Simplify and improve tempnam() and tmpnam().

They're both obsolescent in POSIX.1-2008, and you really shouldn't be
using them, but since we can't actually delete them...

This change makes them both obey $TMPDIR if set, and fall back to
/data/local/tmp otherwise. That's as good as we've managed for anything
else such as tmpfile(3).

Also add some tests.

Bug: http://b/174682340
Test: treehugger
Change-Id: Ieef99dcc2062f84b2b7cbae046787fdfe975e772

6 files changed, 47 insertions, 188 deletions

diff --git a/libc/Android.bp b/libc/Android.bp
index 4d63751f6..447d17b75 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -506,8 +506,6 @@ cc_library_static {
         "upstream-openbsd/lib/libc/stdio/open_wmemstream.c",
         "upstream-openbsd/lib/libc/stdio/rget.c",
         "upstream-openbsd/lib/libc/stdio/setvbuf.c",
-        "upstream-openbsd/lib/libc/stdio/tempnam.c",
-        "upstream-openbsd/lib/libc/stdio/tmpnam.c",
         "upstream-openbsd/lib/libc/stdio/ungetc.c",
         "upstream-openbsd/lib/libc/stdio/ungetwc.c",
         "upstream-openbsd/lib/libc/stdio/vasprintf.c",
diff --git a/libc/NOTICE b/libc/NOTICE
index 58d66795f..f7d73d8f8 100644
--- a/libc/NOTICE
+++ b/libc/NOTICE
@@ -2368,38 +2368,6 @@ SUCH DAMAGE.
 
 -------------------------------------------------------------------
 
-Copyright (c) 1990, 1993, 1994
-   The Regents of the University of California.  All rights reserved.
-
-This code is derived from software contributed to Berkeley by
-Chris Torek.
-
-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.
-
--------------------------------------------------------------------
-
 Copyright (c) 1991 The Regents of the University of California.
 All rights reserved.
 
