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Preserving MD5s of files from old session until the end of the new

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write run. If the write run fails, the old MD5s get restored.
This commit is contained in:
Thomas Schmitt 2013-08-20 11:48:24 +02:00
parent 567d3ddafb
commit 3f29d70aba
3 changed files with 103 additions and 56 deletions
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139
libisofs/ecma119.c
View File

@ -1230,6 +1230,48 @@ int zero_writer_create(Ecma119Image *target, uint32_t num_blocks, int flag)
return ISO_SUCCESS;
}
/* @param flag bit0= restore preserved cx (else dispose them)
*/
static
int process_preserved_cx(IsoDir *dir, int flag)
{
int ret, i;
unsigned int cx_value;
void *xipt;
IsoNode *pos;
pos = dir->children;
for (pos = dir->children; pos != NULL; pos = pos->next) {
if (pos->type == LIBISO_FILE) {
if (flag & 1) {
/* Restore preserved cx state of nodes */
ret = iso_node_get_xinfo(pos, checksum_cx_xinfo_func,
&xipt);
if (ret == 1) {
/* xipt is an int disguised as void pointer */
cx_value = 0;
for (i = 0; i < 4; i++)
cx_value =
(cx_value << 8) | ((unsigned char *) &xipt)[i];
ret = iso_file_set_isofscx((IsoFile *) pos, cx_value, 0);
if (ret < 0)
return ret;
} else if (ret == 0) {
/* Node had no cx before the write run. Delete cx. */
iso_file_set_isofscx((IsoFile *) pos, 0, 1);
}
}
iso_node_remove_xinfo(pos, checksum_cx_xinfo_func);
} else if (pos->type == LIBISO_DIR) {
ret = process_preserved_cx((IsoDir *) pos, flag);
if (ret != 0)
return ret;
}
}
return 0;
}
static
int transplant_checksum_buffer(Ecma119Image *target, int flag)
{
@ -1240,6 +1282,10 @@ int transplant_checksum_buffer(Ecma119Image *target, int flag)
target->checksum_idx_counter + 2, 0);
target->checksum_buffer = NULL;
target->checksum_idx_counter = 0;
/* Delete recorded cx xinfo */
process_preserved_cx(target->image->root, 0);
return 1;
}
@ -1562,10 +1608,8 @@ void *write_function(void *arg)
}
iso_ring_buffer_writer_close(target->buffer, 1);
/* Transplant checksum buffer away from Ecma119Image */
transplant_checksum_buffer(target, 0);
/* Invalidate the transplanted checksum buffer in IsoImage */
iso_image_free_checksums(target->image, 0);
/* Re-activate recorded cx xinfo */
process_preserved_cx(target->image->root, 1);
target->image->generator_is_running = 0;
@ -1605,82 +1649,88 @@ int checksum_prepare_nodes(Ecma119Image *target, IsoNode *node, int flag)
IsoNode *pos;
IsoFile *file;
IsoImage *img;
int ret, i, no_md5 = 0, has_xinfo = 0;
size_t value_length;
int ret, i, no_md5 = 0, has_xinfo = 0, has_attr = 0;
size_t old_cx_value_length = 0;
unsigned int idx = 0;
char *value= NULL;
char *old_cx_value= NULL;
void *xipt = NULL;
static char *cx_names = "isofs.cx";
static size_t cx_value_lengths[1] = {0};
char *cx_valuept = "";
img= target->image;
if (node->type == LIBISO_FILE) {
file = (IsoFile *) node;
if (file->from_old_session) {
/* Record attribute isofs.cx as xinfo before it can get overwritten
for the emerging image.
The recorded index will be used to retrieve the loaded MD5
and it will be brought back into effect if cancellation of
image production prevents that the old MD5 array gets replaced
by the new one.
*/
has_attr = iso_node_lookup_attr(node, "isofs.cx",
&old_cx_value_length, &old_cx_value, 0);
if (has_attr == 1 && old_cx_value_length == 4) {
for (i = 0; i < 4; i++)
idx = (idx << 8) | ((unsigned char *) old_cx_value)[i];
if (idx > 0 && idx < 0x8000000) {
/* xipt is an int disguised as void pointer */
for (i = 0; i < 4; i++)
((char *) &xipt)[i] = old_cx_value[i];
ret = iso_node_add_xinfo(node, checksum_cx_xinfo_func,
xipt);
if (ret < 0)
goto ex;
} else
no_md5 = 1;
}
}
if (file->from_old_session && target->appendable) {
/* Save MD5 data of files from old image which will not
be copied and have an MD5 recorded in the old image. */
has_xinfo = iso_node_get_xinfo(node, checksum_md5_xinfo_func,
&xipt);
if (has_xinfo <= 0) {
ret = iso_node_lookup_attr(node, "isofs.cx", &value_length,
&value, 0);
}
if (has_xinfo > 0) {
/* xinfo MD5 overrides everything else unless data get copied
and checksummed during that copying
*/;
} else if (ret == 1 && img->checksum_array == NULL) {
} else if (has_attr == 1 && img->checksum_array == NULL) {
/* No checksum array loaded. Delete "isofs.cx" */
if (!target->will_cancel)
iso_node_set_attrs(node, (size_t) 1,
&cx_names, cx_value_lengths, &cx_valuept, 4 | 8);
iso_file_set_isofscx((IsoFile *) node, 0, 1);
no_md5 = 1;
} else if (ret == 1 && value_length == 4) {
for (i = 0; i < 4; i++)
idx = (idx << 8) | ((unsigned char *) value)[i];
if (idx > 0 && idx < 0x8000000) {
/* xipt is an int disguised as void pointer */
for (i = 0; i < 4; i++)
((char *) &xipt)[i] = value[i];
ret = iso_node_add_xinfo(node, checksum_cx_xinfo_func,
xipt);
if (ret < 0)
return ret;
} else
no_md5 = 1;
} else {
} else if (!(has_attr == 1 && old_cx_value_length == 4)) {
no_md5 = 1;
}
if (value != NULL) {
free(value);
value= NULL;
}
}
/* Equip nodes with provisory isofs.cx numbers: 4 byte, all 0.
Omit those from old image which will not be copied and have no MD5.
Do not alter the nodes if this is only a will_cancel run.
*/
if (!(target->will_cancel || no_md5)) {
/* Record provisory new index */
ret = iso_file_set_isofscx(file, (unsigned int) 0, 0);
if (ret < 0)
return ret;
goto ex;
}
} else if (node->type == LIBISO_DIR) {
for (pos = ((IsoDir *) node)->children; pos != NULL; pos = pos->next) {
ret = checksum_prepare_nodes(target, pos, 1);
if (ret < 0)
goto ex;
}
}
ret = ISO_SUCCESS;
ex:;
if (old_cx_value != NULL)
free(old_cx_value);
return ret;
}
}
return ISO_SUCCESS;
}
static
int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
{
int ret, i, voldesc_size, nwriters, image_checksums_mad = 0, tag_pos;
int ret, i, voldesc_size, nwriters, tag_pos;
int sa_type;
Ecma119Image *target;
IsoImageWriter *writer;
@ -1994,9 +2044,6 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
nwriters++; /* Tail padding writer */
if ((target->md5_file_checksums & 1) || target->md5_session_checksum) {
nwriters++;
image_checksums_mad = 1; /* from here on the loaded checksums are
not consistent with isofs.cx any more.
*/
ret = checksum_prepare_image(src, 0);
if (ret < 0)
goto target_cleanup;
@ -2367,10 +2414,6 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
if (ret < 0)
goto target_cleanup;
}
/* Dispose old image checksum buffer. The one of target is supposed to
get attached at the end of write_function(). */
iso_image_free_checksums(target->image, 0);
image_checksums_mad = 0;
if (target->apm_block_size == 0) {
if (target->gpt_req_count)
@ -2419,8 +2462,6 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
return ISO_SUCCESS;
target_cleanup: ;
if(image_checksums_mad) /* No checksums is better than mad checksums */
iso_image_free_checksums(target->image, 0);
target->image->generator_is_running = 0;
ecma119_image_free(target);
return ret;

