cosmopolitan/libc/runtime/ezmap.c

64 lines
3.0 KiB
C

/*-*- 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.internal.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_PRIVATE | MAP_POPULATE, 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;
rc = 0;
if (mf->addr && mf->addr != MAP_FAILED) {
rc |= munmap(mf->addr, mf->size);
mf->addr = MAP_FAILED;
}
if (mf->fd != -1) {
rc |= close(mf->fd);
mf->fd = -1;
}
mf->size = 0;
return rc;
}