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984263bc MD |
1 | /*- |
2 | * Copyright (c) 1998 John D. Polstra | |
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: src/usr.bin/gcore/elfcore.c,v 1.5.2.3 2001/07/11 23:59:11 obrien Exp $ | |
27 | */ | |
28 | ||
05220613 MD |
29 | #define _KERNEL_STRUCTURES |
30 | ||
984263bc MD |
31 | #include <sys/param.h> |
32 | #include <sys/lock.h> | |
33 | #include <sys/procfs.h> | |
34 | #include <machine/elf.h> | |
35 | #include <vm/vm_param.h> | |
36 | #include <vm/vm.h> | |
37 | #include <vm/pmap.h> | |
38 | #include <vm/vm_map.h> | |
39 | #include <err.h> | |
40 | #include <errno.h> | |
41 | #include <fcntl.h> | |
42 | #include <stdio.h> | |
43 | #include <stdlib.h> | |
44 | #include <string.h> | |
45 | #include <unistd.h> | |
46 | ||
47 | #include "extern.h" | |
48 | ||
49 | /* | |
50 | * Code for generating ELF core dumps. | |
51 | */ | |
52 | ||
53 | typedef void (*segment_callback)(vm_map_entry_t, void *); | |
54 | ||
55 | /* Closure for cb_put_phdr(). */ | |
56 | struct phdr_closure { | |
57 | Elf_Phdr *phdr; /* Program header to fill in */ | |
58 | Elf_Off offset; /* Offset of segment in core file */ | |
59 | }; | |
60 | ||
61 | /* Closure for cb_size_segment(). */ | |
62 | struct sseg_closure { | |
63 | int count; /* Count of writable segments. */ | |
64 | size_t size; /* Total size of all writable segments. */ | |
65 | }; | |
66 | ||
67 | static void cb_put_phdr(vm_map_entry_t, void *); | |
68 | static void cb_size_segment(vm_map_entry_t, void *); | |
69 | static void each_writable_segment(vm_map_entry_t, segment_callback, | |
70 | void *closure); | |
71 | static void elf_corehdr(int fd, pid_t, vm_map_entry_t, int numsegs, | |
72 | void *hdr, size_t hdrsize); | |
73 | static void elf_puthdr(vm_map_entry_t, void *, size_t *, | |
74 | const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int numsegs); | |
75 | static void elf_putnote(void *dst, size_t *off, const char *name, int type, | |
76 | const void *desc, size_t descsz); | |
77 | static void freemap(vm_map_entry_t); | |
78 | static void readhdrinfo(pid_t, prstatus_t *, prfpregset_t *, prpsinfo_t *); | |
79 | static vm_map_entry_t readmap(pid_t); | |
80 | ||
81 | /* | |
82 | * Write an ELF coredump for the given pid to the given fd. | |
83 | */ | |
84 | void | |
85 | elf_coredump(int fd, pid_t pid) | |
86 | { | |
87 | vm_map_entry_t map; | |
88 | struct sseg_closure seginfo; | |
89 | void *hdr; | |
90 | size_t hdrsize; | |
91 | char memname[64]; | |
92 | int memfd; | |
93 | Elf_Phdr *php; | |
94 | int i; | |
95 | ||
96 | /* Get the program's memory map. */ | |
97 | map = readmap(pid); | |
98 | ||
99 | /* Size the program segments. */ | |
100 | seginfo.count = 0; | |
101 | seginfo.size = 0; | |
102 | each_writable_segment(map, cb_size_segment, &seginfo); | |
103 | ||
104 | /* | |
105 | * Calculate the size of the core file header area by making | |
106 | * a dry run of generating it. Nothing is written, but the | |
107 | * size is calculated. | |
108 | */ | |
109 | hdrsize = 0; | |
2038fb68 | 110 | elf_puthdr(map, NULL, &hdrsize, NULL, NULL, NULL, seginfo.count); |
984263bc MD |
111 | |
112 | /* | |
113 | * Allocate memory for building the header, fill it up, | |
114 | * and write it out. | |
115 | */ | |
116 | hdr = malloc(hdrsize); | |
117 | if ((hdr = malloc(hdrsize)) == NULL) | |
118 | errx(1, "out of memory"); | |
