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
15namespace base {
16
17ProcessIterator::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
69ProcessIterator::~ProcessIterator() {
70}
71
72bool 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
130bool NamedProcessIterator::IncludeEntry() {
131  return (executable_name_ == entry().exe_file() &&
132          ProcessIterator::IncludeEntry());
133}
134
135}  // namespace base
136