cosmopolitan/libc/zipos/get.c

59 lines
2.9 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/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/limits.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/zip.h"
#include "libc/zipos/zipos.internal.h"
/**
* Returns pointer to zip central directory of current executable.
*/
struct Zipos *__zipos_get(void) {
static struct Zipos zipos;
static bool once;
const char *exe;
size_t mapsize;
uint8_t *cdir;
void *map;
if (!once) {
exe = (const char *)getauxval(AT_EXECFN);
if ((zipos.fd = open(exe, O_RDONLY)) != -1) {
if ((mapsize = getfiledescriptorsize(zipos.fd)) != SIZE_MAX &&
(map = mmap(NULL, mapsize, PROT_READ, MAP_SHARED, zipos.fd, 0)) !=
MAP_FAILED) {
if ((cdir = zipfindcentraldir(map, mapsize))) {
zipos.map = map;
zipos.cdir = cdir;
} else {
munmap(map, mapsize);
}
}
}
once = true;
}
return zipos.cdir ? &zipos : NULL;
}