Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 1068 insertions, 0 deletions

diff --git a/onlineupdate/source/libmar/src/Makefile.in b/onlineupdate/source/libmar/src/Makefile.in
new file mode 100644
index 000000000..1da582e5b
--- /dev/null
+++ b/onlineupdate/source/libmar/src/Makefile.in
@@ -0,0 +1,13 @@
+# vim:set ts=8 sw=8 sts=8 noet:
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This makefile just builds support for reading archives.
+
+include $(topsrcdir)/config/rules.mk
+
+# The intermediate (.ii/.s) files for host and target can have the same name...
+# disable parallel builds
+.NOTPARALLEL:
diff --git a/onlineupdate/source/libmar/src/mar_create.c b/onlineupdate/source/libmar/src/mar_create.c
new file mode 100644
index 000000000..599e0a2a7
--- /dev/null
+++ b/onlineupdate/source/libmar/src/mar_create.c
@@ -0,0 +1,398 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <onlineupdate/mar_private.h>
+#include <onlineupdate/mar_cmdline.h>
+#include <onlineupdate/mar.h>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#else
+#include <netinet/in.h>
+#include <unistd.h>
+#endif
+
+struct MarItemStack {
+  void *head;
+  uint32_t size_used;
+  uint32_t size_allocated;
+  uint32_t last_offset;
+};
+
+/**
+ * Push a new item onto the stack of items.  The stack is a single block
+ * of memory.
+ */
+static int mar_push(struct MarItemStack *stack, uint32_t length, uint32_t flags,
+                    const char *name) {
+  int namelen;
+  uint32_t n_offset, n_length, n_flags;
+  uint32_t size;
+  char *data;
+
+  namelen = strlen(name);
+  size = MAR_ITEM_SIZE(namelen);
+
+  if (stack->size_allocated - stack->size_used < size) {
+    /* increase size of stack */
+    size_t size_needed = ROUND_UP(stack->size_used + size, BLOCKSIZE);
+    stack->head = realloc(stack->head, size_needed);
+    if (!stack->head)
+      return -1;
+    stack->size_allocated = size_needed;
+  }
+
+  data = (((char *) stack->head) + stack->size_used);
+
+  n_offset = htonl(stack->last_offset);
+  n_length = htonl(length);
+  n_flags = htonl(flags);
+
+  memcpy(data, &n_offset, sizeof(n_offset));
+  data += sizeof(n_offset);
+
+  memcpy(data, &n_length, sizeof(n_length));
+  data += sizeof(n_length);
+
+  memcpy(data, &n_flags, sizeof(n_flags));
+  data += sizeof(n_flags);
+
+  memcpy(data, name, namelen + 1);
+
+  stack->size_used += size;
+  stack->last_offset += length;
+  return 0;
+}
+
+static int mar_concat_file(FILE *fp, const char *path) {
+  FILE *in;
+  char buf[BLOCKSIZE];
+  size_t len;
+  int rv = 0;
+
+  in = fopen(path, "rb");
+  if (!in) {
+    fprintf(stderr, "ERROR: could not open file in mar_concat_file()\n");
+    perror(path);
+    return -1;
+  }
+
+  while ((len = fread(buf, 1, BLOCKSIZE, in)) > 0) {
+    if (fwrite(buf, len, 1, fp) != 1) {
+      rv = -1;
+      break;
+    }
+  }
+
+  fclose(in);
+  return rv;
+}
+
+/**
+ * Writes out the product information block to the specified file.
+ *
+ * @param fp           The opened MAR file being created.
+ * @param stack        A pointer to the MAR item stack being used to create
+ *                     the MAR
+ * @param infoBlock    The product info block to store in the file.
+ * @return 0 on success.
