Update temp file handling and use a single function to do all

the heavy lifting (most of the heavy lifting stolen from glibc,
but reduced a bit).

1 files changed, 187 insertions, 0 deletions

diff --git a/libc/misc/internals/tempname.c b/libc/misc/internals/tempname.c
new file mode 100644
index 000000000..3c43f9b85
--- /dev/null
+++ b/libc/misc/internals/tempname.c
@@ -0,0 +1,187 @@
+/* Copyright (C) 1991,92,93,94,95,96,97,98,99 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+/* Return nonzero if DIR is an existent directory.  */
+static int direxists (const char *dir)
+{
+    struct stat buf;
+    return stat(dir, &buf) == 0 && S_ISDIR (buf.st_mode);
+}
+
+/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
+   non-null and exists, uses it; otherwise uses the first of $TMPDIR,
+   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable
+   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and
+   doesn't exist, none of the searched dirs exists, or there's not
+   enough space in TMPL. */
+int __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
+	       int try_tmpdir)
+{
+    //const char *d;
+    size_t dlen, plen;
+
+    if (!pfx || !pfx[0])
+    {
+	pfx = "file";
+	plen = 4;
+    }
+    else
+    {
+	plen = strlen (pfx);
+	if (plen > 5)
+	    plen = 5;
+    }
+
+#if 0
+    if (try_tmpdir)
+    {
+	d = __secure_getenv ("TMPDIR");
+	if (d != NULL && direxists (d))
+	    dir = d;
+	else if (dir != NULL && direxists (dir))
+	    /* nothing */ ;
+	else
+	    dir = NULL;
+    }
+#endif	
+    if (dir == NULL)
+    {
+	if (direxists (P_tmpdir))
+	    dir = P_tmpdir;
+	else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
+	    dir = "/tmp";
+	else
+	{
+	    __set_errno (ENOENT);
+	    return -1;
+	}
+    }
+
+    dlen = strlen (dir);
+    while (dlen > 1 && dir[dlen - 1] == '/')
+	dlen--;			/* remove trailing slashes */
+
+    /* check we have room for "${dir}/${pfx}XXXXXX\0" */
+    if (tmpl_len < dlen + 1 + plen + 6 + 1)
+    {
+	__set_errno (EINVAL);
+	return -1;
+    }
+
+    sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
+    return 0;
+}
+
+/* These are the characters used in temporary filenames.  */
+static const char letters[] =
+"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+/* Generate a temporary file name based on TMPL.  TMPL must match the
+   rules for mk[s]temp (i.e. end in "XXXXXX").  The name constructed
+   does not exist at the time of the call to __gen_tempname.  TMPL is
+   overwritten with the result.  If OPENIT is nonzero, creates the
+   file and returns a read-write fd; the file is mode 0600 modulo
+   umask.  If LARGEFILE is nonzero, uses open64() instead of open().
+
+   We use a clever algorithm to get hard-to-predict names. */
+int __gen_tempname (char *tmpl, int openit)
+{
+    int len;
+    char *XXXXXX;
+    static uint64_t value;
+    struct timeval tv;
+    int count, fd;
+    int save_errno = errno;
+
+    len = strlen (tmpl);
+    if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
+    {
+	__set_errno (EINVAL);
+	return -1;
+    }
+
+    /* This is where the Xs start.  */
+    XXXXXX = &tmpl[len - 6];
+
+    /* Get some more or less random data.  */
+    gettimeofday (&tv, NULL);
+    value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
+
+    for (count = 0; count < TMP_MAX; value += 7777, ++count)
+    {
+	uint64_t v = value;
+
+	/* Fill in the random bits.  */
+	XXXXXX[0] = letters[v % 62];
+	v /= 62;
+	XXXXXX[1] = letters[v % 62];
+	v /= 62;
+	XXXXXX[2] = letters[v % 62];
+	v /= 62;
+	XXXXXX[3] = letters[v % 62];
+	v /= 62;
+	XXXXXX[4] = letters[v % 62];
+	v /= 62;
+	XXXXXX[5] = letters[v % 62];
+
+	if (openit)
+	{
+	    fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL, 0600);
+	    if (fd >= 0)
+	    {
+		__set_errno (save_errno);
+		return fd;
+	    }
+	    else if (errno != EEXIST)
+		/* Any other error will apply also to other names we might
+		   try, and there are 2^32 or so of them, so give up now. */
+		return -1;
+	}
+	else
+	{
+	    struct stat st;
+	    if (stat (tmpl, &st) < 0)
+	    {
+		if (errno == ENOENT)
+		{
+		    __set_errno (save_errno);
+		    return 0;
+		}
+		else
+		    /* Give up now. */
+		    return -1;
+	    }
+	}
+    }
+
+    /* We got out of the loop because we ran out of combinations to try.  */
+    __set_errno (EEXIST);
+    return -1;
+}