Add signature scanning

docs/auto-splitters.md

@@ -286,6 +286,44 @@ end
 
         * Cheat Engine is a tool that allows you to easily find Addresses and Pointer Paths for those Addresses, so you don't need to debug the game to figure out the structure of the memory.
 
+## sig_scan
+sig_scan performs a signature/pattern scan on the provided IDA-style byte array and optional integer offset and returns a string representation of the found address
+
+Example:
+`signature = sig_scan("89 5C 24 ?? 89 44 24 ?? 74 ?? 48 8D 15", 4)`
+
+Returns:
+`"14123ce19"`
+
+### Notes
+* Lua automatically handles the conversion of hexadecimal strings to numbers so parsing/casting it manually is not required.
+* Until the address is found, sig_scan returns a 0.
+* Signature scanning is an expensive action. So, once an address has been found, it's recommended to reassign the sig_scan variable with the result of the sig_scan function to stop the scanning.
+
+
+Mini example script with the game SPRAWL:
+```lua
+process('Sprawl-Win64-Shipping.exe')
+
+local featuretest = 0
+
+function state()
+    -- Perform the signature scan to find the initial address
+    featuretest = sig_scan("89 5C 24 ?? 89 44 24 ?? 74 ?? 48 8D 15", 4)
+
+    if featuretest == 0 then
+        print("Signature scan did not find the address.")
+    else
+        -- Read an integer value from the found address
+        local readValue = readAddress('int', 'Sprawl-Win64-Shipping.exe', featuretest)
+        print("Feature test address: ", featuretest)
+        print("Read value: ", readValue)
+    end
+end
+```
+
+
+
 ## getPID
 * Returns the current PID
 

src/auto-splitter.c

@@ -16,6 +16,7 @@
 #include "memory.h"
 #include "process.h"
 #include "settings.h"
+#include "signature.h"
 
 char auto_splitter_file[PATH_MAX];
 int refresh_rate = 60;
@@ -323,6 +324,8 @@ void run_auto_splitter()
     lua_setglobal(L, "process");
     lua_pushcfunction(L, read_address);
     lua_setglobal(L, "readAddress");
+    lua_pushcfunction(L, perform_sig_scan);
+    lua_setglobal(L, "sig_scan");
     lua_pushcfunction(L, getPid);
     lua_setglobal(L, "getPID");
 

