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/* This file is part of GNU Dico.
Copyright (C) 2008-2024 Sergey Poznyakoff
GNU Dico 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, or (at your option)
any later version.
GNU Dico 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 Dico. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <dico.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#ifndef MAP_FAILED
# define MAP_FAILED (void*)-1
#endif
struct _mapfile_stream {
char *filename;
int fd;
int flags;
char *start;
size_t size;
off_t offset;
};
static int
_mapfile_close(void *data)
{
struct _mapfile_stream *mfs = data;
if (mfs->start) {
munmap(mfs->start, mfs->size);
mfs->start = NULL;
mfs->size = 0;
}
close(mfs->fd);
mfs->fd = -1;
return 0;
}
int
_mapfile_destroy(void *data)
{
struct _mapfile_stream *str = data;
free(str->filename);
free(str);
return 0;
}
int
_mapfile_open(void *data, int flags)
{
struct _mapfile_stream *mfs = data;
struct stat st;
int mflags = 0, oflags = 0;
/* Close any previous file. */
_mapfile_close(data);
/* Map the flags to the system equivalent */
if (flags & DICO_STREAM_READ)
mflags |= PROT_READ;
if (flags & DICO_STREAM_WRITE)
mflags |= PROT_WRITE;
if ((flags & (DICO_STREAM_READ|DICO_STREAM_WRITE))
== (DICO_STREAM_READ|DICO_STREAM_WRITE))
oflags = O_RDWR;
else if (flags & DICO_STREAM_READ)
oflags = O_RDONLY;
else
oflags = O_WRONLY;
mfs->fd = open(mfs->filename, oflags);
if (mfs->fd < 0)
return errno;
if (fstat (mfs->fd, &st)) {
int err = errno;
close(mfs->fd);
return err;
}
mfs->size = st.st_size;
if (mfs->size) {
mfs->start = mmap (NULL, mfs->size, mflags, MAP_SHARED, mfs->fd, 0);
if (mfs->start == MAP_FAILED) {
int err = errno;
close(mfs->fd);
mfs->start = NULL;
return err;
}
} else
mfs->start = NULL;
mfs->flags = mflags;
return 0;
}
static int
_mapfile_seek(void *data, off_t needle, int whence, off_t *presult)
{
struct _mapfile_stream *str = data;
off_t offset;
switch (whence) {
case DICO_SEEK_SET:
offset = needle;
break;
case DICO_SEEK_CUR:
offset = str->offset + needle;
break;
case DICO_SEEK_END:
offset = str->size + needle;
break;
default:
return EINVAL;
}
if (offset < 0 || offset > str->size)
return EINVAL;
str->offset = offset;
*presult = offset;
return 0;
}
static int
_mapfile_size(void *data, off_t *presult)
{
struct _mapfile_stream *mfs = data;
if (mfs->start == NULL)
return EINVAL;
*presult = mfs->size;
return 0;
}
static int
_mapfile_read(void *data, char *buf, size_t size, size_t *pret)
{
struct _mapfile_stream *mfs = data;
size_t n;
if (mfs->start == NULL)
return EINVAL;
n = (mfs->offset + size > mfs->size) ? mfs->size - mfs->offset : size;
memcpy(buf, mfs->start + mfs->offset, n);
mfs->offset += n;
*pret = n;
return 0;
}
dico_stream_t
dico_mapfile_stream_create(const char *filename, int flags)
{
int rc;
dico_stream_t str;
struct _mapfile_stream *s = malloc(sizeof(*s));
/* FIXME: Remove this when read-write mapped streams are implemented */
if (flags & DICO_STREAM_WRITE) {
errno = EINVAL;
return NULL;
}
if (!s)
return NULL;
memset(s, 0, sizeof(*s));
s->fd = -1;
s->filename = strdup(filename);
if (!s->filename) {
free(s);
return NULL;
}
rc = dico_stream_create(&str, flags, s);
if (rc) {
free(s->filename);
free(s);
return NULL;
}
dico_stream_set_open(str, _mapfile_open);
dico_stream_set_seek(str, _mapfile_seek);
dico_stream_set_size(str, _mapfile_size);
dico_stream_set_read(str, _mapfile_read);
dico_stream_set_close(str, _mapfile_close);
dico_stream_set_destroy(str, _mapfile_destroy);
return str;
}
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