119 | elf_corehdr(fd, pid, map, seginfo.count, hdr, hdrsize); | |
120 | ||
121 | /* Write the contents of all of the writable segments. */ | |
122 | snprintf(memname, sizeof memname, "/proc/%d/mem", pid); | |
123 | if ((memfd = open(memname, O_RDONLY)) == -1) | |
124 | err(1, "cannot open %s", memname); | |
125 | ||
126 | php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1; | |
127 | for (i = 0; i < seginfo.count; i++) { | |
128 | int nleft = php->p_filesz; | |
129 | ||
130 | lseek(memfd, (off_t)php->p_vaddr, SEEK_SET); | |
131 | while (nleft > 0) { | |
132 | char buf[8*1024]; | |
133 | int nwant; | |
134 | int ngot; | |
135 | ||
136 | nwant = nleft; | |
137 | if (nwant > sizeof buf) | |
138 | nwant = sizeof buf; | |
139 | ngot = read(memfd, buf, nwant); | |
140 | if (ngot == -1) | |
141 | err(1, "read from %s", memname); | |
142 | if (ngot < nwant) | |
143 | errx(1, "short read from %s:" | |
144 | " wanted %d, got %d\n", memname, | |
145 | nwant, ngot); | |
146 | ngot = write(fd, buf, nwant); | |
147 | if (ngot == -1) | |
148 | err(1, "write of segment %d failed", i); | |
149 | if (ngot != nwant) | |
150 | errx(1, "short write"); | |
151 | nleft -= nwant; | |
152 | } | |
153 | php++; | |
154 | } | |
155 | close(memfd); | |
156 | free(hdr); | |
157 | freemap(map); | |
158 | } | |
159 | ||
160 | /* | |
161 | * A callback for each_writable_segment() to write out the segment's | |
162 | * program header entry. | |
163 | */ | |
164 | static void | |
165 | cb_put_phdr(vm_map_entry_t entry, void *closure) | |
166 | { | |
167 | struct phdr_closure *phc = (struct phdr_closure *)closure; | |
168 | Elf_Phdr *phdr = phc->phdr; | |
169 | ||
170 | phc->offset = round_page(phc->offset); | |
171 | ||
172 | phdr->p_type = PT_LOAD; | |
173 | phdr->p_offset = phc->offset; | |
174 | phdr->p_vaddr = entry->start; | |
175 | phdr->p_paddr = 0; | |
176 | phdr->p_filesz = phdr->p_memsz = entry->end - entry->start; | |
177 | phdr->p_align = PAGE_SIZE; | |
178 | phdr->p_flags = 0; | |
179 | if (entry->protection & VM_PROT_READ) | |
180 | phdr->p_flags |= PF_R; | |
181 | if (entry->protection & VM_PROT_WRITE) | |
182 | phdr->p_flags |= PF_W; | |
183 | if (entry->protection & VM_PROT_EXECUTE) | |
184 | phdr->p_flags |= PF_X; | |
185 | ||
186 | phc->offset += phdr->p_filesz; | |
187 | phc->phdr++; | |
188 | } | |
189 | ||
190 | /* | |
191 | * A callback for each_writable_segment() to gather information about | |
192 | * the number of segments and their total size. | |
193 | */ | |
194 | static void | |
195 | cb_size_segment(vm_map_entry_t entry, void *closure) | |
196 | { | |
197 | struct sseg_closure *ssc = (struct sseg_closure *)closure; | |
198 | ||
199 | ssc->count++; | |
200 | ssc->size += entry->end - entry->start; | |
201 | } | |
202 | ||
203 | /* | |
204 | * For each segment in the given memory map, call the given function | |
205 | * with a pointer to the map entry and some arbitrary caller-supplied | |
206 | * data. | |
207 | */ | |
208 | static void | |
209 | each_writable_segment(vm_map_entry_t map, segment_callback func, void *closure) | |
210 | { | |
211 | vm_map_entry_t entry; | |
212 | ||
213 | for (entry = map; entry != NULL; entry = entry->next) | |
214 | (*func)(entry, closure); | |
215 | } | |
216 | ||
217 | /* | |
218 | * Write the core file header to the file, including padding up to | |
219 | * the page boundary. | |
220 | */ | |
221 | static void | |
