// Copyright 2016 The Emscripten Authors. All rights reserved.

// Emscripten is available under two separate licenses, the MIT license and the

// University of Illinois/NCSA Open Source License. Both these licenses can be

// found in the LICENSE file.

#include <assert.h>

#include <dirent.h>

#include <errno.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#define __NEED_struct_iovec

#include "syscall_arch.h"

#include <ctype.h>

#include <emscripten/emscripten.h>

#include <emscripten/fetch.h>

#include <emscripten/threading.h>

#include <fcntl.h>

#include <math.h>

#include <string.h>

#include <sys/stat.h>

#include <time.h>

#include <wasi/api.h>

// Uncomment the following and clear the cache with emcc --clear-cache to rebuild this file to

// enable internal debugging. #define ASMFS_DEBUG

extern "C" {

// http://stackoverflow.com/questions/417142/what-is-the-maximum-length-of-a-url-in-different-browsers

#define MAX_PATHNAME_LENGTH 2000

#define INODE_TYPE uint32_t

#define INODE_FILE 1

#define INODE_DIR 2

struct inode {

char name[NAME_MAX + 1]; // NAME_MAX actual bytes + one byte for null termination.

inode* parent; // ID of the parent node

inode* sibling; // ID of a sibling node (these form a singular linked list that specifies the

// content under a directory)

inode* child; // ID of the first child node in a chain of children (the root of a linked list of

// inodes)

uint32_t uid; // User ID of the owner

uint32_t gid; // Group ID of the owning group

uint32_t mode; // r/w/x modes

time_t ctime; // Time when the inode was last modified

time_t mtime; // Time when the content was last modified

time_t atime; // Time when the content was last accessed

size_t size; // Size of the file in bytes

size_t capacity; // Amount of bytes allocated to pointer data

uint8_t* data; // The actual file contents.

INODE_TYPE type;

emscripten_fetch_t* fetch;

// Specifies a remote server address where this inode can be located.

char* remoteurl;

};

#define EM_FILEDESCRIPTOR_MAGIC 0x64666d65U // 'emfd'

struct FileDescriptor {

uint32_t magic;

ssize_t file_pos;

uint32_t mode;

uint32_t flags;

inode* node;

};

static inode* create_inode(INODE_TYPE type, int mode) {

inode* i = (inode*)malloc(sizeof(inode));

memset(i, 0, sizeof(inode));

i->ctime = i->mtime = i->atime = time(0);

i->type = type;

i->mode = mode;

return i;

}

// The current working directory of the application process.

static inode* cwd_inode = 0;

static inode* filesystem_root() {

static inode* root_node = create_inode(INODE_DIR, 0777);

return root_node;

}

static inode* get_cwd() {

if (!cwd_inode)

cwd_inode = filesystem_root();

return cwd_inode;

}

static void set_cwd(inode* node) { cwd_inode = node; }

static void inode_abspath(inode* node, char* dst, int dstLen) {

if (!node) {

assert(dstLen >= (int)strlen("(null)") + 1);

strcpy(dst, "(null)");

return;

}

if (node == filesystem_root()) {

assert(dstLen >= (int)strlen("/") + 1);

strcpy(dst, "/");

return;

}

#define MAX_DIRECTORY_DEPTH 512

inode* stack[MAX_DIRECTORY_DEPTH];

int depth = 0;

while (node->parent && depth < MAX_DIRECTORY_DEPTH) {

stack[depth++] = node;

node = node->parent;

}

char* dstEnd = dst + dstLen;

*dstEnd-- = '\0';

while (depth > 0 && dst < dstEnd) {

if (dst < dstEnd)

*dst++ = '/';

--depth;

int len = strlen(stack[depth]->name);

if (len > dstEnd - dst)

len = dstEnd - dst;

strncpy(dst, stack[depth]->name, len);

dst += len;

}

}

// Deletes the given inode. Ignores (orphans) any children there might be

static void delete_inode(inode* node) {

if (!node)

return;

if (node == filesystem_root())

return; // As special case, do not allow deleting the filesystem root directory

#ifdef ASMFS_DEBUG

EM_ASM(err('delete_inode: ' + UTF8ToString($0)), node->name);

#endif

if (node->fetch)

emscripten_fetch_close(node->fetch);

free(node->remoteurl);

free(node);

}

// Deletes the given inode and its subtree

static void delete_inode_tree(inode* node) {

if (!node)

return;

#ifdef ASMFS_DEBUG

EM_ASM(err('delete_inode_tree: ' + UTF8ToString($0)), node->name);

