Const-fy char pointers that point to .rodata strings

Using modifiable char pointers to access read-only strings may
lead to invalid memory access.
Signed-off-by: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>

src/Heap.c

@@ -69,7 +69,7 @@ typedef struct
 } storageElement;
 
 static Tree heap;	/**< Tree that holds the allocation records */
-static char* errmsg = "Memory allocation error";
+static const char *errmsg = "Memory allocation error";
 
 
 size_t Heap_roundup(size_t size);
@@ -197,7 +197,7 @@ void checkEyecatchers(char* file, int line, void* p, size_t size)
 	int *sp = (int*)p;
 	char *cp = (char*)p;
 	int us;
-	static char* msg = "Invalid %s eyecatcher %d in heap item at file %s line %d";
+	static const char *msg = "Invalid %s eyecatcher %d in heap item at file %s line %d";
 
 	if ((us = *--sp) != eyecatcher)
 		Log(LOG_ERROR, 13, msg, "start", us, file, line);

src/Log.c

@@ -105,12 +105,12 @@ static enum LOG_LEVELS trace_output_level = INVALID_LEVEL;
 static Log_traceCallback* trace_callback = NULL;
 static traceEntry* Log_pretrace(void);
 static char* Log_formatTraceEntry(traceEntry* cur_entry);
-static void Log_output(enum LOG_LEVELS log_level, char* msg);
+static void Log_output(enum LOG_LEVELS log_level, const char *msg);
 static void Log_posttrace(enum LOG_LEVELS log_level, traceEntry* cur_entry);
-static void Log_trace(enum LOG_LEVELS log_level, char* buf);
+static void Log_trace(enum LOG_LEVELS log_level, const char *buf);
 #if 0
-FILE* Log_destToFile(char* dest);
-int Log_compareEntries(char* entry1, char* entry2);
+FILE* Log_destToFile(const char *dest);
+int Log_compareEntries(const char *entry1, const char *entry2);
 #endif
 
 static int sametime_count = 0;
@@ -316,7 +316,7 @@ static char* Log_formatTraceEntry(traceEntry* cur_entry)
 		strncpy(&msg_buf[buf_pos], cur_entry->name, sizeof(msg_buf)-buf_pos);
 	else
 	{
-		char* format = Messages_get(cur_entry->number, cur_entry->level);
+		const char *format = Messages_get(cur_entry->number, cur_entry->level);
 		if (cur_entry->has_rc == 1)
 			snprintf(&msg_buf[buf_pos], sizeof(msg_buf)-buf_pos, format, cur_entry->thread_id,
 					cur_entry->depth, "", cur_entry->depth, cur_entry->name, cur_entry->line, cur_entry->rc);
@@ -328,7 +328,7 @@ static char* Log_formatTraceEntry(traceEntry* cur_entry)
 }
 
 
-static void Log_output(enum LOG_LEVELS log_level, char* msg)
+static void Log_output(enum LOG_LEVELS log_level, const char *msg)
 {
 	if (trace_destination)
 	{
@@ -368,7 +368,7 @@ static void Log_posttrace(enum LOG_LEVELS log_level, traceEntry* cur_entry)
 }
 
 
-static void Log_trace(enum LOG_LEVELS log_level, char* buf)
+static void Log_trace(enum LOG_LEVELS log_level, const char *buf)
 {
 	traceEntry *cur_entry = NULL;
 
@@ -397,11 +397,11 @@ static void Log_trace(enum LOG_LEVELS log_level, char* buf)
  * @param aFormat the printf format string to be used if the message id does not exist
  * @param ... the printf inserts
  */
-void Log(enum LOG_LEVELS log_level, int msgno, char* format, ...)
+void Log(enum LOG_LEVELS log_level, int msgno, const char *format, ...)
 {
 	if (log_level >= trace_settings.trace_level)
 	{
-		char* temp = NULL;
+		const char *temp = NULL;
 		static char msg_buf[512];
 		va_list args;
 
@@ -471,7 +471,7 @@ void Log_stackTrace(enum LOG_LEVELS log_level, int msgno, int thread_id, int cur
 
 
 #if 0
-FILE* Log_destToFile(char* dest)
+FILE* Log_destToFile(const char *dest)
 {
 	FILE* file = NULL;
 
@@ -490,7 +490,7 @@ FILE* Log_destToFile(char* dest)
 }
 
 
-int Log_compareEntries(char* entry1, char* entry2)
+int Log_compareEntries(const char *entry1, const char *entry2)
 {
 	int comp = strncmp(&entry1[7], &entry2[7], 19);
 

src/Log.h

@@ -75,10 +75,10 @@ typedef struct
 int Log_initialize(Log_nameValue*);
 void Log_terminate(void);
 
-void Log(enum LOG_LEVELS, int, char *, ...);
+void Log(enum LOG_LEVELS, int, const char *, ...);
 void Log_stackTrace(enum LOG_LEVELS, int, int, int, const char*, int, int*);
 
-typedef void Log_traceCallback(enum LOG_LEVELS level, char* message);
+typedef void Log_traceCallback(enum LOG_LEVELS level, const char *message);
 void Log_setTraceCallback(Log_traceCallback* callback);
 void Log_setTraceLevel(enum LOG_LEVELS level);
 

src/MQTTAsync.c

@@ -61,8 +61,8 @@
 
 #include "VersionInfo.h"
 