222 | elf_corehdr(int fd, pid_t pid, vm_map_entry_t map, int numsegs, void *hdr, | |
223 | size_t hdrsize) | |
224 | { | |
225 | size_t off; | |
226 | prstatus_t status; | |
227 | prfpregset_t fpregset; | |
228 | prpsinfo_t psinfo; | |
229 | ||
230 | /* Gather the information for the header. */ | |
231 | readhdrinfo(pid, &status, &fpregset, &psinfo); | |
232 | ||
233 | /* Fill in the header. */ | |
234 | memset(hdr, 0, hdrsize); | |
235 | off = 0; | |
236 | elf_puthdr(map, hdr, &off, &status, &fpregset, &psinfo, numsegs); | |
237 | ||
238 | /* Write it to the core file. */ | |
239 | if (write(fd, hdr, hdrsize) == -1) | |
240 | err(1, "write"); | |
241 | } | |
242 | ||
243 | /* | |
244 | * Generate the ELF coredump header into the buffer at "dst". "dst" may | |
245 | * be NULL, in which case the header is sized but not actually generated. | |
246 | */ | |
247 | static void | |
248 | elf_puthdr(vm_map_entry_t map, void *dst, size_t *off, const prstatus_t *status, | |
249 | const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs) | |
250 | { | |
251 | size_t ehoff; | |
252 | size_t phoff; | |
253 | size_t noteoff; | |
254 | size_t notesz; | |
255 | ||
256 | ehoff = *off; | |
257 | *off += sizeof(Elf_Ehdr); | |
258 | ||
259 | phoff = *off; | |
260 | *off += (numsegs + 1) * sizeof(Elf_Phdr); | |
261 | ||
262 | noteoff = *off; | |
263 | elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status, | |
264 | sizeof *status); | |
265 | elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset, | |
266 | sizeof *fpregset); | |
267 | elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo, | |
268 | sizeof *psinfo); | |
269 | notesz = *off - noteoff; | |
270 | ||
271 | /* Align up to a page boundary for the program segments. */ | |
272 | *off = round_page(*off); | |
273 | ||
274 | if (dst != NULL) { | |
275 | Elf_Ehdr *ehdr; | |
276 | Elf_Phdr *phdr; | |
277 | struct phdr_closure phc; | |
278 | ||
279 | /* | |
280 | * Fill in the ELF header. | |
281 | */ | |
282 | ehdr = (Elf_Ehdr *)((char *)dst + ehoff); | |
283 | ehdr->e_ident[EI_MAG0] = ELFMAG0; | |
284 | ehdr->e_ident[EI_MAG1] = ELFMAG1; | |
285 | ehdr->e_ident[EI_MAG2] = ELFMAG2; | |
286 | ehdr->e_ident[EI_MAG3] = ELFMAG3; | |
287 | ehdr->e_ident[EI_CLASS] = ELF_CLASS; | |
288 | ehdr->e_ident[EI_DATA] = ELF_DATA; | |
289 | ehdr->e_ident[EI_VERSION] = EV_CURRENT; | |
05c07bb4 | 290 | ehdr->e_ident[EI_OSABI] = ELFOSABI_NONE; |
984263bc MD |
291 | ehdr->e_ident[EI_ABIVERSION] = 0; |
292 | ehdr->e_ident[EI_PAD] = 0; | |
293 | ehdr->e_type = ET_CORE; | |
294 | ehdr->e_machine = ELF_ARCH; | |
295 | ehdr->e_version = EV_CURRENT; | |
296 | ehdr->e_entry = 0; | |
297 | ehdr->e_phoff = phoff; | |
298 | ehdr->e_flags = 0; | |
299 | ehdr->e_ehsize = sizeof(Elf_Ehdr); | |
300 | ehdr->e_phentsize = sizeof(Elf_Phdr); | |
301 | ehdr->e_phnum = numsegs + 1; | |
302 | ehdr->e_shentsize = sizeof(Elf_Shdr); | |
303 | ehdr->e_shnum = 0; | |
304 | ehdr->e_shstrndx = SHN_UNDEF; | |
305 | ||
306 | /* | |
307 | * Fill in the program header entries. | |
308 | */ | |
309 | phdr = (Elf_Phdr *)((char *)dst + phoff); | |
310 | ||
311 | /* The note segement. */ | |
312 | phdr->p_type = PT_NOTE; | |
313 | phdr->p_offset = noteoff; | |
314 | phdr->p_vaddr = 0; | |
315 | phdr->p_paddr = 0; | |
316 | phdr->p_filesz = notesz; | |
317 | phdr->p_memsz = 0; | |
318 | phdr->p_flags = 0; | |
319 | phdr->p_align = 0; | |
