Add MSG_PEEK support to pflocal

* libpipe/pq.h (packet_peek): Declare new function.
* libpipe/pq.c (packet_read): Move code to new `packet_fetch' function, call it
with `remove' set to 1.
(packet_fetch): New function with code from `packet_read', but do not remove
data if `remove' is 0.
(packet_peek): New function, calls `packet_fetch' with `remove' set to 0.
* libpipe/dgram.c (dgram_read): When MSG_PEEK is in *flags, do not dequeue
and only peek data.
* libpipe/seqpack.c (seqpack_read): Likewise.
* libpipe/stream.c (stream_read): Likewise.
* pflocal/socket.c (S_socket_recv): Pass MSG_PEEK flag to libpipe.

1 files changed, 7 insertions, 0 deletions

diff --git a/libpipe/pq.h b/libpipe/pq.h
index 0fffe254..4e500b6c 100644
--- a/libpipe/pq.h
+++ b/libpipe/pq.h
@@ -98,6 +98,13 @@ error_t packet_write (struct packet *packet,
 error_t packet_read (struct packet *packet,
 		     char **data, size_t *data_len, size_t amount);
 
+/* Peek up to AMOUNT bytes from the beginning of the data in PACKET, and
+   puts it into *DATA, and the amount read into DATA_LEN.  If more than the
+   original *DATA_LEN bytes are available, new memory is vm_allocated, and
+   the address and length of this array put into DATA and DATA_LEN.  */
+error_t packet_peek (struct packet *packet,
+		     char **data, size_t *data_len, size_t amount);
+
 /* Returns any ports in PACKET in PORTS and NUM_PORTS, and removes them from
    PACKET.  */
 error_t packet_read_ports (struct packet *packet,