1 /**
2  * Copyright © 2020 IBM Corporation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "temporary_file.hpp"
18 
19 #include <errno.h>  // for errno
20 #include <stdlib.h> // for mkstemp()
21 #include <string.h> // for strerror()
22 #include <unistd.h> // for close()
23 
24 #include <stdexcept>
25 #include <string>
26 
27 namespace phosphor::power::util
28 {
29 
30 namespace fs = std::filesystem;
31 
32 TemporaryFile::TemporaryFile()
33 {
34     // Build template path required by mkstemp()
35     std::string templatePath = fs::temp_directory_path() /
36                                "phosphor-power-XXXXXX";
37 
38     // Generate unique file name, create file, and open it.  The XXXXXX
39     // characters are replaced by mkstemp() to make the file name unique.
40     int fd = mkstemp(templatePath.data());
41     if (fd == -1)
42     {
43         throw std::runtime_error{
44             std::string{"Unable to create temporary file: "} + strerror(errno)};
45     }
46 
47     // Store path to temporary file
48     path = templatePath;
49 
50     // Close file descriptor
51     if (close(fd) == -1)
52     {
53         // Save errno value; will likely change when we delete temporary file
54         int savedErrno = errno;
55 
56         // Delete temporary file.  The destructor won't be called because the
57         // exception below causes this constructor to exit without completing.
58         remove();
59 
60         throw std::runtime_error{
61             std::string{"Unable to close temporary file: "} +
62             strerror(savedErrno)};
63     }
64 }
65 
66 TemporaryFile& TemporaryFile::operator=(TemporaryFile&& file)
67 {
68     // Verify not assigning object to itself (a = std::move(a))
69     if (this != &file)
70     {
71         // Delete temporary file owned by this object
72         remove();
73 
74         // Move temporary file path from other object, transferring ownership
75         path = std::move(file.path);
76 
77         // Clear path in other object; after move path is in unspecified state
78         file.path.clear();
79     }
80     return *this;
81 }
82 
83 void TemporaryFile::remove()
84 {
85     if (!path.empty())
86     {
87         // Delete temporary file from file system
88         fs::remove(path);
89 
90         // Clear path to indicate file has been deleted
91         path.clear();
92     }
93 }
94 
95 } // namespace phosphor::power::util
96