/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "mds-message.h"
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
/**
* Initialsie a message slot so that it can
* be used by `mds_message_read`.
*
* @param this Memory slot in which to store the new message
* @return Non-zero on error, errno will be set accordingly.
* Destroy the message on error.
*/
int mds_message_initialise(mds_message_t* this)
{
this->headers = NULL;
this->header_count = 0;
this->payload = NULL;
this->payload_size = 0;
this->payload_ptr = 0;
this->buffer_size = 128;
this->buffer_ptr = 0;
this->buffer = malloc(this->buffer_size * sizeof(char));
this->stage = 0;
if (this->buffer == NULL)
return -1;
return 0;
}
/**
* Release all resources in a message, should
* be done even if initialisation fails
*
* @param this The message
*/
void mds_message_destroy(mds_message_t* this)
{
if (this->headers != NULL)
{
size_t i;
for (i = 0; i < this->header_count; i++)
if (this->headers[i] != NULL)
free(this->headers[i]);
free(this->headers);
}
if (this->payload != NULL)
free(this->payload);
if (this->buffer != NULL)
free(this->buffer);
}
/**
* Read the next message from a file descriptor
*
* @param this Memory slot in which to store the new message
* @param fd The file descriptor
* @return Non-zero on error or interruption, errno will be
* set accordingly. Destroy the message on error,
* be aware that the reading could have been
* interrupted by a signal rather than canonical error.
* If -2 is returned errno will not have been set,
* -2 indicates that the message is malformated,
* which is a state that cannot be recovered from.
*/
int mds_message_read(mds_message_t* this, int fd)
{
size_t header_commit_buffer = 0;
if (this->stage == 2)
{
if (this->headers != NULL)
{
size_t i;
for (i = 0; i < this->header_count; i++)
if (this->headers[i] != NULL)
free(this->headers[i]);
free(this->headers);
}
this->header_count = 0;
if (this->payload != NULL)
free(this->payload);
this->payload_size = 0;
this->payload_ptr = 0;
this->stage = 0;
}
for (;;)
{
size_t n, i;
ssize_t got;
char* p;
if (this->stage == 0)
while ((p = memchr(this->buffer, '\n', this->buffer_ptr)) != NULL)
{
size_t len = (size_t)(p - this->buffer) + 1;
char* header;
if (len == 0)
{
memmove(this->buffer, this->buffer + 1, this->buffer_ptr -= 1);
for (i = 0; i < this->header_count; i++)
if (strstr(this->headers[i], "Length: ") == this->headers[i])
{
header = this->headers[i] + strlen("Length: ");
this->payload_size = (size_t)atoll(header);
for (; *header; header++)
if ((*header < '0') || ('9' < *header))
return -2; /* Malformated value, enters unrecoverable state. */
break;
}
this->stage = 1;
if (this->payload_size > 0)
{
this->payload = malloc(this->payload_size * sizeof(char));
if (this->payload == NULL)
return -1;
}
break;
}
if (header_commit_buffer == 0)
{
header_commit_buffer = 8;
if (this->headers == NULL)
{
this->headers = malloc(header_commit_buffer * sizeof(char*));
if (this->headers == NULL)
return -1;
}
else
{
char** old_headers = this->headers;
n = this->header_count + header_commit_buffer;
this->headers = realloc(this->headers, n * sizeof(char*));
if (this->headers == NULL)
{
this->headers = old_headers;
return -1;
}
}
}
header = malloc(len * sizeof(char));
if (header == NULL)
return -1;
memcpy(header, this->buffer, len);
header[len - 1] = '\0';
memmove(this->buffer, this->buffer + len, this->buffer_ptr -= len);
if ((p = memchr(header, ':', len)) == NULL)
{
/* Buck you, rawmemchr should not segfault the program. */
free(header);
return -2;
}
if (p[1] != ' ') /* Also an invalid format. */
{
free(header);
return -2;
}
this->headers[this->header_count++] = header;
header_commit_buffer -= 1;
}
if ((this->stage == 1) && (this->payload_ptr > 0))
{
size_t need = this->payload_size - this->payload_ptr;
if (this->buffer_ptr <= need)
memcpy(this->payload + this->payload_ptr, this->buffer, this->buffer_ptr);
else
{
memcpy(this->payload + this->payload_ptr, this->buffer, need);
memmove(this->buffer, this->buffer + need, this->buffer_ptr - need);
}
this->payload_ptr += this->buffer_ptr;
this->buffer_ptr = 0;
if (this->payload_ptr == this->payload_size)
{
this->stage = 3;
break;
}
}
