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/param.h>
33 #include <sys/endian.h>
34 #include <sys/pmc.h>
35 #include <sys/imgact_aout.h>
36 #include <sys/imgact_elf.h>
37
38 #include <netinet/in.h>
39
40 #include <assert.h>
41 #include <err.h>
42 #include <fcntl.h>
43 #include <pmc.h>
44 #include <pmclog.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <sysexits.h>
49 #include <unistd.h>
50
51 #include "libpmcstat.h"
52
53 #define min(A,B) ((A) < (B) ? (A) : (B))
54 #define max(A,B) ((A) > (B) ? (A) : (B))
55
56 /*
57 * Add the list of symbols in the given section to the list associated
58 * with the object.
59 */
60 void
pmcstat_image_add_symbols(struct pmcstat_image * image,Elf * e,Elf_Scn * scn,GElf_Shdr * sh)61 pmcstat_image_add_symbols(struct pmcstat_image *image, Elf *e,
62 Elf_Scn *scn, GElf_Shdr *sh)
63 {
64 int firsttime;
65 size_t n, newsyms, nshsyms, nfuncsyms;
66 struct pmcstat_symbol *symptr;
67 char *fnname;
68 GElf_Sym sym;
69 Elf_Data *data;
70
71 if ((data = elf_getdata(scn, NULL)) == NULL)
72 return;
73
74 /*
75 * Determine the number of functions named in this
76 * section.
77 */
78
79 nshsyms = sh->sh_size / sh->sh_entsize;
80 for (n = nfuncsyms = 0; n < nshsyms; n++) {
81 if (gelf_getsym(data, (int) n, &sym) != &sym)
82 return;
83 if (GELF_ST_TYPE(sym.st_info) == STT_FUNC)
84 nfuncsyms++;
85 }
86
87 if (nfuncsyms == 0)
88 return;
89
90 /*
91 * Allocate space for the new entries.
92 */
93 firsttime = image->pi_symbols == NULL;
94 symptr = reallocarray(image->pi_symbols,
95 image->pi_symcount + nfuncsyms, sizeof(*symptr));
96 if (symptr == image->pi_symbols) /* realloc() failed. */
97 return;
98 image->pi_symbols = symptr;
99
100 /*
101 * Append new symbols to the end of the current table.
102 */
103 symptr += image->pi_symcount;
104
105 for (n = newsyms = 0; n < nshsyms; n++) {
106 if (gelf_getsym(data, (int) n, &sym) != &sym)
107 return;
108 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC)
109 continue;
110
111 if (sym.st_shndx == STN_UNDEF)
112 continue;
113
114 if (!firsttime && pmcstat_symbol_search(image, sym.st_value))
115 continue; /* We've seen this symbol already. */
116
117 if ((fnname = elf_strptr(e, sh->sh_link, sym.st_name))
118 == NULL)
119 continue;
120 #ifdef __arm__
121 /* Remove spurious ARM function name. */
122 if (fnname[0] == '$' &&
123 (fnname[1] == 'a' || fnname[1] == 't' ||
124 fnname[1] == 'd') &&
125 fnname[2] == '\0')
126 continue;
127 #endif
128
129 symptr->ps_name = pmcstat_string_intern(fnname);
130 symptr->ps_start = sym.st_value - image->pi_vaddr;
131 symptr->ps_end = symptr->ps_start + sym.st_size;
132
133 symptr++;
134 newsyms++;
135 }
136
137 image->pi_symcount += newsyms;
138 if (image->pi_symcount == 0)
139 return;
140
141 assert(newsyms <= nfuncsyms);
142
143 /*
144 * Return space to the system if there were duplicates.
145 */
146 if (newsyms < nfuncsyms)
147 image->pi_symbols = reallocarray(image->pi_symbols,
148 image->pi_symcount, sizeof(*symptr));
149
150 /*
151 * Keep the list of symbols sorted.
152 */
153 qsort(image->pi_symbols, image->pi_symcount, sizeof(*symptr),
154 pmcstat_symbol_compare);
155
156 /*
157 * Deal with function symbols that have a size of 'zero' by
158 * making them extend to the next higher address. These
159 * symbols are usually defined in assembly code.
