1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/process/process_iterator.h" 6 7 #include <stddef.h> 8 9 #include "base/files/file_util.h" 10 #include "base/logging.h" 11 #include "base/process/internal_linux.h" 12 #include "base/strings/string_split.h" 13 #include "base/strings/string_util.h" 14 #include "base/threading/thread_restrictions.h" 15 16 namespace base { 17 18 namespace { 19 20 // Reads the |field_num|th field from |proc_stats|. 21 // Returns an empty string on failure. 22 // This version only handles VM_COMM and VM_STATE, which are the only fields 23 // that are strings. 24 std::string GetProcStatsFieldAsString( 25 const std::vector<std::string>& proc_stats, 26 internal::ProcStatsFields field_num) { 27 if (field_num < internal::VM_COMM || field_num > internal::VM_STATE) { 28 NOTREACHED(); 29 return std::string(); 30 } 31 32 if (proc_stats.size() > static_cast<size_t>(field_num)) 33 return proc_stats[field_num]; 34 35 NOTREACHED(); 36 return 0; 37 } 38 39 // Reads /proc/<pid>/cmdline and populates |proc_cmd_line_args| with the command 40 // line arguments. Returns true if successful. 41 // Note: /proc/<pid>/cmdline contains command line arguments separated by single 42 // null characters. We tokenize it into a vector of strings using '\0' as a 43 // delimiter. 44 bool GetProcCmdline(pid_t pid, std::vector<std::string>* proc_cmd_line_args) { 45 // Synchronously reading files in /proc is safe. 46 ThreadRestrictions::ScopedAllowIO allow_io; 47 48 FilePath cmd_line_file = internal::GetProcPidDir(pid).Append("cmdline"); 49 std::string cmd_line; 50 if (!ReadFileToString(cmd_line_file, &cmd_line)) 51 return false; 52 std::string delimiters; 53 delimiters.push_back('\0'); 54 *proc_cmd_line_args = SplitString(cmd_line, delimiters, KEEP_WHITESPACE, 55 SPLIT_WANT_NONEMPTY); 56 return true; 57 } 58 59 } // namespace 60 61 ProcessIterator::ProcessIterator(const ProcessFilter* filter) 62 : filter_(filter) { 63 procfs_dir_ = opendir(internal::kProcDir); 64 } 65 66 ProcessIterator::~ProcessIterator() { 67 if (procfs_dir_) { 68 closedir(procfs_dir_); 69 procfs_dir_ = NULL; 70 } 71 } 72 73 bool ProcessIterator::CheckForNextProcess() { 74 // TODO(port): skip processes owned by different UID 75 76 pid_t pid = kNullProcessId; 77 std::vector<std::string> cmd_line_args; 78 std::string stats_data; 79 std::vector<std::string> proc_stats; 80 81 // Arbitrarily guess that there will never be more than 200 non-process 82 // files in /proc. Hardy has 53 and Lucid has 61. 83 int skipped = 0; 84 const int kSkipLimit = 200; 85 while (skipped < kSkipLimit) { 86 dirent* slot = readdir(procfs_dir_); 87 // all done looking through /proc? 88 if (!slot) 89 return false; 90 91 // If not a process, keep looking for one. 92 pid = internal::ProcDirSlotToPid(slot->d_name); 93 if (!pid) { 94 skipped++; 95 continue; 96 } 97 98 if (!GetProcCmdline(pid, &cmd_line_args)) 99 continue; 100 101 if (!internal::ReadProcStats(pid, &stats_data)) 102 continue; 103 if (!internal::ParseProcStats(stats_data, &proc_stats)) 104 continue; 105 106 std::string runstate = 107 GetProcStatsFieldAsString(proc_stats, internal::VM_STATE); 108 if (runstate.size() != 1) { 109 NOTREACHED(); 110 continue; 111 } 112 113 // Is the process in 'Zombie' state, i.e. dead but waiting to be reaped? 114 // Allowed values: D R S T Z 115 if (runstate[0] != 'Z') 116 break; 117 118 // Nope, it's a zombie; somebody isn't cleaning up after their children. 119 // (e.g. WaitForProcessesToExit doesn't clean up after dead children yet.) 120 // There could be a lot of zombies, can't really decrement i here. 121 } 122 if (skipped >= kSkipLimit) { 123 NOTREACHED(); 124 return false; 125 } 126 127 entry_.pid_ = pid; 128 entry_.ppid_ = GetProcStatsFieldAsInt64(proc_stats, internal::VM_PPID); 129 entry_.gid_ = GetProcStatsFieldAsInt64(proc_stats, internal::VM_PGRP); 130 entry_.cmd_line_args_.assign(cmd_line_args.begin(), cmd_line_args.end()); 131 entry_.exe_file_ = GetProcessExecutablePath(pid).BaseName().value(); 132 return true; 133 } 134 135 bool NamedProcessIterator::IncludeEntry() { 136 if (executable_name_ != entry().exe_file()) 137 return false; 138 return ProcessIterator::IncludeEntry(); 139 } 140 141 } // namespace base 142