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 $
41 #include <sys/user.h> /* MUST BE FIRST */
42 #include <sys/param.h>
44 #include <sys/ioctl.h>
46 #include <sys/sysctl.h>
47 #include <sys/linker.h>
50 #include <vm/vm_param.h>
51 #include <vm/swap_pager.h>
53 #include <machine/vmparam.h>
67 #include "kvm_private.h"
69 /* from src/lib/libc/gen/nlist.c */
70 int __fdnlist (int, struct nlist *);
79 * Report an error using printf style arguments. "program" is kd->program
80 * on hard errors, and 0 on soft errors, so that under sun error emulation,
81 * only hard errors are printed out (otherwise, programs like gdb will
82 * generate tons of error messages when trying to access bogus pointers).
85 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...)
90 if (program != NULL) {
91 (void)fprintf(stderr, "%s: ", program);
92 (void)vfprintf(stderr, fmt, ap);
93 (void)fputc('\n', stderr);
95 (void)vsnprintf(kd->errbuf,
96 sizeof(kd->errbuf), (char *)fmt, ap);
102 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...)
108 if (program != NULL) {
109 (void)fprintf(stderr, "%s: ", program);
110 (void)vfprintf(stderr, fmt, ap);
111 (void)fprintf(stderr, ": %s\n", strerror(errno));
113 char *cp = kd->errbuf;
115 (void)vsnprintf(cp, sizeof(kd->errbuf), (char *)fmt, ap);
117 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s",
124 _kvm_malloc(kvm_t *kd, size_t n)
128 if ((p = calloc(n, sizeof(char))) == NULL)
129 _kvm_err(kd, kd->program, "can't allocate %zd bytes: %s",
135 is_proc_mem(const char *p)
137 static char proc[] = "/proc/";
138 static char mem[] = "/mem";
139 if (strncmp(proc, p, sizeof(proc) - 1))
141 p += sizeof(proc) - 1;
142 for (; p != '\0'; ++p)
145 if (!isdigit(*(p - 1)))
147 return !strncmp(p, mem, sizeof(mem) - 1);
151 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
167 else if (strlen(uf) >= MAXPATHLEN) {
168 _kvm_err(kd, kd->program, "exec file name too long");
171 if (flag & ~O_RDWR) {
172 _kvm_err(kd, kd->program, "bad flags arg");
178 if ((kd->pmfd = open(mf, flag, 0)) < 0) {
179 _kvm_syserr(kd, kd->program, "%s", mf);
182 if (fstat(kd->pmfd, &st) < 0) {
183 _kvm_syserr(kd, kd->program, "%s", mf);
186 if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) {
187 _kvm_syserr(kd, kd->program, "%s", mf);
190 if (S_ISCHR(st.st_mode)) {
192 * If this is a character special device, then check that
193 * it's /dev/mem. If so, open kmem too. (Maybe we should
194 * make it work for either /dev/mem or /dev/kmem -- in either
195 * case you're working with a live kernel.)
197 if (strcmp(mf, _PATH_DEVNULL) == 0) {
198 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY);
200 if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) {
201 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
204 if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) {
205 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
209 kd->flags |= KVMF_HOST;
212 * Crash dump or vkernel /proc/$pid/mem file:
213 * can't use kldsym, we are going to need ->nlfd
215 if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) {
216 _kvm_syserr(kd, kd->program, "%s", uf);
219 if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) {
220 _kvm_syserr(kd, kd->program, "%s", uf);
223 if(is_proc_mem(mf)) {
225 * It's /proc/$pid/mem, so we rely on the host
226 * kernel to do address translation for us.
230 kd->flags |= KVMF_VKERN;
232 if (st.st_size <= 0) {
234 _kvm_syserr(kd, kd->program, "empty file");
239 * This is a crash dump.
240 * Initialize the virtual address translation machinery,
241 * but first setup the namelist fd.
243 if (_kvm_initvtop(kd) < 0)
250 * Copy out the error if doing sane error semantics.