160 */
161 for (symptr = image->pi_symbols;
162 symptr < image->pi_symbols + (image->pi_symcount - 1);
163 symptr++)
164 if (symptr->ps_start == symptr->ps_end)
165 symptr->ps_end = (symptr+1)->ps_start;
166 }
167
168 /*
169 * Record the fact that PC values from 'start' to 'end' come from
170 * image 'image'.
171 */
172
173 void
pmcstat_image_link(struct pmcstat_process * pp,struct pmcstat_image * image,uintfptr_t start)174 pmcstat_image_link(struct pmcstat_process *pp, struct pmcstat_image *image,
175 uintfptr_t start)
176 {
177 struct pmcstat_pcmap *pcm, *pcmnew;
178 uintfptr_t offset;
179
180 assert(image->pi_type != PMCSTAT_IMAGE_UNKNOWN &&
181 image->pi_type != PMCSTAT_IMAGE_INDETERMINABLE);
182
183 if ((pcmnew = malloc(sizeof(*pcmnew))) == NULL)
184 err(EX_OSERR, "ERROR: Cannot create a map entry");
185
186 /*
187 * Adjust the map entry to only cover the text portion
188 * of the object.
189 */
190
191 offset = start - image->pi_vaddr;
192 pcmnew->ppm_lowpc = image->pi_start + offset;
193 pcmnew->ppm_highpc = image->pi_end + offset;
194 pcmnew->ppm_image = image;
195
196 assert(pcmnew->ppm_lowpc < pcmnew->ppm_highpc);
197
198 /* Overlapped mmap()'s are assumed to never occur. */
199 TAILQ_FOREACH(pcm, &pp->pp_map, ppm_next)
200 if (pcm->ppm_lowpc >= pcmnew->ppm_highpc)
201 break;
202
203 if (pcm == NULL)
204 TAILQ_INSERT_TAIL(&pp->pp_map, pcmnew, ppm_next);
205 else
206 TAILQ_INSERT_BEFORE(pcm, pcmnew, ppm_next);
207 }
208
209 /*
210 * Determine whether a given executable image is an A.OUT object, and
211 * if so, fill in its parameters from the text file.
212 * Sets image->pi_type.
213 */
214
215 void
pmcstat_image_get_aout_params(struct pmcstat_image * image,struct pmcstat_args * args)216 pmcstat_image_get_aout_params(struct pmcstat_image *image,
217 struct pmcstat_args *args)
218 {
219 int fd;
220 ssize_t nbytes;
221 struct exec ex;
222 const char *path;
223 char buffer[PATH_MAX];
224
225 path = pmcstat_string_unintern(image->pi_execpath);
226 assert(path != NULL);
227
228 if (image->pi_iskernelmodule)
229 errx(EX_SOFTWARE,
230 "ERROR: a.out kernel modules are unsupported \"%s\"", path);
231
232 (void) snprintf(buffer, sizeof(buffer), "%s%s",
233 args->pa_fsroot, path);
234
235 if ((fd = open(buffer, O_RDONLY, 0)) < 0 ||
236 (nbytes = read(fd, &ex, sizeof(ex))) < 0) {
237 if (args->pa_verbosity >= 2)
238 warn("WARNING: Cannot determine type of \"%s\"",
239 path);
240 image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE;
241 if (fd != -1)
242 (void) close(fd);
243 return;
244 }
245
246 (void) close(fd);
247
248 if ((unsigned) nbytes != sizeof(ex) ||
249 N_BADMAG(ex))
250 return;
251
252 image->pi_type = PMCSTAT_IMAGE_AOUT;
253
254 /* TODO: the rest of a.out processing */
255
256 return;
257 }
258
259 /*
260 * Examine an ELF file to determine the size of its text segment.
261 * Sets image->pi_type if anything conclusive can be determined about
262 * this image.
263 */
264
265 void
pmcstat_image_get_elf_params(struct pmcstat_image * image,struct pmcstat_args * args)266 pmcstat_image_get_elf_params(struct pmcstat_image *image,
267 struct pmcstat_args *args)
268 {
269 int fd;
270 size_t i, nph, nsh;
271 const char *path, *elfbase;
272 char *p, *endp;
273 uintfptr_t minva, maxva;
274 Elf *e;
275 Elf_Scn *scn;
276 GElf_Ehdr eh;
277 GElf_Phdr ph;
278 GElf_Shdr sh;
279 enum pmcstat_image_type image_type;
280 char buffer[PATH_MAX];
281
282 assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN);
283
284 image->pi_start = minva = ~(uintfptr_t) 0;
285 image->pi_end = maxva = (uintfptr_t) 0;
286 image->pi_type = image_type = PMCSTAT_IMAGE_INDETERMINABLE;
287 image->pi_isdynamic = 0;
288 image->pi_dynlinkerpath = NULL;
289 image->pi_vaddr = 0;
290
291 path = pmcstat_string_unintern(image->pi_execpath);
292 assert(path != NULL);
293
294 /*
295 * Look for kernel modules under FSROOT/KERNELPATH/NAME,
296 * and user mode executable objects under FSROOT/PATHNAME.
