Implemented <fcntl.h>.

8 files changed, 1157 insertions, 13 deletions

diff --git a/src/library.js b/src/library.js
index 46c396cb..793454de 100644
--- a/src/library.js
+++ b/src/library.js
@@ -679,6 +679,184 @@ LibraryManager.library = {
   },
 
   // ==========================================================================
+  // fcntl.h
+  // ==========================================================================
+
+  __flock_struct_layout: Types.structDefinitions.flock,
+  open__deps: ['$FS', '__setErrNo', '$ERRNO_CODES',
+               'strlen', 'strcpy', 'dirname', 'basename'],
+  open: function(path, oflag, mode) {
+    // int open(const char *path, int oflag, ...);
+    // http://pubs.opengroup.org/onlinepubs/009695399/functions/open.html
+    // NOTE: This implementation tries to mimic glibc rather that strictly
+    // following the POSIX standard.
+
+    // Simplify flags.
+    var accessMode = oflag & 0x3;  // O_ACCMODE.
+    var isWrite = accessMode != 0x0;  // O_RDONLY.
+    var isRead = accessMode != 0x1;  // O_WRONLY.
+    var isCreate = Boolean(oflag & 0x40);  // O_CREAT.
+    var isExistCheck = Boolean(oflag & 0x80);  // O_EXCL.
+    var isTruncate = Boolean(oflag & 0x200);  // O_TRUNC.
+    var isAppend = Boolean(oflag & 0x400);  // O_APPEND.
+
+    // Verify path.
+    var pathStr = Pointer_stringify(path);
+    if (!pathStr) {
+      ___setErrNo(ERRNO_CODES.ENOENT);
+      return -1;
+    }
+    var absolutePath = FS.absolutePath(pathStr);
+    if (absolutePath === null) {
+      ___setErrNo(ERRNO_CODES.ENOENT);
+      return -1;
+    }
+    var buffer = _malloc(_strlen(path) + 1);
+    var parentPath = Pointer_stringify(_dirname(_strcpy(buffer, path)));
+    var name = Pointer_stringify(_basename(_strcpy(buffer, path)));
+    _free(buffer);
+    var parent = FS.findObject(parentPath);
+    if (parent === null) return -1;
+    if (!parent.isFolder || !parent.read) {
+      ___setErrNo(ERRNO_CODES.EACCES);
+      return -1;
+    }
+    var target = parent.contents[name] || null;
+
+    // Verify the file exists, create if needed and allowed.
+    if (target) {
+      if (isCreate && isExistCheck) {
+        ___setErrNo(ERRNO_CODES.EEXIST);
+        return -1;
+      }
+      if ((isWrite || isCreate || isTruncate) && target.isFolder) {
+        ___setErrNo(ERRNO_CODES.EISDIR);
+        return -1;
+      }
+      if (isRead && !target.read || isWrite && !target.write) {
+        ___setErrNo(ERRNO_CODES.EACCES);
+        return -1;
+      }
+      if (isTruncate && !target.isDevice) {
+        target.contents = [];
+      } else {
+        if (!FS.forceLoadFile(target)) {
+          ___setErrNo(ERRNO_CODES.EIO);
+          return -1;
+        }
+      }
+    } else {
+      if (!isCreate) {
+        ___setErrNo(ERRNO_CODES.ENOENT);
+        return -1;
+      }
+      if (!parent.write) {
+        ___setErrNo(ERRNO_CODES.EACCES);
+        return -1;
+      }
+      target = FS.createDataFile(parent, name, [], mode & 0x100, mode & 0x80);  // S_IRUSR, S_IWUSR.
+    }
+
+    // Actually create an open stream.
+    var id = FS.streams.length;
+    FS.streams[id] = {
+      isFolder: false,
+      path: absolutePath,
+      object: target,
+      position: 0,
+      isRead: isRead,
+      isWrite: isWrite,
+      isAppend: isAppend
+    };
+    return id;
+  },
+  creat__deps: ['open'],
+  creat: function(path, mode) {
+    // int creat(const char *path, mode_t mode);
+    // http://pubs.opengroup.org/onlinepubs/009695399/functions/creat.html
+    return _open(path, 0x241, mode);  // O_WRONLY | O_CREAT | O_TRUNC.
