New files to support disk I/O restructuring and (currently broken)

Windows version.

1 files changed, 1 insertions, 289 deletions

diff --git a/support.cc b/support.cc
index 81801f3..388b71a 100644
--- a/support.cc
+++ b/support.cc
@@ -9,9 +9,8 @@
 #define __STDC_LIMIT_MACROS
 #define __STDC_CONSTANT_MACROS
 
-#include <sys/ioctl.h>
 #include <stdio.h>
-#include <string.h>
+#include <string>
 #include <stdint.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -27,10 +26,6 @@
 #define BLKPBSZGET _IO(0x12,123)
 #endif
 
-// Below constant corresponds to an 800GB disk -- a somewhat arbitrary
-// cutoff
-#define SMALLEST_ADVANCED_FORMAT UINT64_C(1677721600)
-
 using namespace std;
 
 // Get a numeric value from the user, between low and high (inclusive).
@@ -205,114 +200,6 @@ char* BytesToSI(uint64_t size, char theValue[]) {
    return theValue;
 } // BlocksToSI()
 
-// Returns block size of device pointed to by fd file descriptor. If the ioctl
-// returns an error condition, print a warning but return a value of SECTOR_SIZE
-// (512)..
-int GetBlockSize(int fd) {
-   int err = -1, result;
-
-#ifdef __APPLE__
-   err = ioctl(fd, DKIOCGETBLOCKSIZE, &result);
-#endif
-#ifdef __FreeBSD__
-   err = ioctl(fd, DIOCGSECTORSIZE, &result);
-#endif
-#ifdef __linux__
-   err = ioctl(fd, BLKSSZGET, &result);
-#endif
-
-   if (err == -1) {
-      result = SECTOR_SIZE;
-      // ENOTTY = inappropriate ioctl; probably being called on a disk image
-      // file, so don't display the warning message....
-      // 32-bit code returns EINVAL, I don't know why. I know I'm treading on
-      // thin ice here, but it should be OK in all but very weird cases....
-      if ((errno != ENOTTY) && (errno != EINVAL)) {
-         printf("\aError %d when determining sector size! Setting sector size to %d\n",
-                errno, SECTOR_SIZE);
-      } // if
-   } // if
-
-/*   if (result != 512) {
-      printf("\aWARNING! Sector size is not 512 bytes! This program is likely to ");
-      printf("misbehave!\nProceed at your own risk!\n\n");
-   } // if */
-
-   return (result);
-} // GetBlockSize()
-
-// My original FindAlignment() function (after this one) isn't working, since
-// the BLKPBSZGET ioctl() isn't doing what I expected (it returns 512 even on
-// a WD Advanced Format drive). Therefore, I'm using a simpler function that
-// returns 1-sector alignment for unusual sector sizes and drives smaller than
-// a size defined by SMALLEST_ADVANCED_FORMAT, and 8-sector alignment for
-// larger drives with 512-byte sectors.
-int FindAlignment(int fd) {
-   int err, result;
-
-   if ((GetBlockSize(fd) == 512) && (disksize(fd, &err) >= SMALLEST_ADVANCED_FORMAT)) {
-      result = 8; // play it safe; align for 4096-byte sectors
-   } else {
-      result = 1; // unusual sector size; assume it's the real physical size
-   } // if/else
-   return result;
-} // FindAlignment
-
-// Return the partition alignment value in sectors. Right now this works
-// only for Linux 2.6.32 and later, since I can't find equivalent ioctl()s
-// for OS X or FreeBSD, and the Linux ioctl is new
-/* int FindAlignment(int fd) {
-   int err = -2, errnum = 0, result = 8, physicalSectorSize = 4096;
-   uint64_t diskSize;
-
-   printf("Entering FindAlignment()\n");
-#if defined (__linux__) && defined (BLKPBSZGET)
-   err = ioctl(fd, BLKPBSZGET, &physicalSectorSize);
-   printf("In FindAlignment(), physicalSectorSize = %d, err = %d\n", physicalSectorSize, err);
-//   printf("Tried to get hardware alignment; err is %d, sector size is %d\n", err, physicalSectorSize);
-#else
-   err = -1;
-#endif
-
-   if (err < 0) { // ioctl didn't work; have to guess....
-      if (GetBlockSize(fd) == 512) {
-         result = 8; // play it safe; align for 4096-byte sectors
-      } else {
-         result = 1; // unusual sector size; assume it's the real physical size
-      } // if/else
-   } else { // ioctl worked; compute alignment
-      result = physicalSectorSize / GetBlockSize(fd);