+*/
+static int
+mar_concat_product_info_block(FILE *fp,
+                              struct MarItemStack *stack,
+                              struct ProductInformationBlock *infoBlock)
+{
+  char buf[PIB_MAX_MAR_CHANNEL_ID_SIZE + PIB_MAX_PRODUCT_VERSION_SIZE];
+  uint32_t additionalBlockID = 1, infoBlockSize, unused;
+  if (!fp || !infoBlock ||
+      !infoBlock->MARChannelID ||
+      !infoBlock->productVersion) {
+    return -1;
+  }
+
+  /* The MAR channel name must be < 64 bytes per the spec */
+  if (strlen(infoBlock->MARChannelID) > PIB_MAX_MAR_CHANNEL_ID_SIZE) {
+    return -1;
+  }
+
+  /* The product version must be < 32 bytes per the spec */
+  if (strlen(infoBlock->productVersion) > PIB_MAX_PRODUCT_VERSION_SIZE) {
+    return -1;
+  }
+
+  /* Although we don't need the product information block size to include the
+     maximum MAR channel name and product version, we allocate the maximum
+     amount to make it easier to modify the MAR file for repurposing MAR files
+     to different MAR channels. + 2 is for the NULL terminators. */
+  infoBlockSize = sizeof(infoBlockSize) +
+                  sizeof(additionalBlockID) +
+                  PIB_MAX_MAR_CHANNEL_ID_SIZE +
+                  PIB_MAX_PRODUCT_VERSION_SIZE + 2;
+  if (stack) {
+    stack->last_offset += infoBlockSize;
+  }
+
+  /* Write out the product info block size */
+  infoBlockSize = htonl(infoBlockSize);
+  if (fwrite(&infoBlockSize,
+      sizeof(infoBlockSize), 1, fp) != 1) {
+    return -1;
+  }
+  infoBlockSize = ntohl(infoBlockSize);
+
+  /* Write out the product info block ID */
+  additionalBlockID = htonl(additionalBlockID);
+  if (fwrite(&additionalBlockID,
+      sizeof(additionalBlockID), 1, fp) != 1) {
+    return -1;
+  }
+  additionalBlockID = ntohl(additionalBlockID);
+
+  /* Write out the channel name and NULL terminator */
+  if (fwrite(infoBlock->MARChannelID,
+      strlen(infoBlock->MARChannelID) + 1, 1, fp) != 1) {
+    return -1;
+  }
+
+  /* Write out the product version string and NULL terminator */
+  if (fwrite(infoBlock->productVersion,
+      strlen(infoBlock->productVersion) + 1, 1, fp) != 1) {
+    return -1;
+  }
+
+  /* Write out the rest of the block that is unused */
+  unused = infoBlockSize - (sizeof(infoBlockSize) +
+                            sizeof(additionalBlockID) +
+                            strlen(infoBlock->MARChannelID) +
+                            strlen(infoBlock->productVersion) + 2);
+  memset(buf, 0, sizeof(buf));
+  if (fwrite(buf, unused, 1, fp) != 1) {
+    return -1;
+  }
+  return 0;
+}
+
+/**
+ * Refreshes the product information block with the new information.
+ * The input MAR must not be signed or the function call will fail.
+ *
+ * @param path             The path to the MAR file whose product info block
+ *                         should be refreshed.
+ * @param infoBlock        Out parameter for where to store the result to
+ * @return 0 on success, -1 on failure
+*/
+int
+refresh_product_info_block(const char *path,
+                           struct ProductInformationBlock *infoBlock)
+{
+  FILE *fp ;
+  int rv;
+  uint32_t numSignatures, additionalBlockSize, additionalBlockID,
+    offsetAdditionalBlocks, numAdditionalBlocks, i;
+  int additionalBlocks, hasSignatureBlock;
+
+  rv = get_mar_file_info(path,
+                         &hasSignatureBlock,
+                         &numSignatures,
+                         &additionalBlocks,
+                         &offsetAdditionalBlocks,
+                         &numAdditionalBlocks);
+  if (rv) {
+    fprintf(stderr, "ERROR: Could not obtain MAR information.\n");
+    return -1;
+  }
+
+  if (hasSignatureBlock && numSignatures) {
+    fprintf(stderr, "ERROR: Cannot refresh a signed MAR\n");
+    return -1;
+  }
+
+  fp = fopen(path, "r+b");
+  if (!fp) {
+    fprintf(stderr, "ERROR: could not open target file: %s\n", path);
+    return -1;
+  }
+
+  if (fseeko(fp, offsetAdditionalBlocks, SEEK_SET)) {
+    fprintf(stderr, "ERROR: could not seek to additional blocks\n");
+    fclose(fp);
+    return -1;
+  }
+
+  for (i = 0; i < numAdditionalBlocks; ++i) {
+    /* Get the position of the start of this block */
+    int64_t oldPos = ftello(fp);
+
+    /* Read the additional block size */
+    if (fread(&additionalBlockSize,
+              sizeof(additionalBlockSize),
+              1, fp) != 1) {
+      fclose(fp);
+      return -1;
+    }
+    additionalBlockSize = ntohl(additionalBlockSize);
+
+    /* Read the additional block ID */
+    if (fread(&additionalBlockID,
+              sizeof(additionalBlockID),
+              1, fp) != 1) {
+      fclose(fp);
+      return -1;
+    }
+    additionalBlockID = ntohl(additionalBlockID);
+
+    if (PRODUCT_INFO_BLOCK_ID == additionalBlockID) {
+      if (fseeko(fp, oldPos, SEEK_SET)) {
+        fprintf(stderr, "Could not seek back to Product Information Block\n");
+        fclose(fp);
+        return -1;
+      }
+
+      if (mar_concat_product_info_block(fp, NULL, infoBlock)) {
+        fprintf(stderr, "Could not concat Product Information Block\n");
+        fclose(fp);
+        return -1;
+      }
+
+      fclose(fp);
+      return 0;
+    } else {
+      /* This is not the additional block you're looking for. Move along. */
+      if (fseek(fp, additionalBlockSize, SEEK_CUR)) {
+        fprintf(stderr, "ERROR: Could not seek past current block.\n");
+        fclose(fp);
+        return -1;
+      }
+    }
+  }
+
+  /* If we had a product info block we would have already returned */
+  fclose(fp);
+  fprintf(stderr, "ERROR: Could not refresh because block does not exist\n");
+  return -1;
+}
+
+/**
+ * Create a MAR file from a set of files.