+  },
+  fcntl__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__flock_struct_layout'],
+  fcntl: function(fildes, cmd, arg) {
+    // int fcntl(int fildes, int cmd, ...);
+    // http://pubs.opengroup.org/onlinepubs/009695399/functions/fcntl.html
+    if (!(fildes in FS.streams)) {
+      ___setErrNo(ERRNO_CODES.EBADF);
+      return -1;
+    }
+    var stream = FS.streams[fildes];
+    switch (cmd) {
+      case 0:  // F_DUPFD.
+        if (arg < 0) {
+          ___setErrNo(ERRNO_CODES.EINVAL);
+          return -1;
+        }
+        var newStream = {};
+        for (var member in stream) {
+          newStream[member] = stream[member];
+        }
+        if (arg in FS.streams) arg = FS.streams.length;
+        FS.streams[arg] = newStream;
+        return arg;
+      case 1:  // F_GETFD.
+      case 2:  // F_SETFD.
+        return 0;  // FD_CLOEXEC makes no sense for a single process.
+      case 3:  // F_GETFL.
+        var flags = 0;
+        if (stream.isRead && stream.isWrite) flags = 0x2;  // O_RDWR.
+        else if (!stream.isRead && stream.isWrite) flags = 0x1;  // O_WRONLY.
+        else if (stream.isRead && !stream.isWrite) flags = 0x0;  // O_RDONLY.
+        if (stream.isAppend) flags |= 0x400;  // O_APPEND.
+        // Synchronization and blocking flags are irrelevant to us.
+        return flags;
+      case 4:  // F_SETFL.
+        stream.isAppend = Boolean(arg | 0x400);  // O_APPEND.
+        // Synchronization and blocking flags are irrelevant to us.
+        return 0;
+      case 5:  // F_GETLK.
+        var offset = ___flock_struct_layout.members.l_type.offset;
+        // We're always unlocked.
+        {{{ makeSetValue('arg', 'offset', '2', 'i16') }}}  // F_UNLCK.
+        return 0;
+      case 6:  // F_SETLK.
+      case 7:  // F_SETLKW.
+        // Pretend that the locking is successful.
+        return 0;
+      case 8:  // F_SETOWN.
+      case 9:  // F_GETOWN.
+        // These are for sockets. We don't have them implemented (yet?).
+        ___setErrNo(ERRNO_CODES.EINVAL);
+        return -1;
+      default:
+        ___setErrNo(ERRNO_CODES.EINVAL);
+        return -1;
+    }
+    // Should never be reached. Only to silence strict warnings.
+    return -1;
+  },
+  posix_fadvise: function(fd, offset, len, advice) {
+    // int posix_fadvise(int fd, off_t offset, off_t len, int advice);
+    // http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_fadvise.html
+    // Advise as much as you wish. We don't care.
+    return 0;
+  },
+  posix_madvise: 'posix_fadvise',
+  posix_fallocate__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
+  posix_fallocate: function(fd, offset, len) {
+    // int posix_fallocate(int fd, off_t offset, off_t len);
+    // http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_fallocate.html
+    if (!(fd in FS.streams) || FS.streams[fd].link ||
+        FS.streams[fd].isFolder || FS.streams[fd].isDevice) {
+      ___setErrNo(ERRNO_CODES.EBADF);
+      return -1;
+    }
+    var contents = FS.streams[fd].object.contents;
+    var limit = offset + len;
+    while (limit > contents.length) contents.push(0);
+    return 0;
+  },
+
+  // ==========================================================================
 
   _scanString: function() {
     // Supports %x, %4x, %d.%d, %s
@@ -1446,17 +1624,6 @@ LibraryManager.library = {
 
   // unix file IO, see http://rabbit.eng.miami.edu/info/functions/unixio.html
 
-  open: function(filename, flags, mode) {
-    filename = Pointer_stringify(filename);
-    if (flags === 0) { // RDONLY
-      return STDIO.open(filename);
-    } else if (flags === 1) { // WRONLY
-      return STDIO.prepare(filename);
-    } else {
-      return assert(false, 'open with odd params: ' + [flags, mode]);
-    }
-  },
-
   __01open64___deps: ['open'],
   __01open64_: function(filename, mode, flags) {
     // open(), but with flags and mode switched.