-      // Disks with larger physical than logical sectors must theoretically
-      // have a total disk size that's a multiple of the physical sector
-      // size; however, some such disks have compatibility jumper settings
-      // meant for one-partition MBR setups, and these reduce the total
-      // number of sectors by 1. If such a setting is used, it'll result
-      // in improper alignment, so look for this condition and warn the
-      // user if it's found....
-      diskSize = disksize(fd, &errnum);
-      if ((diskSize % (uint64_t) result) != 0) {
-         fprintf(stderr, "\aWarning! Disk size (%llu) is not a multiple of alignment\n"
-                         "size (%d), but it should be! Check disk manual and jumper settings!\n",
-                         (unsigned long long) diskSize, result);
-      } // if
-   } // if/else
-   if (result <= 0) // can happen if physical sector size < logical sector size
-      result = 1;
-   return result;
-} // FindAlignment(int) */
-
-// The same as FindAlignment(int), but opens and closes a device by filename
-int FindAlignment(char deviceFilename[]) {
-   int fd;
-   int retval = 1;
-
-   if ((fd = open(deviceFilename, O_RDONLY)) != -1) {
-      retval = FindAlignment(fd);
-      close(fd);
-   } // if
-   return retval;
-} // FindAlignment(char)
-
 // Return a plain-text name for a partition type.
 // Convert a GUID to a string representation, suitable for display
 // to humans....
@@ -463,178 +350,3 @@ uint64_t PowerOf2(int value) {
    } else retval = 0;
    return retval;
 } // PowerOf2()
-
-// An extended file-open function. This includes some system-specific checks.
-// I want them in a function because I use these calls twice and I don't want
-// to forget to change them in one location if I need to change them in
-// the other....
-int OpenForWrite(char* deviceFilename) {
-   int fd;
-
-   fd = open(deviceFilename, O_WRONLY); // try to open the device; may fail....
-#ifdef __APPLE__
-   // MacOS X requires a shared lock under some circumstances....
-   if (fd < 0) {
-      fd = open(deviceFilename, O_WRONLY|O_SHLOCK);
-   } // if
-#endif
-	return fd;
-} // OpenForWrite()
-
-// Resync disk caches so the OS uses the new partition table. This code varies
-// a lot from one OS to another.
-void DiskSync(int fd) {
-   int i;
-
-   sync();
-#ifdef __APPLE__
-   printf("Warning: The kernel may continue to use old or deleted partitions.\n"
-          "You should reboot or remove the drive.\n");
-	    /* don't know if this helps
-	     * it definitely will get things on disk though:
-            * http://topiks.org/mac-os-x/0321278542/ch12lev1sec8.html */
-   i = ioctl(fd, DKIOCSYNCHRONIZECACHE);
-#else
-#ifdef __FreeBSD__
-   sleep(2);
-   i = ioctl(fd, DIOCGFLUSH);
-   printf("Warning: The kernel may continue to use old or deleted partitions.\n"
-          "You should reboot or remove the drive.\n");
-#else
-   sleep(2);
-   i = ioctl(fd, BLKRRPART);
-   if (i)
-      printf("Warning: The kernel is still using the old partition table.\n"
-            "The new table will be used at the next reboot.\n");
-#endif
-#endif
-} // DiskSync()
-
-// A variant on the standard read() function. Done to work around
-// limitations in FreeBSD concerning the matching of the sector
-// size with the number of bytes read
-int myRead(int fd, char* buffer, int numBytes) {
-   int blockSize = 512, i, numBlocks, retval;
-   char* tempSpace;
-
-   // Compute required space and allocate memory
-   blockSize = GetBlockSize(fd);
-   if (numBytes <= blockSize) {
-      numBlocks = 1;
-      tempSpace = (char*) malloc(blockSize);
-   } else {
-      numBlocks = numBytes / blockSize;
-      if ((numBytes % blockSize) != 0) numBlocks++;
-      tempSpace = (char*) malloc(numBlocks * blockSize);
-   } // if/else
-
-   // Read the data into temporary space, then copy it to buffer
-   retval = read(fd, tempSpace, numBlocks * blockSize);
-   for (i = 0; i < numBytes; i++) {
