Fix undefined behaviors

Makefile

@@ -57,7 +57,7 @@ DBGDIR = debug
 DBGEXE = $(DBGDIR)/$(EXE)
 DBGOBJS = $(addprefix $(DBGDIR)/, $(OBJS))
 DBGDEPS = $(addprefix $(DBGDIR)/, $(DEPS))
-DBGCFLAGS = -Og -g3 -D_DEBUG
+DBGCFLAGS = -Og -g3 -D_DEBUG -fsanitize=address,undefined
 
 # Default target
 all: prep release

src/config.c

@@ -278,13 +278,13 @@ CON_COMMAND(help, "Find help about a convar/concommand.") {
 CON_COMMAND(crash, "Cause the editor to crash. (Debug!!)") {
     int crash_type = 0;
     if (args.argc > 1) {
-        crash_type = atoi(args.argv[1]);
+        crash_type = strToInt(args.argv[1]);
     }
 
     switch (crash_type) {
         case 0:
             // SIGSEGV
-            *(char*)0 = 0;
+            *(volatile char*)0 = 0;
             break;
         case 1:
             // SIGABRT
@@ -618,9 +618,9 @@ void editorOpenConfigPrompt(void) {
 }
 
 void editorSetConVar(EditorConVar* thisptr, const char* string_val) {
-    strncpy(thisptr->string_val, string_val, COMMAND_MAX_LENGTH);
+    strncpy(thisptr->string_val, string_val, COMMAND_MAX_LENGTH - 1);
     thisptr->string_val[COMMAND_MAX_LENGTH - 1] = '\0';
-    thisptr->int_val = atoi(string_val);
+    thisptr->int_val = strToInt(string_val);
 
     if (thisptr->callback) {
         thisptr->callback();

src/highlight.c

@@ -15,7 +15,10 @@
 
 void editorUpdateSyntax(EditorFile* file, EditorRow* row) {
     row->hl = realloc_s(row->hl, row->size);
-    memset(row->hl, HL_NORMAL, row->size);
+    if (row->hl) {
+        // realloc might returns NULL when row->size == 0
+        memset(row->hl, HL_NORMAL, row->size);
+    }
 
     EditorSyntax* s = file->syntax;
 

src/prompt.c

@@ -226,24 +226,7 @@ static void editorGotoCallback(char* query, int key) {
         return;
     }
 
-    int line = 0;
-
-    int sign = 1;
-    for (int i = 0; query[i]; i++) {
-        if (query[i] >= '0' && query[i] <= '9') {
-            line *= 10;
-            line += query[i] - '0';
-        } else if (i == 0 && (query[i] == '+' || query[i] == '-')) {
-            if (query[i] == '-') {
-                sign = -1;
-            }
-        } else {
-            line = 0;
-            break;
-        }
-    }
-
-    line *= sign;
+    int line = strToInt(query);
 
     if (line < 0) {
         line = gCurFile->num_rows + 1 + line;

src/utils.c

@@ -1,6 +1,7 @@
 #include "utils.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -68,15 +69,15 @@ void abufAppendN(abuf *ab, const char *s, size_t n) {
 
 void abufFree(abuf *ab) { free(ab->buf); }
 
-static bool isValidColor(const char *color) {
+static int isValidColor(const char *color) {
     if (strlen(color) != 6)
-        return false;
+        return 0;
     for (int i = 0; i < 6; i++) {
         if (!(('0' <= color[i]) || (color[i] <= '9') || ('A' <= color[i]) ||
               (color[i] <= 'F') || ('a' <= color[i]) || (color[i] <= 'f')))
-            return false;
+            return 0;
     }
-    return true;
+    return 1;
 }
 
 Color strToColor(const char *color) {
@@ -274,6 +275,46 @@ char *strCaseStr(const char *str, const char *sub_str) {
     return NULL;
 }
 
+int strToInt(const char *str) {
+    if (!str) {
+        return 0;
+    }
+
+    // Skip front spaces
+    while (*str == ' ' || *str == '\t') {
+        str++;
+    }
+
+    int sign = 1;
+    if (*str == '+' || *str == '-') {
+        sign = (*str++ == '-') ? -1 : 1;
+    }
+
+    int result = 0;
+    while (*str >= '0' && *str <= '9') {
+        if (result > INT_MAX / 10 ||
+            (result == INT_MAX / 10 && (*str - '0') > INT_MAX % 10)) {
+            // Overflow
+            return (sign == -1) ? INT_MIN : INT_MAX;
+        }
+
+        result = result * 10 + (*str - '0');
+        str++;
+    }
+
+    result = sign * result;
+
+    // Skip trailing spaces
+    while (*str != '\0') {
+        if (*str != ' ' && *str != '\t') {
+            return 0;
+        }
+        str++;
+    }
+
+    return result;
+}
+
 // https://opensource.apple.com/source/QuickTimeStreamingServer/QuickTimeStreamingServer-452/CommonUtilitiesLib/base64.c
 
 static const char basis_64[] =

src/utils.h

@@ -1,7 +1,6 @@
 #ifndef UTILS_H
 #define UTILS_H
 
-#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -120,6 +119,7 @@ int getDigit(int n);
 int64_t getLine(char** lineptr, size_t* n, FILE* stream);
 int strCaseCmp(const char* s1, const char* s2);
 char* strCaseStr(const char* str, const char* sub_str);
+int strToInt(const char* str);
 
 // Base64
 static inline int base64EncodeLen(int len) { return ((len + 2) / 3 * 4) + 1; }