@@ -1472,8 +1639,6 @@ LibraryManager.library = {
     return STDIO.read(stream, ptr, numbytes);
   },
 
-  fcntl: function() { }, // TODO...
-
   mmap: function(start, num, prot, flags, stream, offset) {
     // Leaky and non-shared... FIXME
     var info = STDIO.streams[stream];
diff --git a/tests/fcntl-misc/output.txt b/tests/fcntl-misc/output.txt
new file mode 100644
index 00000000..73eae541
--- /dev/null
+++ b/tests/fcntl-misc/output.txt
@@ -0,0 +1,10 @@
+posix_fadvise: 0
+errno: 0
+
+posix_fallocate: 0
+errno: 0
+st_size: 6
+
+posix_fallocate2: 0
+errno: 0
+st_size: 10
diff --git a/tests/fcntl-misc/src.c b/tests/fcntl-misc/src.c
new file mode 100644
index 00000000..73734969
--- /dev/null
+++ b/tests/fcntl-misc/src.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+
+int main() {
+  struct stat s;
+  int f = open("/test", O_RDONLY, 0777);
+
+  printf("posix_fadvise: %d\n", posix_fadvise(f, 3, 2, POSIX_FADV_DONTNEED));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("posix_fallocate: %d\n", posix_fallocate(f, 3, 2));
+  printf("errno: %d\n", errno);
+  stat("/test", &s);
+  printf("st_size: %d\n", s.st_size);
+  memset(&s, 0, sizeof s);
+  printf("\n");
+  errno = 0;
+
+  printf("posix_fallocate2: %d\n", posix_fallocate(f, 3, 7));
+  printf("errno: %d\n", errno);
+  stat("/test", &s);
+  printf("st_size: %d\n", s.st_size);
+  memset(&s, 0, sizeof s);
+
+  return 0;
+}
diff --git a/tests/fcntl-open/output.txt b/tests/fcntl-open/output.txt
new file mode 100644
index 00000000..314ae880
--- /dev/null
+++ b/tests/fcntl-open/output.txt
@@ -0,0 +1,723 @@
+EXISTING FILE 0,0
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,0
+success: 1
+errno: 0
+st_mode: 040000
+
+NON-EXISTING 0,0
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,1
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,2
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,2
+success: 1
+errno: 0
+st_mode: 040000
+
+NON-EXISTING 0,2
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,3
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 0,3
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 0,3
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,4
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,4
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,4
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,5
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,6
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,6
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,6
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,7
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 0,7
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 0,7
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,8
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,8
+success: 1
+errno: 0
+st_mode: 040000
+
+NON-EXISTING 0,8
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,9
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,10
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,10
+success: 1
+errno: 0
+st_mode: 040000
+
+NON-EXISTING 0,10
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,11
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 0,11
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 0,11
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,12
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,12
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,12
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,13
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 0,14
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 0,14
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 0,14
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 0,15
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 0,15
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 0,15
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,0
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,0
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,0
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,1
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,2
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,2
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,2
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,3
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 1,3
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 1,3
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,4
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,4
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,4
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,5
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,6
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,6
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,6
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,7
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 1,7