diff --git a/libc/bionic/tmpfile.cpp b/libc/bionic/tmpfile.cpp
index d7ce897e1..3d04610a4 100644
--- a/libc/bionic/tmpfile.cpp
+++ b/libc/bionic/tmpfile.cpp
@@ -35,6 +35,7 @@
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -99,3 +100,48 @@ FILE* tmpfile() {
   return fp;
 }
 __strong_alias(tmpfile64, tmpfile);
+
+char* tempnam(const char* dir, const char* prefix) {
+  // This function is a terrible idea, marked deprecated in our headers,
+  // and marked obsolescent by POSIX.1-2008, but we make some effort anyway
+  // since we can't easily remove it...
+
+  // $TMPDIR overrides any directory passed in.
+  char* tmpdir = getenv("TMPDIR");
+  if (tmpdir != nullptr) dir = tmpdir;
+
+  // If we still have no directory, we'll give you a default.
+  // It's useless for apps, but good enough for the shell.
+  if (dir == nullptr) dir = "/data/local/tmp";
+
+  // Default prefix?
+  if (prefix == nullptr) prefix = "tempnam.";
+
+  // Make up a mktemp(3) template and defer to it for the real work.
+  char* path = nullptr;
+  if (asprintf(&path, "%s/%sXXXXXXXXXX", dir, prefix) == -1) return nullptr;
+  if (mktemp(path) == nullptr) {
+    free(path);
+    return nullptr;
+  }
+  return path;
+}
+
+char* tmpnam(char* s) {
+  // This function is a terrible idea, marked deprecated in our headers,
+  // and marked obsolescent by POSIX-1.2008, but we make some effort anyway
+  // since we can't easily remove it...
+
+  // Default buffer?
+  static char buf[L_tmpnam];
+  if (s == nullptr) s = buf;
+
+  // Use $TMPDIR if set, or fall back to /data/local/tmp otherwise.
+  // Useless for apps, but good enough for the shell.
+  const char* dir = getenv("TMPDIR");
+  if (dir == nullptr) dir = "/data/local/tmp";
+
+  // Make up a mktemp(3) template and defer to it for the real work.
+  snprintf(s, L_tmpnam, "%s/tmpnam.XXXXXXXXXX", dir);
+  return mktemp(s);
+}
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 1bf578c1d..9de12a47f 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -160,7 +160,7 @@ int sprintf(char* __s, const char* __fmt, ...)
 int vsprintf(char* __s, const char* __fmt, va_list __args)
     __printflike(2, 0) __warnattr_strict("vsprintf is often misused; please use vsnprintf");
 char* tmpnam(char* __s)
-    __warnattr("tempnam is unsafe, use mkstemp or tmpfile instead");
+    __warnattr("tmpnam is unsafe, use mkstemp or tmpfile instead");
 #define P_tmpdir "/tmp/" /* deprecated */
 char* tempnam(const char* __dir, const char* __prefix)
     __warnattr("tempnam is unsafe, use mkstemp or tmpfile instead");
diff --git a/libc/upstream-openbsd/lib/libc/stdio/tempnam.c b/libc/upstream-openbsd/lib/libc/stdio/tempnam.c
deleted file mode 100644
index d2c848c8f..000000000
--- a/libc/upstream-openbsd/lib/libc/stdio/tempnam.c
+++ /dev/null
@@ -1,100 +0,0 @@
-/*	$OpenBSD: tempnam.c,v 1.20 2017/11/28 06:55:49 tb Exp $ */
-/*
- * Copyright (c) 1988, 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 <errno.h>
-#include <limits.h>
-#include <paths.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-__warn_references(tempnam,
-    "tempnam() possibly used unsafely; consider using mkstemp()");
-
-char *
-tempnam(const char *dir, const char *pfx)
-{
-	int sverrno, len;
-	char *f, *name;
-
-	if (!(name = malloc(PATH_MAX)))
-		return(NULL);
-
-	if (!pfx)
-		pfx = "tmp.";
-
-	if (issetugid() == 0 && (f = getenv("TMPDIR")) && *f != '\0') {
-		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
-		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
-		if (len < 0 || len >= PATH_MAX) {
-			errno = ENAMETOOLONG;
-			goto fail;
-		}
-		if ((f = _mktemp(name)))
-			return(f);
-	}
-
-	if (dir != NULL) {
-		f = *dir ? (char *)dir : ".";
-		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
-		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
-		if (len < 0 || len >= PATH_MAX) {
-			errno = ENAMETOOLONG;
-			goto fail;
-		}
-		if ((f = _mktemp(name)))
-			return(f);
-	}
-
-	f = P_tmpdir;
-	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
-	if (len < 0 || len >= PATH_MAX) {
-		errno = ENAMETOOLONG;
-		goto fail;
-	}
-	if ((f = _mktemp(name)))
-		return(f);
-
-	f = _PATH_TMP;
-	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
-	if (len < 0 || len >= PATH_MAX) {
-		errno = ENAMETOOLONG;
-		goto fail;
-	}
-	if ((f = _mktemp(name)))
-		return(f);
-
-fail:
-	sverrno = errno;
-	free(name);
-	errno = sverrno;
-	return(NULL);
-}
diff --git a/libc/upstream-openbsd/lib/libc/stdio/tmpnam.c b/libc/upstream-openbsd/lib/libc/stdio/tmpnam.c
deleted file mode 100644
index 52cd43d94..000000000
--- a/libc/upstream-openbsd/lib/libc/stdio/tmpnam.c
+++ /dev/null
@@ -1,53 +0,0 @@
-/*	$OpenBSD: tmpnam.c,v 1.12 2017/11/28 06:55:49 tb Exp $ */
-/*-
- * Copyright (c) 1990, 1993, 1994
- *	The Regents of the University of California.  All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Chris Torek.
- *
- * 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 <stdio.h>
-#include <unistd.h>
-
-__warn_references(tmpnam,
-    "tmpnam() possibly used unsafely; consider using mkstemp()");
-
-char *
-tmpnam(char *s)
-{
-	static u_long tmpcount;
-	static char buf[L_tmpnam];
-
-	if (s == NULL)
-		s = buf;
-	(void)snprintf(s, L_tmpnam, "%stmp.%lu.XXXXXXXXX", P_tmpdir, tmpcount);
-	++tmpcount;
-	return (_mktemp(s));
-}