1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 #include "jni.h"
27 #include "jni_util.h"
28 #include "java_lang_ProcessHandleImpl.h"
29 #include "java_lang_ProcessHandleImpl_Info.h"
30
31 #include "ProcessHandleImpl_unix.h"
32
33
34 #include <fcntl.h>
35 #include <limits.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 #include <sys/types.h>
39 #include <sys/stat.h>
40
41 #include <string.h>
42 #include <ctype.h>
43
44 /*
45 * Implementation of native ProcessHandleImpl functions for Linux.
46 * See ProcessHandleImpl_unix.c for more details.
47 */
48
49 /* Signatures for internal OS specific functions. */
50 static long long getBoottime(JNIEnv *env);
51
52 /* A static offset in milliseconds since boot. */
53 static long long bootTime_ms;
54 static long clock_ticks_per_second;
55 static int pageSize;
56
57 void os_initNative(JNIEnv *env, jclass clazz) {
58 bootTime_ms = getBoottime(env);
59 clock_ticks_per_second = sysconf(_SC_CLK_TCK);
60 pageSize = sysconf(_SC_PAGESIZE);
61 }
62
63 jint os_getChildren(JNIEnv *env, jlong jpid, jlongArray jarray,
64 jlongArray jparentArray, jlongArray jstimesArray) {
65 return unix_getChildren(env, jpid, jarray, jparentArray, jstimesArray);
66 }
67
68 /**
69 * Read /proc/<pid>/stat and return the ppid, total cputime and start time.
70 * -1 is fail; >= 0 is parent pid
71 * 'total' will contain the running time of 'pid' in nanoseconds.
72 * 'start' will contain the start time of 'pid' in milliseconds since epoch.
73 */
74 pid_t os_getParentPidAndTimings(JNIEnv *env, pid_t pid,
75 jlong *totalTime, jlong* startTime) {
76 FILE* fp;
77 char buffer[2048];
78 int statlen;
79 char fn[32];
80 char* s;
81 int parentPid;
82 long unsigned int utime = 0; // clock tics
83 long unsigned int stime = 0; // clock tics
84 long long unsigned int start = 0; // microseconds
85
86 /*
87 * Try to stat and then open /proc/%d/stat
88 */
89 snprintf(fn, sizeof fn, "/proc/%d/stat", pid);
90
91 fp = fopen(fn, "r");
92 if (fp == NULL) {
93 return -1; // fail, no such /proc/pid/stat
94 }
95
96 /*
97 * The format is: pid (command) state ppid ...
98 * As the command could be anything we must find the right most
99 * ")" and then skip the white spaces that follow it.
100 */
101 statlen = fread(buffer, 1, (sizeof buffer - 1), fp);
102 fclose(fp);
103 if (statlen < 0) {
104 return -1; // parent pid is not available
105 }
106
107 buffer[statlen] = '\0';
108 s = strchr(buffer, '(');
109 if (s == NULL) {
110 return -1; // parent pid is not available
111 }
112 // Found start of command, skip to end
113 s++;
114 s = strrchr(s, ')');
115 if (s == NULL) {
116 return -1; // parent pid is not available
117 }
118 s++;
119
120 // Scan the needed fields from status, retaining only ppid(4),
121 // utime (14), stime(15), starttime(22)
122 if (4 != sscanf(s, " %*c %d %*d %*d %*d %*d %*d %*u %*u %*u %*u %lu %lu %*d %*d %*d %*d %*d %*d %llu",
123 &parentPid, &utime, &stime, &start)) {
124 return 0; // not all values parsed; return error
125 }
126
127 *totalTime = (utime + stime) * (jlong)(1000000000 / clock_ticks_per_second);
128
129 *startTime = bootTime_ms + ((start * 1000) / clock_ticks_per_second);
130
131 return parentPid;
132 }
133
134 void os_getCmdlineAndUserInfo(JNIEnv *env, jobject jinfo, pid_t pid) {
135 int fd;
136 int cmdlen = 0;
137 char *cmdline = NULL, *cmdEnd = NULL; // used for command line args and exe
138 char *args = NULL;
139 jstring cmdexe = NULL;
140 char fn[32];
141 struct stat stat_buf;
142
143 /*
144 * Try to open /proc/<pid>/cmdline
145 */
146 snprintf(fn, sizeof fn, "/proc/%d/cmdline", pid);
147 if ((fd = open(fn, O_RDONLY)) < 0) {
148 return;
149 }
150
151 if (fstat(fd, &stat_buf) == 0) {
152 unix_getUserInfo(env, jinfo, stat_buf.st_uid);
153 }
154
155 do { // Block to break out of on errors
156 int i, truncated = 0;
157 int count;
158 char *s;
159
160 /*
161 * The path name read by readlink() is limited to PATH_MAX characters.