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 1,7
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,8
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,8
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,8
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,9
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,10
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,10
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,10
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,11
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 1,11
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 1,11
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,12
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,12
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,12
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,13
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 1,14
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 1,14
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 1,14
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 1,15
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 1,15
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 1,15
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,0
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,0
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,0
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,1
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,1
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,2
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,2
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,2
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,3
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 2,3
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 2,3
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,4
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,4
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,4
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,5
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,5
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,6
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,6
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,6
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,7
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 2,7
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 2,7
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,8
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,8
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,8
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,9
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,9
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,10
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,10
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,10
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,11
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 2,11
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 2,11
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,12
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,12
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,12
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,13
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,13
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FILE 2,14
+success: 1
+errno: 0
+st_mode: 0100000
+
+EXISTING FOLDER 2,14
+success: 0
+errno: 21
+st_mode: 040000
+
+NON-EXISTING 2,14
+success: 0
+errno: 2
+st_mode: 00
+
+EXISTING FILE 2,15
+success: 0
+errno: 17
+st_mode: 0100000
+
+EXISTING FOLDER 2,15
+success: 0
+errno: 17
+st_mode: 040000
+
+NON-EXISTING 2,15
+success: 1
+errno: 0
+st_mode: 0100000
+
+CREAT
+success: 1
+errno: 0
diff --git a/tests/fcntl-open/src.c b/tests/fcntl-open/src.c
new file mode 100644
index 00000000..52d2e7e4
--- /dev/null
+++ b/tests/fcntl-open/src.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+
+int main() {
+  struct stat s;
+  int modes[] = {O_RDONLY, O_WRONLY, O_RDWR};
+  char nonexistent_name[] = "/noexist-##";
+
+  for (int i = 0; i < 3; i++) {
+    for (int j = 0; j < 16; j++) {
+      int flags = modes[i];
+      if (j & 0x1) flags |= O_CREAT;
+      if (j & 0x2) flags |= O_EXCL;
+      if (j & 0x4) flags |= O_TRUNC;
+      if (j & 0x8) flags |= O_APPEND;
+
+      printf("EXISTING FILE %d,%d\n", i, j);
+      printf("success: %d\n", open("/test-file", flags, 0777) != -1);
+      printf("errno: %d\n", errno);
+      stat("/test-file", &s);
+      printf("st_mode: 0%o\n", s.st_mode & 037777777000);
+      memset(&s, 0, sizeof s);
+      printf("\n");
+      errno = 0;
+
+      printf("EXISTING FOLDER %d,%d\n", i, j);
+      printf("success: %d\n", open("/test-folder", flags, 0777) != -1);
+      printf("errno: %d\n", errno);
+      stat("/test-folder", &s);
