quickjs-mmap.c

#include "defines.h"
#include <cutils.h>
#include <quickjs.h>
#include "utils.h"
#ifdef _WIN32
#include "mmap-win32.h"
#else
#include <sys/mman.h>
#include <errno.h>
#endif

/**
 * \defgroup quickjs-mmap quickjs-mmap: Memory mapped I/O
 * @{
 */
static void
js_mmap_free_func(JSRuntime* rt, void* opaque, void* ptr) {
  munmap(ptr, (size_t)opaque);
}

static JSValue
js_mmap_map(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  uint64_t addr, length, offset;
  int32_t prot, flags, fd;
  void* ptr;

  if(js_is_null_or_undefined(argv[0]))
    addr = 0;
  else if(JS_ToIndex(ctx, &addr, argv[0]))
    return JS_EXCEPTION;
  if(JS_ToIndex(ctx, &length, argv[1]))
    return JS_EXCEPTION;
  if(argc <= 2 || !JS_IsNumber(argv[2]) || JS_ToInt32(ctx, &prot, argv[2]))
    prot = PROT_READ | PROT_WRITE;
  if(argc <= 3 || !JS_IsNumber(argv[3]) || JS_ToInt32(ctx, &flags, argv[3]))
    flags = MAP_ANONYMOUS;
  if(argc <= 4 || !JS_IsNumber(argv[4]) || JS_ToInt32(ctx, &fd, argv[4]))
    fd = -1;
  if(argc <= 5 || !JS_IsNumber(argv[5]) || JS_ToIndex(ctx, &offset, argv[5]))
    offset = 0;

  ptr = mmap((void*)addr, length, prot, flags, fd, offset);

  if(ptr == 0)
    return JS_EXCEPTION;

  if(ptr == MAP_FAILED)
    return JS_NewInt32(ctx, -1);

  return JS_NewArrayBuffer(ctx, ptr, length, &js_mmap_free_func, (void*)length, !!(flags & MAP_SHARED));
}

static JSValue
js_mmap_unmap(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  JS_DetachArrayBuffer(ctx, argv[0]);
  return JS_UNDEFINED;
}

static JSValue
js_mmap_msync(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  uint64_t length;
  uint8_t* data;
  int32_t flags = 0;
  size_t len;

  if(!(data = JS_GetArrayBuffer(ctx, &len, argv[0])))
    return JS_ThrowTypeError(ctx, "argument 1 must be an ArrayBuffer");

  if(!JS_ToIndex(ctx, &length, argv[1])) {
    len = MIN_NUM(len, length);
  }

  JS_ToInt32(ctx, &flags, argv[2]);

  return JS_NewInt32(ctx, msync(data, len, flags));
}

static JSValue
js_mmap_mprotect(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  int64_t offset = 0, length;
  uint8_t* data;
  int32_t flags = 0;
  size_t len;

  if(!(data = JS_GetArrayBuffer(ctx, &len, argv[0])))
    return JS_ThrowTypeError(ctx, "argument 1 must be an ArrayBuffer");

  argc--;
  argv++;

  length = len;

  if(argc >= 3 && JS_IsNumber(argv[0])) {
    JS_ToInt64(ctx, &offset, argv[0]);
    argc--;
    argv++;
  }

  if(argc >= 2 && JS_IsNumber(argv[0])) {

    JS_ToInt64(ctx, &length, argv[0]);
    argc--;
    argv++;
  }

  JS_ToInt32(ctx, &flags, argv[0]);

  return JS_NewInt32(ctx, mprotect(data + offset, MIN_NUM(length, (int64_t)len), flags));
}

static JSValue
js_mmap_filename(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  uint8_t* data;
  size_t len;
  FILE* fp;
  JSValue ret = JS_UNDEFINED;
  char buf[1024];
  size_t start, end;

  if(!(data = JS_GetArrayBuffer(ctx, &len, argv[0])))
    return JS_ThrowTypeError(ctx, "argument 1 must be an ArrayBuffer");

  if((fp = fopen("/proc/self/maps", "r")) == 0)
    return JS_ThrowInternalError(ctx, "Unable to open /proc/self/maps");

  while(fgets(buf, sizeof(buf) - 1, fp)) {

    if(sscanf(buf, "%zx-%zx", &start, &end) < 2)
      continue;

    if((size_t)data >= start && (size_t)data < end) {
      ret = JS_NewString(ctx, &buf[73]);
      break;
    }
  }

