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_libc_support.h" |
41 | #include "third_party/lss/linux_syscall_support.h" |
42 | |
43 | namespace google_breakpad { |
44 | |
45 | // A class for enumerating a directory without using diropen/readdir or other |
46 | // functions which may allocate memory. |
47 | class DirectoryReader { |
48 | public: |
49 | DirectoryReader(int fd) |
50 | : fd_(fd), |
51 | buf_used_(0) { |
52 | } |
53 | |
54 | // Return the next entry from the directory |
55 | // name: (output) the NUL terminated entry name |
56 | // |
57 | // Returns true iff successful (false on EOF). |
58 | // |
59 | // After calling this, one must call |PopEntry| otherwise you'll get the same |
60 | // entry over and over. |
61 | bool GetNextEntry(const char** name) { |
62 | struct kernel_dirent* const dent = |
63 | reinterpret_cast<kernel_dirent*>(buf_); |
64 | |
65 | if (buf_used_ == 0) { |
66 | // need to read more entries. |
67 | const int n = sys_getdents(fd_, dent, sizeof(buf_)); |
68 | if (n < 0) { |
69 | return false; |
70 | } else if (n == 0) { |
71 | hit_eof_ = true; |
72 | } else { |
73 | buf_used_ += n; |
74 | } |
75 | } |
76 | |
77 | if (buf_used_ == 0 && hit_eof_) |
78 | return false; |
79 | |
80 | assert(buf_used_ > 0); |
81 | |
82 | *name = dent->d_name; |
83 | return true; |
84 | } |
85 | |
86 | void PopEntry() { |
87 | if (!buf_used_) |
88 | return; |
89 | |
90 | const struct kernel_dirent* const dent = |
91 | reinterpret_cast<kernel_dirent*>(buf_); |
92 | |
93 | buf_used_ -= dent->d_reclen; |
94 | my_memmove(buf_, buf_ + dent->d_reclen, buf_used_); |
95 | } |
96 | |
97 | private: |
98 | const int fd_; |
99 | bool hit_eof_; |
100 | unsigned buf_used_; |
101 | uint8_t buf_[sizeof(struct kernel_dirent) + NAME_MAX + 1]; |
102 | }; |
103 | |
104 | } // namespace google_breakpad |
105 | |
106 | #endif // CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_ |
107 | |