1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "src/profiling/common/proc_utils.h"
18
19 #include <inttypes.h>
20 #include <sys/stat.h>
21 #include <unistd.h>
22
23 #include "perfetto/ext/base/file_utils.h"
24 #include "perfetto/ext/base/optional.h"
25 #include "perfetto/profiling/normalize.h"
26
27 namespace perfetto {
28 namespace profiling {
29 namespace {
30
GetProcFile(pid_t pid,const char * file,char * filename_buf,size_t size)31 bool GetProcFile(pid_t pid, const char* file, char* filename_buf, size_t size) {
32 ssize_t written = snprintf(filename_buf, size, "/proc/%d/%s", pid, file);
33 if (written < 0 || static_cast<size_t>(written) >= size) {
34 if (written < 0)
35 PERFETTO_ELOG("Failed to concatenate cmdline file.");
36 else
37 PERFETTO_ELOG("Overflow when concatenating cmdline file.");
38 return false;
39 }
40 return true;
41 }
42
ParseProcStatusSize(const std::string & status,const std::string & key)43 base::Optional<uint32_t> ParseProcStatusSize(const std::string& status,
44 const std::string& key) {
45 auto entry_idx = status.find(key);
46 if (entry_idx == std::string::npos)
47 return {};
48 entry_idx = status.find_first_not_of(" \t", entry_idx + key.size());
49 if (entry_idx == std::string::npos)
50 return {};
51 int32_t val = atoi(status.c_str() + entry_idx);
52 if (val < 0) {
53 PERFETTO_ELOG("Unexpected value reading %s", key.c_str());
54 return {};
55 }
56 return static_cast<uint32_t>(val);
57 }
58 } // namespace
59
NormalizeCmdlines(const std::vector<std::string> & cmdlines)60 base::Optional<std::vector<std::string>> NormalizeCmdlines(
61 const std::vector<std::string>& cmdlines) {
62 std::vector<std::string> normalized_cmdlines;
63 normalized_cmdlines.reserve(cmdlines.size());
64
65 for (size_t i = 0; i < cmdlines.size(); i++) {
66 std::string cmdline = cmdlines[i]; // mutable copy
67 // Add nullbyte to make sure it's a C string.
68 cmdline.resize(cmdline.size() + 1, '\0');
69 char* cmdline_cstr = &(cmdline[0]);
70 ssize_t size = NormalizeCmdLine(&cmdline_cstr, cmdline.size());
71 if (size == -1) {
72 PERFETTO_PLOG("Failed to normalize cmdline %s. Stopping the parse.",
73 cmdlines[i].c_str());
74 return base::nullopt;
75 }
76 normalized_cmdlines.emplace_back(cmdline_cstr, static_cast<size_t>(size));
77 }
78 return base::make_optional(normalized_cmdlines);
79 }
80
81 // This is mostly the same as GetHeapprofdProgramProperty in
82 // https://android.googlesource.com/platform/bionic/+/master/libc/bionic/malloc_common.cpp
83 // This should give the same result as GetHeapprofdProgramProperty.
GetCmdlineForPID(pid_t pid,std::string * name)84 bool GetCmdlineForPID(pid_t pid, std::string* name) {
85 std::string filename = "/proc/" + std::to_string(pid) + "/cmdline";
86 base::ScopedFile fd(base::OpenFile(filename, O_RDONLY | O_CLOEXEC));
87 if (!fd) {
88 PERFETTO_DPLOG("Failed to open %s", filename.c_str());
89 return false;
90 }
91 char cmdline[512];
92 const size_t max_read_size = sizeof(cmdline) - 1;
93 ssize_t rd = read(*fd, cmdline, max_read_size);
94 if (rd == -1) {
95 PERFETTO_DPLOG("Failed to read %s", filename.c_str());
96 return false;
97 }
98
99 if (rd == 0) {
100 PERFETTO_DLOG("Empty cmdline for %" PRIdMAX ". Skipping.",
101 static_cast<intmax_t>(pid));
102 return false;
103 }
104
105 // In some buggy kernels (before http://bit.ly/37R7qwL) /proc/pid/cmdline is
106 // not NUL-terminated (see b/147438623). If we read < max_read_size bytes
107 // assume we are hitting the aforementioned kernel bug and terminate anyways.