#endif

inode* child = node->child;

while (child) {

inode* sibling = child->sibling;

delete_inode_tree(child->child);

delete_inode(child);

child = sibling;

}

if (node !=

filesystem_root()) // As special case, do not allow deleting the filesystem root directory

{

delete_inode(node);

} else {

// For filesystem root, just make sure all children are gone.

node->child = 0;

}

}

// Makes node the child of parent.

static void link_inode(inode* node, inode* parent) {

char parentName[PATH_MAX];

inode_abspath(parent, parentName, PATH_MAX);

#ifdef ASMFS_DEBUG

EM_ASM(err('link_inode: node "' + UTF8ToString($0) + '" to parent "' + UTF8ToString($1) + '".'),

node->name, parentName);

#endif

// When linking a node, it can't be part of the filesystem tree (but it can have children of its

// own)

assert(!node->parent);

assert(!node->sibling);

// The inode pointed by 'node' is not yet part of the filesystem, so it's not shared memory and

// only this thread is accessing it. Therefore setting the node's parent here is not yet racy, do

// that operation first.

node->parent = parent;

// This node is to become the first child of the parent, and the old first child of the parent

// should become the sibling of this node, i.e.

// 1) node->sibling = parent->child;

// 2) parent->child = node;

// However these two operations need to occur atomically in order to be coherent. To ensure that,

// run the two operations in a CAS loop, which is possible because the first operation is not racy

// until the node is 'published' to the filesystem tree by the compare_exchange operation.

do {

__atomic_load(

&parent->child, &node->sibling, __ATOMIC_SEQ_CST); // node->sibling <- parent->child

} while (

!__atomic_compare_exchange(&parent->child, &node->sibling, &node, false, __ATOMIC_SEQ_CST,

__ATOMIC_SEQ_CST)); // parent->child <- node if it had not raced to change value in between

}

// Traverse back in sibling linked list, or 0 if no such node exist.

static inode* find_predecessor_sibling(inode* node, inode* parent) {

inode* child = parent->child;

if (child == node)

return 0;

while (child && child->sibling != node)

child = child->sibling;

if (!child->sibling)

return 0;

return child;

}

static void unlink_inode(inode* node) {

#ifdef ASMFS_DEBUG

EM_ASM(

err('unlink_inode: node ' + UTF8ToString($0) + ' from its parent ' + UTF8ToString($1) + '.'),

node->name, node->parent->name);

#endif

inode* parent = node->parent;

if (!parent)

return;

node->parent = 0;

if (parent->child == node) {

parent->child = node->sibling;

} else {

inode* predecessor = find_predecessor_sibling(node, parent);

if (predecessor)

predecessor->sibling = node->sibling;

}

node->parent = node->sibling = 0;

}

// Compares two strings for equality until a '\0' or a '/' is hit. Returns 0 if the strings differ,

// or a pointer to the beginning of the next directory component name of s1 if the strings are

// equal.

static const char* path_cmp(const char* s1, const char* s2, bool* is_directory) {

*is_directory = true;

while (*s1 == *s2) {

if (*s1 == '/')

return s1 + 1;

if (*s1 == '\0') {

*is_directory = false;

return s1;

}

++s1;

++s2;

}

if (*s1 == '/' && *s2 == '\0')

return s1 + 1;

if (*s1 == '\0' && *s2 == '/')

return s1;

return 0;

}

#define NIBBLE_TO_CHAR(x) ("0123456789abcdef"[(x)])

static void uriEncode(char* dst, int dstLengthBytes, const char* src) {

char* end =

dst + dstLengthBytes - 4; // Use last 4 bytes of dst as a guard area to avoid overflow below.

while (*src && dst < end) {

if (isalnum(*src) || *src == '-' || *src == '_' || *src == '.' || *src == '~')

*dst++ = *src;

else if (*src == '/')

*dst++ = *src; // NB. forward slashes should generally be uriencoded, but for file path

// purposes, we want to keep them intact.

else

*dst++ = '%', *dst++ = NIBBLE_TO_CHAR(*src >> 4),

*dst++ = NIBBLE_TO_CHAR(*src & 15); // This charater needs uriencoding.

++src;

}

*dst = '\0';

}

// Copies string 'path' to 'dst', but stops on the first forward slash '/' character.