-      buffer[i] = tempSpace[i];
-   } // for
-
-   // Adjust the return value, if necessary....
-   if (((numBlocks * blockSize) != numBytes) && (retval > 0))
-      retval = numBytes;
-
-   free(tempSpace);
-   return retval;
-} // myRead()
-
-// A variant on the standard write() function. Done to work around
-// limitations in FreeBSD concerning the matching of the sector
-// size with the number of bytes read
-int myWrite(int fd, char* buffer, int numBytes) {
-   int blockSize = 512, i, numBlocks, retval;
-   char* tempSpace;
-
-   // Compute required space and allocate memory
-   blockSize = GetBlockSize(fd);
-   if (numBytes <= blockSize) {
-      numBlocks = 1;
-      tempSpace = (char*) malloc(blockSize);
-   } else {
-      numBlocks = numBytes / blockSize;
-      if ((numBytes % blockSize) != 0) numBlocks++;
-      tempSpace = (char*) malloc(numBlocks * blockSize);
-   } // if/else
-
-   // Copy the data to my own buffer, then write it
-   for (i = 0; i < numBytes; i++) {
-      tempSpace[i] = buffer[i];
-   } // for
-   for (i = numBytes; i < numBlocks * blockSize; i++) {
-      tempSpace[i] = 0;
-   } // for
-   retval = write(fd, tempSpace, numBlocks * blockSize);
-
-   // Adjust the return value, if necessary....
-   if (((numBlocks * blockSize) != numBytes) && (retval > 0))
-      retval = numBytes;
-
-   free(tempSpace);
-   return retval;
-} // myRead()
-
-/**************************************************************************************
- *                                                                                    *
- * Below functions are lifted from various sources, as documented in comments before  *
- * each one.                                                                          *
- *                                                                                    *
- **************************************************************************************/
-
-// The disksize function is taken from the Linux fdisk code and modified
-// greatly since then to enable FreeBSD and MacOS support, as well as to
-// return correct values for disk image files.
-uint64_t disksize(int fd, int *err) {
-   long sz; // Do not delete; needed for Linux
-   long long b; // Do not delete; needed for Linux
-   uint64_t sectors = 0; // size in sectors
-   off_t bytes = 0; // size in bytes
-   struct stat64 st;
-
-   // Note to self: I recall testing a simplified version of
-   // this code, similar to what's in the __APPLE__ block,
-   // on Linux, but I had some problems. IIRC, it ran OK on 32-bit
-   // systems but not on 64-bit. Keep this in mind in case of
-   // 32/64-bit issues on MacOS....
-#ifdef __APPLE__
-   *err = ioctl(fd, DKIOCGETBLOCKCOUNT, &sectors);
-#else
-#ifdef __FreeBSD__
-   *err = ioctl(fd, DIOCGMEDIASIZE, &bytes);
-   b = GetBlockSize(fd);
-   sectors = bytes / b;
-#else
-   *err = ioctl(fd, BLKGETSIZE, &sz);
-   if (*err) {
-      sectors = sz = 0;
-   } // if
-   if ((errno == EFBIG) || (!*err)) {
-      *err = ioctl(fd, BLKGETSIZE64, &b);
-      if (*err || b == 0 || b == sz)
-         sectors = sz;
-      else
-         sectors = (b >> 9);
-   } // if
-   // Unintuitively, the above returns values in 512-byte blocks, no
-   // matter what the underlying device's block size. Correct for this....
-   sectors /= (GetBlockSize(fd) / 512);
-#endif
-#endif
-
-   // The above methods have failed (or it's a bum filename reference),
-   // so let's assume it's a regular file (a QEMU image, dd backup, or
-   // what have you) and see what stat() gives us....
-   if ((sectors == 0) || (*err == -1)) {
-      if (fstat64(fd, &st) == 0) {
-         bytes = (off_t) st.st_size;
-         if ((bytes % UINT64_C(512)) != 0)
-            fprintf(stderr, "Warning: File size is not a multiple of 512 bytes!"
-                            " Misbehavior is likely!\n\a");
-         sectors = bytes / UINT64_C(512);
-      } // if
-   } // if
-   return sectors;
-} // disksize()