diff options
Diffstat (limited to 'lib/libkvm/kvm.c')
| -rw-r--r-- | lib/libkvm/kvm.c | 594 |
1 files changed, 594 insertions, 0 deletions
diff --git a/lib/libkvm/kvm.c b/lib/libkvm/kvm.c new file mode 100644 index 0000000..6c19a14 --- /dev/null +++ b/lib/libkvm/kvm.c @@ -0,0 +1,594 @@ +/*- + * Copyright (c) 1989, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software developed by the Computer Systems + * Engineering group at Lawrence Berkeley Laboratory under DARPA contract + * BG 91-66 and contributed to Berkeley. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#if defined(LIBC_SCCS) && !defined(lint) +#if 0 +static char sccsid[] = "@(#)kvm.c 8.2 (Berkeley) 2/13/94"; +#endif +#endif /* LIBC_SCCS and not lint */ + +#include <sys/param.h> + +#define _WANT_VNET + +#include <sys/user.h> +#include <sys/proc.h> +#include <sys/ioctl.h> +#include <sys/stat.h> +#include <sys/sysctl.h> +#include <sys/linker.h> +#include <sys/pcpu.h> + +#include <net/vnet.h> + +#include <vm/vm.h> +#include <vm/vm_param.h> + +#include <machine/vmparam.h> + +#include <ctype.h> +#include <fcntl.h> +#include <kvm.h> +#include <limits.h> +#include <nlist.h> +#include <paths.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <strings.h> +#include <unistd.h> + +#include "kvm_private.h" + +/* from src/lib/libc/gen/nlist.c */ +int __fdnlist(int, struct nlist *); + +char * +kvm_geterr(kvm_t *kd) +{ + return (kd->errbuf); +} + +#include <stdarg.h> + +/* + * Report an error using printf style arguments. "program" is kd->program + * on hard errors, and 0 on soft errors, so that under sun error emulation, + * only hard errors are printed out (otherwise, programs like gdb will + * generate tons of error messages when trying to access bogus pointers). + */ +void +_kvm_err(kvm_t *kd, const char *program, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + if (program != NULL) { + (void)fprintf(stderr, "%s: ", program); + (void)vfprintf(stderr, fmt, ap); + (void)fputc('\n', stderr); + } else + (void)vsnprintf(kd->errbuf, + sizeof(kd->errbuf), fmt, ap); + + va_end(ap); +} + +void +_kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...) +{ + va_list ap; + int n; + + va_start(ap, fmt); + if (program != NULL) { + (void)fprintf(stderr, "%s: ", program); + (void)vfprintf(stderr, fmt, ap); + (void)fprintf(stderr, ": %s\n", strerror(errno)); + } else { + char *cp = kd->errbuf; + + (void)vsnprintf(cp, sizeof(kd->errbuf), fmt, ap); + n = strlen(cp); + (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s", + strerror(errno)); + } + va_end(ap); +} + +void * +_kvm_malloc(kvm_t *kd, size_t n) +{ + void *p; + + if ((p = calloc(n, sizeof(char))) == NULL) + _kvm_err(kd, kd->program, "can't allocate %zu bytes: %s", + n, strerror(errno)); + return (p); +} + +static kvm_t * +_kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) +{ + struct stat st; + + kd->vmfd = -1; + kd->pmfd = -1; + kd->nlfd = -1; + kd->vmst = 0; + kd->procbase = 0; + kd->argspc = 0; + kd->argv = 0; + + if (uf == 0) + uf = getbootfile(); + else if (strlen(uf) >= MAXPATHLEN) { + _kvm_err(kd, kd->program, "exec file name too long"); + goto failed; + } + if (flag & ~O_RDWR) { + _kvm_err(kd, kd->program, "bad flags arg"); + goto failed; + } + if (mf == 0) + mf = _PATH_MEM; + + if ((kd->pmfd = open(mf, flag, 0)) < 0) { + _kvm_syserr(kd, kd->program, "%s", mf); + goto failed; + } + if (fstat(kd->pmfd, &st) < 0) { + _kvm_syserr(kd, kd->program, "%s", mf); + goto