diff --git a/libc/inet/getaddrinfo.c b/libc/inet/getaddrinfo.c
index b61d69c..168adb1 100644
--- a/libc/inet/getaddrinfo.c
+++ b/libc/inet/getaddrinfo.c
@@ -308,7 +308,7 @@ gaih_local(const char *name, const struct gaih_service *service,
 		char *buf = ((struct sockaddr_un *)ai->ai_addr)->sun_path;
 
 		if (__path_search(buf, L_tmpnam, NULL, NULL, 0) != 0
-		 || __gen_tempname(buf, __GT_NOCREATE, 0) != 0
+		 || __gen_tempname(buf, __GT_NOCREATE, 0, 0) != 0
 		) {
 			return -EAI_SYSTEM;
 		}
diff --git a/libc/misc/internals/tempname.c b/libc/misc/internals/tempname.c
index 18fd823..edcc31c 100644
--- a/libc/misc/internals/tempname.c
+++ b/libc/misc/internals/tempname.c
@@ -177,7 +177,7 @@ static void brain_damaged_fillrand(unsigned char *buf, unsigned int len)
    __GT_DIR:            create a directory with given mode.
 
 */
-int attribute_hidden __gen_tempname (char *tmpl, int kind, mode_t mode)
+int attribute_hidden __gen_tempname (char *tmpl, int kind, int flags, mode_t mode)
 {
     char *XXXXXX;
     unsigned int i;
@@ -219,11 +219,11 @@ int attribute_hidden __gen_tempname (char *tmpl, int kind, mode_t mode)
 			fd = 0;
 		}
 	    case __GT_FILE:
-		fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL, mode);
+		fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);
 		break;
 #if defined __UCLIBC_HAS_LFS__
 	    case __GT_BIGFILE:
-		fd = open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, mode);
+		fd = open64 (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);
 		break;
 #endif
 	    case __GT_DIR:
diff --git a/libc/misc/internals/tempname.h b/libc/misc/internals/tempname.h
index e75b632..edfe26d 100644
--- a/libc/misc/internals/tempname.h
+++ b/libc/misc/internals/tempname.h
@@ -10,7 +10,7 @@ extern int ___path_search (char *tmpl, size_t tmpl_len, const char *dir,
 	        const char *pfx /*, int try_tmpdir */) attribute_hidden;
 #define __path_search(tmpl, tmpl_len, dir, pfx, try_tmpdir) ___path_search(tmpl, tmpl_len, dir, pfx)
 
-extern int __gen_tempname (char *__tmpl, int __kind, mode_t mode) attribute_hidden;
+extern int __gen_tempname (char *__tmpl, int __kind, int flags, mode_t mode) attribute_hidden;
 
 /* The __kind argument to __gen_tempname may be one of: */
 #define __GT_FILE     0       /* create a file */
diff --git a/libc/stdio/tempnam.c b/libc/stdio/tempnam.c
index 232ed02..74bb26e 100644
--- a/libc/stdio/tempnam.c
+++ b/libc/stdio/tempnam.c
@@ -35,7 +35,7 @@ tempnam (const char *dir, const char *pfx)
   if (__path_search (buf, FILENAME_MAX, dir, pfx, 1))
     return NULL;
 
-  if (__gen_tempname (buf, __GT_NOCREATE, 0))
+  if (__gen_tempname (buf, __GT_NOCREATE, 0, 0))
     return NULL;
 
   return strdup (buf);
diff --git a/libc/stdio/tmpfile.c b/libc/stdio/tmpfile.c
index a9bf474..83c85b5 100644
--- a/libc/stdio/tmpfile.c
+++ b/libc/stdio/tmpfile.c
@@ -35,7 +35,7 @@ FILE * tmpfile (void)
 
     if (__path_search (buf, FILENAME_MAX, NULL, "tmpf", 0))
 	return NULL;
-    fd = __gen_tempname (buf, __GT_FILE, S_IRUSR | S_IWUSR);
+    fd = __gen_tempname (buf, __GT_FILE, 0, S_IRUSR | S_IWUSR);
     if (fd < 0)
 	return NULL;
 
diff --git a/libc/stdio/tmpnam.c b/libc/stdio/tmpnam.c
index 88b9bff..ffed862 100644
--- a/libc/stdio/tmpnam.c
+++ b/libc/stdio/tmpnam.c
@@ -40,7 +40,7 @@ tmpnam (char *s)
 			0))
     return NULL;
 
