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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 #include <unistd.h>
     11 
     12 #include "base/logging.h"
     13 #include "base/strings/string_util.h"
     14 
     15 namespace base {
     16 
     17 ProcessIterator::ProcessIterator(const ProcessFilter* filter)
     18     : index_of_kinfo_proc_(0),
     19       filter_(filter) {
     20   // Get a snapshot of all of my processes (yes, as we loop it can go stale, but
     21   // but trying to find where we were in a constantly changing list is basically
     22   // impossible.
     23 
     24   int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_UID, geteuid() };
     25 
     26   // Since more processes could start between when we get the size and when
     27   // we get the list, we do a loop to keep trying until we get it.
     28   bool done = false;
     29   int try_num = 1;
     30   const int max_tries = 10;
     31   do {
     32     // Get the size of the buffer
     33     size_t len = 0;
     34     if (sysctl(mib, arraysize(mib), NULL, &len, NULL, 0) < 0) {
     35       DLOG(ERROR) << "failed to get the size needed for the process list";
     36       kinfo_procs_.resize(0);
     37       done = true;
     38     } else {
     39       size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
     40       // Leave some spare room for process table growth (more could show up
     41       // between when we check and now)
     42       num_of_kinfo_proc += 16;
     43       kinfo_procs_.resize(num_of_kinfo_proc);
     44       len = num_of_kinfo_proc * sizeof(struct kinfo_proc);
     45       // Load the list of processes
     46       if (sysctl(mib, arraysize(mib), &kinfo_procs_[0], &len, NULL, 0) < 0) {
     47         // If we get a mem error, it just means we need a bigger buffer, so
     48         // loop around again.  Anything else is a real error and give up.
     49         if (errno != ENOMEM) {
     50           DLOG(ERROR) << "failed to get the process list";
     51           kinfo_procs_.resize(0);
     52           done = true;
     53         }
     54       } else {
     55         // Got the list, just make sure we're sized exactly right
     56         size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
     57         kinfo_procs_.resize(num_of_kinfo_proc);
     58         done = true;
     59       }
     60     }
     61   } while (!done && (try_num++ < max_tries));
     62 
     63   if (!done) {
     64     DLOG(ERROR) << "failed to collect the process list in a few tries";
     65     kinfo_procs_.resize(0);
     66   }
     67 }
     68 
     69 ProcessIterator::~ProcessIterator() {
     70 }
     71 
     72 bool ProcessIterator::CheckForNextProcess() {
     73   std::string data;
     74   for (; index_of_kinfo_proc_ < kinfo_procs_.size(); ++index_of_kinfo_proc_) {
     75     kinfo_proc& kinfo = kinfo_procs_[index_of_kinfo_proc_];
     76 
     77     // Skip processes just awaiting collection
     78     if ((kinfo.kp_proc.p_pid > 0) && (kinfo.kp_proc.p_stat == SZOMB))
     79       continue;
     80 
     81     int mib[] = { CTL_KERN, KERN_PROCARGS, kinfo.kp_proc.p_pid };
     82 
     83     // Find out what size buffer we need.
     84     size_t data_len = 0;
     85     if (sysctl(mib, arraysize(mib), NULL, &data_len, NULL, 0) < 0) {
     86       DVPLOG(1) << "failed to figure out the buffer size for a commandline";
     87       continue;
     88     }
     89 
     90     data.resize(data_len);
     91     if (sysctl(mib, arraysize(mib), &data[0], &data_len, NULL, 0) < 0) {
     92       DVPLOG(1) << "failed to fetch a commandline";
     93       continue;
     94     }
     95 
     96     // |data| contains all the command line parameters of the process, separated
     97     // by blocks of one or more null characters. We tokenize |data| into a
     98     // vector of strings using '\0' as a delimiter and populate
     99     // |entry_.cmd_line_args_|.
    100     std::string delimiters;
    101     delimiters.push_back('\0');
    102     Tokenize(data, delimiters, &entry_.cmd_line_args_);
    103 
    104     // |data| starts with the full executable path followed by a null character.
    105     // We search for the first instance of '\0' and extract everything before it
    106     // to populate |entry_.exe_file_|.
    107     size_t exec_name_end = data.find('\0');
    108     if (exec_name_end == std::string::npos) {
    109       DLOG(ERROR) << "command line data didn't match expected format";
    110       continue;
    111     }
    112 
    113     entry_.pid_ = kinfo.kp_proc.p_pid;
    114     entry_.ppid_ = kinfo.kp_eproc.e_ppid;
    115     entry_.gid_ = kinfo.kp_eproc.e_pgid;
    116     size_t last_slash = data.rfind('/', exec_name_end);
    117     if (last_slash == std::string::npos)
    118       entry_.exe_file_.assign(data, 0, exec_name_end);
    119     else
    120       entry_.exe_file_.assign(data, last_slash + 1,
    121                               exec_name_end - last_slash - 1);
    122     // Start w/ the next entry next time through
    123     ++index_of_kinfo_proc_;
    124     // Done
    125     return true;
    126   }
    127   return false;
    128 }
    129 
    130 bool NamedProcessIterator::IncludeEntry() {
    131   return (executable_name_ == entry().exe_file() &&
    132           ProcessIterator::IncludeEntry());
    133 }
    134 
    135 }  // namespace base
    136