320 | phdr++; | |
321 | ||
322 | /* All the writable segments from the program. */ | |
323 | phc.phdr = phdr; | |
324 | phc.offset = *off; | |
325 | each_writable_segment(map, cb_put_phdr, &phc); | |
326 | } | |
327 | } | |
328 | ||
329 | /* | |
330 | * Emit one note section to "dst", or just size it if "dst" is NULL. | |
331 | */ | |
332 | static void | |
333 | elf_putnote(void *dst, size_t *off, const char *name, int type, | |
334 | const void *desc, size_t descsz) | |
335 | { | |
336 | Elf_Note note; | |
337 | ||
338 | note.n_namesz = strlen(name) + 1; | |
339 | note.n_descsz = descsz; | |
340 | note.n_type = type; | |
341 | if (dst != NULL) | |
342 | bcopy(¬e, (char *)dst + *off, sizeof note); | |
343 | *off += sizeof note; | |
344 | if (dst != NULL) | |
345 | bcopy(name, (char *)dst + *off, note.n_namesz); | |
346 | *off += roundup2(note.n_namesz, sizeof(Elf_Size)); | |
347 | if (dst != NULL) | |
348 | bcopy(desc, (char *)dst + *off, note.n_descsz); | |
349 | *off += roundup2(note.n_descsz, sizeof(Elf_Size)); | |
350 | } | |
351 | ||
352 | /* | |
353 | * Free the memory map. | |
354 | */ | |
355 | static void | |
356 | freemap(vm_map_entry_t map) | |
357 | { | |
358 | while (map != NULL) { | |
359 | vm_map_entry_t next = map->next; | |
360 | free(map); | |
361 | map = next; | |
362 | } | |
363 | } | |
364 | ||
365 | /* | |
366 | * Read the process information necessary to fill in the core file's header. | |
367 | */ | |
368 | static void | |
369 | readhdrinfo(pid_t pid, prstatus_t *status, prfpregset_t *fpregset, | |
370 | prpsinfo_t *psinfo) | |
371 | { | |
372 | char name[64]; | |
373 | char line[256]; | |
374 | int fd; | |
375 | int i; | |
376 | int n; | |
377 | ||
378 | memset(status, 0, sizeof *status); | |
379 | status->pr_version = PRSTATUS_VERSION; | |
380 | status->pr_statussz = sizeof(prstatus_t); | |
381 | status->pr_gregsetsz = sizeof(gregset_t); | |
382 | status->pr_fpregsetsz = sizeof(fpregset_t); | |
844fcdc6 | 383 | status->pr_osreldate = __DragonFly_version; |
984263bc MD |
384 | status->pr_pid = pid; |
385 | ||
386 | memset(fpregset, 0, sizeof *fpregset); | |
387 | ||
388 | memset(psinfo, 0, sizeof *psinfo); | |
389 | psinfo->pr_version = PRPSINFO_VERSION; | |
390 | psinfo->pr_psinfosz = sizeof(prpsinfo_t); | |
391 | ||
392 | /* Read the general registers. */ | |
393 | snprintf(name, sizeof name, "/proc/%d/regs", pid); | |
394 | if ((fd = open(name, O_RDONLY)) == -1) | |
395 | err(1, "cannot open %s", name); | |
396 | if ((n = read(fd, &status->pr_reg, sizeof status->pr_reg)) == -1) | |
397 | err(1, "read error from %s", name); | |
398 | if (n < sizeof status->pr_reg) | |
424e8382 MD |
399 | errx(1, "short read from %s: wanted %zu, got %d", |
400 | name, sizeof(status->pr_reg), n); | |
984263bc MD |
401 | close(fd); |
402 | ||
403 | /* Read the floating point registers. */ | |
404 | snprintf(name, sizeof name, "/proc/%d/fpregs", pid); | |
405 | if ((fd = open(name, O_RDONLY)) == -1) | |
406 | err(1, "cannot open %s", name); | |
407 | if ((n = read(fd, fpregset, sizeof *fpregset)) == -1) | |
408 | err(1, "read error from %s", name); | |
409 | if (n < sizeof *fpregset) | |
424e8382 MD |
410 | errx(1, "short read from %s: wanted %zu, got %d", |
411 | name, sizeof(*fpregset), n); | |
984263bc MD |
412 | close(fd); |
413 | ||
414 | /* Read and parse the process status. */ | |
415 | snprintf(name, sizeof name, "/proc/%d/status", pid); | |