failed; + } + if (S_ISREG(st.st_mode) && st.st_size <= 0) { + errno = EINVAL; + _kvm_syserr(kd, kd->program, "empty file"); + goto failed; + } + if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) { + _kvm_syserr(kd, kd->program, "%s", mf); + goto failed; + } + if (S_ISCHR(st.st_mode)) { + /* + * If this is a character special device, then check that + * it's /dev/mem. If so, open kmem too. (Maybe we should + * make it work for either /dev/mem or /dev/kmem -- in either + * case you're working with a live kernel.) + */ + if (strcmp(mf, _PATH_DEVNULL) == 0) { + kd->vmfd = open(_PATH_DEVNULL, O_RDONLY); + return (kd); + } else if (strcmp(mf, _PATH_MEM) == 0) { + if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) { + _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); + goto failed; + } + if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) { + _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); + goto failed; + } + return (kd); + } + } + /* + * This is a crash dump. + * Initialize the virtual address translation machinery, + * but first setup the namelist fd. + */ + if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) { + _kvm_syserr(kd, kd->program, "%s", uf); + goto failed; + } + if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) { + _kvm_syserr(kd, kd->program, "%s", uf); + goto failed; + } + if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0) + kd->rawdump = 1; + if (_kvm_initvtop(kd) < 0) + goto failed; + return (kd); +failed: + /* + * Copy out the error if doing sane error semantics. + */ + if (errout != 0) + strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); + (void)kvm_close(kd); + return (0); +} + +kvm_t * +kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag, + char *errout) +{ + kvm_t *kd; + + if ((kd = calloc(1, sizeof(*kd))) == NULL) { + (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); + return (0); + } + kd->program = 0; + return (_kvm_open(kd, uf, mf, flag, errout)); +} + +kvm_t * +kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, + const char *errstr) +{ + kvm_t *kd; + + if ((kd = calloc(1, sizeof(*kd))) == NULL) { + if (errstr != NULL) + (void)fprintf(stderr, "%s: %s\n", + errstr, strerror(errno)); + return (0); + } + kd->program = errstr; + return (_kvm_open(kd, uf, mf, flag, NULL)); +} + +int +kvm_close(kvm_t *kd) +{ + int error = 0; + + if (kd->pmfd >= 0) + error |= close(kd->pmfd); + if (kd->vmfd >= 0) + error |= close(kd->vmfd); + if (kd->nlfd >= 0) + error |= close(kd->nlfd); + if (kd->vmst) + _kvm_freevtop(kd); + if (kd->procbase != 0) + free((void *)kd->procbase); + if (kd->argbuf != 0) + free((void *) kd->argbuf); + if (kd->argspc != 0) + free((void *) kd->argspc); + if (kd->argv != 0) + free((void *)kd->argv); + free((void *)kd); + + return (0); +} + +/* + * Walk the list of unresolved symbols, generate a new list and prefix the + * symbol names, try again, and merge back what we could resolve. + */ +static int +kvm_fdnlist_prefix(kvm_t *kd, struct nlist *nl, int missing, const char *prefix, + uintptr_t (*validate_fn)(kvm_t *, uintptr_t)) +{ + struct nlist *n, *np, *p; + char *cp, *ce; + const char *ccp; + size_t len; + int slen, unresolved; + + /* + * Calculate the space we need to malloc for nlist and names. + * We are going to store the name twice for later lookups: once + * with the prefix and once the unmodified name delmited by \0. + */ + len = 0; + unresolved = 0; + for (p = nl; p->n_name && p->n_name[0]; ++p) { + if (p->n_type != N_UNDF) + continue; + len += sizeof(struct nlist) + strlen(prefix) + + 2 * (strlen(p->n_name) + 1); + unresolved++; + } + if (unresolved == 0) + return (unresolved); + /* Add space for the terminating nlist entry. */ + len += sizeof(struct nlist); + unresolved++; + + /* Alloc one chunk for (nlist, [names]) and setup pointers. */ + n = np = malloc(len); + bzero(n, len); + if (n == NULL) + return (missing); + cp = ce = (char *)np; + cp += unresolved * sizeof(struct nlist); + ce += len; + + /* Generate shortened nlist with special prefix. */ + unresolved = 0; + for (p = nl; p->n_name && p->n_name[0]; ++p) { + if (p->n_type != N_UNDF) + continue; + bcopy(p, np, sizeof(struct nlist)); + /* Save the new\0orig. name so we can later match it again. */ + slen = snprintf(cp, ce - cp, "%s%s%c%s", prefix, + (prefix[0] != '\0' && p->n_name[0] == '_') ? + (p->n_name + 1) : p->n_name, '\0', p->n_name); + if (slen < 0 || slen >= ce - cp) + continue; + np->n_name = cp; + cp += slen + 1; + np++; + unresolved++; + } + + /* Do lookup on the reduced list. */ + np = n; + unresolved = __fdnlist(kd->nlfd, np); + + /* Check if we could resolve further symbols and update the list. */ + if (unresolved >= 0 && unresolved < missing) { + /* Find the first freshly resolved entry. */ + for (; np->n_name && np->n_name[0]; np++) + if (np->n_type != N_UNDF) + break; + /* + * The lists are both in the same order, + * so we can walk them in parallel. + */ + for (p = nl; np->n_name && np->n_name[0] && + p->n_name && p->n_name[0]; ++p) { + if (p->n_type != N_UNDF) + continue; + /* Skip expanded name and compare to orig. one. */ + ccp = np->n_name + strlen(np->n_name) + 1; + if (strcmp(ccp, p->n_name) != 0) + continue; + /* Update nlist with new, translated results. */ + p->n_type = np->n_type; + p->n_other = np->n_other; + p->n_desc = np->n_desc; + if (validate_fn) + p->n_value = (*validate_fn)(kd, np->n_value); + else + p->n_value = np->n_value; + missing--; + /* Find next freshly resolved entry. */ + for (np++; np->n_name && np->n_name[0]; np++) + if (np->n_type != N_UNDF) + break; + } + } + /* We could assert missing = unresolved here. */ + + free(n); + return (unresolved); +} + +int +_kvm_nlist(kvm_t *kd, struct nlist *nl, int initialize) +{ + struct nlist *p; + int nvalid; + struct kld_sym_lookup lookup; + int error; + const char *prefix = ""; + char symname[1024]; /* XXX-BZ symbol name length limit? */ + int tried_vnet, tried_dpcpu; + + /* + * If we can't use the kld symbol lookup, revert to the + * slow library call. + */ + if (!ISALIVE(kd)) { + error = __fdnlist(kd->nlfd, nl); + if (error <= 0) /* Hard error or success. */ + return (error); + + if (_kvm_vnet_initialized(kd, initialize)) + error = kvm_fdnlist_prefix(kd, nl, error, + VNET_SYMPREFIX, _kvm_vnet_validaddr); + + if (error > 0 && _kvm_dpcpu_initialized(kd, initialize)) + error = kvm_fdnlist_prefix(kd, nl, error, + DPCPU_SYMPREFIX, _kvm_dpcpu_validaddr); + + return (error); + } + + /* + * We can use the kld lookup syscall. Go through each nlist entry + * and look it up with a kldsym(2) syscall. + */ + nvalid = 0; + tried_vnet = 0; + tried_dpcpu = 0; +again: + for (p = nl; p->n_name && p->n_name[0]; ++p) { + if (p->n_type != N_UNDF) + continue; + + lookup.version = sizeof(lookup); + lookup.symvalue = 0; + lookup.symsize = 0; + + error = snprintf(symname, sizeof(symname), "%s%s", prefix, + (prefix[0] != '\0' && p->n_name[0] == '_') ? + (p->n_name + 1) : p->n_name); + if (error < 0 || error >= (int)sizeof(symname)) + continue; + lookup.symname = symname; + if (lookup.symname[0] == '_') + lookup.symname++; + + if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { + p->n_type = N_TEXT; + p->n_other = 0; + p->n_desc = 0; + if (_kvm_vnet_initialized(kd, initialize) && + strcmp(prefix, VNET_SYMPREFIX) == 0) + p->n_value = + _kvm_vnet_validaddr(kd, lookup.symvalue); + else if (_kvm_dpcpu_initialized(kd, initialize) && + strcmp(prefix, DPCPU_SYMPREFIX) == 0) + p->n_value = + _kvm_dpcpu_validaddr(kd, lookup.symvalue); + else + p->n_value = lookup.symvalue; + ++nvalid; + /* lookup.symsize */ + } + } + + /* + * Check the number of entries that weren't found. If they exist, + * try again with a prefix for virtualized or DPCPU symbol names. + */ + error = ((p - nl) - nvalid); + if (error && _kvm_vnet_initialized(kd, initialize) && !tried_vnet) { + tried_vnet = 1; + prefix = VNET_SYMPREFIX; + goto again; + } + if (error && _kvm_dpcpu_initialized(kd, initialize) && !tried_dpcpu) { + tried_dpcpu = 1; + prefix = DPCPU_SYMPREFIX; + goto again; + } + + /* + * Return the number of entries that weren't found. If they exist, + * also fill internal error buffer. + */ + error = ((p - nl) - nvalid); + if (error) + _kvm_syserr(kd, kd->program, "kvm_nlist"); + return (error); +} + +int +kvm_nlist(kvm_t *kd, struct nlist *nl) +{ + + /* + * If called via the public interface, permit intialization of + * further virtualized modules on demand. + */ + return (_kvm_nlist(kd, nl, 1)); +} + +ssize_t +kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) +{ + int cc; + ssize_t cr; + off_t pa; + char *cp; + + if (ISALIVE(kd)) { + /* + * We're using /dev/kmem. Just read straight from the + * device and let the active kernel do the address translation. + */ + errno = 0; + if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { + _kvm_err(kd, 0, "invalid address (%lx)", kva); + return (-1); + } + cr = read(kd->vmfd, buf, len); + if (cr < 0) { + _kvm_syserr(kd, 0, "kvm_read"); + return (-1); + } else if (cr < (ssize_t)len) + _kvm_err(kd, kd->program, "short read"); + return (cr); + } + + cp = buf; + while (len > 0) { + cc = _kvm_kvatop(kd, kva, &pa); + if (cc == 0) + return (-1); + if (cc > (ssize_t)len) + cc = len; + errno = 0; + if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { + _kvm_syserr(kd, 0, _PATH_MEM); + break; + } + cr = read(kd->pmfd, cp, cc); + if (cr < 0) { + _kvm_syserr(kd, kd->program, "kvm_read"); + break; + } + /* + * If kvm_kvatop returns a bogus value or our core file is + * truncated, we might wind up seeking beyond the end of the + * core file in which case the read will return 0 (EOF). + */ + if (cr == 0) + break; + cp += cr; + kva += cr; + len -= cr; + } + + return (cp - (char *)buf); +} + +ssize_t +kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) +{ + int cc; + + if (ISALIVE(kd)) { + /* + * Just like kvm_read, only we write. + */ + errno = 0; + if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { + _kvm_err(kd, 0, "invalid address (%lx)", kva); + return (-1); + } + cc = write(kd->vmfd, buf, len); + if (cc < 0) { + _kvm_syserr(kd, 0, "kvm_write"); + return (-1); + } else if ((size_t)cc < len) + _kvm_err(kd, kd->program, "short write"); + return (cc); + } else { + _kvm_err(kd, kd->program, + "kvm_write not implemented for dead kernels"); + return (-1); + } + /* NOTREACHED */ +} |
