1 files changed, 58 insertions, 0 deletions
diff --git a/userland/libc/stdio/fdopen.c b/userland/libc/stdio/fdopen.c
new file mode 100644
index 0000000..9e7c7c6
--- /dev/null
+++ b/userland/libc/stdio/fdopen.c
@@ -0,0 +1,58 @@
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+// FIXME: All modes not implemented
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fdopen.html
+FILE *fdopen(int fildes, const char *mode) {
+  FILE *r = calloc(1, sizeof(FILE));
+  if (!r) {
+    errno = -ENOMEM;
+    return NULL;
+  }
+
+  for (; *mode; mode++) {
+    // r or rb
+    // Open file for reading.
+    // w or wb
+    // Truncate to zero length or create file for writing.
+    // a or ab
+    // Append; open or create file for writing at
+    // end-of-file.
+    switch (*mode) {
+    case 'r':
+      r->can_read = 1;
+      break;
+    case 'w':
+      r->can_write = 1;
+      break;
+    case 'a':
+      r->append = 1;
+      break;
+    }
+  }
+
+  struct stat s;
+  if (-1 == fstat(fildes, &s)) {
+    free(r);
+    errno = -EBADF;
+    return NULL;
+  }
+
+  r->read = read_fd;
+  r->write = write_fd;
+  r->seek = seek_fd;
+  r->has_error = 0;
+  r->is_eof = 0;
+  r->offset_in_file = 0;
+  r->file_size = s.st_size;
+  r->cookie = NULL;
+  r->fd = fildes;
+  r->read_buffer = NULL;
+  r->read_buffer_stored = 0;
+  r->fflush = fflush_fd;
+  r->has_control_over_the_fd = 0;
+  return r;
+}