416 | if ((fd = open(name, O_RDONLY)) == -1) | |
417 | err(1, "cannot open %s", name); | |
418 | if ((n = read(fd, line, sizeof line - 1)) == -1) | |
419 | err(1, "read error from %s", name); | |
420 | if (n > MAXCOMLEN) | |
421 | n = MAXCOMLEN; | |
422 | for (i = 0; i < n && line[i] != ' '; i++) | |
423 | psinfo->pr_fname[i] = line[i]; | |
424 | strncpy(psinfo->pr_psargs, psinfo->pr_fname, PRARGSZ); | |
425 | close(fd); | |
426 | } | |
427 | ||
428 | /* | |
429 | * Read the process's memory map using procfs, and return a list of | |
430 | * VM map entries. Only the non-device read/writable segments are | |
431 | * returned. The map entries in the list aren't fully filled in; only | |
432 | * the items we need are present. | |
433 | */ | |
434 | static vm_map_entry_t | |
435 | readmap(pid_t pid) | |
436 | { | |
437 | char mapname[64]; | |
438 | int mapfd; | |
439 | ssize_t mapsize; | |
440 | size_t bufsize; | |
441 | char *mapbuf; | |
442 | int pos; | |
443 | vm_map_entry_t map; | |
444 | vm_map_entry_t *linkp; | |
445 | ||
446 | snprintf(mapname, sizeof mapname, "/proc/%d/map", pid); | |
447 | if ((mapfd = open(mapname, O_RDONLY)) == -1) | |
448 | err(1, "cannot open %s", mapname); | |
449 | ||
450 | /* | |
451 | * Procfs requires (for consistency) that the entire memory map | |
452 | * be read with a single read() call. Start with a reasonbly sized | |
453 | * buffer, and double it until it is big enough. | |
454 | */ | |
455 | bufsize = 8 * 1024; | |
456 | mapbuf = NULL; | |
457 | for ( ; ; ) { | |
458 | if ((mapbuf = realloc(mapbuf, bufsize + 1)) == NULL) | |
459 | errx(1, "out of memory"); | |
460 | mapsize = read(mapfd, mapbuf, bufsize); | |
461 | if (mapsize != -1 || errno != EFBIG) | |
462 | break; | |
463 | bufsize *= 2; | |
464 | /* This lseek shouldn't be necessary, but it is. */ | |
465 | lseek(mapfd, (off_t)0, SEEK_SET); | |
466 | } | |
467 | if (mapsize == -1) | |
468 | err(1, "read error from %s", mapname); | |
469 | if (mapsize == 0) | |
470 | errx(1, "empty map file %s", mapname); | |
471 | mapbuf[mapsize] = 0; | |
472 | close(mapfd); | |
473 | ||
474 | pos = 0; | |
475 | map = NULL; | |
476 | linkp = ↦ | |
477 | while (pos < mapsize) { | |
478 | vm_map_entry_t ent; | |
479 | vm_offset_t start; | |
480 | vm_offset_t end; | |
481 | char prot[4]; | |
482 | char type[16]; | |
483 | int n; | |
484 | int len; | |
485 | ||
486 | len = 0; | |
e11cf02d | 487 | n = sscanf(mapbuf + pos, "%lx %lx %*d %*d %*x %3[-rwx]" |
05c07bb4 | 488 | " %*d %*d %*x %*s %*s %16s %*s%*[\n]%n", |
984263bc MD |
489 | &start, &end, prot, type, &len); |
490 | if (n != 4) | |
491 | errx(1, "ill-formed line in %s", mapname); | |
492 | pos += len; | |
493 | ||
494 | /* Ignore segments of the wrong kind, and unwritable ones */ | |
495 | if (strncmp(prot, "rw", 2) != 0 || | |
496 | (strcmp(type, "default") != 0 && | |
497 | strcmp(type, "vnode") != 0 && | |
498 | strcmp(type, "swap") != 0)) | |
499 | continue; | |
500 | ||
501 | if ((ent = (vm_map_entry_t)calloc(1, sizeof *ent)) == NULL) | |
502 | errx(1, "out of memory"); | |
503 | ent->start = start; | |
504 | ent->end = end; | |
505 | ent->protection = VM_PROT_READ | VM_PROT_WRITE; | |
506 | if (prot[2] == 'x') | |
507 | ent->protection |= VM_PROT_EXECUTE; | |
508 | ||
509 | *linkp = ent; | |
510 | linkp = &ent->next; | |
511 | } | |
512 | free(mapbuf); | |
513 | return map; | |
514 | } |