// Returns number of bytes written, excluding null terminator

static int strcpy_inodename(char* dst, const char* path) {

char* d = dst;

while (*path && *path != '/')

*dst++ = *path++;

*dst = '\0';

return dst - d;

}

// Copies src to dst, writes at most maxBytesToWrite out. Always null terminates dst. Returns the

// number of characters written, excluding null terminator.

static int strcpy_safe(char* dst, const char* src, int maxBytesToWrite) {

char* dst_start = dst;

char* dst_end = dst + maxBytesToWrite - 1;

while (dst < dst_end && *src)

*dst++ = *src++;

*dst = '\0';

return dst - dst_start;

}

// Returns a pointer to the basename part of the string, i.e. the string after the last occurrence

// of a forward slash character

static const char* basename_part(const char* path) {

const char* s = path;

while (*path) {

if (*path == '/')

s = path + 1;

++path;

}

return s;

}

static inode* create_directory_hierarchy_for_file(

inode* root, const char* path_to_file, unsigned int mode) {

assert(root);

if (!root)

return 0;

// Traverse . and ..

while (path_to_file[0] == '.') {

if (path_to_file[1] == '/')

path_to_file += 2; // Skip over redundant "./././././" blocks

else if (path_to_file[1] == '\0')

path_to_file += 1;

else if (path_to_file[1] == '.' &&

(path_to_file[2] == '/' ||

path_to_file[2] == '\0')) // Go up to parent directories with ".."

{

root = root->parent;

if (!root)

return 0;

assert(

root->type == INODE_DIR); // Anything that is a parent should automatically be a directory.

path_to_file += (path_to_file[2] == '/') ? 3 : 2;

} else

break;

}

if (path_to_file[0] == '\0')

return 0;

inode* node = root->child;

while (node) {

bool is_directory = false;

const char* child_path = path_cmp(path_to_file, node->name, &is_directory);

#ifdef ASMFS_DEBUG

EM_ASM_INT({err('path_cmp ' + UTF8ToString($0) + ', ' + UTF8ToString($1) + ', ' +

UTF8ToString($2) + ' .')},

path_to_file, node->name, child_path);

#endif

if (child_path) {

if (is_directory && node->type != INODE_DIR)

return 0; // "A component used as a directory in pathname is not, in fact, a directory"

// The directory name matches.

path_to_file = child_path;

// Traverse . and ..

while (path_to_file[0] == '.') {

if (path_to_file[1] == '/')

path_to_file += 2; // Skip over redundant "./././././" blocks

else if (path_to_file[1] == '\0')

path_to_file += 1;

else if (path_to_file[1] == '.' &&

(path_to_file[2] == '/' ||

path_to_file[2] == '\0')) // Go up to parent directories with ".."

{

node = node->parent;

if (!node)

return 0;

assert(node->type ==

INODE_DIR); // Anything that is a parent should automatically be a directory.

path_to_file += (path_to_file[2] == '/') ? 3 : 2;

} else

break;

}

if (path_to_file[0] == '\0')

return node;

if (path_to_file[0] == '/' && path_to_file[1] == '\0' /* && node is a directory*/)

return node;

root = node;

node = node->child;

} else {

node = node->sibling;

}

}

const char* basename_pos = basename_part(path_to_file);

#ifdef ASMFS_DEBUG

EM_ASM(err('path_to_file ' + UTF8ToString($0) + ' .'), path_to_file);

EM_ASM(err('basename_pos ' + UTF8ToString($0) + ' .'), basename_pos);

#endif

while (*path_to_file && path_to_file < basename_pos) {

node = create_inode(INODE_DIR, mode);

path_to_file += strcpy_inodename(node->name, path_to_file) + 1;

link_inode(node, root);

#ifdef ASMFS_DEBUG

EM_ASM(out('create_directory_hierarchy_for_file: created directory ' + UTF8ToString($0) +

' under parent ' + UTF8ToString($1) + '.'),

node->name, node->parent->name);

#endif

root = node;

}

return root;

}

#define RETURN_NODE_AND_ERRNO(node, errno) \

do { \

*out_errno = (errno); \

return (node); \

} while (0)

// Given a pathname to a file/directory, finds the inode of the directory that would contain the

// file/directory, or 0 if the intermediate path doesn't exist. Note that the file/directory pointed

// to by path does not need to exist, only its parent does.

static inode* find_parent_inode(inode* root, const char* path, int* out_errno) {

char rootName[PATH_MAX];

inode_abspath(root, rootName, PATH_MAX);

#ifdef ASMFS_DEBUG

EM_ASM(err('find_parent_inode(root="' + UTF8ToString($0) + '", path="' + UTF8ToString($1) + '")'),

rootName, path);

#endif

assert(out_errno); // Passing in error is mandatory.

if (!root)

RETURN_NODE_AND_ERRNO(0, ENOENT);

if (!path)

RETURN_NODE_AND_ERRNO(0, ENOENT);

// Traverse . and ..

while (path[0] == '.') {

if (path[1] == '/')

path += 2; // Skip over redundant "./././././" blocks

else if (path[1] == '\0')

path += 1;

else if (path[1] == '.' &&

(path[2] == '/' || path[2] == '\0')) // Go up to parent directories with ".."