+ * @param dest      The path to the file to create.  This path must be
+ *                  compatible with fopen.
+ * @param numfiles  The number of files to store in the archive.
+ * @param files     The list of null-terminated file paths.  Each file
+ *                  path must be compatible with fopen.
+ * @param infoBlock The information to store in the product information block.
+ * @return A non-zero value if an error occurs.
+ */
+int mar_create(const char *dest, int
+               num_files, char **files,
+               struct ProductInformationBlock *infoBlock) {
+  struct MarItemStack stack;
+  uint32_t offset_to_index = 0, size_of_index,
+    numSignatures, numAdditionalSections;
+  uint64_t sizeOfEntireMAR = 0;
+  struct stat st;
+  FILE *fp;
+  int i, rv = -1;
+
+  memset(&stack, 0, sizeof(stack));
+
+  fp = fopen(dest, "wb");
+  if (!fp) {
+    fprintf(stderr, "ERROR: could not create target file: %s\n", dest);
+    return -1;
+  }
+
+  if (fwrite(MAR_ID, MAR_ID_SIZE, 1, fp) != 1)
+    goto failure;
+  if (fwrite(&offset_to_index, sizeof(uint32_t), 1, fp) != 1)
+    goto failure;
+
+  stack.last_offset = MAR_ID_SIZE +
+                      sizeof(offset_to_index) +
+                      sizeof(numSignatures) +
+                      sizeof(numAdditionalSections) +
+                      sizeof(sizeOfEntireMAR);
+
+  /* We will circle back on this at the end of the MAR creation to fill it */
+  if (fwrite(&sizeOfEntireMAR, sizeof(sizeOfEntireMAR), 1, fp) != 1) {
+    goto failure;
+  }
+
+  /* Write out the number of signatures, for now only at most 1 is supported */
+  numSignatures = 0;
+  if (fwrite(&numSignatures, sizeof(numSignatures), 1, fp) != 1) {
+    goto failure;
+  }
+
+  /* Write out the number of additional sections, for now just 1
+     for the product info block */
+  numAdditionalSections = htonl(1);
+  if (fwrite(&numAdditionalSections,
+             sizeof(numAdditionalSections), 1, fp) != 1) {
+    goto failure;
+  }
+  numAdditionalSections = ntohl(numAdditionalSections);
+
+  if (mar_concat_product_info_block(fp, &stack, infoBlock)) {
+    goto failure;
+  }
+
+  for (i = 0; i < num_files; ++i) {
+    if (stat(files[i], &st)) {
+      fprintf(stderr, "ERROR: file not found: %s\n", files[i]);
+      goto failure;
+    }
+
+    if (mar_push(&stack, st.st_size, st.st_mode & 0777, files[i]))
+      goto failure;
+
+    /* concatenate input file to archive */
+    if (mar_concat_file(fp, files[i]))
+      goto failure;
+  }
+
+  /* write out the index (prefixed with length of index) */
+  size_of_index = htonl(stack.size_used);
+  if (fwrite(&size_of_index, sizeof(size_of_index), 1, fp) != 1)
+    goto failure;
+  if (fwrite(stack.head, stack.size_used, 1, fp) != 1)
+    goto failure;
+
+  /* To protect against invalid MAR files, we assume that the MAR file
+     size is less than or equal to MAX_SIZE_OF_MAR_FILE. */
+  if (ftell(fp) > MAX_SIZE_OF_MAR_FILE) {
+    goto failure;
+  }
+
+  /* write out offset to index file in network byte order */
