commit 24e7b322387957e2b6d670a2afd6c886ebf133ca
Author: haraldwolff <harald@l--n.de>
Date:   Thu Jan 11 23:45:26 2024 +0100

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2dff2f0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+cmake-build-debug
diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..13566b8
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/ddscratch.iml b/.idea/ddscratch.iml
new file mode 100644
index 0000000..f08604b
--- /dev/null
+++ b/.idea/ddscratch.iml
@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module classpath="CMake" type="CPP_MODULE" version="4" />
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..79b3c94
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$" />
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000..a0c2875
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/ddscratch.iml" filepath="$PROJECT_DIR$/.idea/ddscratch.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..109a099
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.26)
+project(ddscratch C)
+
+set(CMAKE_C_STANDARD 11)
+
+add_executable(ddscratch main.c)
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..cb4f2fb
--- /dev/null
+++ b/main.c
@@ -0,0 +1,147 @@
+#include <stdio.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+char devpath[FILENAME_MAX];
+char targetpath[FILENAME_MAX];
+
+int firstSector = -1;
+long offset = -1;
+int cntSectors = -1;
+int sectSize = 4096;
+
+void printUsage();
+int scratch(int dev, int image,int sector,int size);
+
+int main(int argc, char **argv) {
+    int ch;
+    while ((ch = getopt(argc, argv, "o:c:s:h")) != -1){
+        switch (ch){
+            case 'o':
+                offset = strtol(optarg, NULL, 0);
+                break;
+            case 'b':
+                offset = strtol(optarg, NULL, 0);
+                break;
+            case 'c':
+                cntSectors = strtol(optarg, NULL, 0);
+                break;
+            case 's':
+                sectSize = strtol(optarg, NULL, 0);
+            case 'h':
+                printUsage();
+                return 0;
+        }
+    }
+
+    if (optind != (argc-2)){
+        printUsage();
+        return -1;
+    }
+
+    strncpy(devpath, argv[optind], sizeof(devpath));
+    strncpy(targetpath, argv[optind+1], sizeof(targetpath));
+
+    if ((offset != -1) && (firstSector != -1)){
+        printUsage();
+        printf("only first sector OR offset may be given!\n");
+    }
+
+    if (offset != -1)
+        firstSector = (int)(offset / sectSize);
+    if (firstSector == -1)
+        firstSector = 0;
+
+    int dev = open(devpath, O_RDONLY);
+    if (dev == -1){
+        printf("could not open device %s\n", devpath);
+        return -2;
+    }
+
+    long devsize = lseek(dev, 0, SEEK_END);
+    if (cntSectors == -1)
+        cntSectors = (int)(devsize / sectSize);
+
+    int target = open(devpath, O_RDONLY);
+    if (target == -1){
+        printf("could not open target image %s\n", targetpath);
+        close(dev);
+        return -3;
+    }
+
+    printf("target (image file): %s\n", targetpath);
+    printf("device:              %s\n", devpath);
+    printf("sector size:         %i\n", sectSize);
+    printf("offset:              0x%08lx\n", ((long)firstSector * sectSize));
+    printf("first sector:        %i\n", firstSector);
+    printf("sectors:             %i\n", cntSectors);
+
+    for (int n=0;n<cntSectors;n++){
+        scratch(dev, target, firstSector + n, sectSize);
+    }
+
+    close(target);
+    close(dev);
+    return 0;
+}
+
+int scratch(int dev, int image,int sector,int size){
+    char p[size];
+    long offset = (long)sector * size;
+    for (int n = 0; n < 16; n++){
+        printf("\r#%08i 0x%08lX %i", sector, offset, n);
+        if (lseek(dev, offset, SEEK_SET) != offset){
+            printf("\ncould not seek (dev).\n");
+            return -1;
+        }
+        if (lseek(image, offset, SEEK_SET) != offset){
+            printf("\ncould not seek (image).\n");
+            return -1;
+        }
+
+        int nread = read(dev, p, size);
+        if (nread == -1){
+            continue;
+        } else {
+            if (nread < size) {
+                printf("\nshort read!\n");
+            }
+            write(image, p, nread);
+            return size;
+        }
+    }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+void printUsage(){
+    printf("usage: ddscratch ( [-b <firstsector> ] | [-o <offset>] ) [-c <sectorcount>] [-s <sectorsize>] <path> <target>\n");
+}
+
+