{

root = root->parent;

if (!root)

RETURN_NODE_AND_ERRNO(0, ENOENT);

assert(

root->type == INODE_DIR); // Anything that is a parent should automatically be a directory.

path += (path[2] == '/') ? 3 : 2;

} else

break;

}

if (path[0] == '\0')

RETURN_NODE_AND_ERRNO(0, ENOENT);

if (path[0] == '/' && path[1] == '\0')

RETURN_NODE_AND_ERRNO(0, ENOENT);

if (root->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

// TODO: RETURN_ERRNO(ELOOP, "Too many symbolic links were encountered in translating pathname");

// TODO: RETURN_ERRNO(EACCES, "one of the directories in the path prefix of pathname did not allow

// search permission");

const char* basename = basename_part(path);

if (path == basename)

RETURN_NODE_AND_ERRNO(root, 0);

inode* node = root->child;

while (node) {

bool is_directory = false;

const char* child_path = path_cmp(path, node->name, &is_directory);

if (child_path) {

if (is_directory && node->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

// The directory name matches.

path = child_path;

// Traverse . and ..

while (path[0] == '.') {

if (path[1] == '/')

path += 2; // Skip over redundant "./././././" blocks

else if (path[1] == '\0')

path += 1;

else if (path[1] == '.' &&

(path[2] == '/' || path[2] == '\0')) // Go up to parent directories with ".."

{

node = node->parent;

if (!node)

RETURN_NODE_AND_ERRNO(0, ENOENT);

assert(node->type ==

INODE_DIR); // Anything that is a parent should automatically be a directory.

path += (path[2] == '/') ? 3 : 2;

} else

break;

}

if (path >= basename)

RETURN_NODE_AND_ERRNO(node, 0);

if (!*path)

RETURN_NODE_AND_ERRNO(0, ENOENT);

node = node->child;

if (node->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

} else {

node = node->sibling;

}

}

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

}

// Given a root inode of the filesystem and a path relative to it, e.g.

// "some/directory/dir_or_file", returns the inode that corresponds to "dir_or_file", or 0 if it

// doesn't exist. If the parameter out_closest_parent is specified, the closest (grand)parent node

// will be returned.

static inode* find_inode(inode* root, const char* path, int* out_errno) {

char rootName[PATH_MAX];

inode_abspath(root, rootName, PATH_MAX);

#ifdef ASMFS_DEBUG

EM_ASM(err('find_inode(root="' + UTF8ToString($0) + '", path="' + UTF8ToString($1) + '")'),

rootName, path);

#endif

assert(out_errno); // Passing in error is mandatory.

if (!root)

RETURN_NODE_AND_ERRNO(0, ENOENT);

// TODO: RETURN_ERRNO(ELOOP, "Too many symbolic links were encountered in translating pathname");

// TODO: RETURN_ERRNO(EACCES, "one of the directories in the path prefix of pathname did not allow

// search permission");

// special-case finding empty string path "", "." or "/" returns the root searched in.

if (root->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

if (!path)

RETURN_NODE_AND_ERRNO(root, 0);

// Traverse . and ..

while (path[0] == '.') {

if (path[1] == '/')

path += 2; // Skip over redundant "./././././" blocks

else if (path[1] == '\0')

path += 1;

else if (path[1] == '.' &&

(path[2] == '/' || path[2] == '\0')) // Go up to parent directories with ".."

{

root = root->parent;

if (!root)

RETURN_NODE_AND_ERRNO(0, ENOENT);

assert(

root->type == INODE_DIR); // Anything that is a parent should automatically be a directory.

path += (path[2] == '/') ? 3 : 2;

} else

break;

}

if (path[0] == '\0')

RETURN_NODE_AND_ERRNO(root, 0);

inode* node = root->child;

while (node) {

bool is_directory = false;

const char* child_path = path_cmp(path, node->name, &is_directory);

if (child_path) {

if (is_directory && node->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

// The directory name matches.

path = child_path;

// Traverse . and ..

while (path[0] == '.') {

if (path[1] == '/')

path += 2; // Skip over redundant "./././././" blocks

else if (path[1] == '\0')

path += 1;

else if (path[1] == '.' &&

(path[2] == '/' || path[2] == '\0')) // Go up to parent directories with ".."

