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
43namespace google_breakpad {
44
45// A class for enumerating a directory without using diropen/readdir or other
46// functions which may allocate memory.
47class 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