Fix miscellanious size_t related compiler warnings.
[dragonfly.git] / usr.bin / gcore / elfcore.c
CommitLineData
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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 $
3641b7ca 27 * $DragonFly: src/usr.bin/gcore/elfcore.c,v 1.5 2008/06/05 18:06:33 swildner Exp $
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28 */
29
05220613
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30#define _KERNEL_STRUCTURES
31
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32#include <sys/param.h>
33#include <sys/lock.h>
34#include <sys/procfs.h>
35#include <machine/elf.h>
36#include <vm/vm_param.h>
37#include <vm/vm.h>
38#include <vm/pmap.h>
39#include <vm/vm_map.h>
40#include <err.h>
41#include <errno.h>
42#include <fcntl.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48#include "extern.h"
49
50/*
51 * Code for generating ELF core dumps.
52 */
53
54typedef void (*segment_callback)(vm_map_entry_t, void *);
55
56/* Closure for cb_put_phdr(). */
57struct phdr_closure {
58 Elf_Phdr *phdr; /* Program header to fill in */
59 Elf_Off offset; /* Offset of segment in core file */
60};
61
62/* Closure for cb_size_segment(). */
63struct sseg_closure {
64 int count; /* Count of writable segments. */
65 size_t size; /* Total size of all writable segments. */
66};
67
68static void cb_put_phdr(vm_map_entry_t, void *);
69static void cb_size_segment(vm_map_entry_t, void *);
70static void each_writable_segment(vm_map_entry_t, segment_callback,
71 void *closure);
72static void elf_corehdr(int fd, pid_t, vm_map_entry_t, int numsegs,
73 void *hdr, size_t hdrsize);
74static void elf_puthdr(vm_map_entry_t, void *, size_t *,
75 const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int numsegs);
76static void elf_putnote(void *dst, size_t *off, const char *name, int type,
77 const void *desc, size_t descsz);
78static void freemap(vm_map_entry_t);
79static void readhdrinfo(pid_t, prstatus_t *, prfpregset_t *, prpsinfo_t *);
80static vm_map_entry_t readmap(pid_t);
81
82/*
83 * Write an ELF coredump for the given pid to the given fd.
84 */
85void
86elf_coredump(int fd, pid_t pid)
87{
88 vm_map_entry_t map;
89 struct sseg_closure seginfo;
90 void *hdr;
91 size_t hdrsize;
92 char memname[64];
93 int memfd;
94 Elf_Phdr *php;
95 int i;
96
97 /* Get the program's memory map. */
98 map = readmap(pid);
99
100 /* Size the program segments. */
101 seginfo.count = 0;
102 seginfo.size = 0;
103 each_writable_segment(map, cb_size_segment, &seginfo);
104
105 /*
106 * Calculate the size of the core file header area by making
107 * a dry run of generating it. Nothing is written, but the
108 * size is calculated.
109 */
110 hdrsize = 0;
2038fb68 111 elf_puthdr(map, NULL, &hdrsize, NULL, NULL, NULL, seginfo.count);
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112
113 /*
114 * Allocate memory for building the header, fill it up,
115 * and write it out.
116 */
117 hdr = malloc(hdrsize);
118 if ((hdr = malloc(hdrsize)) == NULL)
119 errx(1, "out of memory");
120 elf_corehdr(fd, pid, map, seginfo.count, hdr, hdrsize);
121
122 /* Write the contents of all of the writable segments. */
123 snprintf(memname, sizeof memname, "/proc/%d/mem", pid);
124 if ((memfd = open(memname, O_RDONLY)) == -1)
125 err(1, "cannot open %s", memname);
126
127 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
128 for (i = 0; i < seginfo.count; i++) {
129 int nleft = php->p_filesz;
130
131 lseek(memfd, (off_t)php->p_vaddr, SEEK_SET);
132 while (nleft > 0) {
133 char buf[8*1024];
134 int nwant;
135 int ngot;
136
137 nwant = nleft;
138 if (nwant > sizeof buf)
139 nwant = sizeof buf;
140 ngot = read(memfd, buf, nwant);
141 if (ngot == -1)
142 err(1, "read from %s", memname);
143 if (ngot < nwant)
144 errx(1, "short read from %s:"
145 " wanted %d, got %d\n", memname,
146 nwant, ngot);
147 ngot = write(fd, buf, nwant);
148 if (ngot == -1)
149 err(1, "write of segment %d failed", i);
150 if (ngot != nwant)
151 errx(1, "short write");
152 nleft -= nwant;
153 }
154 php++;
155 }
156 close(memfd);
157 free(hdr);
158 freemap(map);
159}
160
161/*
162 * A callback for each_writable_segment() to write out the segment's
163 * program header entry.