{

node = node->parent;

if (!node)

RETURN_NODE_AND_ERRNO(0, ENOENT);

assert(node->type ==

INODE_DIR); // Anything that is a parent should automatically be a directory.

path += (path[2] == '/') ? 3 : 2;

} else

break;

}

// If we arrived to the end of the search, this is the node we were looking for.

if (path[0] == '\0')

RETURN_NODE_AND_ERRNO(node, 0);

if (path[0] == '/' && node->type != INODE_DIR)

RETURN_NODE_AND_ERRNO(

0, ENOTDIR); // "A component used as a directory in pathname is not, in fact, a directory"

if (path[0] == '/' && path[1] == '\0')

RETURN_NODE_AND_ERRNO(node, 0);

node = node->child;

} else {

node = node->sibling;

}

}

RETURN_NODE_AND_ERRNO(0, ENOENT);

}

// Same as above, but the root node is deduced from 'path'. (either absolute if path starts with

// "/", or relative)

static inode* find_inode(const char* path, int* out_errno) {

inode* root;

if (path[0] == '/')

root = filesystem_root(), ++path;

else

root = get_cwd();

return find_inode(root, path, out_errno);

}

void emscripten_asmfs_set_remote_url(const char* filename, const char* remoteUrl) {

int err;

inode* node = find_inode(filename, &err);

if (!node)

return;

free(node->remoteurl);

node->remoteurl = strdup(remoteUrl);

}

void emscripten_asmfs_set_file_data(const char* filename, char* data, size_t size) {

int err;

inode* node = find_inode(filename, &err);

if (!node) {

free(data);

return;

}

free(node->data);

node->data = (uint8_t*)data;

node->size = node->capacity = size;

}

char* find_last_occurrence(char* str, char ch) {

char* o = 0;

while (*str) {

if (*str == ch)

o = str;

++str;

}

return o;

}

// Given a filename outputs the remote URL address that file can be located in.

void emscripten_asmfs_remote_url(const char* filename, char* outRemoteUrl, int maxBytesToWrite) {

if (maxBytesToWrite <= 0 || !outRemoteUrl)

return;

*outRemoteUrl = '\0';

if (maxBytesToWrite == 1)

return;

char trailing_path[PATH_MAX + 1] = {};

char full_path[PATH_MAX + 1] = {};

char full_path_temp[PATH_MAX + 1] = {};

strcpy(full_path, filename);

int err;

inode* node = find_inode(full_path, &err);

while (!node) {

char* s = find_last_occurrence(full_path, '/');

if (!s) {

node = filesystem_root();

strcpy(full_path_temp, trailing_path);

strcpy(trailing_path, full_path);

if (full_path_temp[0] != '\0') {

strcat(trailing_path, "/");

strcat(trailing_path, full_path_temp);

}

break;

}

*s = '\0';

node = find_inode(full_path, &err);

strcpy(full_path_temp, trailing_path);

strcpy(trailing_path, filename + (s - full_path));

if (full_path_temp[0] != '\0') {

strcat(trailing_path, "/");

strcat(trailing_path, full_path_temp);

}

}

char uriEncodedPathName[3 * PATH_MAX + 4];

full_path[0] = full_path[PATH_MAX] = full_path_temp[0] = full_path_temp[PATH_MAX] = '\0';

while (node) {

if (node->remoteurl && node->remoteurl[0] != '\0') {

int nWritten = strcpy_safe(outRemoteUrl, node->remoteurl, maxBytesToWrite);

if (maxBytesToWrite - nWritten > 1 && outRemoteUrl[nWritten - 1] != '/' &&

full_path[0] != '/') {

outRemoteUrl[nWritten++] = '/';

outRemoteUrl[nWritten] = '\0';

}

strcat(full_path + strlen(full_path), trailing_path);

uriEncode(uriEncodedPathName, 3 * PATH_MAX + 4, full_path);

strcpy_safe(outRemoteUrl + nWritten,

(outRemoteUrl[nWritten - 1] == '/' && uriEncodedPathName[0] == '/')

? (uriEncodedPathName + 1)

: uriEncodedPathName,

maxBytesToWrite - nWritten);

return;

}

strcpy_safe(full_path_temp, full_path, PATH_MAX);

int nWritten = strcpy_safe(full_path, node->name, PATH_MAX);

if (full_path_temp[0] != '\0') {

full_path[nWritten++] = '/';

full_path[nWritten] = '\0';

strcpy_safe(full_path + nWritten, full_path_temp, PATH_MAX - nWritten);

}

node = node->parent;

}

strcat(full_path + strlen(full_path), trailing_path);

uriEncode(uriEncodedPathName, 3 * PATH_MAX + 4, full_path);

strcpy_safe(outRemoteUrl, uriEncodedPathName, maxBytesToWrite);

