODEM_ReadPhonebook(const std::string &filename);
+
 class CFifo {
 public:
 	CFifo(Bitu _size) {
@@ -168,7 +170,7 @@ public:
 	void EnterConnectedState();
         
 	void openConnection(void);
-	bool Dial(char * host);
+	bool Dial(const char *host);
 	void AcceptIncomingCall(void);
 	Bitu ScanNumber(char * & scan);
 	char GetChar(char * & scan);