[CRIU] [PATCH v2 09/28] files: Receive real fd numbers using recv_fd_from_peer()

[Kirill Tkhai]

On 05.12.2016 12:59, Pavel Emelyanov wrote:
> On 11/30/2016 07:30 PM, Kirill Tkhai wrote:
>> Move reopen_fd_as() to this function.
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> ---
>>  criu/files.c |   16 +++++++++-------
>>  1 file changed, 9 insertions(+), 7 deletions(-)
>>
>> diff --git a/criu/files.c b/criu/files.c
>> index 628b0d1..1643664 100644
>> --- a/criu/files.c
>> +++ b/criu/files.c
>> @@ -933,7 +933,10 @@ int recv_fd_from_peer(struct fdinfo_list_entry *fle)
>>  	BUG_ON(fle->received);
>>  	fle->received = 1;
>>  
>> -	return fd;
>> +	if (reopen_fd_as(fle->fe->fd, fd) < 0)
>> +		return -1;
>> +
>> +	return fle->fe->fd;
>>  }
>>  
>>  int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle)
>> @@ -1046,7 +1049,7 @@ static int open_fd(int pid, struct fdinfo_list_entry *fle)
>>  
>>  static int receive_fd(int pid, struct fdinfo_list_entry *fle)
>>  {
>> -	int tmp;
>> +	int fd;
>>  	struct fdinfo_list_entry *flem;
>>  
>>  	flem = file_master(fle->desc);
>> @@ -1055,14 +1058,13 @@ static int receive_fd(int pid, struct fdinfo_list_entry *fle)
>>  
>>  	pr_info("\tReceive fd for %d\n", fle->fe->fd);
>>  
>> -	tmp = recv_fd_from_peer(fle);
>> -	if (tmp < 0) {
>> -		pr_err("Can't get fd %d\n", tmp);
>> +	fd = recv_fd_from_peer(fle);
> 
> This routine is used outside of files.c, why are other callers not patched?

Other callers do not reopen received fd. They can work with any fd number,
as the fd is reopened later in generic open code. Also, they can work with
fle->fd like a particular case.

I'll add a comment about that in v3.

>> +	if (fd < 0) {
>> +		pr_err("Can't get fd=%d, pid=%d\n", fle->fe->fd, fle->pid);
>>  		return -1;
>>  	}
>>  
>> -	if (reopen_fd_as(fle->fe->fd, tmp) < 0)
>> -		return -1;
>> +	BUG_ON(fd != fle->fe->fd);
>>  
>>  	if (fcntl(fle->fe->fd, F_SETFD, fle->fe->flags) == -1) {
>>  		pr_perror("Unable to set file descriptor flags");
>>
>> .
>>
>