}

// Debug function that dumps out the filesystem tree to console.

void emscripten_dump_fs_tree(inode* root, char* path) {

char str[256];

sprintf(str, "%s:", path);

EM_ASM(out(UTF8ToString($0)), str);

// Print out:

// file mode | number of links | owner name | group name | file size in bytes | file last modified

// time | path name which aligns with "ls -AFTRl" on console

inode* child = root->child;

uint64_t totalSize = 0;

while (child) {

sprintf(str, "%c%c%c%c%c%c%c%c%c%c %d user%u group%u %lu Jan 1 1970 %s%c",

child->type == INODE_DIR ? 'd' : '-', (child->mode & S_IRUSR) ? 'r' : '-',

(child->mode & S_IWUSR) ? 'w' : '-', (child->mode & S_IXUSR) ? 'x' : '-',

(child->mode & S_IRGRP) ? 'r' : '-', (child->mode & S_IWGRP) ? 'w' : '-',

(child->mode & S_IXGRP) ? 'x' : '-', (child->mode & S_IROTH) ? 'r' : '-',

(child->mode & S_IWOTH) ? 'w' : '-', (child->mode & S_IXOTH) ? 'x' : '-',

1, // number of links to this file

child->uid, child->gid,

child->size ? child->size : (child->fetch ? (int)child->fetch->numBytes : 0), child->name,

child->type == INODE_DIR ? '/' : ' ');

EM_ASM(out(UTF8ToString($0)), str);

totalSize += child->size;

child = child->sibling;

}

sprintf(str, "total %llu bytes\n", totalSize);

EM_ASM(out(UTF8ToString($0)), str);

child = root->child;

char* path_end = path + strlen(path);

while (child) {

if (child->type == INODE_DIR) {

strcpy(path_end, child->name);

strcat(path_end, "/");

emscripten_dump_fs_tree(child, path);

}

child = child->sibling;

}

}

void emscripten_asmfs_dump() {

EM_ASM({err('emscripten_asmfs_dump()')});

char path[PATH_MAX] = "/";

emscripten_dump_fs_tree(filesystem_root(), path);

}

void emscripten_asmfs_discard_tree(const char* path) {

#ifdef ASMFS_DEBUG

emscripten_asmfs_dump();

EM_ASM(err('emscripten_asmfs_discard_tree: ' + UTF8ToString($0)), path);

#endif

int err;

inode* node = find_inode(path, &err);

if (node && !err) {

unlink_inode(node);

delete_inode_tree(node);

}

#ifdef ASMFS_DEBUG

else

EM_ASM(err('emscripten_asmfs_discard_tree failed, error ' + $0), err);

emscripten_asmfs_dump();

#endif

}

#ifdef ASMFS_DEBUG

#define RETURN_ERRNO(errno, error_reason) \

do { \

EM_ASM(err(UTF8ToString($0) + '() returned errno ' + #errno + '(' + $1 + '): ' + \

error_reason + '!'), \

__FUNCTION__, errno); \

return -errno; \

} while (0)

#else

#define RETURN_ERRNO(errno, error_reason) \

do { \

return -(errno); \

} while (0)

#endif

static char stdout_buffer[4096] = {};

static int stdout_buffer_end = 0;

static char stderr_buffer[4096] = {};

static int stderr_buffer_end = 0;

static void print_stream(void* bytes, int numBytes, bool stdout) {

char* buffer = stdout ? stdout_buffer : stderr_buffer;

int& buffer_end = stdout ? stdout_buffer_end : stderr_buffer_end;

memcpy(buffer + buffer_end, bytes, numBytes);

buffer_end += numBytes;

int new_buffer_start = 0;

for (int i = 0; i < buffer_end; ++i) {

if (buffer[i] == '\n') {

buffer[i] = 0;

EM_ASM_INT({out(UTF8ToString($0))}, buffer + new_buffer_start);

new_buffer_start = i + 1;

}

}

size_t new_buffer_size = buffer_end - new_buffer_start;

memmove(buffer, buffer + new_buffer_start, new_buffer_size);

buffer_end = new_buffer_size;

}

// TODO: Make thread-local storage.

static emscripten_asmfs_open_t __emscripten_asmfs_file_open_behavior_mode =

EMSCRIPTEN_ASMFS_OPEN_REMOTE_DISCOVER;

void emscripten_asmfs_set_file_open_behavior(emscripten_asmfs_open_t behavior) {

__emscripten_asmfs_file_open_behavior_mode = behavior;

}

emscripten_asmfs_open_t emscripten_asmfs_get_file_open_behavior() {

return __emscripten_asmfs_file_open_behavior_mode;

}

// Returns true if the given file can be synchronously read by the main browser thread.

static bool emscripten_asmfs_file_is_synchronously_accessible(inode* node) {

return node->data // If file was created from memory without XHR, e.g. via fopen("foo.txt", "w"),

// it will have node->data ptr backing.

||

(node->fetch && node->fetch->data); // If the file was downloaded, it will be backed here.