+  offset_to_index = htonl(stack.last_offset);
+  if (fseek(fp, MAR_ID_SIZE, SEEK_SET))
+    goto failure;
+  if (fwrite(&offset_to_index, sizeof(offset_to_index), 1, fp) != 1)
+    goto failure;
+  offset_to_index = ntohl(stack.last_offset);
+
+  sizeOfEntireMAR = ((uint64_t)stack.last_offset) +
+                    stack.size_used +
+                    sizeof(size_of_index);
+  sizeOfEntireMAR = HOST_TO_NETWORK64(sizeOfEntireMAR);
+  if (fwrite(&sizeOfEntireMAR, sizeof(sizeOfEntireMAR), 1, fp) != 1)
+    goto failure;
+  sizeOfEntireMAR = NETWORK_TO_HOST64(sizeOfEntireMAR);
+
+  rv = 0;
+failure:
+  if (stack.head)
+    free(stack.head);
+  fclose(fp);
+  if (rv)
+    remove(dest);
+  return rv;
+}
diff --git a/onlineupdate/source/libmar/src/mar_extract.c b/onlineupdate/source/libmar/src/mar_extract.c
new file mode 100644
index 000000000..11e570242
--- /dev/null
+++ b/onlineupdate/source/libmar/src/mar_extract.c
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <onlineupdate/mar_private.h>
+#include <onlineupdate/mar.h>
+
+#ifdef _WIN32
+#include <io.h>
+#include <direct.h>
+#endif
+
+/* Ensure that the directory containing this file exists */
+static int mar_ensure_parent_dir(const char *path)
+{
+  char *slash = strrchr(path, '/');
+  if (slash)
+  {
+    *slash = '\0';
+    mar_ensure_parent_dir(path);
+#ifdef _WIN32
+    _mkdir(path);
+#else
+    mkdir(path, 0755);
+#endif
+    *slash = '/';
+  }
+  return 0;
+}
+
+static int mar_test_callback(MarFile *mar, const MarItem *item, void *unused) {
+  FILE *fp;
+  char buf[BLOCKSIZE];
+  int fd, len, offset = 0;
+
+  (void) unused; // avoid warnings
+
+  if (mar_ensure_parent_dir(item->name))
+    return -1;
+
+#ifdef _WIN32
+  fd = _open(item->name, _O_BINARY|_O_CREAT|_O_TRUNC|_O_WRONLY, item->flags);
+#else
+  fd = creat(item->name, item->flags);
+#endif
+  if (fd == -1) {
+    fprintf(stderr, "ERROR: could not create file in mar_test_callback()\n");
+    perror(item->name);
+    return -1;
+  }
+
+  fp = fdopen(fd, "wb");
+  if (!fp)
+    return -1;
+
+  while ((len = mar_read(mar, item, offset, buf, sizeof(buf))) > 0) {
+    if (fwrite(buf, len, 1, fp) != 1)
+      break;
+    offset += len;
+  }
+
+  fclose(fp);
+  return len == 0 ? 0 : -1;
+}
+
+int mar_extract(const char *path) {
+  MarFile *mar;
+  int rv;
+
+  mar = mar_open(path);
+  if (!mar)
+    return -1;
+
+  rv = mar_enum_items(mar, mar_test_callback, NULL);
+
+  mar_close(mar);
+  return rv;
+}
diff --git a/onlineupdate/source/libmar/src/mar_read.c b/onlineupdate/source/libmar/src/mar_read.c
new file mode 100644
index 000000000..2a6238ca2
--- /dev/null
+++ b/onlineupdate/source/libmar/src/mar_read.c
@@ -0,0 +1,572 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <onlineupdate/mar_private.h>
+#include <onlineupdate/mar.h>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#else
+#include <netinet/in.h>
+#endif
+
+
+/* this is the same hash algorithm used by nsZipArchive.cpp */
+static uint32_t mar_hash_name(const char *name) {
+  uint32_t val = 0;
