srn_mmap.c

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/* -*- C -*-
 * Serene programming language
 * Copyright (C) 2019-2026 Sameer Rahmani <lxsameer@lxsameer.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <https://www.gnu.org/licenses/>.
 */
 
// This implementation is based on libgit2's api
#include "serene/utils/srn_mmap.h"
 
#if !PMAP_WIN32
 
#  include <sys/mman.h>
#  include <unistd.h>
 
#  include "serene/rt/context.h"
#  include "serene/rt/errors.h"
 
srn_error_t *srn_mmap(
  srn_context_t *ctx, srn_mmap_buffer_t *out, size_t len, int prot, int flags, int fd,
  off64_t offset
) {
  int mprot = PROT_READ;
  int mflag = 0;
 
  SRN_MMAP_VALIDATE(out, len, prot, flags);
 
  out->data = nullptr;
  out->len  = 0;
 
  if (prot & SRN_PROT_WRITE) {
    mprot |= PROT_WRITE;
  }
 
  if ((flags & SRN_MAP_TYPE) == SRN_MAP_SHARED) {
    mflag = MAP_SHARED;
  } else if ((flags & SRN_MAP_TYPE) == SRN_MAP_PRIVATE) {
    mflag = MAP_PRIVATE;
  } else {
    mflag = MAP_SHARED;
  }
 
  out->data = mmap(NULL, len, mprot, mflag, fd, offset);
 
  if (!out->data || out->data == MAP_FAILED) {
    auto err = ERR(ctx, MEMORY_MAP_FAILED, "failed to mmap. Could not write data");
    return err;
  }
 
  out->len = len;
 
  return nullptr;
}
 
int srn_munmap(srn_mmap_buffer_t *map) {
  PANIC_IF_NULL(map);
  munmap(map->data, map->len);
  map->data = NULL;
  map->len  = 0;
 
  return 0;
}
 
#endif