1 // Copyright (c) 2013, 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_PROC_CPUINFO_READER_H_ 31 #define CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_ 32 33 #include <stdint.h> 34 #include <assert.h> 35 #include <string.h> 36 37 #include "client/linux/minidump_writer/line_reader.h" 38 #include "common/linux/linux_libc_support.h" 39 #include "third_party/lss/linux_syscall_support.h" 40 41 namespace google_breakpad { 42 43 // A class for reading /proc/cpuinfo without using fopen/fgets or other 44 // functions which may allocate memory. 45 class ProcCpuInfoReader { 46 public: ProcCpuInfoReader(int fd)47 ProcCpuInfoReader(int fd) 48 : line_reader_(fd), pop_count_(-1) { 49 } 50 51 // Return the next field name, or NULL in case of EOF. 52 // field: (output) Pointer to zero-terminated field name. 53 // Returns true on success, or false on EOF or error (line too long). GetNextField(const char ** field)54 bool GetNextField(const char** field) { 55 for (;;) { 56 const char* line; 57 unsigned line_len; 58 59 // Try to read next line. 60 if (pop_count_ >= 0) { 61 line_reader_.PopLine(pop_count_); 62 pop_count_ = -1; 63 } 64 65 if (!line_reader_.GetNextLine(&line, &line_len)) 66 return false; 67 68 pop_count_ = static_cast<int>(line_len); 69 70 const char* line_end = line + line_len; 71 72 // Expected format: <field-name> <space>+ ':' <space> <value> 73 // Note that: 74 // - empty lines happen. 75 // - <field-name> can contain spaces. 76 // - some fields have an empty <value> 77 char* sep = static_cast<char*>(my_memchr(line, ':', line_len)); 78 if (sep == NULL) 79 continue; 80 81 // Record the value. Skip leading space after the column to get 82 // its start. 83 const char* val = sep+1; 84 while (val < line_end && my_isspace(*val)) 85 val++; 86 87 value_ = val; 88 value_len_ = static_cast<size_t>(line_end - val); 89 90 // Remove trailing spaces before the column to properly 0-terminate 91 // the field name. 92 while (sep > line && my_isspace(sep[-1])) 93 sep--; 94 95 if (sep == line) 96 continue; 97 98 // zero-terminate field name. 99 *sep = '\0'; 100 101 *field = line; 102 return true; 103 } 104 } 105 106 // Return the field value. This must be called after a succesful 107 // call to GetNextField(). GetValue()108 const char* GetValue() { 109 assert(value_); 110 return value_; 111 } 112 113 // Same as GetValue(), but also returns the length in characters of 114 // the value. GetValueAndLen(size_t * length)115 const char* GetValueAndLen(size_t* length) { 116 assert(value_); 117 *length = value_len_; 118 return value_; 119 } 120 121 private: 122 LineReader line_reader_; 123 int pop_count_; 124 const char* value_; 125 size_t value_len_; 126 }; 127 128 } // namespace google_breakpad 129 130 #endif // CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_ 131