auto import from //depot/cupcake/@135843
diff --git a/libc/stdio/mktemp.c b/libc/stdio/mktemp.c
new file mode 100644
index 0000000..951f803
--- /dev/null
+++ b/libc/stdio/mktemp.c
@@ -0,0 +1,184 @@
+/* $OpenBSD: mktemp.c,v 1.19 2005/08/08 08:05:36 espie Exp $ */
+/*
+ * Copyright (c) 1987, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <unistd.h>
+
+static int _gettemp(char *, int *, int, int);
+
+extern uint32_t arc4random();
+
+int
+mkstemps(char *path, int slen)
+{
+ int fd;
+
+ return (_gettemp(path, &fd, 0, slen) ? fd : -1);
+}
+
+int
+mkstemp(char *path)
+{
+ int fd;
+
+ return (_gettemp(path, &fd, 0, 0) ? fd : -1);
+}
+
+char *
+mkdtemp(char *path)
+{
+ return(_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
+}
+
+char *_mktemp(char *);
+
+char *
+_mktemp(char *path)
+{
+ return(_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
+}
+
+__warn_references(mktemp,
+ "warning: mktemp() possibly used unsafely; consider using mkstemp()");
+
+char *
+mktemp(char *path)
+{
+ return(_mktemp(path));
+}
+
+
+static int
+_gettemp(char *path, int *doopen, int domkdir, int slen)
+{
+ char *start, *trv, *suffp;
+ struct stat sbuf;
+ int rval;
+ pid_t pid;
+
+ if (doopen && domkdir) {
+ errno = EINVAL;
+ return(0);
+ }
+
+ for (trv = path; *trv; ++trv)
+ ;
+ trv -= slen;
+ suffp = trv;
+ --trv;
+ if (trv < path) {
+ errno = EINVAL;
+ return (0);
+ }
+ pid = getpid();
+ while (trv >= path && *trv == 'X' && pid != 0) {
+ *trv-- = (pid % 10) + '0';
+ pid /= 10;
+ }
+ while (trv >= path && *trv == 'X') {
+ char c;
+
+ pid = (arc4random() & 0xffff) % (26+26);
+ if (pid < 26)
+ c = pid + 'A';
+ else
+ c = (pid - 26) + 'a';
+ *trv-- = c;
+ }
+ start = trv + 1;
+
+ /*
+ * check the target directory; if you have six X's and it
+ * doesn't exist this runs for a *very* long time.
+ */
+ if (doopen || domkdir) {
+ for (;; --trv) {
+ if (trv <= path)
+ break;
+ if (*trv == '/') {
+ *trv = '\0';
+ rval = stat(path, &sbuf);
+ *trv = '/';
+ if (rval != 0)
+ return(0);
+ if (!S_ISDIR(sbuf.st_mode)) {
+ errno = ENOTDIR;
+ return(0);
+ }
+ break;
+ }
+ }
+ }
+
+ for (;;) {
+ if (doopen) {
+ if ((*doopen =
+ open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
+ return(1);
+ if (errno != EEXIST)
+ return(0);
+ } else if (domkdir) {
+ if (mkdir(path, 0700) == 0)
+ return(1);
+ if (errno != EEXIST)
+ return(0);
+ } else if (lstat(path, &sbuf))
+ return(errno == ENOENT ? 1 : 0);
+
+ /* tricky little algorithm for backward compatibility */
+ for (trv = start;;) {
+ if (!*trv)
+ return (0);
+ if (*trv == 'Z') {
+ if (trv == suffp)
+ return (0);
+ *trv++ = 'a';
+ } else {
+ if (isdigit(*trv))
+ *trv = 'a';
+ else if (*trv == 'z') /* inc from z to A */
+ *trv = 'A';
+ else {
+ if (trv == suffp)
+ return (0);
+ ++*trv;
+ }
+ break;
+ }
+ }
+ }
+ /*NOTREACHED*/
+}