1 files changed, 74 insertions, 0 deletions
diff --git a/stdio/fopen.c b/stdio/fopen.c
new file mode 100644
index 0000000..a5e0b05
--- /dev/null
+++ b/stdio/fopen.c
@@ -0,0 +1,74 @@
+/*-*- 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/stdio.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/o.h"
+
+static const char *fixpathname(const char *pathname, int flags) {
+  if ((flags & O_ACCMODE) == O_RDONLY && strcmp(pathname, "-") == 0) {
+    return "/dev/stdin";
+  } else if ((flags & O_ACCMODE) == O_WRONLY && strcmp(pathname, "-") == 0) {
+    return "/dev/stdout";
+  } else {
+    return pathname;
+  }
+}
+
+static int openpathname(const char *pathname, int flags, bool *out_noclose) {
+  if ((flags & O_ACCMODE) == O_RDONLY && strcmp(pathname, "/dev/stdin") == 0) {
+    *out_noclose = true;
+    return fileno(stdin);
+  } else if ((flags & O_ACCMODE) == O_WRONLY &&
+             strcmp(pathname, "/dev/stdout") == 0) {
+    *out_noclose = true;
+    return fileno(stdout);
+  } else {
+    *out_noclose = false;
+    return open(pathname, flags, 0666);
+  }
+}
+
+/**
+ * Opens file as stream object.
+ *
+ * @param pathname is a utf-8 ideally relative filename
+ * @param mode is the string mode/flag DSL see fopenflags()
+ * @return new object to be free'd by fclose() or NULL w/ errno
+ * @note microsoft unilaterally deprecated this function lool
+ */
+FILE *fopen(const char *pathname, const char *mode) {
+  FILE *f;
+  bool noclose;
+  int fd, flags;
+  flags = fopenflags(mode);
+  pathname = fixpathname(pathname, flags);
+  if ((fd = openpathname(pathname, flags, &noclose)) != -1) {
+    if ((f = fdopen(fd, mode)) != NULL) {
+      f->noclose = noclose;
+      return f;
+    } else {
+      if (!noclose) close(fd);
+      return NULL;
+    }
+  } else {
+    return NULL;
+  }
+}