164 */
165static void
166cb_put_phdr(vm_map_entry_t entry, void *closure)
167{
168 struct phdr_closure *phc = (struct phdr_closure *)closure;
169 Elf_Phdr *phdr = phc->phdr;
170
171 phc->offset = round_page(phc->offset);
172
173 phdr->p_type = PT_LOAD;
174 phdr->p_offset = phc->offset;
175 phdr->p_vaddr = entry->start;
176 phdr->p_paddr = 0;
177 phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
178 phdr->p_align = PAGE_SIZE;
179 phdr->p_flags = 0;
180 if (entry->protection & VM_PROT_READ)
181 phdr->p_flags |= PF_R;
182 if (entry->protection & VM_PROT_WRITE)
183 phdr->p_flags |= PF_W;
184 if (entry->protection & VM_PROT_EXECUTE)
185 phdr->p_flags |= PF_X;
186
187 phc->offset += phdr->p_filesz;
188 phc->phdr++;
189}
190
191/*
192 * A callback for each_writable_segment() to gather information about
193 * the number of segments and their total size.
194 */
195static void
196cb_size_segment(vm_map_entry_t entry, void *closure)
197{
198 struct sseg_closure *ssc = (struct sseg_closure *)closure;
199
200 ssc->count++;
201 ssc->size += entry->end - entry->start;
202}
203
204/*
205 * For each segment in the given memory map, call the given function
206 * with a pointer to the map entry and some arbitrary caller-supplied
207 * data.
208 */
209static void
210each_writable_segment(vm_map_entry_t map, segment_callback func, void *closure)
211{
212 vm_map_entry_t entry;
213
214 for (entry = map; entry != NULL; entry = entry->next)
215 (*func)(entry, closure);
216}
217
218/*
219 * Write the core file header to the file, including padding up to
220 * the page boundary.
221 */
222static void
223elf_corehdr(int fd, pid_t pid, vm_map_entry_t map, int numsegs, void *hdr,
224 size_t hdrsize)
225{
226 size_t off;
227 prstatus_t status;
228 prfpregset_t fpregset;
229 prpsinfo_t psinfo;
230
231 /* Gather the information for the header. */
232 readhdrinfo(pid, &status, &fpregset, &psinfo);
233
234 /* Fill in the header. */
235 memset(hdr, 0, hdrsize);
236 off = 0;
237 elf_puthdr(map, hdr, &off, &status, &fpregset, &psinfo, numsegs);
238
239 /* Write it to the core file. */
240 if (write(fd, hdr, hdrsize) == -1)
241 err(1, "write");
242}
243
244/*
245 * Generate the ELF coredump header into the buffer at "dst". "dst" may
246 * be NULL, in which case the header is sized but not actually generated.
247 */
248static void
249elf_puthdr(vm_map_entry_t map, void *dst, size_t *off, const prstatus_t *status,
250 const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
251{
252 size_t ehoff;
253 size_t phoff;
254 size_t noteoff;
255 size_t notesz;
256
257 ehoff = *off;
258 *off += sizeof(Elf_Ehdr);
259
260 phoff = *off;
261 *off += (numsegs + 1) * sizeof(Elf_Phdr);
262
263 noteoff = *off;
264 elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
265 sizeof *status);
266 elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
267 sizeof *fpregset);
268 elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
269 sizeof *psinfo);
270 notesz = *off - noteoff;
271
272 /* Align up to a page boundary for the program segments. */
273 *off = round_page(*off);
274
275 if (dst != NULL) {
276 Elf_Ehdr *ehdr;
277 Elf_Phdr *phdr;
278 struct phdr_closure phc;
279
280 /*
281 * Fill in the ELF header.