+      printf("st_mode: 0%o\n", s.st_mode & 037777777000);
+      memset(&s, 0, sizeof s);
+      printf("\n");
+      errno = 0;
+
+      nonexistent_name[9] = 'a' + i;
+      nonexistent_name[10] = 'a' + j;
+      printf("NON-EXISTING %d,%d\n", i, j);
+      printf("success: %d\n", open(nonexistent_name, flags, 0777) != -1);
+      printf("errno: %d\n", errno);
+      stat(nonexistent_name, &s);
+      printf("st_mode: 0%o\n", s.st_mode & 037777777000);
+      memset(&s, 0, sizeof s);
+      printf("\n");
+      errno = 0;
+    }
+  }
+
+  printf("CREAT\n");
+  printf("success: %d\n", creat("/creat-me", 0777) != -1);
+  printf("errno: %d\n", errno);
+
+  return 0;
+}
diff --git a/tests/fcntl/output.txt b/tests/fcntl/output.txt
new file mode 100644
index 00000000..1077e89b
--- /dev/null
+++ b/tests/fcntl/output.txt
@@ -0,0 +1,42 @@
+F_DUPFD: 100
+errno: 0
+
+F_DUPFD/error1: -1
+errno: 9
+
+F_DUPFD/error2: -1
+errno: 22
+
+F_GETFD: 0
+errno: 0
+
+F_SETFD: 0
+errno: 0
+
+F_GETFL: 2
+errno: 0
+
+F_SETFL: 0
+errno: 0
+
+F_GETFL/2: 0x402
+errno: 0
+
+F_GETLK: 0
+errno: 0
+lk.l_type == F_UNLCK: 1
+
+F_SETLK: 0
+errno: 0
+
+F_SETLKW: 0
+errno: 0
+
+F_SETOWN: -1
+errno: 22
+
+F_GETOWN: -1
+errno: 22
+
+INVALID: -1
+errno: 22
diff --git a/tests/fcntl/src.c b/tests/fcntl/src.c
new file mode 100644
index 00000000..1e9a1536
--- /dev/null
+++ b/tests/fcntl/src.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+
+int main() {
+  int f = open("/test", O_RDWR, 0777);
+
+  printf("F_DUPFD: %d\n", fcntl(f, F_DUPFD, 100));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_DUPFD/error1: %d\n", fcntl(50, F_DUPFD, 200));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_DUPFD/error2: %d\n", fcntl(f, F_DUPFD, -1));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_GETFD: %d\n", fcntl(f, F_GETFD));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_SETFD: %d\n", fcntl(f, F_SETFD));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_GETFL: %d\n", fcntl(f, F_GETFL));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_SETFL: %d\n", fcntl(f, F_SETFL, O_APPEND));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_GETFL/2: %#x\n", fcntl(f, F_GETFL));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  flock lk;
+  lk.l_type = 42;
+  printf("F_GETLK: %d\n", fcntl(f, F_GETLK, &lk));
+  printf("errno: %d\n", errno);
+  printf("lk.l_type == F_UNLCK: %d\n", lk.l_type == F_UNLCK);
+  printf("\n");
+  errno = 0;
+
+  printf("F_SETLK: %d\n", fcntl(f, F_SETLK, &lk));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_SETLKW: %d\n", fcntl(f, F_SETLK, &lk));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_SETOWN: %d\n", fcntl(f, F_SETOWN, 123));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("F_GETOWN: %d\n", fcntl(f, F_GETOWN));
+  printf("errno: %d\n", errno);
+  printf("\n");
+  errno = 0;
+
+  printf("INVALID: %d\n", fcntl(f, 123));
+  printf("errno: %d\n", errno);
+
+  return 0;
+}
diff --git a/tests/runner.py b/tests/runner.py
index 27c19867..4a91f59e 100644
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -2173,6 +2173,43 @@ if 'benchmark' not in sys.argv:
       expected = open(path_from_root('tests', 'stat', 'output.txt'), 'r').read()
       self.do_test(src, expected, post_build=addPreRun)
 
+    def test_fcntl(self):
+      def addPreRun(filename):
+        src = open(filename, 'r').read().replace(
+          '// {{PRE_RUN_ADDITIONS}}',
+          "FS.createDataFile('/', 'test', 'abcdef', true, true);"
+        )
+        open(filename, 'w').write(src)
+      src = open(path_from_root('tests', 'fcntl', 'src.c'), 'r').read()
+      expected = open(path_from_root('tests', 'fcntl', 'output.txt'), 'r').read()
+      self.do_test(src, expected, post_build=addPreRun)
+
+    def test_fcntl_open(self):
+      def addPreRun(filename):
+        src = open(filename, 'r').read().replace(
+          '// {{PRE_RUN_ADDITIONS}}',
+          '''
+            FS.createDataFile('/', 'test-file', 'abcdef', true, true);
+            FS.createFolder('/', 'test-folder', true, true);
+            FS.root.write = true;
+          '''
+        )
+        open(filename, 'w').write(src)
+      src = open(path_from_root('tests', 'fcntl-open', 'src.c'), 'r').read()
+      expected = open(path_from_root('tests', 'fcntl-open', 'output.txt'), 'r').read()
+      self.do_test(src, expected, post_build=addPreRun)
+
+    def test_fcntl_misc(self):
+      def addPreRun(filename):
+        src = open(filename, 'r').read().replace(
+          '// {{PRE_RUN_ADDITIONS}}',
+          "FS.createDataFile('/', 'test', 'abcdef', true, true);"
+        )
+        open(filename, 'w').write(src)
+      src = open(path_from_root('tests', 'fcntl-misc', 'src.c'), 'r').read()
+      expected = open(path_from_root('tests', 'fcntl-misc', 'output.txt'), 'r').read()
+      self.do_test(src, expected, post_build=addPreRun)
+
     def test_statvfs(self):
       src = r'''
         #include <stdio.h>