New API call iso_image_generator_is_running().

Prevented a potential race condition between Ecma119Image disposal by
burn_source and final activities of ISO generator thread.
This commit is contained in:
Thomas Schmitt 2010-10-06 17:33:46 +02:00
parent bb28c69cae
commit 8a75d35c46
6 changed files with 84 additions and 15 deletions

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@ -59,6 +59,12 @@ void ecma119_image_free(Ecma119Image *t)
if (t == NULL)
return;
if (t->refcount > 1) {
t->refcount--;
return;
}
if (t->root != NULL)
ecma119_node_free(t->root);
if (t->image != NULL)
@ -1315,6 +1321,12 @@ void *write_function(void *arg)
if (res <= 0)
goto write_error;
target->image->generator_is_running = 0;
/* Give up reference claim made in ecma119_image_new().
Eventually free target */
ecma119_image_free(target);
#ifdef Libisofs_with_pthread_exiT
pthread_exit(NULL);
#else
@ -1340,6 +1352,12 @@ void *write_function(void *arg)
/* Invalidate the transplanted checksum buffer in IsoImage */
iso_image_free_checksums(target->image, 0);
target->image->generator_is_running = 0;
/* Give up reference claim made in ecma119_image_new().
Eventually free target */
ecma119_image_free(target);
#ifdef Libisofs_with_pthread_exiT
pthread_exit(NULL);
#else
@ -1460,6 +1478,10 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
if (target == NULL) {
return ISO_OUT_OF_MEM;
}
/* This reference will be transfered to the burn_source and released by
bs_free_data.
*/
target->refcount = 1;
/* create the tree for file caching */
ret = iso_rbtree_new(iso_file_src_cmp, &(target->files));
@ -1923,9 +1945,24 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
pthread_attr_init(&(target->th_attr));
pthread_attr_setdetachstate(&(target->th_attr), PTHREAD_CREATE_JOINABLE);
/* To avoid race conditions with the caller, this mark must be set
before the thread starts. So the caller can rely on a value of 0
really meaning that the write has ended, and not that it might not have
begun yet.
In normal processing, the value will be changed to 0 at the end of
write_function().
*/
target->image->generator_is_running = 1;
/* Claim that target may not get destroyed by bs_free_data() before
write_function() is done with it */
target->refcount++;
ret = pthread_create(&(target->wthread), &(target->th_attr),
write_function, (void *) target);
if (ret != 0) {
target->refcount--;
iso_msg_submit(target->image->id, ISO_THREAD_ERROR, 0,
"Cannot create writer thread");
ret = ISO_THREAD_ERROR;
@ -1945,6 +1982,7 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
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;
}
@ -1995,7 +2033,7 @@ static void bs_free_data(struct burn_source *bs)
iso_ring_buffer_get_times_full(target->buffer),
iso_ring_buffer_get_times_empty(target->buffer));
/* now we can safety free target */
/* The reference to target was inherited from ecma119_image_new() */
ecma119_image_free(target);
}

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@ -345,6 +345,8 @@ typedef struct Iso_Image_Writer IsoImageWriter;
struct ecma119_image
{
int refcount;
IsoImage *image;
Ecma119Node *root;

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@ -89,6 +89,7 @@ int iso_image_new(const char *name, IsoImage **image)
img->checksum_end_lba = 0;
img->checksum_idx_count = 0;
img->checksum_array = NULL;
img->generator_is_running = 0;
*image = img;
return ISO_SUCCESS;
}
@ -607,3 +608,8 @@ int iso_image_set_checksums(IsoImage *image, char *checksum_array,
return 1;
}
int iso_image_generator_is_running(IsoImage *image)
{
return image->generator_is_running;
}

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@ -166,6 +166,12 @@ struct Iso_Image
uint32_t checksum_idx_count;
char *checksum_array;
/**
* Whether a write run has been started by iso_image_create_burn_source()
* and has not yet been finished.
*/
int generator_is_running;
};

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@ -1870,11 +1870,9 @@ int iso_write_opts_set_part_offset(IsoWriteOpts *opts,
* The option set to be manipulated.
* @param libjte_handle
* Pointer to a struct libjte_env e.g. created by libjte_new().
* It must stay existent from the start of image writing by
* It must stay existent from the start of image generation by
* iso_image_create_burn_source() until the write thread has ended.
* >>> ts B00928 Need a way to inquire run status independent of libburn.
* This can be inquired by iso_image_generator_is_running().
* In order to keep the libisofs API identical with and without
* libjte support the parameter type is (void *).
* @return
@ -1940,6 +1938,20 @@ int iso_write_opts_set_tail_blocks(IsoWriteOpts *opts, uint32_t num_blocks);
int iso_write_opts_get_data_start(IsoWriteOpts *opts, uint32_t *data_start,
int flag);
/**
* Update the sizes of all files added to image.
*
* This may be called just before iso_image_create_burn_source() to force
* libisofs to check the file sizes again (they're already checked when added
* to IsoImage). It is useful if you have changed some files after adding then
* to the image.
*
* @return
* 1 on success, < 0 on error
* @since 0.6.8
*/
int iso_image_update_sizes(IsoImage *image);
/**
* Create a burn_source and a thread which immediately begins to generate
* the image. That burn_source can be used with libburn as a data source
@ -1966,18 +1978,22 @@ int iso_image_create_burn_source(IsoImage *image, IsoWriteOpts *opts,
struct burn_source **burn_src);
/**
* Update the sizes of all files added to image.
*
* This may be called just before iso_image_create_burn_source() to force
* libisofs to check the file sizes again (they're already checked when added
* to IsoImage). It is useful if you have changed some files after adding then
* to the image.
*
* Inquire whether the image generator thread is still at work. As soon as the
* reply is 0, the caller of iso_image_create_burn_source() may assume that
* the image generation has ended.
* Nevertheless there may still be readily formatted output data pending in
* the burn_source or its consumers. So the final delivery of the image has
* also to be checked at the data consumer side,e.g. by burn_drive_get_status()
* in case of libburn as consumer.
* @param image
* The image to inquire.
* @return
* 1 on success, < 0 on error
* @since 0.6.8
* 1 generating of image stream is still in progress
* 0 generating of image stream has ended meanwhile
*
* @since 0.6.38
*/
int iso_image_update_sizes(IsoImage *image);
int iso_image_generator_is_running(IsoImage *image);
/**
* Creates an IsoReadOpts for reading an existent image. You should set the

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@ -80,6 +80,7 @@ iso_image_fs_get_publisher_id;
iso_image_fs_get_system_id;
iso_image_fs_get_volset_id;
iso_image_fs_get_volume_id;
iso_image_generator_is_running;
iso_image_get_abstract_file_id;
iso_image_get_all_boot_imgs;
iso_image_get_application_id;