cgpt/cgpt_find.c - third_party/vboot_reference - Git at Google

 // Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include <ctype.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>

 #include "cgpt.h"
 #include "cgpt_nor.h"
 #include "cgptlib_internal.h"
 #include "vboot_host.h"

 #define BUFSIZE 1024
 // FIXME: currently we only support 512-byte sectors.
 #define LBA_SIZE 512


 // fill comparebuf with the data to be examined, returning true on success.
 static int FillBuffer(CgptFindParams *params, int fd, uint64_t pos,
                        uint64_t count) {
   uint8_t *bufptr = params->comparebuf;

   if (-1 == lseek(fd, pos, SEEK_SET))
     return 0;

   // keep reading until done or error
   while (count) {
     ssize_t bytes_read = read(fd, bufptr, count);
     // negative means error, 0 means (unexpected) EOF
     if (bytes_read <= 0)
       return 0;
     count -= bytes_read;
     bufptr += bytes_read;
   }

   return 1;
 }

 // check partition data content. return true for match, 0 for no match or error
 static int match_content(CgptFindParams *params, struct drive *drive,
                              GptEntry *entry) {
   uint64_t part_size;

   if (!params->matchlen)
     return 1;

   // Ensure that the region we want to match against is inside the partition.
   part_size = LBA_SIZE * (entry->ending_lba - entry->starting_lba + 1);
   if (params->matchoffset + params->matchlen > part_size) {
     return 0;
   }

   // Read the partition data.
   if (!FillBuffer(params,
                   drive->fd,
                   (LBA_SIZE * entry->starting_lba) + params->matchoffset,
                   params->matchlen)) {
     Error("unable to read partition data\n");
     return 0;
   }

   // Compare it
   if (0 == memcmp(params->matchbuf, params->comparebuf, params->matchlen)) {
     return 1;
   }

   // Nope.
   return 0;
 }

 // This needs to handle /dev/mmcblk0 -> /dev/mmcblk0p3, /dev/sda -> /dev/sda3
 static void showmatch(CgptFindParams *params, char *filename,
                       int partnum, GptEntry *entry) {
   char * format = "%s%d\n";

   /*
    * Follow convention from disk_name() in kernel block/partition-generic.c
    * code:
    * If the last digit of the device name is a number, add a 'p' between the
    * device name and the partition number.
    */
   if (isdigit(filename[strlen(filename) - 1]))
     format = "%sp%d\n";

   if (params->numeric) {
     printf("%d\n", partnum);
   } else {
     if (params->show_fn) {
       params->show_fn(params, filename, partnum, entry);
     } else {
       printf(format, filename, partnum);
     }
   }
   if (params->verbose > 0)
     EntryDetails(entry, partnum - 1, params->numeric);
 }

 // This handles the MTD devices. ChromeOS uses /dev/mtdX for kernel partitions,
 // /dev/ubiblockX_0 for root partitions, and /dev/ubiX for stateful partition.
 static void chromeos_mtd_show(CgptFindParams *params, char *filename,
                               int partnum, GptEntry *entry) {
   if (GuidEqual(&guid_chromeos_kernel, &entry->type)) {
     printf("/dev/mtd%d\n", partnum);
   } else if (GuidEqual(&guid_chromeos_rootfs, &entry->type)) {
     printf("/dev/ubiblock%d_0\n", partnum);
   } else {
     printf("/dev/ubi%d_0\n", partnum);
   }
 }

 // This returns true if a GPT partition matches the search criteria. If a match
 // isn't found (or if the file doesn't contain a GPT), it returns false. The
 // filename and partition number that matched is left in a global, since we
 // could have multiple hits.
 static int gpt_search(CgptFindParams *params, struct drive *drive,
                       char *filename) {
   int i;
   GptEntry *entry;
   int retval = 0;
   char partlabel[GPT_PARTNAME_LEN];

   if (GPT_SUCCESS != GptSanityCheck(&drive->gpt)) {
     return 0;
   }

   for (i = 0; i < GetNumberOfEntries(drive); ++i) {
     entry = GetEntry(&drive->gpt, ANY_VALID, i);

     if (GuidIsZero(&entry->type))
       continue;

     int found = 0;
     if ((params->set_unique && GuidEqual(&params->unique_guid, &entry->unique))
         || (params->set_type && GuidEqual(&params->type_guid, &entry->type))) {
       found = 1;
     } else if (params->set_label) {
       if (CGPT_OK != UTF16ToUTF8(entry->name,
                                  sizeof(entry->name) / sizeof(entry->name[0]),
                                  (uint8_t *)partlabel, sizeof(partlabel))) {
         Error("The label cannot be converted from UTF16, so abort.\n");
         return 0;
       }
       if (!strncmp(params->label, partlabel, sizeof(partlabel)))
         found = 1;
     }
     if (found && match_content(params, drive, entry)) {
       params->hits++;
       retval++;
       showmatch(params, filename, i+1, entry);
       if (!params->match_partnum)
         params->match_partnum = i+1;
     }
   }

   return retval;
 }

 static int do_search(CgptFindParams *params, char *fileName) {
   int retval;
   struct drive drive;

   if (CGPT_OK != DriveOpen(fileName, &drive, O_RDONLY, params->drive_size))
     return 0;

   retval = gpt_search(params, &drive, fileName);