+  unsigned char* c;
+
+  for (c = (unsigned char *) name; *c; ++c)
+    val = val*37 + *c;
+
+  return val % TABLESIZE;
+}
+
+static int mar_insert_item(MarFile *mar, const char *name, int namelen,
+                           uint32_t offset, uint32_t length, uint32_t flags) {
+  MarItem *item, *root;
+  uint32_t hash;
+
+  item = (MarItem *) malloc(sizeof(MarItem) + namelen);
+  if (!item)
+    return -1;
+  item->next = NULL;
+  item->offset = offset;
+  item->length = length;
+  item->flags = flags;
+  memcpy(item->name, name, namelen + 1);
+
+  hash = mar_hash_name(name);
+
+  root = mar->item_table[hash];
+  if (!root) {
+    mar->item_table[hash] = item;
+  } else {
+    /* append item */
+    while (root->next)
+      root = root->next;
+    root->next = item;
+  }
+  return 0;
+}
+
+static int mar_consume_index(MarFile *mar, char **buf, const char *buf_end) {
+  /*
+   * Each item has the following structure:
+   *   uint32_t offset      (network byte order)
+   *   uint32_t length      (network byte order)
+   *   uint32_t flags       (network byte order)
+   *   char     name[N]     (where N >= 1)
+   *   char     null_byte;
+   */
+  uint32_t offset;
+  uint32_t length;
+  uint32_t flags;
+  const char *name;
+  int namelen;
+
+  if ((buf_end - *buf) < (int)(3*sizeof(uint32_t) + 2))
+    return -1;
+
+  memcpy(&offset, *buf, sizeof(offset));
+  *buf += sizeof(offset);
+
+  memcpy(&length, *buf, sizeof(length));
+  *buf += sizeof(length);
+
+  memcpy(&flags, *buf, sizeof(flags));
+  *buf += sizeof(flags);
+
+  offset = ntohl(offset);
+  length = ntohl(length);
+  flags = ntohl(flags);
+
+  name = *buf;
+  /* find namelen; must take care not to read beyond buf_end */
+  while (**buf) {
+    if (*buf == buf_end)
+      return -1;
+    ++(*buf);
+  }
+  namelen = (*buf - name);
+  /* consume null byte */
+  if (*buf == buf_end)
+    return -1;
+  ++(*buf);
+
+  return mar_insert_item(mar, name, namelen, offset, length, flags);
+}
+
+static int mar_read_index(MarFile *mar) {
+  char id[MAR_ID_SIZE], *buf, *bufptr, *bufend;
+  uint32_t offset_to_index, size_of_index;
+
+  /* verify MAR ID */
+  if (fread(id, MAR_ID_SIZE, 1, mar->fp) != 1)
+    return -1;
+  if (memcmp(id, MAR_ID, MAR_ID_SIZE) != 0)
+    return -1;
+
+  if (fread(&offset_to_index, sizeof(uint32_t), 1, mar->fp) != 1)
+    return -1;
+  offset_to_index = ntohl(offset_to_index);
+
+  if (fseek(mar->fp, offset_to_index, SEEK_SET))
+    return -1;
+  if (fread(&size_of_index, sizeof(uint32_t), 1, mar->fp) != 1)
+    return -1;
+  size_of_index = ntohl(size_of_index);
+
+  buf = (char *) malloc(size_of_index);
+  if (!buf)
+    return -1;
+  if (fread(buf, size_of_index, 1, mar->fp) != 1) {
+    free(buf);
+    return -1;
+  }
+
+  bufptr = buf;
+  bufend = buf + size_of_index;
+  while (bufptr < bufend && mar_consume_index(mar, &bufptr, bufend) == 0);
+
+  free(buf);
+  return (bufptr == bufend) ? 0 : -1;
+}
+
+/**
+ * Internal shared code for mar_open and mar_wopen.
+ * On failure, will fclose(fp).