-  if (__builtin_expect (__gen_tempname (tmpbuf, __GT_NOCREATE, 0), 0))
+  if (__builtin_expect (__gen_tempname (tmpbuf, __GT_NOCREATE, 0, 0), 0))
     return NULL;
 
   if (s == NULL)
diff --git a/libc/stdio/tmpnam_r.c b/libc/stdio/tmpnam_r.c
index 8cde84d..bfd60a4 100644
--- a/libc/stdio/tmpnam_r.c
+++ b/libc/stdio/tmpnam_r.c
@@ -27,7 +27,7 @@ char * tmpnam_r (char *s)
 
     if (__path_search (s, L_tmpnam, NULL, NULL, 0))
 	return NULL;
-    if (__gen_tempname (s, __GT_NOCREATE, 0))
+    if (__gen_tempname (s, __GT_NOCREATE, 0, 0))
 	return NULL;
 
     return s;
diff --git a/libc/stdlib/mkdtemp.c b/libc/stdlib/mkdtemp.c
index da7598a..e6d4a36 100644
--- a/libc/stdlib/mkdtemp.c
+++ b/libc/stdlib/mkdtemp.c
@@ -29,7 +29,7 @@
    (This function comes from OpenBSD.) */
 char * mkdtemp (char *template)
 {
-  if (__gen_tempname (template, __GT_DIR, S_IRUSR | S_IWUSR | S_IXUSR))
+  if (__gen_tempname (template, __GT_DIR, 0, S_IRUSR | S_IWUSR | S_IXUSR))
     return NULL;
   else
     return template;
diff --git a/libc/stdlib/mkostemp.c b/libc/stdlib/mkostemp.c
index 0369235..912be30 100644
--- a/libc/stdlib/mkostemp.c
+++ b/libc/stdlib/mkostemp.c
@@ -17,6 +17,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <fcntl.h>
 #include "../misc/internals/tempname.h"
 
 /* Generate a unique temporary file name from TEMPLATE.
@@ -26,5 +27,6 @@
 int
 mkostemp (char *template, int flags)
 {
-  return __gen_tempname (template, __GT_FILE, flags);
+  flags -= flags & O_ACCMODE; /* Remove O_RDONLY, O_WRONLY, and O_RDWR. */
+  return __gen_tempname (template, __GT_FILE, flags, S_IRUSR | S_IWUSR);
 }
diff --git a/libc/stdlib/mkostemp64.c b/libc/stdlib/mkostemp64.c
index d21def5..c6d6d84 100644
--- a/libc/stdlib/mkostemp64.c
+++ b/libc/stdlib/mkostemp64.c
@@ -27,5 +27,5 @@
 int
 mkostemp64 (char *template, int flags)
 {
-  return __gen_tempname (template, __GT_BIGFILE, flags | O_LARGEFILE);
+  return __gen_tempname (template, __GT_BIGFILE, flags | O_LARGEFILE, S_IRUSR | S_IWUSR | S_IXUSR);
 }
diff --git a/libc/stdlib/mkstemp.c b/libc/stdlib/mkstemp.c
index 61c7175..a3a1595 100644
--- a/libc/stdlib/mkstemp.c
+++ b/libc/stdlib/mkstemp.c
@@ -26,5 +26,5 @@
    Then open the file and return a fd. */
 int mkstemp (char *template)
 {
-    return __gen_tempname (template, __GT_FILE, S_IRUSR | S_IWUSR);
+    return __gen_tempname (template, __GT_FILE, 0, S_IRUSR | S_IWUSR);
 }
diff --git a/libc/stdlib/mkstemp64.c b/libc/stdlib/mkstemp64.c
index e29be2d..6f2ee3e 100644
--- a/libc/stdlib/mkstemp64.c
+++ b/libc/stdlib/mkstemp64.c
@@ -26,5 +26,5 @@
    Then open the file and return a fd. */
 int mkstemp64 (char *template)
 {
-    return __gen_tempname (template, __GT_BIGFILE, S_IRUSR | S_IWUSR);
+    return __gen_tempname (template, __GT_BIGFILE, 0, S_IRUSR | S_IWUSR);
 }
diff --git a/libc/stdlib/mktemp.c b/libc/stdlib/mktemp.c
index edd001d..1ff93da 100644
--- a/libc/stdlib/mktemp.c
+++ b/libc/stdlib/mktemp.c
@@ -24,7 +24,7 @@
  * they are replaced with a string that makes the filename unique.  */
 char *mktemp(char *template)
 {
-	if (__gen_tempname (template, __GT_NOCREATE, 0) < 0)
+	if (__gen_tempname (template, __GT_NOCREATE, 0, 0) < 0)
 		/* We return the null string if we can't find a unique file name.  */
 		template[0] = '\0';
 
