xref: /freebsd/lib/libpmcstat/libpmcstat_process.c (revision e6bfd18d21b225af6a0ed67ceeaf1293b7b9eba5)
1 /*-
2  * Copyright (c) 2003-2008 Joseph Koshy
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 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/types.h>
31 #include <sys/cpuset.h>
32 #include <sys/event.h>
33 #include <sys/param.h>
34 #include <sys/socket.h>
35 #include <sys/stat.h>
36 #include <sys/module.h>
37 #include <sys/pmc.h>
38 
39 #include <assert.h>
40 #include <ctype.h>
41 #include <err.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <limits.h>
45 #include <netdb.h>
46 #include <pmc.h>
47 #include <pmclog.h>
48 #include <signal.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <strings.h>
53 #include <sysexits.h>
54 #include <unistd.h>
55 
56 #include "libpmcstat.h"
57 
58 /*
59  * Associate an AOUT image with a process.
60  */
61 
62 void
63 pmcstat_process_aout_exec(struct pmcstat_process *pp,
64     struct pmcstat_image *image, uintptr_t baseaddr)
65 {
66 	(void) pp;
67 	(void) image;
68 	(void) baseaddr;
69 	/* TODO Implement a.out handling */
70 }
71 
72 /*
73  * Associate an ELF image with a process.
74  */
75 
76 void
77 pmcstat_process_elf_exec(struct pmcstat_process *pp,
78     struct pmcstat_image *image, uintptr_t baseaddr, uintptr_t dynaddr,
79     struct pmcstat_args *args, struct pmc_plugins *plugins,
80     struct pmcstat_stats *pmcstat_stats)
81 {
82 	struct pmcstat_image *rtldimage;
83 
84 	assert(image->pi_type == PMCSTAT_IMAGE_ELF32 ||
85 	    image->pi_type == PMCSTAT_IMAGE_ELF64);
86 
87 	/*
88 	 * The exact address where the executable gets mapped in will vary for
89 	 * PIEs.  The dynamic address recorded at process exec time corresponds
90 	 * to the address where the executable's file object had been mapped to.
91 	 */
92 	pmcstat_image_link(pp, image, image->pi_vaddr + dynaddr);
93 
94 	/*
95 	 * For dynamically linked executables we need to determine
96 	 * where the dynamic linker was mapped to for this process,
97 	 * Subsequent executable objects that are mapped in by the
98 	 * dynamic linker will be tracked by log events of type
99 	 * PMCLOG_TYPE_MAP_IN.
100 	 */
101 
102 	if (image->pi_isdynamic) {
103 
104 		/*
105 		 * The runtime loader gets loaded just after the maximum
106 		 * possible heap address.  Like so:
107 		 *
108 		 * [  TEXT DATA BSS HEAP -->*RTLD  SHLIBS   <--STACK]
109 		 * ^					            ^
110 		 * 0				   VM_MAXUSER_ADDRESS
111 		 *
112 		 * The exact address where the loader gets mapped in
113 		 * will vary according to the size of the executable
114 		 * and the limits on the size of the process'es data
115 		 * segment at the time of exec().  The base address
116 		 * recorded at process exec time corresponds to the
117 		 * address where the runtime loader's file object had
118 		 * been mapped to.
119 		 */
120 		rtldimage = pmcstat_image_from_path(image->pi_dynlinkerpath,
121 		    0, args, plugins);
122 		if (rtldimage == NULL) {
123 			warnx("WARNING: Cannot find image for \"%s\".",
124 			    pmcstat_string_unintern(image->pi_dynlinkerpath));
125 			pmcstat_stats->ps_exec_errors++;
126 			return;
127 		}
128 
129 		if (rtldimage->pi_type == PMCSTAT_IMAGE_UNKNOWN)
130 			pmcstat_image_get_elf_params(rtldimage, args);
131 
132 		if (rtldimage->pi_type != PMCSTAT_IMAGE_ELF32 &&
133 		    rtldimage->pi_type != PMCSTAT_IMAGE_ELF64) {
134 			warnx("WARNING: rtld not an ELF object \"%s\".",
135 			    pmcstat_string_unintern(image->pi_dynlinkerpath));
136 			return;
137 		}
138 
139 		pmcstat_image_link(pp, rtldimage, baseaddr);
140 	}
141 }
142 
143 /*
144  * Associate an image and a process.