src/signature.c

@@ -0,0 +1,234 @@
+#include "signature.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include "memory.h"
+#include "process.h"
+
+#include <luajit.h>
+
+extern game_process process;
+
+// Error handling macro
+#define HANDLE_ERROR(msg) \
+    do {                  \
+        perror(msg);      \
+        return NULL;      \
+    } while (0)
+
+// Error logging function
+void log_error(const char* format, ...)
+{
+    va_list args;
+    va_start(args, format);
+    fprintf(stderr, "Error in sig_scan: ");
+    vfprintf(stderr, format, args);
+    fprintf(stderr, "\n");
+    va_end(args);
+}
+
+MemoryRegion* get_memory_regions(pid_t pid, int* count)
+{
+    char maps_path[256];
+    if (snprintf(maps_path, sizeof(maps_path), "/proc/%d/maps", pid) < 0) {
+        HANDLE_ERROR("Failed to create maps path");
+    }
+
+    FILE* maps_file = fopen(maps_path, "r");
+    if (!maps_file) {
+        HANDLE_ERROR("Failed to open maps file");
+    }
+
+    MemoryRegion* regions = NULL;
+    int capacity = 0;
+    *count = 0;
+
+    char line[256];
+    while (fgets(line, sizeof(line), maps_file)) {
+        if (*count >= capacity) {
+            capacity = capacity == 0 ? 10 : capacity * 2;
+            MemoryRegion* temp = realloc(regions, capacity * sizeof(MemoryRegion));
+            if (!temp) {
+                free(regions);
+                fclose(maps_file);
+                HANDLE_ERROR("Failed to allocate memory for regions");
+            }
+            regions = temp;
+        }
+
+        uintptr_t start, end;
+        if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &start, &end) != 2) {
+            continue; // Skip lines that don't match the expected format
+        }
+        regions[*count].start = start;
+        regions[*count].end = end;
+        (*count)++;
+    }
+
+    fclose(maps_file);
+    return regions;
+}
+
+bool match_pattern(const uint8_t* data, const uint16_t* pattern, size_t pattern_size)
+{
+    for (size_t i = 0; i < pattern_size; ++i) {
+        uint8_t byte = pattern[i] & 0xFF;
+        bool ignore = (pattern[i] >> 8) & 0x1;
+        if (!ignore && data[i] != byte) {
+            return false;
+        }
+    }
+    return true;
+}
+
+uint16_t* convert_signature(const char* signature, size_t* pattern_size)
+{
+    char* signature_copy = strdup(signature);
+    if (!signature_copy) {
+        return NULL;
+    }
+
+    char* token = strtok(signature_copy, " ");
+    size_t size = 0;
+    size_t capacity = 10;
+    uint16_t* pattern = (uint16_t*)malloc(capacity * sizeof(uint16_t));
+    if (!pattern) {
+        free(signature_copy);
+        return NULL;
+    }
+
+    while (token != NULL) {
+        if (size >= capacity) {
+            capacity *= 2;
+            uint16_t* temp = (uint16_t*)realloc(pattern, capacity * sizeof(uint16_t));
+            if (!temp) {
+                free(pattern);
+                free(signature_copy);
+                return NULL;
+            }
+            pattern = temp;
+        }
+
+        if (strcmp(token, "??") == 0) {
+            pattern[size] = 0xFF00; // Set the upper byte to 1 to indicate ignoring this byte
+        } else {
+            pattern[size] = strtol(token, NULL, 16);
+        }
+        size++;
+        token = strtok(NULL, " ");
+    }
+
+    free(signature_copy);
+    *pattern_size = size;
+    return pattern;
+}
+
+bool validate_process_memory(pid_t pid, uintptr_t address, void* buffer, size_t size)
+{
+    struct iovec local_iov = { buffer, size };
+    struct iovec remote_iov = { (void*)address, size };
+    ssize_t nread = process_vm_readv(pid, &local_iov, 1, &remote_iov, 1, 0);
+
+    return nread == (ssize_t)size;
+}
+
+int perform_sig_scan(lua_State* L)
+{
+    if (lua_gettop(L) != 2) {
+        log_error("Invalid number of arguments: expected 2 (signature, offset)");
+        lua_pushnil(L);
+        return 1;
+    }
+
+    if (!lua_isstring(L, 1) || !lua_isnumber(L, 2)) {
+        log_error("Invalid argument types: expected (string, number)");
+        lua_pushnil(L);
+        return 1;
+    }
+
+    pid_t p_pid = process.pid;
+    const char* signature = lua_tostring(L, 1);
+    int offset = lua_tointeger(L, 2);
+
+    // Validate signature string
+    if (strlen(signature) == 0) {
+        log_error("Signature string cannot be empty");
+        lua_pushnil(L);
+        return 1;
+    }
+
+    size_t pattern_length;
+    uint16_t* pattern = convert_signature(signature, &pattern_length);
+    if (!pattern) {
+        log_error("Failed to convert signature");
+        lua_pushnil(L);
+        return 1;
+    }
+
+    int regions_count = 0;
+    MemoryRegion* regions = get_memory_regions(p_pid, &regions_count);
+    if (!regions) {
+        free(pattern);
+        log_error("Failed to get memory regions");
+        lua_pushnil(L);
+        return 1;
+    }
+
+    for (int i = 0; i < regions_count; i++) {
+        MemoryRegion region = regions[i];
+        ssize_t region_size = region.end - region.start;
+        uint8_t* buffer = malloc(region_size);
+        if (!buffer) {
+            free(pattern);
+            free(regions);
+            log_error("Failed to allocate memory for region buffer");
+            lua_pushnil(L);
+            return 1;
+        }
+
+        if (!validate_process_memory(p_pid, region.start, buffer, region_size)) {
+            free(buffer);
+            continue; // Continue to next region
+        }
+
+        for (size_t j = 0; j <= region_size - pattern_length; ++j) {
+            if (match_pattern(buffer + j, pattern, pattern_length)) {
+                uintptr_t result = region.start + j + offset;
+
+                char full_hex_str[32]; // Increased buffer size for safety
+                if (snprintf(full_hex_str, sizeof(full_hex_str), "0x%" PRIxPTR, result) < 0) {
+                    free(buffer);
+                    free(pattern);
+                    free(regions);
+                    log_error("Failed to convert result to string");
+                    lua_pushnil(L);
+                    return 1;
+                }
+
+                free(buffer);
+                free(pattern);
+                free(regions);
+
+                lua_pushstring(L, full_hex_str);
+                return 1;
+            }
+        }
+
+        free(buffer);
+    }
+
+    free(pattern);
+    free(regions);
+
+    // No match found
+    log_error("No match found for the given signature");
+    lua_pushnil(L);
+    return 1;
+}

src/signature.h

@@ -0,0 +1,21 @@
+#ifndef __SIGNATURE_H__
+#define __SIGNATURE_H__
+
+#include <luajit.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+typedef struct {
+    uintptr_t start;
+    uintptr_t end;
+} MemoryRegion;
+
+MemoryRegion* get_memory_regions(pid_t pid, int* count);
+bool match_pattern(const uint8_t* data, const uint16_t* pattern, size_t pattern_size);
+uint16_t* convert_signature(const char* signature, size_t* pattern_size);
+bool validate_process_memory(pid_t pid, uintptr_t address, void* buffer, size_t size);
+int perform_sig_scan(lua_State* L);
+
+#endif /* __SIGNATURE_H__ */