1// Copyright (c) 2012, Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8//     * Redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer.
10//     * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14//     * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// mkdtemp() wasn't declared in <stdlib.h> until NDK r9b due to a simple
31// packaging bug (the function has always been implemented in all versions
32// of the C library). This header is provided to build Breakpad with earlier
33// NDK revisions (e.g. the one used by Chromium). It may be removed in the
34// future once all major projects upgrade to use a more recent NDK.
35//
36// The reason this is inlined here is to avoid linking a new object file
37// into each unit test program (i.e. keep build files simple).
38
39#ifndef GOOGLE_BREAKPAD_COMMON_ANDROID_TESTING_MKDTEMP_H
40#define GOOGLE_BREAKPAD_COMMON_ANDROID_TESTING_MKDTEMP_H
41
42#include <assert.h>
43#include <errno.h>
44#include <stdlib.h>
45#include <stdio.h>
46#include <string.h>
47#include <sys/stat.h>
48
49// Using a macro renaming trick here is necessary when building against
50// NDK r9b. Otherwise the compiler will complain that calls to mkdtemp()
51// are ambiguous.
52#define mkdtemp breakpad_mkdtemp
53
54namespace {
55
56char* breakpad_mkdtemp(char* path) {
57  if (path == NULL) {
58    errno = EINVAL;
59    return NULL;
60  }
61
62  // 'path' must be terminated with six 'X'
63  const char kSuffix[] = "XXXXXX";
64  const size_t kSuffixLen = strlen(kSuffix);
65  char* path_end = path + strlen(path);
66
67  if (static_cast<size_t>(path_end - path) < kSuffixLen ||
68      memcmp(path_end - kSuffixLen, kSuffix, kSuffixLen) != 0) {
69    errno = EINVAL;
70    return NULL;
71  }
72
73  // If 'path' contains a directory separator, check that it exists to
74  // avoid looping later.
75  char* sep = strrchr(path, '/');
76  if (sep != NULL) {
77    struct stat st;
78    int ret;
79    *sep = '\0';  // temporarily zero-terminate the dirname.
80    ret = stat(path, &st);
81    *sep = '/';   // restore full path.
82    if (ret < 0)
83      return NULL;
84    if (!S_ISDIR(st.st_mode)) {
85      errno = ENOTDIR;
86      return NULL;
87    }
88  }
89
90  // Loop. On each iteration, replace the XXXXXX suffix with a random
91  // number.
92  int tries;
93  for (tries = 128; tries > 0; tries--) {
94    int random = rand() % 1000000;
95
96    snprintf(path_end - kSuffixLen, kSuffixLen + 1, "%0d", random);
97    if (mkdir(path, 0700) == 0)
98      return path;  // Success
99
100    if (errno != EEXIST)
101      return NULL;
102  }
103
104  assert(errno == EEXIST);
105  return NULL;
106}
107
108}  // namespace
109
110#endif  // GOOGLE_BREAKPAD_COMMON_ANDROID_TESTING_MKDTEMP_H
111