282 */
283 ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
284 ehdr->e_ident[EI_MAG0] = ELFMAG0;
285 ehdr->e_ident[EI_MAG1] = ELFMAG1;
286 ehdr->e_ident[EI_MAG2] = ELFMAG2;
287 ehdr->e_ident[EI_MAG3] = ELFMAG3;
288 ehdr->e_ident[EI_CLASS] = ELF_CLASS;
289 ehdr->e_ident[EI_DATA] = ELF_DATA;
290 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
291 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
292 ehdr->e_ident[EI_ABIVERSION] = 0;
293 ehdr->e_ident[EI_PAD] = 0;
294 ehdr->e_type = ET_CORE;
295 ehdr->e_machine = ELF_ARCH;
296 ehdr->e_version = EV_CURRENT;
297 ehdr->e_entry = 0;
298 ehdr->e_phoff = phoff;
299 ehdr->e_flags = 0;
300 ehdr->e_ehsize = sizeof(Elf_Ehdr);
301 ehdr->e_phentsize = sizeof(Elf_Phdr);
302 ehdr->e_phnum = numsegs + 1;
303 ehdr->e_shentsize = sizeof(Elf_Shdr);
304 ehdr->e_shnum = 0;
305 ehdr->e_shstrndx = SHN_UNDEF;
306
307 /*
308 * Fill in the program header entries.
309 */
310 phdr = (Elf_Phdr *)((char *)dst + phoff);
311
312 /* The note segement. */
313 phdr->p_type = PT_NOTE;
314 phdr->p_offset = noteoff;
315 phdr->p_vaddr = 0;
316 phdr->p_paddr = 0;
317 phdr->p_filesz = notesz;
318 phdr->p_memsz = 0;
319 phdr->p_flags = 0;
320 phdr->p_align = 0;
321 phdr++;
322
323 /* All the writable segments from the program. */
324 phc.phdr = phdr;
325 phc.offset = *off;
326 each_writable_segment(map, cb_put_phdr, &phc);
327 }
328}
329
330/*
331 * Emit one note section to "dst", or just size it if "dst" is NULL.
332 */
333static void
334elf_putnote(void *dst, size_t *off, const char *name, int type,
335 const void *desc, size_t descsz)
336{
337 Elf_Note note;
338
339 note.n_namesz = strlen(name) + 1;
340 note.n_descsz = descsz;
341 note.n_type = type;
342 if (dst != NULL)
343 bcopy(&note, (char *)dst + *off, sizeof note);
344 *off += sizeof note;
345 if (dst != NULL)
346 bcopy(name, (char *)dst + *off, note.n_namesz);
347 *off += roundup2(note.n_namesz, sizeof(Elf_Size));
348 if (dst != NULL)
349 bcopy(desc, (char *)dst + *off, note.n_descsz);
350 *off += roundup2(note.n_descsz, sizeof(Elf_Size));
351}
352
353/*
354 * Free the memory map.
355 */
356static void
357freemap(vm_map_entry_t map)
358{
359 while (map != NULL) {
360 vm_map_entry_t next = map->next;
361 free(map);
362 map = next;
363 }
364}
365
366/*
367 * Read the process information necessary to fill in the core file's header.
368 */
369static void
370readhdrinfo(pid_t pid, prstatus_t *status, prfpregset_t *fpregset,
371 prpsinfo_t *psinfo)
372{
373 char name[64];
374 char line[256];
375 int fd;
376 int i;
377 int n;
378
379 memset(status, 0, sizeof *status);
380 status->pr_version = PRSTATUS_VERSION;
381 status->pr_statussz = sizeof(prstatus_t);
382 status->pr_gregsetsz = sizeof(gregset_t);
383 status->pr_fpregsetsz = sizeof(fpregset_t);
844fcdc6 384 status->pr_osreldate = __DragonFly_version;
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385 status->pr_pid = pid;
386
387 memset(fpregset, 0, sizeof *fpregset);
388
389 memset(psinfo, 0, sizeof *psinfo);
390 psinfo->pr_version = PRPSINFO_VERSION;
391 psinfo->pr_psinfosz = sizeof(prpsinfo_t);
392
393 /* Read the general registers. */
394 snprintf(name, sizeof name, "/proc/%d/regs", pid);
395 if ((fd = open(name, O_RDONLY)) == -1)
396 err(1, "cannot open %s", name);
397 if ((n = read(fd, &status->pr_reg, sizeof status->pr_reg)) == -1)
398 err(1, "read error from %s", name);
399 if (n < sizeof status->pr_reg)
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400 errx(1, "short read from %s: wanted %zu, got %d",
401 name, sizeof(status->pr_reg), n);