145  */
146 
147 void
148 pmcstat_process_exec(struct pmcstat_process *pp,
149     pmcstat_interned_string path, uintptr_t baseaddr, uintptr_t dynaddr,
150     struct pmcstat_args *args, struct pmc_plugins *plugins,
151     struct pmcstat_stats *pmcstat_stats)
152 {
153 	struct pmcstat_image *image;
154 
155 	if ((image = pmcstat_image_from_path(path, 0,
156 	    args, plugins)) == NULL) {
157 		pmcstat_stats->ps_exec_errors++;
158 		return;
159 	}
160 
161 	if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
162 		pmcstat_image_determine_type(image, args);
163 
164 	assert(image->pi_type != PMCSTAT_IMAGE_UNKNOWN);
165 
166 	switch (image->pi_type) {
167 	case PMCSTAT_IMAGE_ELF32:
168 	case PMCSTAT_IMAGE_ELF64:
169 		pmcstat_stats->ps_exec_elf++;
170 		pmcstat_process_elf_exec(pp, image, baseaddr, dynaddr,
171 		    args, plugins, pmcstat_stats);
172 		break;
173 
174 	case PMCSTAT_IMAGE_AOUT:
175 		pmcstat_stats->ps_exec_aout++;
176 		pmcstat_process_aout_exec(pp, image, baseaddr);
177 		break;
178 
179 	case PMCSTAT_IMAGE_INDETERMINABLE:
180 		pmcstat_stats->ps_exec_indeterminable++;
181 		break;
182 
183 	default:
184 		err(EX_SOFTWARE,
185 		    "ERROR: Unsupported executable type for \"%s\"",
186 		    pmcstat_string_unintern(path));
187 	}
188 }
189 
190 /*
191  * Find the map entry associated with process 'p' at PC value 'pc'.
192  */
193 
194 struct pmcstat_pcmap *
195 pmcstat_process_find_map(struct pmcstat_process *p, uintfptr_t pc)
196 {
197 	struct pmcstat_pcmap *ppm;
198 
199 	TAILQ_FOREACH(ppm, &p->pp_map, ppm_next) {
200 		if (pc >= ppm->ppm_lowpc && pc < ppm->ppm_highpc)
201 			return (ppm);
202 		if (pc < ppm->ppm_lowpc)
203 			return (NULL);
204 	}
205 
206 	return (NULL);
207 }
208 
209 /*
210  * Find the process descriptor corresponding to a PID.  If 'allocate'
211  * is zero, we return a NULL if a pid descriptor could not be found or
212  * a process descriptor process.  If 'allocate' is non-zero, then we
213  * will attempt to allocate a fresh process descriptor.  Zombie
214  * process descriptors are only removed if a fresh allocation for the
215  * same PID is requested.
216  */
217 
218 struct pmcstat_process *
219 pmcstat_process_lookup(pid_t pid, int allocate)
220 {
221 	uint32_t hash;
222 	struct pmcstat_pcmap *ppm, *ppmtmp;
223 	struct pmcstat_process *pp, *pptmp;
224 
225 	hash = (uint32_t) pid & PMCSTAT_HASH_MASK;	/* simplicity wins */
226 
227 	LIST_FOREACH_SAFE(pp, &pmcstat_process_hash[hash], pp_next, pptmp)
228 		if (pp->pp_pid == pid) {
229 			/* Found a descriptor, check and process zombies */
230 			if (allocate && pp->pp_isactive == 0) {
231 				/* remove maps */
232 				TAILQ_FOREACH_SAFE(ppm, &pp->pp_map, ppm_next,
233 				    ppmtmp) {
234 					TAILQ_REMOVE(&pp->pp_map, ppm,
235 					    ppm_next);
236 					free(ppm);
237 				}
238 				/* remove process entry */
239 				LIST_REMOVE(pp, pp_next);
240 				free(pp);
241 				break;
242 			}
243 			return (pp);
244 		}
245 
246 	if (!allocate)
247 		return (NULL);
248 
249 	if ((pp = malloc(sizeof(*pp))) == NULL)
250 		err(EX_OSERR, "ERROR: Cannot allocate pid descriptor");
251 
252 	pp->pp_pid = pid;
253 	pp->pp_isactive = 1;
254 
255 	TAILQ_INIT(&pp->pp_map);
256 
257 	LIST_INSERT_HEAD(&pmcstat_process_hash[hash], pp, pp_next);
258 	return (pp);