162 * The content of /proc/<pid>/cmdline is limited to PAGE_SIZE characters.
163 */
164 cmdline = (char*)malloc((PATH_MAX > pageSize ? PATH_MAX : pageSize) + 1);
165 if (cmdline == NULL) {
166 break;
167 }
168
169 /*
170 * On Linux, the full path to the executable command is the link in
171 * /proc/<pid>/exe. But it is only readable for processes we own.
172 */
173 snprintf(fn, sizeof fn, "/proc/%d/exe", pid);
174 if ((cmdlen = readlink(fn, cmdline, PATH_MAX)) > 0) {
175 // null terminate and create String to store for command
176 cmdline[cmdlen] = '\0';
177 cmdexe = JNU_NewStringPlatform(env, cmdline);
178 (*env)->ExceptionClear(env); // unconditionally clear any exception
179 }
180
181 /*
182 * The command-line arguments appear as a set of strings separated by
183 * null bytes ('\0'), with a further null byte after the last
184 * string. The last string is only null terminated if the whole command
185 * line is not exceeding (PAGE_SIZE - 1) characters.
186 */
187 cmdlen = 0;
188 s = cmdline;
189 while ((count = read(fd, s, pageSize - cmdlen)) > 0) {
190 cmdlen += count;
191 s += count;
192 }
193 if (count < 0) {
194 break;
195 }
196 // We have to null-terminate because the process may have changed argv[]
197 // or because the content in /proc/<pid>/cmdline is truncated.
198 cmdline[cmdlen] = '\0';
199 if (cmdlen == pageSize && cmdline[pageSize - 1] != '\0') {
200 truncated = 1;
201 } else if (cmdlen == 0) {
202 // /proc/<pid>/cmdline was empty. This usually happens for kernel processes
203 // like '[kthreadd]'. We could try to read /proc/<pid>/comm in the future.
204 }
205 if (cmdlen > 0 && (cmdexe == NULL || truncated)) {
206 // We have no exact command or the arguments are truncated.
207 // In this case we save the command line from /proc/<pid>/cmdline.
208 args = (char*)malloc(pageSize + 1);
209 if (args != NULL) {
210 memcpy(args, cmdline, cmdlen + 1);
211 for (i = 0; i < cmdlen; i++) {
212 if (args[i] == '\0') {
213 args[i] = ' ';
214 }
215 }
216 }
217 }
218 i = 0;
219 if (!truncated) {
220 // Count the arguments
221 cmdEnd = &cmdline[cmdlen];
222 for (s = cmdline; *s != '\0' && (s < cmdEnd); i++) {
223 s += strnlen(s, (cmdEnd - s)) + 1;
224 }
225 }
226 unix_fillArgArray(env, jinfo, i, cmdline, cmdEnd, cmdexe, args);
227 } while (0);
228
229 if (cmdline != NULL) {
230 free(cmdline);
231 }
232 if (args != NULL) {
233 free(args);
234 }
235 if (fd >= 0) {
236 close(fd);
237 }
238 }
239
240 /**
241 * Read the boottime from /proc/stat.
242 */
243 static long long getBoottime(JNIEnv *env) {
244 FILE *fp;
245 char *line = NULL;
246 size_t len = 0;
247 long long bootTime = 0;
248
249 fp = fopen("/proc/stat", "r");
250 if (fp == NULL) {
251 return -1;
252 }
253
254 while (getline(&line, &len, fp) != -1) {
255 if (sscanf(line, "btime %llu", &bootTime) == 1) {
256 break;
257 }
258 }
259 free(line);
260
261 if (fp != 0) {
262 fclose(fp);
263 }
264
265 return bootTime * 1000;
266 }