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402 close(fd);
403
404 /* Read the floating point registers. */
405 snprintf(name, sizeof name, "/proc/%d/fpregs", pid);
406 if ((fd = open(name, O_RDONLY)) == -1)
407 err(1, "cannot open %s", name);
408 if ((n = read(fd, fpregset, sizeof *fpregset)) == -1)
409 err(1, "read error from %s", name);
410 if (n < sizeof *fpregset)
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411 errx(1, "short read from %s: wanted %zu, got %d",
412 name, sizeof(*fpregset), n);
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413 close(fd);
414
415 /* Read and parse the process status. */
416 snprintf(name, sizeof name, "/proc/%d/status", pid);
417 if ((fd = open(name, O_RDONLY)) == -1)
418 err(1, "cannot open %s", name);
419 if ((n = read(fd, line, sizeof line - 1)) == -1)
420 err(1, "read error from %s", name);
421 if (n > MAXCOMLEN)
422 n = MAXCOMLEN;
423 for (i = 0; i < n && line[i] != ' '; i++)
424 psinfo->pr_fname[i] = line[i];
425 strncpy(psinfo->pr_psargs, psinfo->pr_fname, PRARGSZ);
426 close(fd);
427}
428
429/*
430 * Read the process's memory map using procfs, and return a list of
431 * VM map entries. Only the non-device read/writable segments are
432 * returned. The map entries in the list aren't fully filled in; only
433 * the items we need are present.
434 */
435static vm_map_entry_t
436readmap(pid_t pid)
437{
438 char mapname[64];
439 int mapfd;
440 ssize_t mapsize;
441 size_t bufsize;
442 char *mapbuf;
443 int pos;
444 vm_map_entry_t map;
445 vm_map_entry_t *linkp;
446
447 snprintf(mapname, sizeof mapname, "/proc/%d/map", pid);
448 if ((mapfd = open(mapname, O_RDONLY)) == -1)
449 err(1, "cannot open %s", mapname);
450
451 /*
452 * Procfs requires (for consistency) that the entire memory map
453 * be read with a single read() call. Start with a reasonbly sized
454 * buffer, and double it until it is big enough.
455 */
456 bufsize = 8 * 1024;
457 mapbuf = NULL;
458 for ( ; ; ) {
459 if ((mapbuf = realloc(mapbuf, bufsize + 1)) == NULL)
460 errx(1, "out of memory");
461 mapsize = read(mapfd, mapbuf, bufsize);
462 if (mapsize != -1 || errno != EFBIG)
463 break;
464 bufsize *= 2;
465 /* This lseek shouldn't be necessary, but it is. */
466 lseek(mapfd, (off_t)0, SEEK_SET);
467 }
468 if (mapsize == -1)
469 err(1, "read error from %s", mapname);
470 if (mapsize == 0)
471 errx(1, "empty map file %s", mapname);
472 mapbuf[mapsize] = 0;
473 close(mapfd);
474
475 pos = 0;
476 map = NULL;
477 linkp = &map;
478 while (pos < mapsize) {
479 vm_map_entry_t ent;
480 vm_offset_t start;
481 vm_offset_t end;
482 char prot[4];
483 char type[16];
484 int n;
485 int len;
486
487 len = 0;
424e8382 488 n = sscanf(mapbuf + pos, "%p %p %*d %*d %*x %3[-rwx]"
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489 " %*d %*d %*x %*s %*s %16s%*[\n]%n",
490 &start, &end, prot, type, &len);
491 if (n != 4)
492 errx(1, "ill-formed line in %s", mapname);
493 pos += len;
494
495 /* Ignore segments of the wrong kind, and unwritable ones */
496 if (strncmp(prot, "rw", 2) != 0 ||
497 (strcmp(type, "default") != 0 &&
498 strcmp(type, "vnode") != 0 &&
499 strcmp(type, "swap") != 0))
500 continue;
501
502 if ((ent = (vm_map_entry_t)calloc(1, sizeof *ent)) == NULL)
503 errx(1, "out of memory");
504 ent->start = start;
505 ent->end = end;
506 ent->protection = VM_PROT_READ | VM_PROT_WRITE;
507 if (prot[2] == 'x')
508 ent->protection |= VM_PROT_EXECUTE;
509
510 *linkp = ent;
511 linkp = &ent->next;
512 }
513 free(mapbuf);
514 return map;
515}