✨ Add error messaging

.vscode/settings.json

@@ -7,7 +7,8 @@
     "fileutilities.h": "c",
     "stdio.h": "c",
     "stdlib.h": "c",
-    "stdbool.h": "c"
+    "stdbool.h": "c",
+    "errorandexit.h": "c"
   },
   "cSpell.words": [
     "init",

README.md

@@ -11,7 +11,7 @@ To compile:
 To use:
 
 ```
-./patcher-installer --disk /tmp/patcher/cdn-patch.swtor.com/patch/assets_swtor_main/assets_swtor_main_-1to0/assets_swtor_main_-1to0.z08 --offset 267071107 --size 165738618 --keys 3393608425 2820264972 3930508185 > ../swtor_main_gfx_1.tor
+./patcher-installer --disk /tmp/patcher/cdn-patch.swtor.com/patch/assets_swtor_main/assets_swtor_main_-1to0/assets_swtor_main_-1to0.z08 --offset 267071107 --size 165738618 --keys 3393608425,2820264972,3930508185 > ../swtor_main_gfx_1.tor
 ```
 
 # Dependencies

src/errorAndExit.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "errorAndExit.h"
+
+void errorAndExit() {
+  fprintf(stderr, "\nUsage:\n");
+  fprintf(stderr, "  ./patcher-installer --disk main.z01 --offset 456z --size 1000 [--keys 123,123,123] [--prev oldfile.tor]\n");
+  fprintf(stderr, "Options:\n");
+  fprintf(stderr, "  -d, --disk: The path to the disk file that contains the file we want to extract.\n");
+  fprintf(stderr, "  -o, --offset: The offset into the disk, given in bytes, where the local file header of the file we want to extract starts.\n");
+  fprintf(stderr, "  -s, --size: The stored size of the file we want to extract (= the compressed size). After inflation, the file will likely be bigger than this.\n");
+  fprintf(stderr, "  -k, --keys: Optionally, the three decryption keys used to decrypt the file before inflation.\n");
+  fprintf(stderr, "  -p, --prev: Optionally, the location of the previous version of this file, in case this disk only contains the xdelta3 differences and not an actual file.\n");
+  exit(1);
+}

src/errorAndExit.h

@@ -0,0 +1 @@
+void errorAndExit();

src/fileReader.c

@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "errorAndExit.h"
 #include "fileReader.h"
 #include "utils/fileUtilities.h"
 #include "utils/min.h"
@@ -13,8 +14,8 @@ void initFileReader(char path[], unsigned long offset) {
 
   file.filePointer = fopen(file.name, "r");
   if (file.filePointer == NULL) {
-    fprintf(stderr, "Could not open file %s for reading: %s\n", file.name, strerror(errno));
+    fprintf(stderr, "Could not open file \"%s\" for reading: %s\n", file.name, strerror(errno));
-    exit(1);
+    errorAndExit();
   }
 
   //get file size

src/inflate.c

@@ -11,6 +11,7 @@
 #define MINIZ_NO_MALLOC
 #include "../lib/miniz/miniz.h"
 
+#include "errorAndExit.h"
 #include "inflate.h"
 
 //The compressed and uncompressed buffer arrays
@@ -85,7 +86,7 @@ struct InflateOutput inflateInflate(unsigned long numInputBytes, bool hasMoreByt
       } else {
         // Decompression failed.
         fprintf(stderr, "tinfl_decompress() failed with status %i!\n", status);
-        exit(1);
+        errorAndExit();
       }
     }
 

src/main.c

@@ -6,24 +6,29 @@
 
 //Import our code
 #include "decrypt.h"
+#include "errorAndExit.h"
 #include "fileReader.h"
 #include "inflate.h"
 #include "parseArguments.h"
 #include "utils/min.h"
 
+//The size of the buffers where the compressed and uncompressed data is stored
 #define BUFFER_SIZE 512UL * 1024UL //512 KiB
+//If a file is encrypted, there are 12 random bytes before the start of the file contents
 #define ENCRYPTION_HEADER_LENGTH 12UL
+//Each local file header in a .zip file has the magic bytes "50 4b 03 04" at the beginning
 #define LOCAL_FILE_HEADER_MAGIC (uint32_t)0x04034b50
 
+//Convenience functions for reading integers from a char array
 uint16_t getUint16(uint8_t* buffer) {
-  return (uint16_t)buffer[0] | \
+  return ((uint16_t)buffer[0]) | \
-    (uint16_t)buffer[1] << 8;
+    ((uint16_t)buffer[1]) << 8;
 }
 uint32_t getUint32(uint8_t* buffer) {
-  return (uint32_t)buffer[0] | \
+  return ((uint32_t)buffer[0]) | \
-    (uint32_t)buffer[1] << 8 | \
+    ((uint32_t)buffer[1]) << 8 | \
-    (uint32_t)buffer[2] << 16  | \
+    ((uint32_t)buffer[2]) << 16  | \
-    (uint32_t)buffer[3] << 24;
+    ((uint32_t)buffer[3]) << 24;
 }
 
