2 * Copyright (c) 1989, 1992, 1993
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5 * This code is derived from software developed by the Computer Systems
6 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
7 * BG 91-66 and contributed to Berkeley.
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37 * @(#)kvm.c 8.2 (Berkeley) 2/13/94
38 * $FreeBSD: src/lib/libkvm/kvm.c,v 1.12.2.3 2002/09/13 14:53:43 nectar Exp $
39 * $DragonFly: src/lib/libkvm/kvm.c,v 1.10 2007/04/29 01:36:04 dillon Exp $
42 #include <sys/user.h> /* MUST BE FIRST */
43 #include <sys/param.h>
45 #include <sys/ioctl.h>
47 #include <sys/sysctl.h>
48 #include <sys/linker.h>
51 #include <vm/vm_param.h>
52 #include <vm/swap_pager.h>
54 #include <machine/vmparam.h>
68 #include "kvm_private.h"
70 /* from src/lib/libc/gen/nlist.c */
71 int __fdnlist (int, struct nlist *);
80 * Report an error using printf style arguments. "program" is kd->program
81 * on hard errors, and 0 on soft errors, so that under sun error emulation,
82 * only hard errors are printed out (otherwise, programs like gdb will
83 * generate tons of error messages when trying to access bogus pointers).
86 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...)
91 if (program != NULL) {
92 (void)fprintf(stderr, "%s: ", program);
93 (void)vfprintf(stderr, fmt, ap);
94 (void)fputc('\n', stderr);
96 (void)vsnprintf(kd->errbuf,
97 sizeof(kd->errbuf), (char *)fmt, ap);
103 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...)
109 if (program != NULL) {
110 (void)fprintf(stderr, "%s: ", program);
111 (void)vfprintf(stderr, fmt, ap);
112 (void)fprintf(stderr, ": %s\n", strerror(errno));
114 char *cp = kd->errbuf;
116 (void)vsnprintf(cp, sizeof(kd->errbuf), (char *)fmt, ap);
118 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s",
125 _kvm_malloc(kvm_t *kd, size_t n)
129 if ((p = calloc(n, sizeof(char))) == NULL)
130 _kvm_err(kd, kd->program, "can't allocate %u bytes: %s",
136 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
151 else if (strlen(uf) >= MAXPATHLEN) {
152 _kvm_err(kd, kd->program, "exec file name too long");
155 if (flag & ~O_RDWR) {
156 _kvm_err(kd, kd->program, "bad flags arg");
162 if ((kd->pmfd = open(mf, flag, 0)) < 0) {
163 _kvm_syserr(kd, kd->program, "%s", mf);
166 if (fstat(kd->pmfd, &st) < 0) {
167 _kvm_syserr(kd, kd->program, "%s", mf);
170 if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) {
171 _kvm_syserr(kd, kd->program, "%s", mf);
174 if (S_ISCHR(st.st_mode)) {
176 * If this is a character special device, then check that
177 * it's /dev/mem. If so, open kmem too. (Maybe we should
178 * make it work for either /dev/mem or /dev/kmem -- in either
179 * case you're working with a live kernel.)
181 if (strcmp(mf, _PATH_DEVNULL) == 0) {
182 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY);
183 } else if (strcmp(mf, _PATH_MEM) != 0) {
184 _kvm_err(kd, kd->program,
185 "%s: not physical memory device", mf);
188 if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) {
189 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
192 if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) {
193 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
199 * This is a crash dump.
200 * Initialize the virtual address translation machinery,
201 * but first setup the namelist fd.
203 if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) {
204 _kvm_syserr(kd, kd->program, "%s", uf);
207 if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) {
208 _kvm_syserr(kd, kd->program, "%s", uf);
211 if (_kvm_initvtop(kd) < 0)
217 * Copy out the error if doing sane error semantics.
