1 files changed, 50 insertions, 0 deletions
diff --git a/stdio/fdopen.c b/stdio/fdopen.c
new file mode 100644
index 0000000..0f786fa
--- /dev/null
+++ b/stdio/fdopen.c
@@ -0,0 +1,50 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/mem/mem.h"
+#include "libc/stdio/internal.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Allocates stream object for already-opened file descriptor.
+ *
+ * @param fd existing file descriptor or -1 for plain old buffer
+ * @param mode is passed to fopenflags()
+ * @return new stream or NULL w/ errno
+ * @error ENOMEM
+ */
+FILE *fdopen(int fd, const char *mode) {
+  FILE *f;
+  if ((f = calloc(1, sizeof(FILE)))) {
+    f->fd = fd;
+    f->bufmode = ischardev(fd) ? _IOLBF : _IOFBF;
+    f->iomode = fopenflags(mode);
+    f->size = BUFSIZ;
+    if ((f->buf = malloc(f->size))) {
+      if ((f->iomode & O_ACCMODE) != O_RDONLY) {
+        __fflush_register(f);
+      }
+      return f;
+    }
+    free(f);
+  }
+  return NULL;
+}