   (void) DriveClose(&drive, 0);

   return retval;
 }


 #define PROC_MTD "/proc/mtd"
 #define PROC_PARTITIONS "/proc/partitions"
 #define DEV_DIR "/dev"
 #define SYS_BLOCK_DIR "/sys/block"
 #define MAX_PARTITION_NAME_LEN 128

 static const char *devdirs[] = { "/dev", "/devices", "/devfs", 0 };

 // Given basename "foo", see if we can find a whole, real device by that name.
 // This is copied from the logic in the linux utility 'findfs', although that
 // does more exhaustive searching.
 static char *is_wholedev(const char *basename) {
   int i;
   struct stat statbuf;
   static char pathname[BUFSIZE];        // we'll return this.
   char tmpname[BUFSIZE];

   // It should be a block device under /dev/,
   for (i = 0; devdirs[i]; i++) {
     sprintf(pathname, "%s/%s", devdirs[i], basename);

     if (0 != stat(pathname, &statbuf))
       continue;

     if (!S_ISBLK(statbuf.st_mode))
       continue;

     // It should have a symlink called /sys/block/*/device
     sprintf(tmpname, "%s/%s/device", SYS_BLOCK_DIR, basename);

     if (0 != lstat(tmpname, &statbuf))
       continue;

     if (!S_ISLNK(statbuf.st_mode))
       continue;

     // found it
     return pathname;
   }

   return 0;
 }

 // This scans all the physical devices it can find, looking for a match. It
 // returns true if any matches were found, false otherwise.
 static int scan_real_devs(CgptFindParams *params) {
   int found = 0;
   char partname[MAX_PARTITION_NAME_LEN];
   char partname_prev[MAX_PARTITION_NAME_LEN];
   FILE *fp;
   char *pathname;

   fp = fopen(PROC_PARTITIONS, "re");
   if (!fp) {
     perror("can't read " PROC_PARTITIONS);
     return found;
   }

   size_t line_length = 0;
   char *line = NULL;
   partname_prev[0] = '\0';
   while (getline(&line, &line_length, fp) != -1) {
     int ma, mi;
     long long unsigned int sz;

     if (sscanf(line, " %d %d %llu %127[^\n ]", &ma, &mi, &sz, partname) != 4)
       continue;

     /* Only check devices that have partitions under them.
      * We can tell by checking that an entry like "sda" is immediately
      * followed by one like "sda0". */
     if (!strncmp(partname_prev, partname, strlen(partname_prev)) &&
         strlen(partname_prev)) {
       if ((pathname = is_wholedev(partname_prev))) {
         if (do_search(params, pathname)) {
           found++;
         }
       }
     }

     strcpy(partname_prev, partname);
   }

   fclose(fp);

   fp = fopen(PROC_MTD, "re");
   if (!fp) {
     free(line);
     return found;
   }

   while (getline(&line, &line_length, fp) != -1) {
     uint64_t sz;
     uint32_t erasesz;
     char name[128];
     // dev:  size  erasesize  name
     if (sscanf(line, "%64[^:]: %" PRIx64 " %x \"%127[^\"]\"",
                partname, &sz, &erasesz, name) != 4)
       continue;
     if (strcmp(partname, "mtd0") == 0) {
       char temp_dir[] = "/tmp/cgpt_find.XXXXXX";
       if (params->drive_size == 0) {
         if (GetMtdSize("/dev/mtd0", &params->drive_size) != 0) {
           perror("GetMtdSize");
           goto cleanup;
         }
       }
       if (ReadNorFlash(temp_dir) != 0) {
         perror("ReadNorFlash");
         goto cleanup;
       }
       char nor_file[64];
       if (snprintf(nor_file, sizeof(nor_file), "%s/rw_gpt", temp_dir) > 0) {
         params->show_fn = chromeos_mtd_show;
         if (do_search(params, nor_file)) {
           found++;
         }
         params->show_fn = NULL;
       }
       RemoveDir(temp_dir);
       break;
     }
   }
 cleanup:
   fclose(fp);
   free(line);
   return found;
 }


 void CgptFind(CgptFindParams *params) {
   if (params == NULL)
     return;

   if (params->drive_name != NULL)
     do_search(params, params->drive_name);
   else
     scan_real_devs(params);
 }
	// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include <ctype.h>
	#include <string.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>