108 const size_t rd_u = static_cast<size_t>(rd);
109 if (rd_u >= max_read_size && memchr(cmdline, '\0', rd_u) == nullptr) {
110 // We did not manage to read the first argument.
111 PERFETTO_DLOG("Overflow reading cmdline for %" PRIdMAX,
112 static_cast<intmax_t>(pid));
113 errno = EOVERFLOW;
114 return false;
115 }
116
117 cmdline[rd] = '\0';
118 char* cmdline_start = cmdline;
119 ssize_t size = NormalizeCmdLine(&cmdline_start, rd_u);
120 if (size == -1)
121 return false;
122 name->assign(cmdline_start, static_cast<size_t>(size));
123 return true;
124 }
125
FindAllProfilablePids(std::set<pid_t> * pids)126 void FindAllProfilablePids(std::set<pid_t>* pids) {
127 ForEachPid([pids](pid_t pid) {
128 if (pid == getpid())
129 return;
130
131 char filename_buf[128];
132 if (!GetProcFile(pid, "cmdline", filename_buf, sizeof(filename_buf)))
133 return;
134 struct stat statbuf;
135 // Check if we have permission to the process.
136 if (stat(filename_buf, &statbuf) == 0)
137 pids->emplace(pid);
138 });
139 }
140
FindPidsForCmdlines(const std::vector<std::string> & cmdlines,std::set<pid_t> * pids)141 void FindPidsForCmdlines(const std::vector<std::string>& cmdlines,
142 std::set<pid_t>* pids) {
143 ForEachPid([&cmdlines, pids](pid_t pid) {
144 if (pid == getpid())
145 return;
146 std::string process_cmdline;
147 process_cmdline.reserve(512);
148 GetCmdlineForPID(pid, &process_cmdline);
149 for (const std::string& cmdline : cmdlines) {
150 if (process_cmdline == cmdline)
151 pids->emplace(static_cast<pid_t>(pid));
152 }
153 });
154 }
155
ReadStatus(pid_t pid)156 base::Optional<std::string> ReadStatus(pid_t pid) {
157 std::string path = "/proc/" + std::to_string(pid) + "/status";
158 std::string status;
159 bool read_proc = base::ReadFile(path, &status);
160 if (!read_proc) {
161 PERFETTO_ELOG("Failed to read %s", path.c_str());
162 return base::nullopt;
163 }
164 return base::Optional<std::string>(status);
165 }
166
GetRssAnonAndSwap(const std::string & status)167 base::Optional<uint32_t> GetRssAnonAndSwap(const std::string& status) {
168 auto anon_rss = ParseProcStatusSize(status, "RssAnon:");
169 auto swap = ParseProcStatusSize(status, "VmSwap:");
170 if (anon_rss.has_value() && swap.has_value()) {
171 return *anon_rss + *swap;
172 }
173 return base::nullopt;
174 }
175
RemoveUnderAnonThreshold(uint32_t min_size_kb,std::set<pid_t> * pids)176 void RemoveUnderAnonThreshold(uint32_t min_size_kb, std::set<pid_t>* pids) {
177 for (auto it = pids->begin(); it != pids->end();) {
178 const pid_t pid = *it;
179
180 base::Optional<std::string> status = ReadStatus(pid);
181 base::Optional<uint32_t> rss_and_swap;
182 if (status)
183 rss_and_swap = GetRssAnonAndSwap(*status);
184
185 if (rss_and_swap && rss_and_swap < min_size_kb) {
186 PERFETTO_LOG("Removing pid %d from profiled set (anon: %d kB < %" PRIu32
187 ")",
188 pid, *rss_and_swap, min_size_kb);
189 it = pids->erase(it);
190 } else {
191 ++it;
192 }
193 }
194 }
195
196 } // namespace profiling
197 } // namespace perfetto
198