297 */
298 if (image->pi_iskernelmodule)
299 (void) snprintf(buffer, sizeof(buffer), "%s%s/%s",
300 args->pa_fsroot, args->pa_kernel, path);
301 else
302 (void) snprintf(buffer, sizeof(buffer), "%s%s",
303 args->pa_fsroot, path);
304
305 e = NULL;
306 if ((fd = open(buffer, O_RDONLY, 0)) < 0) {
307 warnx("WARNING: Cannot open \"%s\".",
308 buffer);
309 goto done;
310 }
311
312 if (elf_version(EV_CURRENT) == EV_NONE) {
313 warnx("WARNING: failed to init elf\n");
314 goto done;
315 }
316
317 if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
318 warnx("WARNING: Cannot read \"%s\".",
319 buffer);
320 goto done;
321 }
322
323 if (elf_kind(e) != ELF_K_ELF) {
324 if (args->pa_verbosity >= 2)
325 warnx("WARNING: Cannot determine the type of \"%s\".",
326 buffer);
327 goto done;
328 }
329
330 if (gelf_getehdr(e, &eh) != &eh) {
331 warnx(
332 "WARNING: Cannot retrieve the ELF Header for \"%s\": %s.",
333 buffer, elf_errmsg(-1));
334 goto done;
335 }
336
337 if (eh.e_type != ET_EXEC && eh.e_type != ET_DYN &&
338 !(image->pi_iskernelmodule && eh.e_type == ET_REL)) {
339 warnx("WARNING: \"%s\" is of an unsupported ELF type.",
340 buffer);
341 goto done;
342 }
343
344 image_type = eh.e_ident[EI_CLASS] == ELFCLASS32 ?
345 PMCSTAT_IMAGE_ELF32 : PMCSTAT_IMAGE_ELF64;
346
347 /*
348 * Determine the virtual address where an executable would be
349 * loaded. Additionally, for dynamically linked executables,
350 * save the pathname to the runtime linker.
351 */
352 if (eh.e_type == ET_EXEC) {
353 if (elf_getphnum(e, &nph) == 0) {
354 warnx(
355 "WARNING: Could not determine the number of program headers in \"%s\": %s.",
356 buffer,
357 elf_errmsg(-1));
358 goto done;
359 }
360 for (i = 0; i < eh.e_phnum; i++) {
361 if (gelf_getphdr(e, i, &ph) != &ph) {
362 warnx(
363 "WARNING: Retrieval of PHDR entry #%ju in \"%s\" failed: %s.",
364 (uintmax_t) i, buffer, elf_errmsg(-1));
365 goto done;
366 }
367 switch (ph.p_type) {
368 case PT_DYNAMIC:
369 image->pi_isdynamic = 1;
370 break;
371 case PT_INTERP:
372 if ((elfbase = elf_rawfile(e, NULL)) == NULL) {
373 warnx(
374 "WARNING: Cannot retrieve the interpreter for \"%s\": %s.",
375 buffer, elf_errmsg(-1));
376 goto done;
377 }
378 image->pi_dynlinkerpath =
379 pmcstat_string_intern(elfbase +
380 ph.p_offset);
381 break;
382 case PT_LOAD:
383 if ((ph.p_flags & PF_X) != 0 &&
384 (ph.p_offset & (-ph.p_align)) == 0)
385 image->pi_vaddr = ph.p_vaddr & (-ph.p_align);
386 break;
387 }
388 }
389 }
390
391 /*
392 * Get the min and max VA associated with this ELF object.