 int main(int argc, char *argv[]) {
@@ -35,13 +40,13 @@ int main(int argc, char *argv[]) {
   uint8_t* compressedChunk = malloc(BUFFER_SIZE);
   if (compressedChunk == NULL) {
     fprintf(stderr, "Could not allocate %lu bytes for compressed buffer.\n", BUFFER_SIZE);
-    exit(1);
+    errorAndExit();
   }
 
   uint8_t* uncompressedChunk = malloc(BUFFER_SIZE);
   if (uncompressedChunk == NULL) {
     fprintf(stderr, "Could not allocate %lu bytes for uncompressed buffer.\n", BUFFER_SIZE);
-    exit(1);
+    errorAndExit();
   }
   memset(uncompressedChunk, (uint8_t)0, BUFFER_SIZE);
 
@@ -55,8 +60,8 @@ int main(int argc, char *argv[]) {
   //Check that header is correct
   const uint32_t magic = getUint32(compressedChunk);
   if (magic != LOCAL_FILE_HEADER_MAGIC) {
-    fprintf(stderr, "Wrong magic in local file header, expected %#010x but found %#010x.", LOCAL_FILE_HEADER_MAGIC, magic);
+    fprintf(stderr, "Wrong magic in local file header, expected %#010x but found %#010x.\n", LOCAL_FILE_HEADER_MAGIC, magic);
-    exit(1);
+    errorAndExit();
   }
   //Read additional length
   const unsigned long additionalLength = getUint16(compressedChunk + 26) + getUint16(compressedChunk + 28);
@@ -89,7 +94,6 @@ int main(int argc, char *argv[]) {
 
       //Decrypt file if it is encrypted
       if (state.isEncrypted) {
-        //TODO: For highest performance, we need to move if condition outside of while loop
         decrypt(compressedChunk, chunkSize);
       }
     }

src/parseArguments.c

@@ -3,8 +3,11 @@
 #include <stdlib.h>
 
 #include "decrypt.h"
+#include "errorAndExit.h"
 #include "parseArguments.h"
 
+//Uses GNU's getopt_long_only(), see https://www.gnu.org/software/libc/manual/html_node/Getopt-Long-Options.html
+
 static struct option long_options[] = {
   {"disk", required_argument, 0, 'd'},
   {"offset", required_argument, 0, 'o'},
@@ -18,13 +21,15 @@ struct arguments parseArguments(int argc, char *argv[]) {
   //Stores current state from command line arguments, initialized to zero
   struct arguments state = {};
 
-  int requiredOptions = 0;
+  bool hasDisk = false;
+  bool hasOffset = false;
+  bool hasSize = false;
 
   while (1) {
-    //in this variable, getopt_long stores the current position in the command line args array
+    //In this variable, getopt_long stores the current long option that was found. Unused since we don't use flags in our long options
-    int option_index = 0;
+    int optionIndex = 0;
 
-    int curOption = getopt_long(argc, argv, "d:o:s:k:p:", long_options, &option_index);
+    int curOption = getopt_long_only(argc, argv, "d:o:s:k:p:", long_options, &optionIndex);
 
     //end of command line arguments reached
     if (curOption == -1) {
@@ -34,15 +39,15 @@ struct arguments parseArguments(int argc, char *argv[]) {
     switch (curOption) {
       case 'd': //disk name
         state.diskName = optarg;
-        requiredOptions |= 1;
+        hasDisk = true;
         break;
       case 'o': //offset
         state.diskOffset = atol(optarg);
-        requiredOptions |= 2;
+        hasOffset = true;
         break;
       case 's': //size
         state.fileSize = atol(optarg);
-        requiredOptions |= 4;
+        hasSize = true;
         break;
       case 'k': { //decryption keys
         //TODO: parse from optarg
@@ -57,15 +62,33 @@ struct arguments parseArguments(int argc, char *argv[]) {
       case 'p': //prev file for xdelta3
         //TODO
         break;
+      case '?':
+        errorAndExit();
+        break;
       default:
-        fprintf(stderr, "Unknown option '%c'.", (char)curOption);
+        fprintf(stderr, "Unknown option '%c'.\n", (char)curOption);
-        exit(1);
+        errorAndExit();
     }
   }
 
-  if (requiredOptions != 7) {
+  if (!hasDisk) {
-    fprintf(stderr, "Missing arguments, received %i.", requiredOptions);
+    fprintf(stderr, "Missing required argument --disk.\n");
-    exit(1);
+    errorAndExit();
+  }
+
+  if (!hasOffset) {
+    fprintf(stderr, "Missing required argument --offset.\n");
+    errorAndExit();
+  }
+
+  if (!hasSize) {
+    fprintf(stderr, "Missing required argument --size.\n");
+    errorAndExit();
+  }
+
+  if (optind < argc) {
+    fprintf(stderr, "Found %i arguments without an option. All arguments must be preceded by an option.\n", argc - optind);
+    errorAndExit();
   }
 
   return state;