3
libisofs/md5.c
View File

@ -540,13 +540,12 @@ int checksum_copy_old_nodes(Ecma119Image *target, IsoNode *node, int flag)
if (value != NULL)
free(value);
/* ts B30114 : It is unclear why these are removed here.
/* >>> ts B30114 : It is unclear why these are removed here.
At least with the opts->will_cancel runs,
this is not appropriate.
*/
iso_node_remove_xinfo(node, checksum_md5_xinfo_func);
}
iso_node_remove_xinfo(node, checksum_cx_xinfo_func);
}
} else if (node->type == LIBISO_DIR) {
for (pos = ((IsoDir *) node)->children; pos != NULL; pos = pos->next) {

9
libisofs/node.c
View File

@ -2756,6 +2756,8 @@ int iso_node_cmp_ino(IsoNode *n1, IsoNode *n2, int flag)
}
/* @param flag bit0= delete isofs.cx rather than setting it
*/
int iso_file_set_isofscx(IsoFile *file, unsigned int checksum_index,
int flag)
{
@ -2765,9 +2767,14 @@ int iso_file_set_isofscx(IsoFile *file, unsigned int checksum_index,
char *valuept;
int i, ret;
valuept= (char *) value;
if (flag & 1) {
ret = iso_node_set_attrs((IsoNode *) file, (size_t) 1,
&names, value_lengths, &valuept, 4 | 8);
return ret;
}
for(i = 0; i < 4; i++)
value[3 - i] = (checksum_index >> (8 * i)) & 0xff;
valuept= (char *) value;
ret = iso_node_set_attrs((IsoNode *) file, (size_t) 1,
&names, value_lengths, &valuept, 2 | 8);
return ret;