1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <errno.h> 34 #include <signal.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <sys/stat.h> 38 #include <sys/types.h> 39 #include <unistd.h> 40 41 #include "private/ErrnoRestorer.h" 42 #include "private/ScopedSignalBlocker.h" 43 44 static FILE* __tmpfile_dir(const char* tmp_dir) { 45 char* path = NULL; 46 if (asprintf(&path, "%s/tmp.XXXXXXXXXX", tmp_dir) == -1) { 47 return NULL; 48 } 49 50 int fd; 51 { 52 ScopedSignalBlocker ssb; 53 fd = mkstemp(path); 54 if (fd == -1) { 55 free(path); 56 return NULL; 57 } 58 59 // Unlink the file now so that it's removed when closed. 60 unlink(path); 61 free(path); 62 63 // Can we still use the file now it's unlinked? 64 // File systems without hard link support won't have the usual Unix semantics. 65 struct stat sb; 66 int rc = fstat(fd, &sb); 67 if (rc == -1) { 68 ErrnoRestorer errno_restorer; 69 close(fd); 70 return NULL; 71 } 72 } 73 74 // Turn the file descriptor into a FILE*. 75 FILE* fp = fdopen(fd, "w+"); 76 if (fp != NULL) { 77 return fp; 78 } 79 80 // Failure. Clean up. We already unlinked, so we just need to close. 81 ErrnoRestorer errno_restorer; 82 close(fd); 83 return NULL; 84 } 85 86 FILE* tmpfile() { 87 // TODO: get this app's temporary directory from the framework ("/data/data/app/cache"). 88 89 // $EXTERNAL_STORAGE turns out not to be very useful because it doesn't support hard links. 90 // This means we can't do the usual trick of calling unlink before handing the file back. 91 92 FILE* fp = __tmpfile_dir("/data/local/tmp"); 93 if (fp == NULL) { 94 // P_tmpdir is "/tmp/", but POSIX explicitly says that tmpdir(3) should try P_tmpdir before 95 // giving up. This is potentially useful for bionic on the host anyway. 96 fp = __tmpfile_dir(P_tmpdir); 97 } 98 return fp; 99 } 100 __strong_alias(tmpfile64, tmpfile); 101
