Dump machine-readable MBR or GPT details.

Looks for both MBR and GPT headers, and dumps the most relevant
table in a machine-readable format.  Silences noisy underlying
library to avoid parsing trouble.

Change-Id: I2c3077929758df4b84dc52d8d4791d333bb625ca

sgdisk.cc

@@ -9,13 +9,89 @@
 /* This program is copyright (c) 2009-2011 by Roderick W. Smith. It is distributed
   under the terms of the GNU GPL version 2, as detailed in the COPYING file. */
 
+#include <iostream>
+#include <fstream>
+#include <string.h>
+#include <string>
+#include <iostream>
+#include <sstream>
+#include <errno.h>
 #include "gptcl.h"
+#include <fcntl.h>
 
 using namespace std;
 
 #define MAX_OPTIONS 50
 
+/*
+ * Dump partition details in a machine readable format:
+ *
+ * DISK [mbr|gpt] [guid]
+ * PART [n] [type] [guid]
+ */
+static int android_dump(char* device) {
+    BasicMBRData mbrData;
+    GPTData gptData;
+    GPTPart partData;
+    int numParts = 0;
+    stringstream res;
+
+    /* Silence noisy underlying library */
+    int stdout = dup(STDOUT_FILENO);
+    int silence = open("/dev/null", 0);
+    dup2(silence, STDOUT_FILENO);
+    dup2(silence, STDERR_FILENO);
+
+    if (!mbrData.ReadMBRData((string) device)) {
+        cerr << "Failed to read MBR" << endl;
+        return 8;
+    }
+
+    switch (mbrData.GetValidity()) {
+    case mbr:
+        res << "DISK mbr" << endl;
+        for (int i = 0; i < MAX_MBR_PARTS; i++) {
+            if (mbrData.GetLength(i) > 0) {
+                res << "PART " << (i + 1) << " " << hex
+                        << (int) mbrData.GetType(i) << dec << endl;
+            }
+        }
+        break;
+    case gpt:
+        gptData.JustLooking();
+        if (!gptData.LoadPartitions((string) device)) {
+            cerr << "Failed to read GPT" << endl;
+            return 9;
+        }
+
+        res << "DISK gpt " << gptData.GetDiskGUID() << endl;
+        numParts = gptData.GetNumParts();
+        for (int i = 0; i < numParts; i++) {
+            partData = gptData[i];
+            if (partData.GetFirstLBA() > 0) {
+                res << "PART " << (i + 1) << " " << partData.GetType() << " "
+                        << partData.GetUniqueGUID() << endl;
+            }
+        }
+        break;
+    default:
+        cerr << "Unknown partition table" << endl;
+        return 10;
+    }
+
+    /* Write our actual output */
+    string resString = res.str();
+    write(stdout, resString.c_str(), resString.length());
+    return 0;
+}
+
 int main(int argc, char *argv[]) {
-   GPTDataCL theGPT;
-   return theGPT.DoOptions(argc, argv);
-} // main
+    for (int i = 0; i < argc; i++) {
+        if (!strcmp("--android-dump", argv[i])) {
+            return android_dump(argv[i + 1]);
+        }
+    }
+
+    GPTDataCL theGPT;
+    return theGPT.DoOptions(argc, argv);
+}