259 }
260 
261 void
262 pmcstat_create_process(int *pmcstat_sockpair, struct pmcstat_args *args,
263     int pmcstat_kq)
264 {
265 	char token;
266 	pid_t pid;
267 	struct kevent kev;
268 	struct pmcstat_target *pt;
269 
270 	if (socketpair(AF_UNIX, SOCK_STREAM, 0, pmcstat_sockpair) < 0)
271 		err(EX_OSERR, "ERROR: cannot create socket pair");
272 
273 	switch (pid = fork()) {
274 	case -1:
275 		err(EX_OSERR, "ERROR: cannot fork");
276 		/*NOTREACHED*/
277 
278 	case 0:		/* child */
279 		(void) close(pmcstat_sockpair[PARENTSOCKET]);
280 
281 		/* Write a token to tell our parent we've started executing. */
282 		if (write(pmcstat_sockpair[CHILDSOCKET], "+", 1) != 1)
283 			err(EX_OSERR, "ERROR (child): cannot write token");
284 
285 		/* Wait for our parent to signal us to start. */
286 		if (read(pmcstat_sockpair[CHILDSOCKET], &token, 1) < 0)
287 			err(EX_OSERR, "ERROR (child): cannot read token");
288 		(void) close(pmcstat_sockpair[CHILDSOCKET]);
289 
290 		/* exec() the program requested */
291 		execvp(*args->pa_argv, args->pa_argv);
292 		/* and if that fails, notify the parent */
293 		kill(getppid(), SIGCHLD);
294 		err(EX_OSERR, "ERROR: execvp \"%s\" failed", *args->pa_argv);
295 		/*NOTREACHED*/
296 
297 	default:	/* parent */
298 		(void) close(pmcstat_sockpair[CHILDSOCKET]);
299 		break;
300 	}
301 
302 	/* Ask to be notified via a kevent when the target process exits. */
303 	EV_SET(&kev, pid, EVFILT_PROC, EV_ADD | EV_ONESHOT, NOTE_EXIT, 0,
304 	    NULL);
305 	if (kevent(pmcstat_kq, &kev, 1, NULL, 0, NULL) < 0)
306 		err(EX_OSERR, "ERROR: cannot monitor child process %d", pid);
307 
308 	if ((pt = malloc(sizeof(*pt))) == NULL)
309 		errx(EX_SOFTWARE, "ERROR: Out of memory.");
310 
311 	pt->pt_pid = pid;
312 	SLIST_INSERT_HEAD(&args->pa_targets, pt, pt_next);
313 
314 	/* Wait for the child to signal that its ready to go. */
315 	if (read(pmcstat_sockpair[PARENTSOCKET], &token, 1) < 0)
316 		err(EX_OSERR, "ERROR (parent): cannot read token");
317 
318 	return;
319 }
320 
321 /*
322  * Do process profiling
323  *
324  * If a pid was specified, attach each allocated PMC to the target
325  * process.  Otherwise, fork a child and attach the PMCs to the child,
326  * and have the child exec() the target program.
327  */
328 
329 void
330 pmcstat_start_process(int *pmcstat_sockpair)
331 {
332 	/* Signal the child to proceed. */
333 	if (write(pmcstat_sockpair[PARENTSOCKET], "!", 1) != 1)
334 		err(EX_OSERR, "ERROR (parent): write of token failed");
335 
336 	(void) close(pmcstat_sockpair[PARENTSOCKET]);
337 }
338 
339 void
340 pmcstat_attach_pmcs(struct pmcstat_args *args)
341 {
342 	struct pmcstat_ev *ev;
343 	struct pmcstat_target *pt;
344 	int count;
345 
346 	/* Attach all process PMCs to target processes. */
347 	count = 0;
348 	STAILQ_FOREACH(ev, &args->pa_events, ev_next) {
349 		if (PMC_IS_SYSTEM_MODE(ev->ev_mode))
350 			continue;
351 		SLIST_FOREACH(pt, &args->pa_targets, pt_next) {
352 			if (pmc_attach(ev->ev_pmcid, pt->pt_pid) == 0)
353 				count++;
354 			else if (errno != ESRCH)
355 				err(EX_OSERR,
356 "ERROR: cannot attach pmc \"%s\" to process %d",
357 				    ev->ev_name, (int)pt->pt_pid);
358 		}
359 	}
360 
361 	if (count == 0)
362 		errx(EX_DATAERR, "ERROR: No processes were attached to.");
363 }
364