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      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 <errno.h>
      8 #include <sys/sysctl.h>
      9 #include <sys/types.h>
     10 
     11 #include "base/logging.h"
     12 #include "base/strings/string_util.h"
     13 
     14 namespace base {
     15 
     16 ProcessIterator::ProcessIterator(const ProcessFilter* filter)
     17     : index_of_kinfo_proc_(0),
     18       filter_(filter) {
     19   // Get a snapshot of all of my processes (yes, as we loop it can go stale, but
     20   // but trying to find where we were in a constantly changing list is basically
     21   // impossible.
     22 
     23   int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_UID, geteuid() };
     24 
     25   // Since more processes could start between when we get the size and when
     26   // we get the list, we do a loop to keep trying until we get it.
     27   bool done = false;
     28   int try_num = 1;
     29   const int max_tries = 10;
     30   do {
     31     // Get the size of the buffer
     32     size_t len = 0;
     33     if (sysctl(mib, arraysize(mib), NULL, &len, NULL, 0) < 0) {
     34       DLOG(ERROR) << "failed to get the size needed for the process list";
     35       kinfo_procs_.resize(0);
     36       done = true;
     37     } else {
     38       size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
     39       // Leave some spare room for process table growth (more could show up
     40       // between when we check and now)
     41       num_of_kinfo_proc += 16;
     42       kinfo_procs_.resize(num_of_kinfo_proc);
     43       len = num_of_kinfo_proc * sizeof(struct kinfo_proc);
     44       // Load the list of processes
     45       if (sysctl(mib, arraysize(mib), &kinfo_procs_[0], &len, NULL, 0) < 0) {
     46         // If we get a mem error, it just means we need a bigger buffer, so
     47         // loop around again.  Anything else is a real error and give up.
     48         if (errno != ENOMEM) {
     49           DLOG(ERROR) << "failed to get the process list";
     50           kinfo_procs_.resize(0);
     51           done = true;
     52         }
     53       } else {
     54         // Got the list, just make sure we're sized exactly right
     55         size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
     56         kinfo_procs_.resize(num_of_kinfo_proc);
     57         done = true;
     58       }
     59     }
     60   } while (!done && (try_num++ < max_tries));
     61 
     62   if (!done) {
     63     DLOG(ERROR) << "failed to collect the process list in a few tries";
     64     kinfo_procs_.resize(0);
     65   }
     66 }
     67 
     68 ProcessIterator::~ProcessIterator() {
     69 }
     70 
     71 bool ProcessIterator::CheckForNextProcess() {
     72   std::string data;
     73   for (; index_of_kinfo_proc_ < kinfo_procs_.size(); ++index_of_kinfo_proc_) {
     74     kinfo_proc& kinfo = kinfo_procs_[index_of_kinfo_proc_];
     75 
     76     // Skip processes just awaiting collection
     77     if ((kinfo.kp_proc.p_pid > 0) && (kinfo.kp_proc.p_stat == SZOMB))
     78       continue;
     79 
     80     int mib[] = { CTL_KERN, KERN_PROCARGS, kinfo.kp_proc.p_pid };
     81 
     82     // Find out what size buffer we need.
     83     size_t data_len = 0;
     84     if (sysctl(mib, arraysize(mib), NULL, &data_len, NULL, 0) < 0) {
     85       DVPLOG(1) << "failed to figure out the buffer size for a commandline";
     86       continue;
     87     }
     88 
     89     data.resize(data_len);
     90     if (sysctl(mib, arraysize(mib), &data[0], &data_len, NULL, 0) < 0) {
     91       DVPLOG(1) << "failed to fetch a commandline";
     92       continue;
     93     }
     94 
     95     // |data| contains all the command line parameters of the process, separated
     96     // by blocks of one or more null characters. We tokenize |data| into a
     97     // vector of strings using '\0' as a delimiter and populate
     98     // |entry_.cmd_line_args_|.
     99     std::string delimiters;
    100     delimiters.push_back('\0');
    101     Tokenize(data, delimiters, &entry_.cmd_line_args_);
    102 
    103     // |data| starts with the full executable path followed by a null character.
    104     // We search for the first instance of '\0' and extract everything before it
    105     // to populate |entry_.exe_file_|.
    106     size_t exec_name_end = data.find('\0');
    107     if (exec_name_end == std::string::npos) {
    108       DLOG(ERROR) << "command line data didn't match expected format";
    109       continue;
    110     }
    111 
    112     entry_.pid_ = kinfo.kp_proc.p_pid;
    113     entry_.ppid_ = kinfo.kp_eproc.e_ppid;
    114     entry_.gid_ = kinfo.kp_eproc.e_pgid;
    115     size_t last_slash = data.rfind('/', exec_name_end);
    116     if (last_slash == std::string::npos)
    117       entry_.exe_file_.assign(data, 0, exec_name_end);
    118     else
    119       entry_.exe_file_.assign(data, last_slash + 1,
    120                               exec_name_end - last_slash - 1);
    121     // Start w/ the next entry next time through
    122     ++index_of_kinfo_proc_;
    123     // Done
    124     return true;
    125   }
    126   return false;
    127 }
    128 
    129 bool NamedProcessIterator::IncludeEntry() {
    130   return (executable_name_ == entry().exe_file() &&
    131           ProcessIterator::IncludeEntry());
    132 }
    133 
    134 }  // namespace base
    135