253 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
259 kvm_openfiles(const char *uf, const char *mf, const char *sf, int flag,
264 if ((kd = malloc(sizeof(*kd))) == NULL) {
265 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
268 memset(kd, 0, sizeof(*kd));
270 return (_kvm_open(kd, uf, mf, flag, errout));
274 kvm_open(const char *uf, const char *mf, const char *sf, int flag,
279 if ((kd = malloc(sizeof(*kd))) == NULL) {
281 (void)fprintf(stderr, "%s: %s\n",
282 errstr, strerror(errno));
285 memset(kd, 0, sizeof(*kd));
286 kd->program = errstr;
287 return (_kvm_open(kd, uf, mf, flag, NULL));
296 error |= close(kd->pmfd);
298 error |= close(kd->vmfd);
300 error |= close(kd->nlfd);
303 if (kd->procbase != NULL)
306 free((void *)kd->argv);
313 kvm_nlist(kvm_t *kd, struct nlist *nl)
317 struct kld_sym_lookup lookup;
321 * If we can't use the kld symbol lookup, revert to the
325 return (__fdnlist(kd->nlfd, nl));
328 * We can use the kld lookup syscall. Go through each nlist entry
329 * and look it up with a kldsym(2) syscall.
332 for (p = nl; p->n_name && p->n_name[0]; ++p) {
333 lookup.version = sizeof(lookup);
334 lookup.symname = p->n_name;
338 if (lookup.symname[0] == '_')
341 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) {
345 p->n_value = lookup.symvalue;
351 * Return the number of entries that weren't found. If they exist,
352 * also fill internal error buffer.
354 error = ((p - nl) - nvalid);
356 _kvm_syserr(kd, kd->program, "kvm_nlist");
361 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
366 if (kvm_notrans(kd)) {
368 * We're using /dev/kmem. Just read straight from the
369 * device and let the active kernel do the address translation.
372 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
373 _kvm_err(kd, 0, "invalid address (%lx)", kva);
378 * Try to pre-fault the user memory to reduce instances of
379 * races within the kernel. XXX workaround for kernel bug
380 * where kernel does a sanity check, but user faults during
381 * the copy can block and race against another kernel entity
382 * unmapping the memory in question.
385 cc = read(kd->vmfd, buf, len);
387 _kvm_syserr(kd, 0, "kvm_read");
390 _kvm_err(kd, kd->program, "short read");
397 cc = _kvm_kvatop(kd, kva, &pa);
403 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
404 _kvm_syserr(kd, 0, _PATH_MEM);
408 cc = read(kd->pmfd, cp, cc);
410 _kvm_syserr(kd, kd->program, "kvm_read");
414 * If kvm_kvatop returns a bogus value or our core
415 * file is truncated, we might wind up seeking beyond
416 * the end of the core file in which case the read will
421 cp = (char *)cp + cc;
425 return ((char *)cp - (char *)buf);
431 kvm_readstr(kvm_t *kd, u_long kva, char *buf, size_t *lenp)
441 _kvm_syserr(kd, kd->program, "kvm_readstr");
448 if (kvm_notrans(kd)) {
450 * We're using /dev/kmem. Just read straight from the
451 * device and let the active kernel do the address translation.
454 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
455 _kvm_err(kd, 0, "invalid address (%lx)", kva);
459 for (pos = 0, ch = -1; ch != 0; pos++) {
460 cc = read(kd->vmfd, &ch, 1);
461 if ((ssize_t)cc < 0) {
462 _kvm_syserr(kd, 0, "kvm_readstr");
465 _kvm_err(kd, kd->program, "short read");
467 buf = realloc(buf, asize *= 2);
469 _kvm_syserr(kd, kd->program, "kvm_readstr");
486 for (pos = 0, ch = -1; ch != 0; pos++, left--, kva++) {
490 left = _kvm_kvatop(kd, kva, &pa);
494 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) {
495 _kvm_syserr(kd, 0, _PATH_MEM);
499 cc = read(kd->pmfd, &ch, 1);
500 if ((ssize_t)cc < 0) {
501 _kvm_syserr(kd, 0, "kvm_readstr");
504 _kvm_err(kd, kd->program, "short read");
506 buf = realloc(buf, asize *= 2);
508 _kvm_syserr(kd, kd->program, "kvm_readstr");
528 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
532 if (kvm_notrans(kd)) {
534 * Just like kvm_read, only we write.
537 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
538 _kvm_err(kd, 0, "invalid address (%lx)", kva);
541 cc = write(kd->vmfd, buf, len);
543 _kvm_syserr(kd, 0, "kvm_write");
546 _kvm_err(kd, kd->program, "short write");
549 _kvm_err(kd, kd->program,
550 "kvm_write not implemented for dead kernels");