1 // Copyright 2013 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_PROC_CPUINFO_READER_H_ 30 #define CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_ 31 32 #include <stdint.h> 33 #include <assert.h> 34 #include <string.h> 35 36 #include "client/linux/minidump_writer/line_reader.h" 37 #include "common/linux/linux_libc_support.h" 38 #include "third_party/lss/linux_syscall_support.h" 39 40 namespace google_breakpad { 41 42 // A class for reading /proc/cpuinfo without using fopen/fgets or other 43 // functions which may allocate memory. 44 class ProcCpuInfoReader { 45 public: ProcCpuInfoReader(int fd)46 ProcCpuInfoReader(int fd) 47 : line_reader_(fd), pop_count_(-1) { 48 } 49 50 // Return the next field name, or NULL in case of EOF. 51 // field: (output) Pointer to zero-terminated field name. 52 // Returns true on success, or false on EOF or error (line too long). GetNextField(const char ** field)53 bool GetNextField(const char** field) { 54 for (;;) { 55 const char* line; 56 unsigned line_len; 57 58 // Try to read next line. 59 if (pop_count_ >= 0) { 60 line_reader_.PopLine(pop_count_); 61 pop_count_ = -1; 62 } 63 64 if (!line_reader_.GetNextLine(&line, &line_len)) 65 return false; 66 67 pop_count_ = static_cast<int>(line_len); 68 69 const char* line_end = line + line_len; 70 71 // Expected format: <field-name> <space>+ ':' <space> <value> 72 // Note that: 73 // - empty lines happen. 74 // - <field-name> can contain spaces. 75 // - some fields have an empty <value> 76 char* sep = static_cast<char*>(my_memchr(line, ':', line_len)); 77 if (sep == NULL) 78 continue; 79 80 // Record the value. Skip leading space after the column to get 81 // its start. 82 const char* val = sep+1; 83 while (val < line_end && my_isspace(*val)) 84 val++; 85 86 value_ = val; 87 value_len_ = static_cast<size_t>(line_end - val); 88 89 // Remove trailing spaces before the column to properly 0-terminate 90 // the field name. 91 while (sep > line && my_isspace(sep[-1])) 92 sep--; 93 94 if (sep == line) 95 continue; 96 97 // zero-terminate field name. 98 *sep = '\0'; 99 100 *field = line; 101 return true; 102 } 103 } 104 105 // Return the field value. This must be called after a succesful 106 // call to GetNextField(). GetValue()107 const char* GetValue() { 108 assert(value_); 109 return value_; 110 } 111 112 // Same as GetValue(), but also returns the length in characters of 113 // the value. GetValueAndLen(size_t * length)114 const char* GetValueAndLen(size_t* length) { 115 assert(value_); 116 *length = value_len_; 117 return value_; 118 } 119 120 private: 121 LineReader line_reader_; 122 int pop_count_; 123 const char* value_; 124 size_t value_len_; 125 }; 126 127 } // namespace google_breakpad 128 129 #endif // CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_ 130