1 // Copyright 2022 Google LLC
2 //
3 // Redistribution and use in source and binary forms, with or without
4 // modification, are permitted provided that the following conditions are
5 // met:
6 //
7 // * Redistributions of source code must retain the above copyright
8 // notice, this list of conditions and the following disclaimer.
9 // * Redistributions in binary form must reproduce the above
10 // copyright notice, this list of conditions and the following disclaimer
11 // in the documentation and/or other materials provided with the
12 // distribution.
13 // * Neither the name of Google LLC nor the names of its
14 // contributors may be used to endorse or promote products derived from
15 // this software without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 // Utility class for creating a temporary file that is deleted in the
30 // destructor.
31
32 #ifdef HAVE_CONFIG_H
33 #include <config.h> // Must come first
34 #endif
35
36 #include "common/linux/scoped_tmpfile.h"
37
38 #include <fcntl.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <sys/types.h>
42 #include <unistd.h>
43
44 #include "common/linux/eintr_wrapper.h"
45
46 #if !defined(__ANDROID__)
47 #define TEMPDIR "/tmp"
48 #else
49 #define TEMPDIR "/data/local/tmp"
50 #endif
51
52 namespace google_breakpad {
53
54 ScopedTmpFile::ScopedTmpFile() = default;
55
~ScopedTmpFile()56 ScopedTmpFile::~ScopedTmpFile() {
57 if (fd_ >= 0) {
58 close(fd_);
59 fd_ = -1;
60 }
61 }
62
InitEmpty()63 bool ScopedTmpFile::InitEmpty() {
64 // Prevent calling Init when fd_ is already valid, leaking the file.
65 if (fd_ != -1) {
66 return false;
67 }
68
69 // Respect the TMPDIR environment variable.
70 const char* tempdir = getenv("TMPDIR");
71 if (!tempdir) {
72 tempdir = TEMPDIR;
73 }
74
75 // Create a temporary file that is not linked in to the filesystem, and that
76 // is only accessible by the current user.
77 fd_ = open(tempdir, O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
78
79 return fd_ >= 0;
80 }
81
InitString(const char * text)82 bool ScopedTmpFile::InitString(const char* text) {
83 return InitData(text, strlen(text));
84 }
85
InitData(const void * data,size_t data_len)86 bool ScopedTmpFile::InitData(const void* data, size_t data_len) {
87 if (!InitEmpty()) {
88 return false;
89 }
90
91 return SetContents(data, data_len);
92 }
93
SetContents(const void * data,size_t data_len)94 bool ScopedTmpFile::SetContents(const void* data, size_t data_len) {
95 ssize_t r = HANDLE_EINTR(write(fd_, data, data_len));
96 if (r != static_cast<ssize_t>(data_len)) {
97 return false;
98 }
99
100 return 0 == lseek(fd_, 0, SEEK_SET);
101 }
102
103 } // namespace google_breakpad
104