}

static long open(const char* pathname, int flags, int mode) {

#ifdef ASMFS_DEBUG

EM_ASM(err('open(pathname="' + UTF8ToString($0) + '", flags=0x' + ($1).toString(16) + ', mode=0' +

($2).toString(8) + ')'),

pathname, flags, mode);

#endif

int accessMode = (flags & O_ACCMODE);

if ((flags & O_ASYNC))

RETURN_ERRNO(ENOTSUP, "TODO: Opening files with O_ASYNC flag is not supported in ASMFS");

if ((flags & O_DIRECT))

RETURN_ERRNO(ENOTSUP, "TODO: O_DIRECT flag is not supported in ASMFS");

if ((flags & O_DSYNC))

RETURN_ERRNO(ENOTSUP, "TODO: O_DSYNC flag is not supported in ASMFS");

// Spec says that the result of O_EXCL without O_CREAT is undefined.

// We could enforce it as an error condition, as follows:

// if ((flags & O_EXCL) && !(flags & O_CREAT)) RETURN_ERRNO(EINVAL, "open() with O_EXCL flag

//needs to always be paired with O_CREAT");

// However existing earlier unit tests in Emscripten expect that O_EXCL is simply ignored when

// O_CREAT was not passed. So do that for now.

if ((flags & O_EXCL) && !(flags & O_CREAT)) {

#ifdef ASMFS_DEBUG

EM_ASM(err('warning: open(pathname="' + UTF8ToString($0) + '", flags=0x' + ($1).toString(16) +

', mode=0' + ($2).toString(8) +

': flag O_EXCL should always be paired with O_CREAT. Ignoring O_EXCL)'),

pathname, flags, mode);

#endif

flags &= ~O_EXCL;

}

if ((flags & (O_NONBLOCK | O_NDELAY)))

RETURN_ERRNO(

ENOTSUP, "TODO: Opening files with O_NONBLOCK or O_NDELAY flags is not supported in ASMFS");

if ((flags & O_PATH))

RETURN_ERRNO(ENOTSUP, "TODO: Opening files with O_PATH flag is not supported in ASMFS");

if ((flags & O_SYNC))

RETURN_ERRNO(ENOTSUP, "TODO: Opening files with O_SYNC flag is not supported in ASMFS");

// The flags:O_CLOEXEC flag is ignored, doesn't have meaning for Emscripten

// TODO: the flags:O_DIRECT flag seems like a great way to let applications explicitly control

// XHR/IndexedDB read/write buffering behavior?

// The flags:O_LARGEFILE flag is ignored, we should always be largefile-compatible

// TODO: The flags:O_NOATIME is ignored, file access times have not been implemented yet

// The flags O_NOCTTY, O_NOFOLLOW

if ((flags & O_TMPFILE)) {

if (accessMode != O_WRONLY && accessMode != O_RDWR)

RETURN_ERRNO(

EINVAL, "O_TMPFILE was specified in flags, but neither O_WRONLY nor O_RDWR was specified");

else

RETURN_ERRNO(

EOPNOTSUPP, "TODO: The filesystem containing pathname does not support O_TMPFILE");

}

// TODO: if (too_many_files_open) RETURN_ERRNO(EMFILE, "The per-process limit on the number of

// open file descriptors has been reached, see getrlimit(RLIMIT_NOFILE)");

int len = strlen(pathname);

if (len > MAX_PATHNAME_LENGTH)

RETURN_ERRNO(ENAMETOOLONG, "pathname was too long");

if (len == 0)

RETURN_ERRNO(ENOENT, "pathname is empty");

// Find if this file exists already in the filesystem?

inode* root = (pathname[0] == '/') ? filesystem_root() : get_cwd();

const char* relpath = (pathname[0] == '/') ? pathname + 1 : pathname;

int err;

inode* node = find_inode(root, relpath, &err);

if (err == ENOTDIR)

RETURN_ERRNO(

ENOTDIR, "A component used as a directory in pathname is not, in fact, a directory");

if (err == ELOOP)

RETURN_ERRNO(ELOOP, "Too many symbolic links were encountered in resolving pathname");

if (err == EACCES)