  fclose(fp);
  return ret;
}

static JSValue
js_mmap_tostring(JSContext* ctx, JSValueConst this_val, int argc, JSValueConst argv[]) {
  JSValue ret = JS_UNDEFINED;
  if(js_is_arraybuffer(ctx, argv[0])) {
    uint8_t* data;
    size_t len;
    if((data = JS_GetArrayBuffer(ctx, &len, argv[0]))) {
      ret = JS_NewStringLen(ctx, (const char*)data, len);
    }
  }
  return ret;
}

static const JSCFunctionListEntry js_mmap_funcs[] = {
    JS_CFUNC_DEF("mmap", 2, js_mmap_map),
    JS_CFUNC_DEF("munmap", 1, js_mmap_unmap),
    JS_CFUNC_DEF("msync", 3, js_mmap_msync),
    JS_CFUNC_DEF("mprotect", 3, js_mmap_mprotect),
    JS_CFUNC_DEF("filename", 1, js_mmap_filename),
    JS_CFUNC_DEF("toString", 1, js_mmap_tostring),
    JS_PROP_INT32_DEF("PROT_READ", 0x01, 0),
    JS_PROP_INT32_DEF("PROT_WRITE", 0x02, 0),
    JS_PROP_INT32_DEF("PROT_EXEC", 0x04, 0),
    // JS_PROP_INT32_DEF("PROT_SEM", 0x08, 0),
    JS_PROP_INT32_DEF("PROT_NONE", 0x00, 0),
    JS_PROP_INT32_DEF("PROT_GROWSDOWN", 0x01000000, 0),
    JS_PROP_INT32_DEF("PROT_GROWSUP", 0x02000000, 0),
    JS_PROP_INT32_DEF("MAP_SHARED", 0x01, 0),
    JS_PROP_INT32_DEF("MAP_PRIVATE", 0x02, 0),
    JS_PROP_INT32_DEF("MAP_TYPE", 0x0f, 0),
    JS_PROP_INT32_DEF("MAP_FIXED", 0x10, 0),
    JS_PROP_INT32_DEF("MAP_ANONYMOUS", 0x20, 0),
    JS_PROP_INT32_DEF("MAP_GROWSDOWN", 0x0100, 0),
    JS_PROP_INT32_DEF("MAP_DENYWRITE", 0x0800, 0),
    JS_PROP_INT32_DEF("MAP_EXECUTABLE", 0x1000, 0),
    JS_PROP_INT32_DEF("MAP_LOCKED", 0x2000, 0),
    JS_PROP_INT32_DEF("MAP_NORESERVE", 0x4000, 0),
    JS_PROP_INT32_DEF("MAP_POPULATE", 0x8000, 0),
    JS_PROP_INT32_DEF("MAP_NONBLOCK", 0x10000, 0),
    JS_PROP_INT32_DEF("MAP_STACK", 0x20000, 0),
    JS_PROP_INT32_DEF("MAP_HUGETLB", 0x40000, 0),
    JS_PROP_INT32_DEF("MAP_FAILED", -1, 0),
#ifdef EBUSY
    JS_CONSTANT(EBUSY),
#endif
#ifdef EFAULT
    JS_CONSTANT(EFAULT),
#endif
#ifdef EINVAL
    JS_CONSTANT(EINVAL),
#endif
#ifdef ENOMEM
    JS_CONSTANT(ENOMEM),
#endif
#ifdef MS_ASYNC
    JS_CONSTANT(MS_ASYNC),
#endif
#ifdef MS_INVALIDATE
    JS_CONSTANT(MS_INVALIDATE),
#endif
#ifdef MS_SYNC
    JS_CONSTANT(MS_SYNC),
#endif
#ifdef PROT_SAO
    JS_CONSTANT(PROT_SAO),
#endif
#ifdef PROT_SEM
    JS_CONSTANT(PROT_SEM),
#endif
};

static int
js_mmap_init(JSContext* ctx, JSModuleDef* m) {
  JS_SetModuleExportList(ctx, m, js_mmap_funcs, countof(js_mmap_funcs));
  return 0;
}

#ifdef JS_SHARED_LIBRARY
#define JS_INIT_MODULE js_init_module
#else
#define JS_INIT_MODULE js_init_module_mmap
#endif

VISIBLE JSModuleDef*
JS_INIT_MODULE(JSContext* ctx, const char* module_name) {
  JSModuleDef* m;

  if((m = JS_NewCModule(ctx, module_name, js_mmap_init))) {
    JS_AddModuleExportList(ctx, m, js_mmap_funcs, countof(js_mmap_funcs));
  }

  return m;
}

/**
 * @}
 */