	#include "cgpt.h"
	#include "cgpt_nor.h"
	#include "cgptlib_internal.h"
	#include "vboot_host.h"

	#define BUFSIZE 1024
	// FIXME: currently we only support 512-byte sectors.
	#define LBA_SIZE 512


	// fill comparebuf with the data to be examined, returning true on success.
	static int FillBuffer(CgptFindParams *params, int fd, uint64_t pos,
	uint64_t count) {
	uint8_t *bufptr = params->comparebuf;

	if (-1 == lseek(fd, pos, SEEK_SET))
	return 0;

	// keep reading until done or error
	while (count) {
	ssize_t bytes_read = read(fd, bufptr, count);
	// negative means error, 0 means (unexpected) EOF
	if (bytes_read <= 0)
	return 0;
	count -= bytes_read;
	bufptr += bytes_read;
	}

	return 1;
	}

	// check partition data content. return true for match, 0 for no match or error
	static int match_content(CgptFindParams params, struct drive drive,
	GptEntry *entry) {
	uint64_t part_size;

	if (!params->matchlen)
	return 1;

	// Ensure that the region we want to match against is inside the partition.
	part_size = LBA_SIZE * (entry->ending_lba - entry->starting_lba + 1);
	if (params->matchoffset + params->matchlen > part_size) {
	return 0;
	}

	// Read the partition data.
	if (!FillBuffer(params,
	drive->fd,
	(LBA_SIZE * entry->starting_lba) + params->matchoffset,
	params->matchlen)) {
	Error("unable to read partition data\n");
	return 0;
	}

	// Compare it
	if (0 == memcmp(params->matchbuf, params->comparebuf, params->matchlen)) {
	return 1;
	}

	// Nope.
	return 0;
	}

	// This needs to handle /dev/mmcblk0 -> /dev/mmcblk0p3, /dev/sda -> /dev/sda3
	static void showmatch(CgptFindParams params, char filename,
	int partnum, GptEntry *entry) {
	char * format = "%s%d\n";

	/*
	* Follow convention from disk_name() in kernel block/partition-generic.c
	* code:
	* If the last digit of the device name is a number, add a 'p' between the
	* device name and the partition number.
	*/
	if (isdigit(filename[strlen(filename) - 1]))
	format = "%sp%d\n";

	if (params->numeric) {
	printf("%d\n", partnum);
	} else {
	if (params->show_fn) {
	params->show_fn(params, filename, partnum, entry);
	} else {
	printf(format, filename, partnum);
	}
	}
	if (params->verbose > 0)
	EntryDetails(entry, partnum - 1, params->numeric);
	}

	// This handles the MTD devices. ChromeOS uses /dev/mtdX for kernel partitions,
	// /dev/ubiblockX_0 for root partitions, and /dev/ubiX for stateful partition.
	static void chromeos_mtd_show(CgptFindParams params, char filename,
	int partnum, GptEntry *entry) {
	if (GuidEqual(&guid_chromeos_kernel, &entry->type)) {
	printf("/dev/mtd%d\n", partnum);
	} else if (GuidEqual(&guid_chromeos_rootfs, &entry->type)) {
	printf("/dev/ubiblock%d_0\n", partnum);
	} else {
	printf("/dev/ubi%d_0\n", partnum);
	}
	}

	// This returns true if a GPT partition matches the search criteria. If a match
	// isn't found (or if the file doesn't contain a GPT), it returns false. The
	// filename and partition number that matched is left in a global, since we
	// could have multiple hits.
	static int gpt_search(CgptFindParams params, struct drive drive,
	char *filename) {
	int i;
	GptEntry *entry;
	int retval = 0;
	char partlabel[GPT_PARTNAME_LEN];

	if (GPT_SUCCESS != GptSanityCheck(&drive->gpt)) {
	return 0;
	}

	for (i = 0; i < GetNumberOfEntries(drive); ++i) {
	entry = GetEntry(&drive->gpt, ANY_VALID, i);

	if (GuidIsZero(&entry->type))
	continue;

	int found = 0;
	if ((params->set_unique && GuidEqual(&params->unique_guid, &entry->unique))
	\|\| (params->set_type && GuidEqual(&params->type_guid, &entry->type))) {
	found = 1;
	} else if (params->set_label) {
	if (CGPT_OK != UTF16ToUTF8(entry->name,
	sizeof(entry->name) / sizeof(entry->name[0]),
	(uint8_t *)partlabel, sizeof(partlabel))) {
	Error("The label cannot be converted from UTF16, so abort.\n");
	return 0;
	}
	if (!strncmp(params->label, partlabel, sizeof(partlabel)))
	found = 1;
	}
	if (found && match_content(params, drive, entry)) {
	params->hits++;
	retval++;
	showmatch(params, filename, i+1, entry);
	if (!params->match_partnum)
	params->match_partnum = i+1;
	}
	}

	return retval;
	}

	static int do_search(CgptFindParams params, char fileName) {
	int retval;
	struct drive drive;

	if (CGPT_OK != DriveOpen(fileName, &drive, O_RDONLY, params->drive_size))
	return 0;

	retval = gpt_search(params, &drive, fileName);