RETURN_ERRNO(EACCES,

"Search permission is denied for one of the directories in the path prefix of pathname");

if (err && err != ENOENT)

RETURN_ERRNO(err, "find_inode() error");

if (node) {

if ((flags & O_DIRECTORY) && node->type != INODE_DIR)

RETURN_ERRNO(ENOTDIR, "O_DIRECTORY was specified and pathname was not a directory");

if (!(node->mode & 0444))

RETURN_ERRNO(EACCES, "The requested access to the file is not allowed");

if ((flags & O_CREAT) && (flags & O_EXCL))

RETURN_ERRNO(EEXIST, "pathname already exists and O_CREAT and O_EXCL were used");

if (node->type == INODE_DIR && accessMode != O_RDONLY)

RETURN_ERRNO(EISDIR, "pathname refers to a directory and the access requested involved writing (that is, O_WRONLY or O_RDWR is set)");

if (node->type == INODE_DIR && (flags & O_TRUNC))

RETURN_ERRNO(EISDIR,

"pathname refers to a directory and the access flags specified invalid flag O_TRUNC");

// A current download exists to the file? Then wait for it to complete.

if (node->fetch) {

// On the main thread, the fetch must have already completed before we come here. If not, we

// cannot stop to wait for it to finish, and must return a failure (file not found)

if (emscripten_is_main_browser_thread()) {

if (emscripten_fetch_wait(node->fetch, 0) != EMSCRIPTEN_RESULT_SUCCESS) {

RETURN_ERRNO(ENOENT, "Attempted to open a file that is still downloading on the main browser thread. Could not block to wait! (try preloading the file to the filesystem before application start)");

}

} else {

// On worker threads, we can pause to wait for the fetch.

emscripten_fetch_wait(node->fetch, INFINITY);

}

}

}

if ((flags & O_CREAT) && ((flags & O_TRUNC) || (flags & O_EXCL))) {

// Create a new empty file or truncate existing one.

if (node) {

if (node->fetch)

emscripten_fetch_close(node->fetch);

node->fetch = 0;

node->size = 0;

} else if ((flags & O_CREAT)) {

inode* directory = create_directory_hierarchy_for_file(root, relpath, mode);

node = create_inode((flags & O_DIRECTORY) ? INODE_DIR : INODE_FILE, mode);

strcpy(node->name, basename_part(pathname));

link_inode(node, directory);

}

} else if (!node || (node->type == INODE_FILE && !node->fetch && !node->data)) {

emscripten_fetch_t* fetch = 0;

if (!(flags & O_DIRECTORY) && accessMode != O_WRONLY) // Opening a file for reading?

{

// If there's no inode entry, check if we're not even interested in downloading the file?

if (!node &&

__emscripten_asmfs_file_open_behavior_mode != EMSCRIPTEN_ASMFS_OPEN_REMOTE_DISCOVER) {

RETURN_ERRNO(

ENOENT, "O_CREAT is not set, the named file does not exist in local filesystem and EMSCRIPTEN_ASMFS_OPEN_REMOTE_DISCOVER is not specified");

}

// Report an error if there is an inode entry, but file data is not synchronously available

// and it should have been.

if (node && !node->data &&

__emscripten_asmfs_file_open_behavior_mode == EMSCRIPTEN_ASMFS_OPEN_MEMORY) {

RETURN_ERRNO(

ENOENT, "O_CREAT is not set, the named file exists, but file data is not synchronously available in memory (EMSCRIPTEN_ASMFS_OPEN_MEMORY specified)");

}

if (emscripten_is_main_browser_thread() &&

(!node || !emscripten_asmfs_file_is_synchronously_accessible(node))) {

RETURN_ERRNO(ENOENT,

"O_CREAT is not set, the named file exists, but file data is not synchronously available in memory, and file open is attempted on the main thread which cannot synchronously open files! (try preloading the file to the filesystem before application start)");

}

// Kick off the file download, either from IndexedDB or via an XHR.

emscripten_fetch_attr_t attr;

emscripten_fetch_attr_init(&attr);

strcpy(attr.requestMethod, "GET");

attr.attributes = EMSCRIPTEN_FETCH_APPEND | EMSCRIPTEN_FETCH_LOAD_TO_MEMORY |

EMSCRIPTEN_FETCH_WAITABLE | EMSCRIPTEN_FETCH_PERSIST_FILE;

// If asked to only do a read from IndexedDB, don't perform an XHR.

if (__emscripten_asmfs_file_open_behavior_mode == EMSCRIPTEN_ASMFS_OPEN_INDEXEDDB) {

attr.attributes |= EMSCRIPTEN_FETCH_NO_DOWNLOAD;

}