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/* message.h - Message buffer definitions.
Copyright (C) 2008 Free Software Foundation, Inc.
Written by Neal H. Walfield <neal@gnu.org>.
This file is part of the GNU Hurd.
GNU Hurd is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
GNU Hurd 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Hurd. If not, see
<http://www.gnu.org/licenses/>. */
#ifndef _VIENGOOS_MESSAGE_H
#define _VIENGOOS_MESSAGE_H 1
#include <stdint.h>
#include <assert.h>
#include <viengoos/addr.h>
#include <hurd/stddef.h>
/* A message.
When handing a message structure to a messenger, it must start at
the beginning of a page and it cannot extend past the end of that
page. */
struct vg_message
{
union
{
struct
{
/* The number of capability addresses in the message. */
uint16_t cap_count;
/* The number of bytes of data transferred in this message. */
uint16_t data_count;
vg_addr_t caps[/* cap_count */];
// char data[data_count];
};
char raw[PAGESIZE];
};
};
/* Clear the msg so that it references no capabilities and
contains no data. */
static inline void
vg_message_clear (struct vg_message *msg)
{
msg->cap_count = 0;
msg->data_count = 0;
}
/* Return the number of capabilities referenced by MSG. */
static inline int
vg_message_cap_count (struct vg_message *msg)
{
int max = (PAGESIZE - __builtin_offsetof (struct vg_message, caps))
/ sizeof (vg_addr_t);
int count = msg->cap_count;
if (count > max)
count = max;
return count;
}
/* Return the number of bytes of data in MSG. */
static inline int
vg_message_data_count (struct vg_message *msg)
{
int max = PAGESIZE
- vg_message_cap_count (msg) * sizeof (vg_addr_t)
- __builtin_offsetof (struct vg_message, caps);
int count = msg->data_count;
if (count > max)
count = max;
return count;
}
/* Return the start of the capability address array in msg MSG. */
static inline vg_addr_t *
vg_message_caps (struct vg_message *msg)
{
return msg->caps;
}
/* Return capability IDX in msg MSG. */
static inline vg_addr_t
vg_message_cap (struct vg_message *msg, int idx)
{
assert (idx < msg->cap_count);
return msg->caps[idx];
}
/* Return the start of the data in msg MSG. */
static inline char *
vg_message_data (struct vg_message *msg)
{
return (void *) msg
+ __builtin_offsetof (struct vg_message, caps)
+ msg->cap_count * sizeof (vg_addr_t);
}
/* Return data word WORD in msg MSG. */
static inline uintptr_t
vg_message_word (struct vg_message *msg, int word)
{
assert (word < msg->data_count / sizeof (uintptr_t));
return ((uintptr_t *) vg_message_data (msg))[word];
}
/* Append the array of capability addresses CAPS to the msg MSG.
There must be sufficient room in the message buffer. */
static inline void
vg_message_append_caps (struct vg_message *msg, int cap_count, vg_addr_t *caps)
{
assert ((void *) vg_message_data (msg) - (void *) msg
+ vg_message_data_count (msg) + cap_count * sizeof (*caps)
<= PAGESIZE);
__builtin_memmove (&msg->caps[msg->cap_count + cap_count],
&msg->caps[msg->cap_count],
msg->data_count);
__builtin_memcpy (&msg->caps[msg->cap_count],
caps,
cap_count * sizeof (vg_addr_t));
msg->cap_count += cap_count;
}
/* Append the capability address CAP to the msg MSG. There must be
sufficient room in the message buffer. */
static inline void
vg_message_append_cap (struct vg_message *msg, vg_addr_t vg_cap)
{
vg_message_append_caps (msg, 1, &vg_cap);
}
/* Append DATA to the msg MSG. There must be sufficient room in the
message buffer. */
static inline void
vg_message_append_data (struct vg_message *msg, int bytes, char *data)
{
int dstart = __builtin_offsetof (struct vg_message, caps)
+ msg->cap_count * sizeof (vg_addr_t);
int dend = dstart + msg->data_count;
int new_dend = dend + bytes;
assert (new_dend <= PAGESIZE);
msg->data_count += bytes;
__builtin_memcpy ((void *) msg + dend, data, bytes);
}
/* Append the word WORD to the msg MSG. There must be
sufficient room in the message buffer. */
static inline void
vg_message_append_word (struct vg_message *msg, uintptr_t word)
{
vg_message_append_data (msg, sizeof (word), (char *) &word);
}
/* Return data word WORD in msg MSG. */
static inline void
vg_message_word_set (struct vg_message *msg, int pos, uintptr_t word)
{
if (msg->data_count < pos * sizeof (uintptr_t))
msg->data_count = pos * sizeof (uintptr_t);
((uintptr_t *) vg_message_data (msg))[pos] = word;
}
#include <s-printf.h>
static inline void
vg_message_dump (struct vg_message *message)
{
s_printf ("%d bytes, %d caps\n",
vg_message_data_count (message),
vg_message_cap_count (message));
char d2h[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F' };
unsigned char *data = vg_message_data (message);
int i = 0;
while (i < vg_message_data_count (message))
{
s_printf ("%d: ", i);
int j, k;
for (j = 0, k = 0;
i < vg_message_data_count (message) && j < 4 * 8;
j ++, i ++)
{
s_printf ("%c%c", d2h[data[i] >> 4], d2h[data[i] & 0xf]);
if (j % 4 == 3)
s_printf (" ");
}
s_printf ("\n");
}
for (i = 0; i < vg_message_cap_count (message); i ++)
s_printf ("cap %d: " VG_ADDR_FMT "\n",
i, VG_ADDR_PRINTF (vg_message_cap (message, i)));
}
#endif /* _VIENGOOS_MESSAGE_H */
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