-char* client_timestamp_eye = "MQTTAsyncV3_Timestamp " BUILD_TIMESTAMP;
-char* client_version_eye = "MQTTAsyncV3_Version " CLIENT_VERSION;
+const char *client_timestamp_eye = "MQTTAsyncV3_Timestamp " BUILD_TIMESTAMP;
+const char *client_version_eye = "MQTTAsyncV3_Version " CLIENT_VERSION;
 
 #if !defined(min)
 #define min(a, b) (((a) < (b)) ? (a) : (b))

src/MQTTAsync.h

@@ -347,7 +347,7 @@ typedef struct
 	/** A numeric code identifying the error. */
 	int code;
 	/** Optional text explaining the error. Can be NULL. */
-	char* message;
+	const char *message;
 } MQTTAsync_failureData;
 
 /** The data returned on completion of a successful API call in the response callback onSuccess. */

src/MQTTClient.c

@@ -65,8 +65,8 @@
 
 #include "VersionInfo.h"
 
-char* client_timestamp_eye = "MQTTClientV3_Timestamp " BUILD_TIMESTAMP;
-char* client_version_eye = "MQTTClientV3_Version " CLIENT_VERSION;
+const char *client_timestamp_eye = "MQTTClientV3_Timestamp " BUILD_TIMESTAMP;
+const char *client_version_eye = "MQTTClientV3_Version " CLIENT_VERSION;
 
 static ClientStates ClientState =
 {

src/MQTTPacket.c

@@ -43,14 +43,14 @@
 /**
  * List of the predefined MQTT v3 packet names.
  */
-static char* packet_names[] =
+static const char *packet_names[] =
 {
 	"RESERVED", "CONNECT", "CONNACK", "PUBLISH", "PUBACK", "PUBREC", "PUBREL",
 	"PUBCOMP", "SUBSCRIBE", "SUBACK", "UNSUBSCRIBE", "UNSUBACK",
 	"PINGREQ", "PINGRESP", "DISCONNECT"
 };
 
-char** MQTTClient_packet_names = packet_names;
+const char** MQTTClient_packet_names = packet_names;
 
 
 /**
@@ -58,7 +58,7 @@ char** MQTTClient_packet_names = packet_names;
  * @param ptype packet code
  * @return the corresponding string, or "UNKNOWN"
  */
-char* MQTTPacket_name(int ptype)
+const char* MQTTPacket_name(int ptype)
 {
 	return (ptype >= 0 && ptype <= DISCONNECT) ? packet_names[ptype] : "UNKNOWN";
 }

src/MQTTPacket.h

@@ -225,7 +225,7 @@ void writeChar(char** pptr, char c);
 void writeInt(char** pptr, int anInt);
 void writeUTF(char** pptr, const char* string);
 
-char* MQTTPacket_name(int ptype);
+const char* MQTTPacket_name(int ptype);
 
 void* MQTTPacket_Factory(networkHandles* net, int* error);
 int MQTTPacket_send(networkHandles* net, Header header, char* buffer, size_t buflen, int free);

src/MQTTPersistenceDefault.c

@@ -718,8 +718,8 @@ int main (int argc, char *argv[])
 	int rc;
 	char *handle;
 	char *perdir = ".";
-	char *clientID = "TheUTClient";
-	char *serverURI = "127.0.0.1:1883";
+	const char *clientID = "TheUTClient";
+	const char *serverURI = "127.0.0.1:1883";
 
 	char *stem = MSTEM;
 	int msgId, i;

src/Messages.c

@@ -35,7 +35,7 @@
 
 #define max_msg_len 120
 
-static char* protocol_message_list[] =
+static const char *protocol_message_list[] =
 {
 	"%d %s -> CONNECT cleansession: %d (%d)", /* 0, was 131, 68 and 69 */
 	"%d %s <- CONNACK rc: %d", /* 1, was 132 */
@@ -69,7 +69,7 @@ static char* protocol_message_list[] =
 	"Socket error for client identifier %s, socket %d, peer address %s; ending connection", /* 29 */
 };
 
-static char* trace_message_list[] =
+static const char *trace_message_list[] =
 {
 	"Failed to remove client from bstate->clients", /* 0 */
 	"Removed client %s from bstate->clients, socket %d", /* 1 */
@@ -92,9 +92,9 @@ static char* trace_message_list[] =
  * @param log_level the log level, used to determine which message list to use
  * @return the message format string
  */
-char* Messages_get(int index, enum LOG_LEVELS log_level)
+const char* Messages_get(int index, enum LOG_LEVELS log_level)
 {
-	char* msg = NULL;
+	const char *msg = NULL;
 
 	if (log_level == TRACE_PROTOCOL)
 		msg = (index >= 0 && index < ARRAY_SIZE(protocol_message_list)) ? protocol_message_list[index] : NULL;

src/Messages.h

@@ -19,6 +19,6 @@
 
 #include "Log.h"
 
-char* Messages_get(int, enum LOG_LEVELS);
+const char* Messages_get(int, enum LOG_LEVELS);
 
 #endif