/**
* returns 0 on success, or an errno value on failure.
* errno values include ENOENT if the parent folder doesn't exist,
* plus the errno values set by tr_mkdirp () and open ().
*/
static int
cached_file_open (struct tr_cached_file * o,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size)
{
int flags;
struct stat sb;
bool alreadyExisted;
/* create subfolders, if any */
if (writable)
{
char * dir = tr_dirname (filename);
const int err = tr_mkdirp (dir, 0777) ? errno : 0;
if (err) {
tr_err (_("Couldn't create \"%1$s\": %2$s"), dir, tr_strerror (err));
tr_free (dir);
return err;
}
tr_free (dir);
}
alreadyExisted = !stat (filename, &sb) && S_ISREG (sb.st_mode);
if (writable && !alreadyExisted && (allocation == TR_PREALLOCATE_FULL))
if (preallocate_file_full (filename, file_size))
tr_dbg ("Preallocated file \"%s\"", filename);
/* open the file */
flags = writable ? (O_RDWR | O_CREAT) : O_RDONLY;
flags |= O_LARGEFILE | O_BINARY | O_SEQUENTIAL;
o->fd = open (filename, flags, 0666);
if (o->fd == -1)
{
const int err = errno;
tr_err (_("Couldn't open \"%1$s\": %2$s"), filename, tr_strerror (err));
return err;
}
/* If the file already exists and it's too large, truncate it.
* This is a fringe case that happens if a torrent's been updated
* and one of the updated torrent's files is smaller.
* http://trac.transmissionbt.com/ticket/2228
* https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
*/
if (alreadyExisted && (file_size < (uint64_t)sb.st_size))
{
if (ftruncate (o->fd, file_size) == -1)
{
const int err = errno;
tr_err (_("Couldn't truncate \"%1$s\": %2$s"), filename, tr_strerror (err));
return err;
}
}
if (writable && !alreadyExisted && (allocation == TR_PREALLOCATE_SPARSE))
preallocate_file_sparse (o->fd, file_size);
/* Many (most?) clients request blocks in ascending order,
* so increase the readahead buffer.
* Also, disable OS-level caching because "inactive memory" angers users. */
tr_set_file_for_single_pass (o->fd);
return 0;
}
/**
* returns 0 on success, or an errno value on failure.
* errno values include ENOENT if the parent folder doesn't exist,
* plus the errno values set by tr_sys_dir_create () and tr_sys_file_open ().
*/
static int
cached_file_open (struct tr_cached_file * o,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size)
{
int flags;
tr_sys_path_info info;
bool already_existed;
bool resize_needed;
tr_sys_file_t fd = TR_BAD_SYS_FILE;
tr_error * error = NULL;
/* create subfolders, if any */
if (writable)
{
char * dir = tr_sys_path_dirname (filename, NULL);
if (!tr_sys_dir_create (dir, TR_SYS_DIR_CREATE_PARENTS, 0777, &error))
{
tr_logAddError (_("Couldn't create \"%1$s\": %2$s"), dir, error->message);
tr_free (dir);
goto fail;
}
tr_free (dir);
}
already_existed = tr_sys_path_get_info (filename, 0, &info, NULL) && info.type == TR_SYS_PATH_IS_FILE;
/* we can't resize the file w/o write permissions */
resize_needed = already_existed && (file_size < info.size);
writable |= resize_needed;
/* open the file */
flags = writable ? (TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE) : 0;
flags |= TR_SYS_FILE_READ | TR_SYS_FILE_SEQUENTIAL;
fd = tr_sys_file_open (filename, flags, 0666, &error);
if (fd == TR_BAD_SYS_FILE)
{
tr_logAddError (_("Couldn't open \"%1$s\": %2$s"), filename, error->message);
goto fail;
}
if (writable && !already_existed && allocation != TR_PREALLOCATE_NONE)
{
bool success = false;
const char * type = NULL;
if (allocation == TR_PREALLOCATE_FULL)
{
success = preallocate_file_full (fd, file_size, &error);
type = _("full");
}
else if (allocation == TR_PREALLOCATE_SPARSE)
{
success = preallocate_file_sparse (fd, file_size, &error);
type = _("sparse");
}
assert (type != NULL);
if (!success)
{
tr_logAddError (_("Couldn't preallocate file \"%1$s\" (%2$s, size: %3$"PRIu64"): %4$s"),
filename, type, file_size, error->message);
goto fail;
}
tr_logAddDebug (_("Preallocated file \"%1$s\" (%2$s, size: %3$"PRIu64")"), filename, type, file_size);
}
/* If the file already exists and it's too large, truncate it.
* This is a fringe case that happens if a torrent's been updated
* and one of the updated torrent's files is smaller.
* http://trac.transmissionbt.com/ticket/2228
* https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
*/
if (resize_needed && !tr_sys_file_truncate (fd, file_size, &error))
{
tr_logAddError (_("Couldn't truncate \"%1$s\": %2$s"), filename, error->message);
goto fail;
}
o->fd = fd;
return 0;
fail:
{
const int err = error->code;
tr_error_free (error);
if (fd != TR_BAD_SYS_FILE)
tr_sys_file_close (fd, NULL);
return err;
}
}
