cosmopolitan/libc/runtime/ezmap.c

59 lines
2.9 KiB
C
Raw Normal View History

2020-06-15 14:18:57 +00:00
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/bits/safemacros.h"
#include "libc/calls/calls.h"
#include "libc/limits.h"
#include "libc/runtime/ezmap.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
/**
* Memory-maps file for reading.
* An internal veneer for a common mmap() use-case.
*/
int mapfileread(const char *filename, struct MappedFile *mf) {
mf->addr = MAP_FAILED;
if ((mf->fd = open(filename, O_RDONLY)) != -1 &&
(mf->size = getfiledescriptorsize(mf->fd)) < INT_MAX &&
(mf->addr = mf->size
? mmap(NULL, mf->size, PROT_READ, MAP_SHARED, mf->fd, 0)
: NULL) != MAP_FAILED) {
return 0;
} else {
unmapfile(mf);
return -1;
}
}
/**
* Releases resource returned by mapfileread().
*/
int unmapfile(struct MappedFile *mf) {
int rc = 0;
rc |= munmap(mf->addr, mf->size);
rc |= close(mf->fd);
mf->fd = -1;
mf->addr = MAP_FAILED;
mf->size = 0;
return rc;
}