+ */
+static MarFile *mar_fpopen(FILE *fp)
+{
+  MarFile *mar;
+
+  mar = (MarFile *) malloc(sizeof(*mar));
+  if (!mar) {
+    fclose(fp);
+    return NULL;
+  }
+
+  mar->fp = fp;
+  memset(mar->item_table, 0, sizeof(mar->item_table));
+  if (mar_read_index(mar)) {
+    mar_close(mar);
+    return NULL;
+  }
+
+  return mar;
+}
+
+MarFile *mar_open(const char *path) {
+  FILE *fp;
+
+  fp = fopen(path, "rb");
+  if (!fp) {
+    fprintf(stderr, "ERROR: could not open file in mar_open()\n");
+    perror(path);
+    return NULL;
+  }
+
+  return mar_fpopen(fp);
+}
+
+#ifdef _WIN32
+MarFile *mar_wopen(const wchar_t *path) {
+  FILE *fp;
+
+  _wfopen_s(&fp, path, L"rb");
+  if (!fp) {
+    fprintf(stderr, "ERROR: could not open file in mar_wopen()\n");
+    _wperror(path);
+    return NULL;
+  }
+
+  return mar_fpopen(fp);
+}
+#endif
+
+void mar_close(MarFile *mar) {
+  MarItem *item;
+  int i;
+
+  fclose(mar->fp);
+
+  for (i = 0; i < TABLESIZE; ++i) {
+    item = mar->item_table[i];
+    while (item) {
+      MarItem *temp = item;
+      item = item->next;
+      free(temp);
+    }
+  }
+
+  free(mar);
+}
+
+/**
+ * Determines the MAR file information.
+ *
+ * @param fp                     An opened MAR file in read mode.
+ * @param hasSignatureBlock      Optional out parameter specifying if the MAR
+ *                               file has a signature block or not.
+ * @param numSignatures          Optional out parameter for storing the number
+ *                               of signatures in the MAR file.
+ * @param hasAdditionalBlocks    Optional out parameter specifying if the MAR
+ *                               file has additional blocks or not.
+ * @param offsetAdditionalBlocks Optional out parameter for the offset to the
+ *                               first additional block. Value is only valid if
+ *                               hasAdditionalBlocks is not equal to 0.
+ * @param numAdditionalBlocks    Optional out parameter for the number of
+ *                               additional blocks.  Value is only valid if
+ *                               hasAdditionalBlocks is not equal to 0.
+ * @return 0 on success and non-zero on failure.
+ */
+int get_mar_file_info_fp(FILE *fp,
+                         int *hasSignatureBlock,
+                         uint32_t *numSignatures,
+                         int *hasAdditionalBlocks,
+                         uint32_t *offsetAdditionalBlocks,
+                         uint32_t *numAdditionalBlocks)
+{
+  uint32_t offsetToIndex, offsetToContent, signatureCount, signatureLen, i;
+
+  /* One of hasSignatureBlock or hasAdditionalBlocks must be non NULL */
+  if (!hasSignatureBlock && !hasAdditionalBlocks) {
+    return -1;
+  }
+
+
+  /* Skip to the start of the offset index */
+  if (fseek(fp, MAR_ID_SIZE, SEEK_SET)) {
+    return -1;
+  }
+
+  /* Read the offset to the index. */
+  if (fread(&offsetToIndex, sizeof(offsetToIndex), 1, fp) != 1) {
+    return -1;
+  }
+  offsetToIndex = ntohl(offsetToIndex);
+
+  if (numSignatures) {
+     /* Skip past the MAR file size field */
+    if (fseek(fp, sizeof(uint64_t), SEEK_CUR)) {
+      return -1;
+    }
+
+    /* Read the number of signatures field */
+    if (fread(numSignatures, sizeof(*numSignatures), 1, fp) != 1) {
+      return -1;
+    }
+    *numSignatures = ntohl(*numSignatures);
+  }
+
+  /* Skip to the first index entry past the index size field
+     We do it in 2 calls because offsetToIndex + sizeof(uint32_t)
+     could overflow in theory. */
+  if (fseek(fp, offsetToIndex, SEEK_SET)) {
+    return -1;
+  }
+
+  if (fseek(fp, sizeof(uint32_t), SEEK_CUR)) {
+    return -1;
+  }
+
+  /* Read the first offset to content field. */
+  if (fread(&offsetToContent, sizeof(offsetToContent), 1, fp) != 1) {
+    return -1;
+  }
+  offsetToContent = ntohl(offsetToContent);
+
+  /* Check if we have a new or old MAR file */
+  if (hasSignatureBlock) {
+    if (offsetToContent == MAR_ID_SIZE + sizeof(uint32_t)) {
+      *hasSignatureBlock = 0;
+    } else {
+      *hasSignatureBlock = 1;
+    }
+  }
+
+  /* If the caller doesn't care about the product info block
+     value, then just return */
+  if (!hasAdditionalBlocks) {
+    return 0;
+  }
+