393 */
394 if (elf_getshnum(e, &nsh) == 0) {
395 warnx(
396 "WARNING: Could not determine the number of sections for \"%s\": %s.",
397 buffer, elf_errmsg(-1));
398 goto done;
399 }
400
401 for (i = 0; i < nsh; i++) {
402 if ((scn = elf_getscn(e, i)) == NULL ||
403 gelf_getshdr(scn, &sh) != &sh) {
404 warnx(
405 "WARNING: Could not retrieve section header #%ju in \"%s\": %s.",
406 (uintmax_t) i, buffer, elf_errmsg(-1));
407 goto done;
408 }
409 if (sh.sh_flags & SHF_EXECINSTR) {
410 minva = min(minva, sh.sh_addr);
411 maxva = max(maxva, sh.sh_addr + sh.sh_size);
412 }
413 if (sh.sh_type == SHT_SYMTAB || sh.sh_type == SHT_DYNSYM)
414 pmcstat_image_add_symbols(image, e, scn, &sh);
415 }
416
417 image->pi_start = minva;
418 image->pi_end = maxva;
419 image->pi_type = image_type;
420 image->pi_fullpath = pmcstat_string_intern(buffer);
421
422 /* Build display name
423 */
424 endp = buffer;
425 for (p = buffer; *p; p++)
426 if (*p == '/')
427 endp = p+1;
428 image->pi_name = pmcstat_string_intern(endp);
429
430 done:
431 (void) elf_end(e);
432 if (fd >= 0)
433 (void) close(fd);
434 return;
435 }
436
437 /*
438 * Given an image descriptor, determine whether it is an ELF, or AOUT.
439 * If no handler claims the image, set its type to 'INDETERMINABLE'.
440 */
441
442 void
pmcstat_image_determine_type(struct pmcstat_image * image,struct pmcstat_args * args)443 pmcstat_image_determine_type(struct pmcstat_image *image,
444 struct pmcstat_args *args)
445 {
446 assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN);
447
448 /* Try each kind of handler in turn */
449 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
450 pmcstat_image_get_elf_params(image, args);
451 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
452 pmcstat_image_get_aout_params(image, args);
453
454 /*
455 * Otherwise, remember that we tried to determine
456 * the object's type and had failed.
457 */
458 if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
459 image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE;
460 }
461
462 /*
463 * Locate an image descriptor given an interned path, adding a fresh
464 * descriptor to the cache if necessary. This function also finds a
465 * suitable name for this image's sample file.
466 *
467 * We defer filling in the file format specific parts of the image
468 * structure till the time we actually see a sample that would fall
469 * into this image.
470 */
471
472 struct pmcstat_image *
pmcstat_image_from_path(pmcstat_interned_string internedpath,int iskernelmodule,struct pmcstat_args * args,struct pmc_plugins * plugins)473 pmcstat_image_from_path(pmcstat_interned_string internedpath,
474 int iskernelmodule, struct pmcstat_args *args,
475 struct pmc_plugins *plugins)
476 {
477 int hash;
478 struct pmcstat_image *pi;
479
480 hash = pmcstat_string_lookup_hash(internedpath);
481
482 /* First, look for an existing entry. */
483 LIST_FOREACH(pi, &pmcstat_image_hash[hash], pi_next)
484 if (pi->pi_execpath == internedpath &&
485 pi->pi_iskernelmodule == iskernelmodule)
486 return (pi);
487
488 /*
489 * Allocate a new entry and place it at the head of the hash
490 * and LRU lists.
491 */
492 pi = malloc(sizeof(*pi));
493 if (pi == NULL)
494 return (NULL);
495
496 pi->pi_type = PMCSTAT_IMAGE_UNKNOWN;
497 pi->pi_execpath = internedpath;
498 pi->pi_start = ~0;
499 pi->pi_end = 0;
500 pi->pi_entry = 0;
501 pi->pi_vaddr = 0;
502 pi->pi_isdynamic = 0;
503 pi->pi_iskernelmodule = iskernelmodule;
504 pi->pi_dynlinkerpath = NULL;
505 pi->pi_symbols = NULL;
506 pi->pi_symcount = 0;
507 pi->pi_addr2line = NULL;
508
509 if (plugins[args->pa_pplugin].pl_initimage != NULL)
510 plugins[args->pa_pplugin].pl_initimage(pi);
511 if (plugins[args->pa_plugin].pl_initimage != NULL)
512 plugins[args->pa_plugin].pl_initimage(pi);
513
514 LIST_INSERT_HEAD(&pmcstat_image_hash[hash], pi, pi_next);
515
516 return (pi);
517 }
518