xref: /freebsd/usr.bin/procstat/procstat_kstack.c (revision 2a664c03e55254b0f3b32dcdfc78179c0a57a8d2)
1 /*-
2  * Copyright (c) 2007 Robert N. M. Watson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/sysctl.h>
31 #include <sys/user.h>
32 
33 #include <err.h>
34 #include <errno.h>
35 #include <libprocstat.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 
40 #include "procstat.h"
41 
42 /*
43  * Walk the stack trace provided by the kernel and reduce it to what we
44  * actually want to print.  This involves stripping true instruction pointers,
45  * frame numbers, and carriage returns as generated by stack(9).  If -kk is
46  * specified, print the function and offset, otherwise just the function.
47  */
48 enum trace_state { TS_FRAMENUM, TS_PC, TS_AT, TS_FUNC, TS_OFF };
49 
50 static enum trace_state
51 kstack_nextstate(enum trace_state ts)
52 {
53 
54 	switch (ts) {
55 	case TS_FRAMENUM:
56 		return (TS_PC);
57 
58 	case TS_PC:
59 		return (TS_AT);
60 
61 	case TS_AT:
62 		return (TS_FUNC);
63 
64 	case TS_FUNC:
65 		return (TS_OFF);
66 
67 	case TS_OFF:
68 		return TS_FRAMENUM;
69 
70 	default:
71 		errx(-1, "kstack_nextstate");
72 	}
73 }
74 
75 static void
76 kstack_cleanup(const char *old, char *new, int kflag)
77 {
78 	enum trace_state old_ts, ts;
79 	const char *cp_old;
80 	char *cp_new;
81 
82 	ts = TS_FRAMENUM;
83 	for (cp_old = old, cp_new = new; *cp_old != '\0'; cp_old++) {
84 		switch (*cp_old) {
85 		case ' ':
86 		case '\n':
87 		case '+':
88 			old_ts = ts;
89 			ts = kstack_nextstate(old_ts);
90 			if (old_ts == TS_OFF) {
91 				*cp_new = ' ';
92 				cp_new++;
93 			}
94 			if (kflag > 1 && old_ts == TS_FUNC) {
95 				*cp_new = '+';
96 				cp_new++;
97 			}
98 			continue;
99 		}
100 		if (ts == TS_FUNC || (kflag > 1 && ts == TS_OFF)) {
101 			*cp_new = *cp_old;
102 			cp_new++;
103 		}
104 	}
105 	*cp_new = '\0';
106 }
107 
108 /*
109  * Sort threads by tid.
110  */
111 static int
112 kinfo_kstack_compare(const void *a, const void *b)
113 {
114 
115         return ((const struct kinfo_kstack *)a)->kkst_tid -
116             ((const struct kinfo_kstack *)b)->kkst_tid;
117 }
118 
119 static void
120 kinfo_kstack_sort(struct kinfo_kstack *kkstp, int count)
121 {
122 
123         qsort(kkstp, count, sizeof(*kkstp), kinfo_kstack_compare);
124 }
125 
126 
127 void
128 procstat_kstack(struct kinfo_proc *kipp, int kflag)
129 {
130 	struct kinfo_kstack *kkstp, *kkstp_free;
131 	struct kinfo_proc *kip, *kip_free;
132 	char trace[KKST_MAXLEN];
133 	int error, name[4];
134 	unsigned int i, j;
135 	size_t kip_len, kstk_len;
136 
137 	if (!hflag)
138 		printf("%5s %6s %-16s %-16s %-29s\n", "PID", "TID", "COMM",
139 		    "TDNAME", "KSTACK");
140 
141 	name[0] = CTL_KERN;
142 	name[1] = KERN_PROC;
143 	name[2] = KERN_PROC_KSTACK;
144 	name[3] = kipp->ki_pid;
145 
146 	kstk_len = 0;
147 	error = sysctl(name, 4, NULL, &kstk_len, NULL, 0);
148 	if (error < 0 && errno != ESRCH && errno != EPERM && errno != ENOENT) {
149 		warn("sysctl: kern.proc.kstack: %d", kipp->ki_pid);
150 		return;
151 	}
152 	if (error < 0 && errno == ENOENT) {
153 		warnx("sysctl: kern.proc.kstack unavailable");
154 		errx(-1, "options DDB or options STACK required in kernel");
155 	}
156 	if (error < 0)
157 		return;
158 
159 	kkstp = kkstp_free = malloc(kstk_len);
160 	if (kkstp == NULL)
161 		err(-1, "malloc");
162 
163 	if (sysctl(name, 4, kkstp, &kstk_len, NULL, 0) < 0) {
164 		warn("sysctl: kern.proc.pid: %d", kipp->ki_pid);
165 		free(kkstp);
166 		return;
167 	}
168 
169 	/*
170 	 * We need to re-query for thread information, so don't use *kipp.
171 	 */
172 	name[0] = CTL_KERN;
173 	name[1] = KERN_PROC;
174 	name[2] = KERN_PROC_PID | KERN_PROC_INC_THREAD;
175 	name[3] = kipp->ki_pid;
176 
177 	kip_len = 0;
178 	error = sysctl(name, 4, NULL, &kip_len, NULL, 0);
179 	if (error < 0 && errno != ESRCH) {
180 		warn("sysctl: kern.proc.pid: %d", kipp->ki_pid);
181 		return;
182 	}
183 	if (error < 0)
184 		return;
185 
186 	kip = kip_free = malloc(kip_len);
187 	if (kip == NULL)
188 		err(-1, "malloc");
189 
190 	if (sysctl(name, 4, kip, &kip_len, NULL, 0) < 0) {
191 		warn("sysctl: kern.proc.pid: %d", kipp->ki_pid);
192 		free(kip);
193 		return;
194 	}
195 
196 	kinfo_kstack_sort(kkstp, kstk_len / sizeof(*kkstp));
197 	for (i = 0; i < kstk_len / sizeof(*kkstp); i++) {
198 		kkstp = &kkstp_free[i];
199 
200 		/*
201 		 * Look up the specific thread using its tid so we can
202 		 * display the per-thread command line.
203 		 */
204 		kipp = NULL;
205 		for (j = 0; j < kip_len / sizeof(*kipp); j++) {
206 			kipp = &kip_free[j];
207 			if (kkstp->kkst_tid == kipp->ki_tid)
208 				break;
209 		}
210 		if (kipp == NULL)
211 			continue;
212 
213 		printf("%5d ", kipp->ki_pid);
214 		printf("%6d ", kkstp->kkst_tid);
215 		printf("%-16s ", kipp->ki_comm);
216 		printf("%-16s ", (strlen(kipp->ki_tdname) &&
217 		    (strcmp(kipp->ki_comm, kipp->ki_tdname) != 0)) ?
218 		    kipp->ki_tdname : "-");
219 
220 		switch (kkstp->kkst_state) {
221 		case KKST_STATE_RUNNING:
222 			printf("%-29s\n", "<running>");
223 			continue;
224 
225 		case KKST_STATE_SWAPPED:
226 			printf("%-29s\n", "<swapped>");
227 			continue;
228 
229 		case KKST_STATE_STACKOK:
230 			break;
231 
232 		default:
233 			printf("%-29s\n", "<unknown>");
234 			continue;
235 		}
236 
237 		/*
238 		 * The kernel generates a trace with carriage returns between
239 		 * entries, but for a more compact view, we convert carriage
240 		 * returns to spaces.
241 		 */
242 		kstack_cleanup(kkstp->kkst_trace, trace, kflag);
243 		printf("%-29s\n", trace);
244 	}
245 	free(kip_free);
246 	free(kkstp_free);
247 }
248