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qemu_fclose: return last_error if set (v3)

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This will make sure no error will be missed as long as callers always
check for qemu_fclose() return value. For reference, this is the
complete list of qemu_fclose() callers:

 - exec_close(): already fixed to check for negative values, not -1
 - migrate_fd_cleanup(): already fixed to consider only negative values
   as error, not any non-zero value
 - exec_accept_incoming_migration(): no return value check (yet)
 - fd_accept_incoming_migration(): no return value check (yet)
 - tcp_accept_incoming_migration(): no return value check (yet)
 - unix_accept_incoming_migration(): no return value check (yet)
 - do_savevm(): no return value check (yet)
 - load_vmstate(): no return value check (yet)

Changes v1 -> v2:
 - Add small comment about the need to return previously-spotted errors

Changes v2 -> v3:
 - Add braces to "if" statements to match coding style

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Eduardo Habkost 2011-11-10 10:41:43 -02:00 committed by Anthony Liguori
parent a6d34a949c
commit d82ca91587
1 changed files with 48 additions and 3 deletions
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51
savevm.c
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@ -436,6 +436,22 @@ void qemu_file_set_error(QEMUFile *f, int ret)
f->last_error = ret;
}
/** Sets last_error conditionally
*
* Sets last_error only if ret is negative _and_ no error
* was set before.
*/
static void qemu_file_set_if_error(QEMUFile *f, int ret)
{
if (ret < 0 && !f->last_error) {
qemu_file_set_error(f, ret);
}
}
/** Flushes QEMUFile buffer
*
* In case of error, last_error is set.
*/
void qemu_fflush(QEMUFile *f)
{
if (!f->put_buffer)
@ -482,12 +498,41 @@ static void qemu_fill_buffer(QEMUFile *f)
qemu_file_set_error(f, len);
}
int qemu_fclose(QEMUFile *f)
/** Calls close function and set last_error if needed
*
* Internal function. qemu_fflush() must be called before this.
*
* Returns f->close() return value, or 0 if close function is not set.
*/
static int qemu_close(QEMUFile *f)
{
int ret = 0;
qemu_fflush(f);
if (f->close)
if (f->close) {
ret = f->close(f->opaque);
qemu_file_set_if_error(f, ret);
}
return ret;
}
/** Closes the file
*
* Returns negative error value if any error happened on previous operations or
* while closing the file. Returns 0 or positive number on success.
*
* The meaning of return value on success depends on the specific backend
* being used.
*/
int qemu_fclose(QEMUFile *f)
{
int ret;
qemu_fflush(f);
ret = qemu_close(f);
/* If any error was spotted before closing, we should report it
* instead of the close() return value.
*/
if (f->last_error) {
ret = f->last_error;
}
g_free(f);
return ret;
}