1 // Copyright 2009 Google LLC 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are 5 // met: 6 // 7 // * Redistributions of source code must retain the above copyright 8 // notice, this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above 10 // copyright notice, this list of conditions and the following disclaimer 11 // in the documentation and/or other materials provided with the 12 // distribution. 13 // * Neither the name of Google LLC nor the names of its 14 // contributors may be used to endorse or promote products derived from 15 // this software without specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29 #ifndef CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_ 30 #define CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_ 31 32 #include <stdint.h> 33 #include <unistd.h> 34 #include <limits.h> 35 #include <assert.h> 36 #include <errno.h> 37 #include <string.h> 38 39 #include "common/linux/linux_libc_support.h" 40 #include "third_party/lss/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: DirectoryReader(int fd)48 DirectoryReader(int fd) 49 : fd_(fd), 50 buf_used_(0) { 51 } 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. GetNextEntry(const char ** name)60 bool GetNextEntry(const char** name) { 61 struct kernel_dirent* const dent = 62 reinterpret_cast<kernel_dirent*>(buf_); 63 64 if (buf_used_ == 0) { 65 // need to read more entries. 66 const int n = sys_getdents(fd_, dent, sizeof(buf_)); 67 if (n < 0) { 68 return false; 69 } else if (n == 0) { 70 hit_eof_ = true; 71 } else { 72 buf_used_ += n; 73 } 74 } 75 76 if (buf_used_ == 0 && hit_eof_) 77 return false; 78 79 assert(buf_used_ > 0); 80 81 *name = dent->d_name; 82 return true; 83 } 84 PopEntry()85 void PopEntry() { 86 if (!buf_used_) 87 return; 88 89 const struct kernel_dirent* const dent = 90 reinterpret_cast<kernel_dirent*>(buf_); 91 92 buf_used_ -= dent->d_reclen; 93 my_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_ 106