terom@118: /**
terom@118:  * @file
terom@118:  *
terom@118:  * A read-only sock_stream implementation for linux fifo(7).
terom@118:  */
terom@118: #include "sock_fd.h"
terom@118: 
terom@118: #include <stdlib.h>
terom@118: #include <sys/types.h>
terom@118: #include <sys/stat.h>
terom@118: #include <fcntl.h>
terom@118: #include <string.h>
terom@118: 
terom@118: struct fifo {
terom@118:     /** The base fd operations */
terom@118:     struct sock_fd base_fd;
terom@118:     
terom@118:     /** The path to the fifo */
terom@118:     char *path;
terom@118: };
terom@118: 
terom@118: /**
terom@118:  * Get a sock_fd pointer from a sock_fifo pointer
terom@118:  */
terom@118: #define FIFO_FD(sock_ptr) (&(sock_ptr)->base_fd)
terom@118: 
terom@118: /**
terom@118:  * Get a sock_base pointer from a sock_fifo pointer
terom@118:  */
terom@118: #define FIFO_BASE(sock_ptr) SOCK_FD_BASE(FIFO_FD(sock_ptr))
terom@118: 
terom@118: /**
terom@118:  * Get the sock_stream.err pointer from a sock_fifo pointer
terom@118:  */
terom@118: #define FIFO_ERR(sock_ptr) SOCK_ERR(FIFO_BASE(sock_ptr))
terom@118: 
terom@118: 
terom@118: 
terom@118: /**
terom@118:  * (re)open the fifo, closing it if already open, and keeping any event callbacks registered.
terom@118:  */
terom@118: static err_t fifo_open (struct fifo *fifo, struct error_info *err)
terom@118: {
terom@118:     int fd;
terom@118: 
terom@118:     // open(2) the path in non-blocking mode
terom@118:     // XXX: hardoded read-only
terom@118:     if ((fd = open(fifo->path, O_RDONLY | O_NONBLOCK)) < 0)
terom@118:         RETURN_SET_ERROR_ERRNO(err, ERR_OPEN);
terom@118: 
terom@118:     // set the new fd
terom@118:     if ((ERROR_CODE(err) = sock_fd_set(FIFO_FD(fifo), fd)))
terom@118:         return ERROR_CODE(err);
terom@118:     
terom@118:     // ok
terom@118:     return SUCCESS;
terom@118: }
terom@118: 
terom@118: /**
terom@118:  * Destroy the fifo, releasing all resources
terom@118:  */
terom@118: static void fifo_destroy (struct fifo *fifo)
terom@118: {
terom@118:     // close if open
terom@118:     if (FIFO_FD(fifo)->fd >= 0)
terom@118:         sock_fd_close(FIFO_FD(fifo));
terom@118: 
terom@118:     // release the path
terom@118:     free(fifo->path);
terom@118:     free(fifo);
terom@118: }
terom@118: 
terom@118: /**
terom@118:  * sock_stream_methods::read implementation.
terom@118:  *
terom@118:  * Try and do a normal sock_fd_read call, but re-open with EAGAIN on EOF
terom@118:  */
terom@118: err_t fifo_read (struct sock_stream *base_sock, void *buf, size_t *len, struct error_info *err)
terom@118: {
terom@118:     struct fifo *fifo = SOCK_FROM_BASE(base_sock, struct fifo);
terom@118: 
terom@118:     // passthru ERR_READ_EOF unless it's READ_EOF
terom@118:     if (sock_fd_read(base_sock, buf, len, err) != ERR_READ_EOF)
terom@118:         return ERROR_CODE(err);
terom@118:     
terom@118:     // re-open it
terom@118:     // XXX: re-add events?
terom@118:     if (fifo_open(fifo, err))
terom@118:         goto error;
terom@118: 
terom@118:     // ok, act as if it was EAGAIN
terom@118:     *len = 0;
terom@118: 
terom@118:     return SUCCESS;
terom@118: 
terom@118: error:
terom@118:     return ERROR_CODE(err);
terom@118: }
terom@118: 
terom@118: /**
terom@118:  * sock_stream_methods::release implementation
terom@118:  */
terom@118: static void fifo_release (struct sock_stream *base_sock)
terom@118: {
terom@118:     struct fifo *fifo = SOCK_FROM_BASE(base_sock, struct fifo);
terom@118:     
terom@118:     fifo_destroy(fifo);
terom@118: }
terom@118: 
terom@118: /*
terom@118:  * Our sock_stream_type
terom@118:  */
terom@118: static struct sock_stream_type fifo_stream_type = {
terom@118:     .methods                = {
terom@118:         .read               = &fifo_read,
terom@118:         .write              = NULL,
terom@118:         .event_init         = &sock_fd_event_init,
terom@118:         .event_enable       = &sock_fd_event_enable,
terom@118:         .release            = &fifo_release,
terom@118:     },
terom@118: };
terom@118: 
terom@118: err_t fifo_open_read (struct sock_stream **stream_ptr, const char *path, struct error_info *err)
terom@118: {
terom@118:     struct fifo *fifo;
terom@118: 
terom@118:     // alloc
terom@118:     if ((fifo = calloc(1, sizeof(*fifo))) == NULL)
terom@118:         return SET_ERROR(err, ERR_CALLOC);
terom@118: 
terom@118:     // copy the path
terom@118:     if ((fifo->path = strdup(path)) == NULL)
terom@118:         return SET_ERROR(err, ERR_STRDUP);
terom@118: 
terom@118:     // init
terom@139:     sock_stream_init(FIFO_BASE(fifo), &fifo_stream_type, NULL, NULL);
terom@118:     sock_fd_init(FIFO_FD(fifo), -1);
terom@118: 
terom@118:     // open the fifo
terom@118:     if (fifo_open(fifo, err))
terom@118:         goto error;
terom@118: 
terom@118:     // ok
terom@118:     *stream_ptr = FIFO_BASE(fifo);
terom@118: 
terom@118:     return SUCCESS;
terom@118: 
terom@118: error:
terom@118:     // cleanup
terom@118:     fifo_destroy(fifo);
terom@118: 
terom@118:     return ERROR_CODE(err);
terom@118: }