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: DirectoryReader(int fd)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. GetNextEntry(const char ** name)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 PopEntry()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