+   /* Skip to the start of the signature block */
+  if (fseeko(fp, SIGNATURE_BLOCK_OFFSET, SEEK_SET)) {
+    return -1;
+  }
+
+  /* Get the number of signatures */
+  if (fread(&signatureCount, sizeof(signatureCount), 1, fp) != 1) {
+    return -1;
+  }
+  signatureCount = ntohl(signatureCount);
+
+  /* Check that we have less than the max amount of signatures so we don't
+     waste too much of either updater's or signmar's time. */
+  if (signatureCount > MAX_SIGNATURES) {
+    return -1;
+  }
+
+  /* Skip past the whole signature block */
+  for (i = 0; i < signatureCount; i++) {
+    /* Skip past the signature algorithm ID */
+    if (fseek(fp, sizeof(uint32_t), SEEK_CUR)) {
+      return -1;
+    }
+
+    /* Read the signature length and skip past the signature */
+    if (fread(&signatureLen, sizeof(uint32_t), 1, fp) != 1) {
+      return -1;
+    }
+    signatureLen = ntohl(signatureLen);
+    if (fseek(fp, signatureLen, SEEK_CUR)) {
+      return -1;
+    }
+  }
+
+  if (ftell(fp) == (long)offsetToContent) {
+    *hasAdditionalBlocks = 0;
+  } else {
+    if (numAdditionalBlocks) {
+      /* We have an additional block, so read in the number of additional blocks
+         and set the offset. */
+      *hasAdditionalBlocks = 1;
+      if (fread(numAdditionalBlocks, sizeof(uint32_t), 1, fp) != 1) {
+        return -1;
+      }
+      *numAdditionalBlocks = ntohl(*numAdditionalBlocks);
+      if (offsetAdditionalBlocks) {
+        *offsetAdditionalBlocks = ftell(fp);
+      }
+    } else if (offsetAdditionalBlocks) {
+      /* numAdditionalBlocks is not specified but offsetAdditionalBlocks
+         is, so fill it! */
+      *offsetAdditionalBlocks = ftell(fp) + sizeof(uint32_t);
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Reads the product info block from the MAR file's additional block section.
+ * The caller is responsible for freeing the fields in infoBlock
+ * if the return is successful.
+ *
+ * @param infoBlock Out parameter for where to store the result to
+ * @return 0 on success, -1 on failure
+*/
+int
+read_product_info_block(char *path,
+                        struct ProductInformationBlock *infoBlock)
+{
+  int rv;
+  MarFile mar;
+  mar.fp = fopen(path, "rb");
+  if (!mar.fp) {
+    fprintf(stderr, "ERROR: could not open file in read_product_info_block()\n");
+    perror(path);
+    return -1;
+  }
+  rv = mar_read_product_info_block(&mar, infoBlock);
+  fclose(mar.fp);
+  return rv;
+}
+
+/**
+ * Reads the product info block from the MAR file's additional block section.
+ * The caller is responsible for freeing the fields in infoBlock
+ * if the return is successful.
+ *
+ * @param infoBlock Out parameter for where to store the result to
+ * @return 0 on success, -1 on failure
+*/
+int
+mar_read_product_info_block(MarFile *mar,
+                            struct ProductInformationBlock *infoBlock)
+{
+  uint32_t i, offsetAdditionalBlocks, numAdditionalBlocks,
+    additionalBlockSize, additionalBlockID;
+  int hasAdditionalBlocks;
+
+  /* The buffer size is 97 bytes because the MAR channel name < 64 bytes, and
+     product version < 32 bytes + 3 NULL terminator bytes. */
+  char buf[97] = { '\0' };
+  int ret = get_mar_file_info_fp(mar->fp, NULL, NULL,
+                                 &hasAdditionalBlocks,
+                                 &offsetAdditionalBlocks,
+                                 &numAdditionalBlocks);
+  if (ret)
+    return ret;
+  for (i = 0; i < numAdditionalBlocks; ++i) {
+    /* Read the additional block size */
+    if (fread(&additionalBlockSize,
+              sizeof(additionalBlockSize),
+              1, mar->fp) != 1) {
+      return -1;
+    }
+    additionalBlockSize = ntohl(additionalBlockSize) -
+                          sizeof(additionalBlockSize) -
+                          sizeof(additionalBlockID);
+
+    /* Read the additional block ID */
+    if (fread(&additionalBlockID,
+              sizeof(additionalBlockID),
+              1, mar->fp) != 1) {
+      return -1;
+    }
+    additionalBlockID = ntohl(additionalBlockID);
+
+    if (PRODUCT_INFO_BLOCK_ID == additionalBlockID) {
+      const char *location;
+      int len;
+
+      /* This block must be at most 104 bytes.