n = this->buffer_size - this->buffer_ptr;
if (n < 128)
{
char* old_buffer = this->buffer;
this->buffer_size <<= 1;
this->buffer = realloc(this->buffer, this->buffer_size * sizeof(char));
if (this->buffer == NULL)
{
this->buffer = old_buffer;
this->buffer_size >>= 1;
return -1;
}
n = this->buffer_size - this->buffer_ptr;
}
errno = 0;
got = read(fd, this->buffer + this->buffer_ptr, n);
if (errno)
{
this->buffer_ptr += (size_t)(got < 0 ? 0 : got);
return -1;
}
}
return 0;
}
/**
* Get the required allocation size for `data` of the
* function `mds_message_marshal`
*
* @param this The message
* @param include_buffer Whether buffer should be marshalled (state serialisation, not communication)
* @return The size of the message when marshalled
*/
size_t mds_message_marshal_size(mds_message_t* this, int include_buffer)
{
size_t rc = this->header_count + this->payload_size;
size_t i;
for (i = 0; i < this->header_count; i++)
rc += strlen(this->headers[i]);
rc *= sizeof(char);
rc += (include_buffer ? 4 : 2) * sizeof(size_t);
rc += (include_buffer ? 1 : 0) * sizeof(int);
return rc;
}
/**
* Marshal a message, this can be used both when serialising
* the servers state or to get the byte stream to send to
* the recipient of the message
*
* @param this The message
* @param data Output buffer for the marshalled data
* @param include_buffer Whether buffer should be marshalled (state serialisation, not communication)
*/
void mds_message_marshal(mds_message_t* this, char* data, int include_buffer)
{
size_t i, n;
((size_t*)data)[0] = this->header_count;
((size_t*)data)[1] = this->payload_size;
if (include_buffer)
{
((size_t*)data)[2] = this->payload_ptr;
((size_t*)data)[3] = this->buffer_ptr;
}
data += (include_buffer ? 4 : 2) * sizeof(size_t) / sizeof(char);
if (include_buffer)
{
((int*)data)[0] = this->stage;
data += sizeof(int) / sizeof(char);
}
for (i = 0; i < this->header_count; i++)
{
n = strlen(this->headers[i]) + 1;
memcpy(data, this->headers[i], n * sizeof(char));
data += n;
}
memcpy(data, this->payload, this->payload_size * sizeof(char));
if (include_buffer)
{
data += this->payload_size;
memcpy(data, this->buffer, this->buffer_ptr * sizeof(char));
}
}
/**
* Unmarshal a message, it is assumed that the buffer is marshalled
*
* @param this Memory slot in which to store the new message
* @param data In buffer with the marshalled data
* @return Non-zero on error, errno will be set accordingly.
* Destroy the message on error.
*/
int mds_message_unmarshal(mds_message_t* this, char* data)
{
size_t i, n, header_count;
header_count = ((size_t*)data)[0];
this->header_count = 0;
this->payload_size = ((size_t*)data)[1];
this->payload_ptr = ((size_t*)data)[2];
this->buffer_ptr = ((size_t*)data)[3];
this->buffer_size = this->buffer_ptr;
this->headers = NULL;
this->payload = NULL;
this->buffer = NULL;
data += 4 * sizeof(size_t) / sizeof(char);
this->stage = ((int*)data)[0];
data += sizeof(int) / sizeof(char);
/* To 2-power-multiple of 128 bytes. */
this->buffer_size >>= 7;
if (this->buffer_size == 0)
this->buffer_size = 1;
else
{
this->buffer_size -= 1;
this->buffer_size |= this->buffer_size >> 1;
this->buffer_size |= this->buffer_size >> 2;
this->buffer_size |= this->buffer_size >> 4;
this->buffer_size |= this->buffer_size >> 8;
this->buffer_size |= this->buffer_size >> 16;
#if __WORDSIZE == 64
this->buffer_size |= this->buffer_size >> 32;
#endif
this->buffer_size += 1;
}
this->buffer_size <<= 7;
if (header_count > 0)
{
this->headers = malloc(header_count * sizeof(char*));
if (this->headers == NULL)
return -1;
}
if (this->payload_size > 0)
{
this->payload = malloc(this->payload_size * sizeof(char));
if (this->payload == NULL)
return -1;
}
this->buffer = malloc(this->buffer_size * sizeof(char));
if (this->buffer == NULL)
return -1;
for (i = 0; i < this->header_count; i++)
{
n = strlen(data) + 1;
this->headers[i] = malloc(n * sizeof(char));
if (this->headers[i] == NULL)
return -1;
memcpy(this->headers[i], data, n * sizeof(char));
data += n;
this->header_count++;
}
memcpy(this->payload, data, this->payload_size * sizeof(char));
data += this->payload_size;
memcpy(this->buffer, data, this->buffer_ptr * sizeof(char));
return 0;
}
