1 : // Copyright (c) 2009, 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 : #ifndef CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
31 : #define CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
32 :
33 : #include <stdint.h>
34 : #include <unistd.h>
35 : #include <limits.h>
36 : #include <assert.h>
37 : #include <errno.h>
38 : #include <string.h>
39 :
40 : #include "common/linux/linux_syscall_support.h"
41 :
42 : namespace google_breakpad {
43 :
44 : // A class for enumerating a directory without using diropen/readdir or other
45 : // functions which may allocate memory.
46 : class DirectoryReader {
47 : public:
48 0 : DirectoryReader(int fd)
49 : : fd_(fd),
50 0 : buf_used_(0) {
51 0 : }
52 :
53 : // Return the next entry from the directory
54 : // name: (output) the NUL terminated entry name
55 : //
56 : // Returns true iff successful (false on EOF).
57 : //
58 : // After calling this, one must call |PopEntry| otherwise you'll get the same
59 : // entry over and over.
60 0 : bool GetNextEntry(const char** name) {
61 : struct kernel_dirent* const dent =
62 0 : reinterpret_cast<kernel_dirent*>(buf_);
63 :
64 0 : if (buf_used_ == 0) {
65 : // need to read more entries.
66 0 : const int n = sys_getdents(fd_, dent, sizeof(buf_));
67 0 : if (n < 0) {
68 0 : return false;
69 0 : } else if (n == 0) {
70 0 : hit_eof_ = true;
71 : } else {
72 0 : buf_used_ += n;
73 : }
74 : }
75 :
76 0 : if (buf_used_ == 0 && hit_eof_)
77 0 : return false;
78 :
79 0 : assert(buf_used_ > 0);
80 :
81 0 : *name = dent->d_name;
82 0 : return true;
83 : }
84 :
85 0 : void PopEntry() {
86 0 : if (!buf_used_)
87 0 : return;
88 :
89 : const struct kernel_dirent* const dent =
90 0 : reinterpret_cast<kernel_dirent*>(buf_);
91 :
92 0 : buf_used_ -= dent->d_reclen;
93 0 : memmove(buf_, buf_ + dent->d_reclen, buf_used_);
94 : }
95 :
96 : private:
97 : const int fd_;
98 : bool hit_eof_;
99 : unsigned buf_used_;
100 : uint8_t buf_[sizeof(struct kernel_dirent) + NAME_MAX + 1];
101 : };
102 :
103 : } // namespace google_breakpad
104 :
105 : #endif // CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
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