	(void) DriveClose(&drive, 0);

	return retval;
	}


	#define PROC_MTD "/proc/mtd"
	#define PROC_PARTITIONS "/proc/partitions"
	#define DEV_DIR "/dev"
	#define SYS_BLOCK_DIR "/sys/block"
	#define MAX_PARTITION_NAME_LEN 128

	static const char *devdirs[] = { "/dev", "/devices", "/devfs", 0 };

	// Given basename "foo", see if we can find a whole, real device by that name.
	// This is copied from the logic in the linux utility 'findfs', although that
	// does more exhaustive searching.
	static char is_wholedev(const char basename) {
	int i;
	struct stat statbuf;
	static char pathname[BUFSIZE]; // we'll return this.
	char tmpname[BUFSIZE];

	// It should be a block device under /dev/,
	for (i = 0; devdirs[i]; i++) {
	sprintf(pathname, "%s/%s", devdirs[i], basename);

	if (0 != stat(pathname, &statbuf))
	continue;

	if (!S_ISBLK(statbuf.st_mode))
	continue;

	// It should have a symlink called /sys/block/*/device
	sprintf(tmpname, "%s/%s/device", SYS_BLOCK_DIR, basename);

	if (0 != lstat(tmpname, &statbuf))
	continue;

	if (!S_ISLNK(statbuf.st_mode))
	continue;

	// found it
	return pathname;
	}

	return 0;
	}

	// This scans all the physical devices it can find, looking for a match. It
	// returns true if any matches were found, false otherwise.
	static int scan_real_devs(CgptFindParams *params) {
	int found = 0;
	char partname[MAX_PARTITION_NAME_LEN];
	char partname_prev[MAX_PARTITION_NAME_LEN];
	FILE *fp;
	char *pathname;

	fp = fopen(PROC_PARTITIONS, "re");
	if (!fp) {
	perror("can't read " PROC_PARTITIONS);
	return found;
	}

	size_t line_length = 0;
	char *line = NULL;
	partname_prev[0] = '\0';
	while (getline(&line, &line_length, fp) != -1) {
	int ma, mi;
	long long unsigned int sz;

	if (sscanf(line, " %d %d %llu %127[^\n ]", &ma, &mi, &sz, partname) != 4)
	continue;

	/* Only check devices that have partitions under them.
	* We can tell by checking that an entry like "sda" is immediately
	* followed by one like "sda0". */
	if (!strncmp(partname_prev, partname, strlen(partname_prev)) &&
	strlen(partname_prev)) {
	if ((pathname = is_wholedev(partname_prev))) {
	if (do_search(params, pathname)) {
	found++;
	}
	}
	}

	strcpy(partname_prev, partname);
	}

	fclose(fp);

	fp = fopen(PROC_MTD, "re");
	if (!fp) {
	free(line);
	return found;
	}

	while (getline(&line, &line_length, fp) != -1) {
	uint64_t sz;
	uint32_t erasesz;
	char name[128];
	// dev: size erasesize name
	if (sscanf(line, "%64[^:]: %" PRIx64 " %x \"%127[^\"]\"",
	partname, &sz, &erasesz, name) != 4)
	continue;
	if (strcmp(partname, "mtd0") == 0) {
	char temp_dir[] = "/tmp/cgpt_find.XXXXXX";
	if (params->drive_size == 0) {
	if (GetMtdSize("/dev/mtd0", &params->drive_size) != 0) {
	perror("GetMtdSize");
	goto cleanup;
	}
	}
	if (ReadNorFlash(temp_dir) != 0) {
	perror("ReadNorFlash");
	goto cleanup;
	}
	char nor_file[64];
	if (snprintf(nor_file, sizeof(nor_file), "%s/rw_gpt", temp_dir) > 0) {
	params->show_fn = chromeos_mtd_show;
	if (do_search(params, nor_file)) {
	found++;
	}
	params->show_fn = NULL;
	}
	RemoveDir(temp_dir);
	break;
	}
	}
	cleanup:
	fclose(fp);
	free(line);
	return found;
	}


	void CgptFind(CgptFindParams *params) {
	if (params == NULL)
	return;

	if (params->drive_name != NULL)
	do_search(params, params->drive_name);
	else
	scan_real_devs(params);
	}