cosmopolitan/libc/runtime/zipos-mmap.c
2024-06-01 16:30:43 -04:00

103 lines
4.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/iovec.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/strace.internal.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/zipos.internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/s.h"
#include "libc/sysv/errfuns.h"
#include "libc/zip.internal.h"
#define IP(X) (intptr_t)(X)
#define VIP(X) (void *)IP(X)
/**
* Map zipos file into memory. See mmap.
*
* @param addr should be 0 or a compatible address
* @param size must be >0 and will be rounded up to FRAMESIZE
* automatically.
* @param prot can have PROT_READ/PROT_WRITE/PROT_EXEC/PROT_NONE/etc.
* @param flags cannot have `MAP_SHARED` or `MAP_ANONYMOUS`, there is
* no actual file backing for zipos files. `MAP_SHARED` could be
* simulated for non-writable mappings, but that would require
* tracking zipos mappings to prevent making it PROT_WRITE.
* @param h is a zip store object
* @param off specifies absolute byte index of h's file for mapping,
* it does not need to be 64kb aligned.
* @return virtual base address of new mapping, or MAP_FAILED w/ errno
*/
void *__zipos_mmap(void *addr, size_t size, int prot, int flags,
struct ZiposHandle *h, int64_t off) {
if (off < 0) {
STRACE("negative zipos mmap offset");
return VIP(einval());
}
if (h->cfile == ZIPOS_SYNTHETIC_DIRECTORY ||
S_ISDIR(GetZipCfileMode(h->zipos->map + h->cfile))) {
return VIP(eisdir());
}
if (flags & (MAP_SHARED | MAP_ANONYMOUS)) {
STRACE("ZipOS bad flags");
return VIP(einval());
}
if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC)) {
STRACE("ZipOS bad protection");
return VIP(einval());
}
flags &= MAP_FIXED | MAP_FIXED_NOREPLACE;
flags |= MAP_PRIVATE | MAP_ANONYMOUS;
const int tempProt = !IsXnu() ? prot | PROT_WRITE : PROT_WRITE;
void *outAddr = __mmap_unlocked(addr, size, tempProt, flags, -1, 0);
if (outAddr == MAP_FAILED) {
return MAP_FAILED;
}
do {
if (__zipos_read(h, &(struct iovec){outAddr, size}, 1, off) == -1) {
strace_enabled(-1);
break;
} else if (prot != tempProt) {
strace_enabled(-1);
if (mprotect(outAddr, size, prot) == -1) {
break;
}
strace_enabled(+1);
}
return outAddr;
} while (0);
const int e = errno;
__munmap_unlocked(outAddr, size);
errno = e;
strace_enabled(+1);
return MAP_FAILED;
}