/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
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â Copyright 2023 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/iovec.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/likely.h"
#include "libc/intrin/strace.internal.h"
#include "libc/runtime/internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.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
 */
noasan void *__zipos_Mmap(void *addr, size_t size, int prot, int flags,
                          struct ZiposHandle *h, int64_t off) {
  if (!(flags & MAP_PRIVATE) ||
      (flags & ~(MAP_PRIVATE | MAP_FILE | MAP_FIXED | MAP_FIXED_NOREPLACE)) ||
      (!!(flags & MAP_FIXED) ^ !!(flags & MAP_FIXED_NOREPLACE))) {
    STRACE(
        "zipos mappings currently only support MAP_PRIVATE with select flags");
    return VIP(einval());
  }

  if (VERY_UNLIKELY(off < 0)) {
    STRACE("neg off");
    return VIP(einval());
  }

  const int tempProt = !IsXnu() ? prot | PROT_WRITE : PROT_WRITE;
  void *outAddr =
      _Mmap(addr, size, tempProt, (flags & (~MAP_FILE)) | MAP_ANONYMOUS, -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;
}