diff --git a/libpthread/nptl/sem_open.c b/libpthread/nptl/sem_open.c
index 1b36164..3a72079 100644
--- a/libpthread/nptl/sem_open.c
+++ b/libpthread/nptl/sem_open.c
@@ -336,7 +336,7 @@ sem_open (const char *name, int oflag, ...)
       mempcpy (mempcpy (tmpfname, mountpoint.dir, mountpoint.dirlen),
 	"XXXXXX", 7);
 
-      fd = __gen_tempname (tmpfname, __GT_FILE, mode);
+      fd = __gen_tempname (tmpfname, __GT_FILE, 0, mode);
       if (fd == -1)
         return SEM_FAILED;
 
diff --git a/test/.gitignore b/test/.gitignore
index 8f32031..5944f0a 100644
--- a/test/.gitignore
+++ b/test/.gitignore
@@ -274,6 +274,8 @@ stdlib/testarc4random
 stdlib/testatexit
 stdlib/test-canon
 stdlib/test-canon2
+stdlib/test-mkostemp-O_CLOEXEC
+stdlib/test-mkostemp-child
 stdlib/teston_exit
 stdlib/teststrtol
 stdlib/teststrtoq
diff --git a/test/stdlib/test-mkostemp-O_CLOEXEC.c b/test/stdlib/test-mkostemp-O_CLOEXEC.c
new file mode 100644
index 0000000..5652086
--- /dev/null
+++ b/test/stdlib/test-mkostemp-O_CLOEXEC.c
@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <errno.h>
+
+int main(int argc, char *argv[]) {
+    int fd, status;
+    char buff[5];
+    char template[] = "/tmp/test-mkostemp.XXXXXX";
+
+    fd = mkostemp(template, O_CLOEXEC);
+    unlink(template);
+
+    snprintf(buff, 5, "%d", fd);
+
+    if(!fork())
+        if(execl("./test-mkostemp-child", "test-mkostemp-child", buff, NULL) == -1)
+            exit(EXIT_FAILURE);
+
+    wait(&status);
+
+    memset(buff, 0, 5);
+    lseek(fd, 0, SEEK_SET);
+    errno = 0;
+    if(read(fd, buff, 5) == -1)
+        exit(EXIT_FAILURE);
+
+    if(!strncmp(buff, "test", 5))
+        exit(EXIT_FAILURE);
+    else
+        exit(EXIT_SUCCESS);
+
+    close(fd);
+    exit(EXIT_SUCCESS);
+}
diff --git a/test/stdlib/test-mkostemp-child.c b/test/stdlib/test-mkostemp-child.c
new file mode 100644
index 0000000..708bd80
--- /dev/null
+++ b/test/stdlib/test-mkostemp-child.c
@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[]) {
+    int fd;
+
+    /* This file gets built and run as a test, but its
+     * really just a helper for test-mkostemp-O_CLOEXEC.c.
+     * So, we'll always return succcess.
+     */
+    if(argc != 2)
+        exit(EXIT_SUCCESS);
+
+    sscanf(argv[1], "%d", &fd);
+
+    if(write(fd, "test\0", 5) == -1)
+        ; /* Don't Panic!  Failure is okay here. */
+
+    close(fd);
+    exit(EXIT_SUCCESS);
+}
