glibc/mach/devstream.c

145 lines
3.4 KiB
C

/* stdio on a Mach device port.
Translates \n to \r\n on output, echos and translates \r to \n on input.
Copyright (C) 1992-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <mach.h>
#include <device/device.h>
#include <errno.h>
#include <string.h>
static ssize_t
devstream_write (void *cookie, const char *buffer, size_t n)
{
const device_t dev = (device_t) cookie;
int write_some (const char *p, size_t to_write)
{
kern_return_t err;
int wrote;
int thiswrite;
while (to_write > 0)
{
thiswrite = to_write;
if (thiswrite > IO_INBAND_MAX)
thiswrite = IO_INBAND_MAX;
if (err = device_write_inband (dev, 0, 0, p, thiswrite, &wrote))
{
errno = err;
return 0;
}
p += wrote;
to_write -= wrote;
}
return 1;
}
int write_crlf (void)
{
static const char crlf[] = "\r\n";
return write_some (crlf, 2);
}
/* Search for newlines (LFs) in the buffer. */
const char *start = buffer, *p;
while ((p = memchr (start, '\n', n)) != NULL)
{
/* Found one. Write out through the preceding character,
and then write a CR/LF pair. */
if ((p > start && !write_some (start, p - start))
|| !write_crlf ())
return (start - buffer) ?: -1;
n -= p + 1 - start;
start = p + 1;
}
/* Write the remainder of the buffer. */
if (write_some (start, n))
start += n;
return (start - buffer) ?: -1;
}
static ssize_t
devstream_read (void *cookie, char *buffer, size_t to_read)
{
const device_t dev = (device_t) cookie;
kern_return_t err;
mach_msg_type_number_t nread = to_read;
err = device_read_inband (dev, 0, 0, to_read, buffer, &nread);
if (err)
{
errno = err;
return -1;
}
/* Translate CR to LF. */
{
char *p;
for (p = memchr (buffer, '\r', nread); p;
p = memchr (p + 1, '\r', (buffer + nread) - (p + 1)))
*p = '\n';
}
/* Echo back what we read. */
(void) devstream_write (cookie, buffer, nread);
return nread;
}
static int
dealloc_ref (void *cookie)
{
if (mach_port_deallocate (mach_task_self (), (mach_port_t) cookie))
{
errno = EINVAL;
return -1;
}
return 0;
}
FILE *
mach_open_devstream (mach_port_t dev, const char *mode)
{
FILE *stream;
if (mach_port_mod_refs (mach_task_self (), dev, MACH_PORT_RIGHT_SEND, 1))
{
errno = EINVAL;
return NULL;
}
stream = fopencookie ((void *) dev, mode,
(cookie_io_functions_t) { write: devstream_write,
read: devstream_read,
close: dealloc_ref });
if (stream == NULL)
{
mach_port_deallocate (mach_task_self (), dev);
return NULL;
}
return stream;
}