int git_index__parse(git_index *index, const char *buffer, size_t buffer_size)
{
unsigned int i;
struct index_header header;
git_oid checksum_calculated, checksum_expected;
#define seek_forward(_increase) { \
if (_increase >= buffer_size) \
return GIT_EOBJCORRUPTED; \
buffer += _increase; \
buffer_size -= _increase;\
}
if (buffer_size < INDEX_HEADER_SIZE + INDEX_FOOTER_SIZE)
return GIT_EOBJCORRUPTED;
/* Precalculate the SHA1 of the files's contents -- we'll match it to
* the provided SHA1 in the footer */
git_hash_buf(&checksum_calculated, (const void *)buffer, buffer_size - INDEX_FOOTER_SIZE);
/* Parse header */
if (read_header(&header, buffer) < 0)
return GIT_EOBJCORRUPTED;
seek_forward(INDEX_HEADER_SIZE);
index->entry_count = header.entry_count;
/* If there is already a entires array, reuse it if it can hold all the
* entries. If not, free and reallocate */
if (index->entry_count > index->entries_size) {
free(index->entries);
index->entries_size = (uint32_t)(index->entry_count * 1.3f);
index->entries = git__malloc(index->entries_size * sizeof(git_index_entry));
}
/* Parse all the entries */
for (i = 0; i < index->entry_count && buffer_size > INDEX_FOOTER_SIZE; ++i) {
size_t entry_size;
entry_size = read_entry(&index->entries[i], buffer, buffer_size);
/* 0 bytes read means an object corruption */
if (entry_size == 0)
return GIT_EOBJCORRUPTED;
seek_forward(entry_size);
}
if (i != index->entry_count)
return GIT_EOBJCORRUPTED;
/* There's still space for some extensions! */
while (buffer_size > INDEX_FOOTER_SIZE) {
size_t extension_size;
extension_size = read_extension(index, buffer, buffer_size);
/* see if we have read any bytes from the extension */
if (extension_size == 0)
return GIT_EOBJCORRUPTED;
seek_forward(extension_size);
}
if (buffer_size != INDEX_FOOTER_SIZE)
return GIT_EOBJCORRUPTED;
/* 160-bit SHA-1 over the content of the index file before this checksum. */
git_oid_mkraw(&checksum_expected, (const unsigned char *)buffer);
if (git_oid_cmp(&checksum_calculated, &checksum_expected) != 0)
return GIT_EOBJCORRUPTED;
#undef seek_forward
return 0;
}
static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
{
unsigned int i;
struct index_header header;
git_oid checksum_calculated, checksum_expected;
#define seek_forward(_increase) { \
if (_increase >= buffer_size) \
return git__throw(GIT_EOBJCORRUPTED, "Failed to seek forward. Buffer size exceeded"); \
buffer += _increase; \
buffer_size -= _increase;\
}
if (buffer_size < INDEX_HEADER_SIZE + INDEX_FOOTER_SIZE)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Buffer too small");
/* Precalculate the SHA1 of the files's contents -- we'll match it to
* the provided SHA1 in the footer */
git_hash_buf(&checksum_calculated, buffer, buffer_size - INDEX_FOOTER_SIZE);
/* Parse header */
if (read_header(&header, buffer) < GIT_SUCCESS)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Header is corrupted");
seek_forward(INDEX_HEADER_SIZE);
git_vector_clear(&index->entries);
/* Parse all the entries */
for (i = 0; i < header.entry_count && buffer_size > INDEX_FOOTER_SIZE; ++i) {
size_t entry_size;
git_index_entry *entry;
entry = git__malloc(sizeof(git_index_entry));
if (entry == NULL)
return GIT_ENOMEM;
entry_size = read_entry(entry, buffer, buffer_size);
/* 0 bytes read means an object corruption */
if (entry_size == 0)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Entry size is zero");
if (git_vector_insert(&index->entries, entry) < GIT_SUCCESS)
return GIT_ENOMEM;
seek_forward(entry_size);
}
if (i != header.entry_count)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Header entries changed while parsing");
/* There's still space for some extensions! */
while (buffer_size > INDEX_FOOTER_SIZE) {
size_t extension_size;
extension_size = read_extension(index, buffer, buffer_size);
/* see if we have read any bytes from the extension */
if (extension_size == 0)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Extension size is zero");
seek_forward(extension_size);
}
if (buffer_size != INDEX_FOOTER_SIZE)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Buffer size does not match index footer size");
/* 160-bit SHA-1 over the content of the index file before this checksum. */
git_oid_fromraw(&checksum_expected, (const unsigned char *)buffer);
if (git_oid_cmp(&checksum_calculated, &checksum_expected) != 0)
return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Calculated checksum does not match expected checksum");
#undef seek_forward
/* force sorting in the vector: the entries are
* assured to be sorted on the index */
index->entries.sorted = 1;
return GIT_SUCCESS;
}