+         MAR channel name < 64 bytes, and product version < 32 bytes + 3 NULL
+         terminator bytes. We only check for 96 though because we remove 8
+         bytes above from the additionalBlockSize: We subtract
+         sizeof(additionalBlockSize) and sizeof(additionalBlockID) */
+      if (additionalBlockSize > 96) {
+        return -1;
+      }
+
+    if (fread(buf, additionalBlockSize, 1, mar->fp) != 1) {
+        return -1;
+      }
+
+      /* Extract the MAR channel name from the buffer.  For now we
+         point to the stack allocated buffer but we strdup this
+         if we are within bounds of each field's max length. */
+      location = buf;
+      len = strlen(location);
+      infoBlock->MARChannelID = location;
+      location += len + 1;
+      if (len >= 64) {
+        infoBlock->MARChannelID = NULL;
+        return -1;
+      }
+
+      /* Extract the version from the buffer */
+      len = strlen(location);
+      infoBlock->productVersion = location;
+      location += len + 1;
+      if (len >= 32) {
+        infoBlock->MARChannelID = NULL;
+        infoBlock->productVersion = NULL;
+        return -1;
+      }
+      infoBlock->MARChannelID =
+        strdup(infoBlock->MARChannelID);
+      infoBlock->productVersion =
+        strdup(infoBlock->productVersion);
+      return 0;
+    } else {
+      /* This is not the additional block you're looking for. Move along. */
+      if (fseek(mar->fp, additionalBlockSize, SEEK_CUR)) {
+        return -1;
+      }
+    }
+  }
+
+  /* If we had a product info block we would have already returned */
+  return -1;
+}
+
+const MarItem *mar_find_item(MarFile *mar, const char *name) {
+  uint32_t hash;
+  const MarItem *item;
+
+  hash = mar_hash_name(name);
+
+  item = mar->item_table[hash];
+  while (item && strcmp(item->name, name) != 0)
+    item = item->next;
+
+  return item;
+}
+
+int mar_enum_items(MarFile *mar, MarItemCallback callback, void *closure) {
+  MarItem *item;
+  int i;
+
+  for (i = 0; i < TABLESIZE; ++i) {
+    item = mar->item_table[i];
+    while (item) {
+      int rv = callback(mar, item, closure);
+      if (rv)
+        return rv;
+      item = item->next;
+    }
+  }
+
+  return 0;
+}
+
+int mar_read(MarFile *mar, const MarItem *item, int offset, char *buf,
+             int bufsize) {
+  int nr;
+
+  if (offset == (int) item->length)
+    return 0;
+  if (offset > (int) item->length)
+    return -1;
+
+  nr = item->length - offset;
+  if (nr > bufsize)
+    nr = bufsize;
+
+  if (fseek(mar->fp, item->offset + offset, SEEK_SET))
+    return -1;
+
+  return fread(buf, 1, nr, mar->fp);
+}
+
+/**
+ * Determines the MAR file information.
+ *
+ * @param path                   The path of the MAR file to check.
+ * @param hasSignatureBlock      Optional out parameter specifying if the MAR
+ *                               file has a signature block or not.
+ * @param numSignatures          Optional out parameter for storing the number
+ *                               of signatures in the MAR file.
+ * @param hasAdditionalBlocks    Optional out parameter specifying if the MAR
+ *                               file has additional blocks or not.
+ * @param offsetAdditionalBlocks Optional out parameter for the offset to the
+ *                               first additional block. Value is only valid if
+ *                               hasAdditionalBlocks is not equal to 0.
+ * @param numAdditionalBlocks    Optional out parameter for the number of
+ *                               additional blocks.  Value is only valid if
+ *                               has_additional_blocks is not equal to 0.
+ * @return 0 on success and non-zero on failure.
+ */
+int get_mar_file_info(const char *path,
+                      int *hasSignatureBlock,
+                      uint32_t *numSignatures,
+                      int *hasAdditionalBlocks,
+                      uint32_t *offsetAdditionalBlocks,
+                      uint32_t *numAdditionalBlocks)
+{
+  int rv;
+  FILE *fp = fopen(path, "rb");
+  if (!fp) {
+    fprintf(stderr, "ERROR: could not open file in get_mar_file_info()\n");
+    perror(path);
+    return -1;
+  }
+
+  rv = get_mar_file_info_fp(fp, hasSignatureBlock,
+                            numSignatures, hasAdditionalBlocks,
+                            offsetAdditionalBlocks, numAdditionalBlocks);
+
+  fclose(fp);
+  return rv;
+}