cosmopolitan/libc/runtime/zipos-mmap.c
Justine Tunney 6ffed14b9c
Rewrite memory manager
Actually Portable Executable now supports Android. Cosmo's old mmap code
required a 47 bit address space. The new implementation is very agnostic
and supports both smaller address spaces (e.g. embedded) and even modern
56-bit PML5T paging for x86 which finally came true on Zen4 Threadripper

Cosmopolitan no longer requires UNIX systems to observe the Windows 64kb
granularity; i.e. sysconf(_SC_PAGE_SIZE) will now report the host native
page size. This fixes a longstanding POSIX conformance issue, concerning
file mappings that overlap the end of file. Other aspects of conformance
have been improved too, such as the subtleties of address assignment and
and the various subtleties surrounding MAP_FIXED and MAP_FIXED_NOREPLACE

On Windows, mappings larger than 100 megabytes won't be broken down into
thousands of independent 64kb mappings. Support for MAP_STACK is removed
by this change; please use NewCosmoStack() instead.

Stack overflow avoidance is now being implemented using the POSIX thread
APIs. Please use GetStackBottom() and GetStackAddr(), instead of the old
error-prone GetStackAddr() and HaveStackMemory() APIs which are removed.
2024-06-22 05:45:11 -07:00

104 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/maps.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 granularity
* 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(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(outAddr, size);
errno = e;
strace_enabled(+1);
return MAP_FAILED;
}