Replace all fgets() calls by readline() to become independent of all existing line length limitations (#43)

config.c

@@ -82,8 +82,13 @@ void read_FTLconf(void)
 		logg("   QUERY_DISPLAY: Hide queries");
 
 	logg("Finished config file parsing");
-	free(conflinebuffer);
-	conflinebuffer = NULL;
+
+	if(conflinebuffer != NULL)
+	{
+		free(conflinebuffer);
+		conflinebuffer = NULL;
+	}
+
 	if(fp != NULL)
 		fclose(fp);
 }
@@ -95,17 +100,22 @@ char *parse_FTLconf(FILE *fp, const char * key)
 		return NULL;
 
 	char * keystr = calloc(strlen(key)+2,sizeof(char));
-	conflinebuffer = calloc(1024,sizeof(char));
-
+	if(keystr == NULL)
+	{
+		logg("WARN: parse_FTLconf failed: could not allocate memory for keystr");
+		return NULL;
+	}
 	sprintf(keystr, "%s=", key);
 
 	// Go to beginning of file
 	fseek(fp, 0L, SEEK_SET);
 
-	while(fgets(conflinebuffer, 1023, fp) != NULL)
+	size_t size;
+	errno = 0;
+	while(getline(&conflinebuffer, &size, fp) != -1)
 	{
-		// Strip newline from fgets output
-		conflinebuffer[strlen(conflinebuffer) - 1] = '\0';
+		// Strip (possible) newline
+		conflinebuffer[strcspn(conflinebuffer, "\n")] = '\0';
 
 		// Skip comment lines
 		if(conflinebuffer[0] == '#' || conflinebuffer[0] == ';')
@@ -120,7 +130,11 @@ char *parse_FTLconf(FILE *fp, const char * key)
 		return (find_equals(conflinebuffer) + 1);
 	}
 
+	if(errno == ENOMEM)
+		logg("WARN: parse_FTLconf failed: could not allocate memory for getline");
+
 	// Key not found -> return NULL
 	free(keystr);
+
 	return NULL;
 }

daemon.c

@@ -37,15 +37,28 @@ int detect_FTL_process(void)
 				FILE* fp;
 				if((fp = fopen(buffer, "r")) != NULL)
 				{
-					if (fgets(buffer, sizeof(buffer), fp) != NULL)
+					char *linebuffer = NULL;
+					size_t size = 0;
+
+					errno = 0;
+					if (getline(&linebuffer, &size, fp) != -1)
 					{
-						if (strstr(buffer, "pihole-FTL") != 0)
+						if (strstr(linebuffer, "pihole-FTL") != 0)
 						{
 							fclose(fp);
-							logg("%i - %s", pid, buffer);
+							logg("%i - %s", pid, linebuffer);
 							return pid;
 						}
 					}
+
+					if(errno == ENOMEM)
+						logg("WARN: process_pihole_log failed: could not allocate memory for getline");
+
+					if(linebuffer != NULL)
+					{
+						free(linebuffer);
+						linebuffer = NULL;
+					}
 					fclose(fp);
 				}
 			}

grep.c

@@ -74,8 +74,8 @@ int countlines(const char* fname)
 void readWildcardsList()
 {
 	FILE *fp;
-	char *buffer, *domain;
-	char linebuffer[512];
+	char *domain = NULL, *buffer = NULL, *linebuffer = NULL;
+	size_t size = 0;
 	int i;
 
 	if((fp = fopen(files.wildcards, "r")) == NULL) {
@@ -84,9 +84,23 @@ void readWildcardsList()
 	}
 
 	// Search through file
-	while(fgets(linebuffer, 511, fp))
+	errno = 0;
+	while(getline(&linebuffer, &size, fp) != -1)
 	{
-		buffer = calloc(512,sizeof(char));
+		// the read line has always to be larger than what we want to extract, so
+		// we can use the length as an upper limit for allocating memory for the buffer
+
+		buffer = calloc(size, 1);
+		if(buffer == NULL)
+		{
+			logg("WARN: readWildcardsList failed to allocate memory");
+			fclose(fp);
+
+			// Free allocated memory
+			free(linebuffer);
+
+			return;
+		}
 		// Try to read up to 511 characters
 		if(sscanf(linebuffer, "address=/%511[^/]/%*[^\n]\n", buffer) > 0)
 		{
@@ -112,7 +126,13 @@ void readWildcardsList()
 						break;
 					}
 				}
-				if(known) continue;
+				if(known)
+				{
+					// Free allocated memory
+					free(buffer);
+					buffer = NULL;
+					continue;
+				}
 
 				// Add wildcard entry
 				// Enlarge wildcarddomains pointer array
@@ -126,10 +146,22 @@ void readWildcardsList()
 				counters.wildcarddomains++;
 			}
 		}
+
+		// Free allocated memory
 		free(buffer);
 		buffer = NULL;
 	}
 
+	if(errno == ENOMEM)
+		logg("WARN: readWildcardsList failed: could not allocate memory for getline");
+
+	// Free allocated memory
+	if(linebuffer != NULL)
+	{
+		free(linebuffer);
+		linebuffer = NULL;
+	}
+
 	// Close the file
 	fclose(fp);
 