220 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
226 kvm_openfiles(const char *uf, const char *mf, const char *sf, int flag,
231 if ((kd = malloc(sizeof(*kd))) == NULL) {
232 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
235 memset(kd, 0, sizeof(*kd));
237 return (_kvm_open(kd, uf, mf, flag, errout));
241 kvm_open(const char *uf, const char *mf, const char *sf, int flag,
246 if ((kd = malloc(sizeof(*kd))) == NULL) {
248 (void)fprintf(stderr, "%s: %s\n",
249 errstr, strerror(errno));
252 memset(kd, 0, sizeof(*kd));
253 kd->program = errstr;
254 return (_kvm_open(kd, uf, mf, flag, NULL));
263 error |= close(kd->pmfd);
265 error |= close(kd->vmfd);
267 error |= close(kd->nlfd);
270 if (kd->procbase != NULL)
273 free((void *)kd->argv);
280 kvm_nlist(kvm_t *kd, struct nlist *nl)
284 struct kld_sym_lookup lookup;
287 * If we can't use the kld symbol lookup, revert to the
291 return (__fdnlist(kd->nlfd, nl));
294 * We can use the kld lookup syscall. Go through each nlist entry
295 * and look it up with a kldsym(2) syscall.
298 for (p = nl; p->n_name && p->n_name[0]; ++p) {
299 lookup.version = sizeof(lookup);
300 lookup.symname = p->n_name;
304 if (lookup.symname[0] == '_')
307 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) {
311 p->n_value = lookup.symvalue;
317 * Return the number of entries that weren't found.
319 return ((p - nl) - nvalid);
323 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
330 * We're using /dev/kmem. Just read straight from the
331 * device and let the active kernel do the address translation.
334 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
335 _kvm_err(kd, 0, "invalid address (%x)", kva);
340 * Try to pre-fault the user memory to reduce instances of
341 * races within the kernel. XXX workaround for kernel bug
342 * where kernel does a sanity check, but user faults during
343 * the copy can block and race against another kernel entity
344 * unmapping the memory in question.
347 cc = read(kd->vmfd, buf, len);
349 _kvm_syserr(kd, 0, "kvm_read");
352 _kvm_err(kd, kd->program, "short read");
359 cc = _kvm_kvatop(kd, kva, &pa);
365 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) {
366 _kvm_syserr(kd, 0, _PATH_MEM);
370 cc = read(kd->pmfd, cp, cc);
372 _kvm_syserr(kd, kd->program, "kvm_read");
376 * If kvm_kvatop returns a bogus value or our core
377 * file is truncated, we might wind up seeking beyond
378 * the end of the core file in which case the read will
383 cp = (char *)cp + cc;
387 return ((char *)cp - (char *)buf);
393 kvm_readstr(kvm_t *kd, u_long kva, char *buf, size_t *lenp)
403 _kvm_syserr(kd, kd->program, "kvm_readstr");
412 * We're using /dev/kmem. Just read straight from the
413 * device and let the active kernel do the address translation.
416 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
417 _kvm_err(kd, 0, "invalid address (%x)", kva);
421 for (pos = 0, ch = -1; ch != 0; pos++) {
422 cc = read(kd->vmfd, &ch, 1);
423 if ((ssize_t)cc < 0) {
424 _kvm_syserr(kd, 0, "kvm_readstr");
427 _kvm_err(kd, kd->program, "short read");
429 buf = realloc(buf, asize *= 2);
431 _kvm_syserr(kd, kd->program, "kvm_readstr");
448 for (pos = 0, ch = -1; ch != 0; pos++, left--, kva++) {
452 left = _kvm_kvatop(kd, kva, &pa);
456 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) {
457 _kvm_syserr(kd, 0, _PATH_MEM);
461 cc = read(kd->vmfd, &ch, 1);
462 if ((ssize_t)cc < 0) {
463 _kvm_syserr(kd, 0, "kvm_readstr");
466 _kvm_err(kd, kd->program, "short read");
468 buf = realloc(buf, asize *= 2);
470 _kvm_syserr(kd, kd->program, "kvm_readstr");
490 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
496 * Just like kvm_read, only we write.
499 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
500 _kvm_err(kd, 0, "invalid address (%x)", kva);
503 cc = write(kd->vmfd, buf, len);
505 _kvm_syserr(kd, 0, "kvm_write");
508 _kvm_err(kd, kd->program, "short write");
511 _kvm_err(kd, kd->program,
512 "kvm_write not implemented for dead kernels");