@@ -139,18 +171,26 @@ int countlineswith(const char* str, const char* fname)
 {
 	FILE *fp;
 	int found = 0;
-	char buffer[512];
+	char *buffer = NULL;
+	size_t size = 0;
 
 	if((fp = fopen(fname, "r")) == NULL) {
 		return -1;
 	}
 
 	// Search through file
-	// fgets reads a string from the specified file up to either a newline character or EOF
-	while(fgets(buffer, sizeof(buffer), fp) != NULL)
+	// getline reads a string from the specified file up to either a newline character or EOF
+	while(getline(&buffer, &size, fp) != -1)
 		if((strstr(buffer, str)) != NULL)
 			found++;
 
+	// Free allocated memory
+	if(buffer != NULL)
+	{
+		free(buffer);
+		buffer = NULL;
+	}
+
 	// Close the file
 	fclose(fp);
 

parser.c

@@ -134,8 +134,9 @@ void *pihole_log_thread(void *val)
 void process_pihole_log(int file)
 {
 	int i;
-	char readbuffer[1024] = "";
-	char readbuffer2[1024] = "";
+	char *readbuffer = NULL;
+	char *readbuffer2 = NULL;
+	size_t size1 = 0, size2 = 0;
 	FILE *fp;
 
 	if(file == 0)
@@ -169,18 +170,19 @@ void process_pihole_log(int file)
 	long int fposbck = ftell(fp);
 
 	// Read pihole log from current position until EOF line by line
-	while( fgets (readbuffer , sizeof(readbuffer)-1 , fp) != NULL )
+	errno = 0;
+	while(getline(&readbuffer, &size1, fp) != -1)
 	{
 		// Ensure that the line we read ended with a newline
 		// It can happen that we read too fast and dnsmasq didn't had the time
-		// to finish writing to the log. In this case, fgets() will not stop
+		// to finish writing to the log. In this case, getline() will not stop
 		// at a newline character, but at EOF. If we detect this scenario, we
 		// have to wait a little longer and re-try reading
 		if(feof(fp))
 		{
 			fseek(fp, fposbck, SEEK_SET);
 			sleepms(10);
-			if(fgets (readbuffer , sizeof(readbuffer)-1 , fp) == NULL)
+			if(getline(&readbuffer, &size1, fp) == -1)
 				break;
 		}
 
@@ -309,7 +311,7 @@ void process_pihole_log(int file)
 			int forwardID = -1;
 			for(i=0; i<200; i++)
 			{
-				if(fgets (readbuffer2 , sizeof(readbuffer2) , fp) != NULL)
+				if(getline(&readbuffer2, &size2, fp) != -1)
 				{
 					// Process only matching lines
 					if(strstr(readbuffer2, domainwithspaces) != NULL)
@@ -367,9 +369,17 @@ void process_pihole_log(int file)
 					}
 				}
 			}
+
 			// Return to previous file pointer position
 			fseek(fp, fpos, SEEK_SET);
 
+			// Free memory allocated by readline
+			if(readbuffer2 != NULL)
+			{
+				free(readbuffer2);
+				readbuffer2 = NULL;
+			}
+
 			// Go through already knows domains and see if it is one of them
 			// Check struct size
 			memory_check(DOMAINS);
@@ -595,6 +605,13 @@ void process_pihole_log(int file)
 		}
 	}
 
+	if(errno == ENOMEM)
+		logg("WARN: process_pihole_log failed: could not allocate memory for getline");
+
+	// Free memory allocated by readline
+	if(readbuffer != NULL)
+		free(readbuffer);
+
 	// IF we are reading the main log, we want to store the last read
 	// position so that we can jump to this position in the next round
 	if(file == 0)

setupVars.c

@@ -9,7 +9,6 @@
 *  Please see LICENSE file for your rights under this license. */
 
 #include "FTL.h"
-#define SETUPVARSLINELENGTH 100000
 
 char ** setupVarsArray = NULL;
 
@@ -54,15 +53,22 @@ char * read_setupVarsconf(const char * key)
 		return NULL;
 	}
 
+	// Allocate keystr
 	char * keystr = calloc(strlen(key)+2, sizeof(char));
-	linebuffer = calloc(SETUPVARSLINELENGTH, sizeof(char));
-
+	if(keystr == NULL)
+	{
+		logg("WARN: read_setupVarsconf failed: could not allocate memory for keystr");
+		fclose(setupVarsfp);
+		return NULL;
+	}
 	sprintf(keystr, "%s=", key);
 
-	while(fgets(linebuffer, SETUPVARSLINELENGTH, setupVarsfp) != NULL)
+	size_t size;
+	errno = 0;
+	while(getline(&linebuffer, &size, setupVarsfp) != -1)
 	{
-		// Strip newline from fgets output
-		linebuffer[strlen(linebuffer) - 1] = '\0';
+		// Strip (possible) newline
+		linebuffer[strcspn(linebuffer, "\n")] = '\0';
 
 		// Skip comment lines
 		if(linebuffer[0] == '#' || linebuffer[0] == ';')
@@ -78,15 +84,22 @@ char * read_setupVarsconf(const char * key)
 		return (find_equals(linebuffer) + 1);
 	}
 
+	if(errno == ENOMEM)
+		logg("WARN: read_setupVarsconf failed: could not allocate memory for getline");
+
 	// Key not found -> return NULL
 	fclose(setupVarsfp);
 
-	// setting unused pointers to NULL
-	// protecting against dangling pointer bugs
+	// Freeing keystr, not setting to NULL, since not used outside of this routine
 	free(keystr);
-	keystr = NULL;
-	free(linebuffer);
-	linebuffer = NULL;
+
+	// Freeing and setting to NULL to prevent a dangling pointer
+	if(linebuffer != NULL)
+	{
+		free(linebuffer);
+		linebuffer = NULL;
+	}
+
 	return NULL;
 }