Index: head/lib/libkvm/kvm.c =================================================================== --- head/lib/libkvm/kvm.c (revision 315646) +++ head/lib/libkvm/kvm.c (revision 315647) @@ -1,480 +1,484 @@ /*- * 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. * 3. 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 __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 #include #define _WANT_VNET #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "kvm_private.h" SET_DECLARE(kvm_arch, struct kvm_arch); char * kvm_geterr(kvm_t *kd) { return (kd->errbuf); } static int _kvm_read_kernel_ehdr(kvm_t *kd) { Elf *elf; if (elf_version(EV_CURRENT) == EV_NONE) { _kvm_err(kd, kd->program, "Unsupported libelf"); return (-1); } elf = elf_begin(kd->nlfd, ELF_C_READ, NULL); if (elf == NULL) { _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); return (-1); } if (elf_kind(elf) != ELF_K_ELF) { _kvm_err(kd, kd->program, "kernel is not an ELF file"); return (-1); } if (gelf_getehdr(elf, &kd->nlehdr) == NULL) { _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); elf_end(elf); return (-1); } elf_end(elf); switch (kd->nlehdr.e_ident[EI_DATA]) { case ELFDATA2LSB: case ELFDATA2MSB: return (0); default: _kvm_err(kd, kd->program, "unsupported ELF data encoding for kernel"); return (-1); } } static kvm_t * _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) { struct kvm_arch **parch; struct stat st; kd->vmfd = -1; kd->pmfd = -1; kd->nlfd = -1; kd->vmst = NULL; kd->procbase = NULL; kd->argspc = NULL; kd->argv = NULL; if (uf == NULL) 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 == NULL) mf = _PATH_MEM; if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 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 (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 | O_CLOEXEC); return (kd); } else if (strcmp(mf, _PATH_MEM) == 0) { if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < 0) { _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); goto failed; } return (kd); } } /* * This is either a crash dump or a remote live system with its physical * memory fully accessible via a special device. * Open the namelist fd and determine the architecture. */ if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { _kvm_syserr(kd, kd->program, "%s", uf); goto failed; } if (_kvm_read_kernel_ehdr(kd) < 0) goto failed; if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 || strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) { kd->rawdump = 1; kd->writable = 1; } SET_FOREACH(parch, kvm_arch) { if ((*parch)->ka_probe(kd)) { kd->arch = *parch; break; } } if (kd->arch == NULL) { _kvm_err(kd, kd->program, "unsupported architecture"); goto failed; } /* * Non-native kernels require a symbol resolver. */ if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) { _kvm_err(kd, kd->program, "non-native kernel requires a symbol resolver"); goto failed; } /* * Initialize the virtual address translation machinery. */ if (kd->arch->ka_initvtop(kd) < 0) goto failed; return (kd); failed: /* * Copy out the error if doing sane error semantics. */ if (errout != NULL) strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); (void)kvm_close(kd); return (NULL); } 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) { if (errout != NULL) (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); return (NULL); } 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 (NULL); } kd->program = errstr; return (_kvm_open(kd, uf, mf, flag, NULL)); } kvm_t * kvm_open2(const char *uf, const char *mf, int flag, char *errout, int (*resolver)(const char *, kvaddr_t *)) { kvm_t *kd; if ((kd = calloc(1, sizeof(*kd))) == NULL) { if (errout != NULL) (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); return (NULL); } kd->resolve_symbol = resolver; return (_kvm_open(kd, uf, mf, flag, errout)); } int kvm_close(kvm_t *kd) { int error = 0; + if (kd == NULL) { + errno = EINVAL; + return (-1); + } if (kd->vmst != NULL) kd->arch->ka_freevtop(kd); 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->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); if (kd->pt_map != NULL) free(kd->pt_map); free((void *)kd); return (error); } int kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl) { /* * If called via the public interface, permit initialization of * further virtualized modules on demand. */ return (_kvm_nlist(kd, nl, 1)); } int kvm_nlist(kvm_t *kd, struct nlist *nl) { struct kvm_nlist *kl; int count, i, nfail; /* * Avoid reporting truncated addresses by failing for non-native * cores. */ if (!kvm_native(kd)) { _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore"); return (-1); } for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0'; count++) ; if (count == 0) return (0); kl = calloc(count + 1, sizeof(*kl)); for (i = 0; i < count; i++) kl[i].n_name = nl[i].n_name; nfail = kvm_nlist2(kd, kl); for (i = 0; i < count; i++) { nl[i].n_type = kl[i].n_type; nl[i].n_other = 0; nl[i].n_desc = 0; nl[i].n_value = kl[i].n_value; } return (nfail); } ssize_t kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) { return (kvm_read2(kd, kva, buf, len)); } ssize_t kvm_read2(kvm_t *kd, kvaddr_t 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 (0x%jx)", (uintmax_t)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 = kd->arch->ka_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 ka_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; ssize_t cw; off_t pa; const char *cp; if (!ISALIVE(kd) && !kd->writable) { _kvm_err(kd, kd->program, "kvm_write not implemented for dead kernels"); return (-1); } 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); } cp = buf; while (len > 0) { cc = kd->arch->ka_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; } cw = write(kd->pmfd, cp, cc); if (cw < 0) { _kvm_syserr(kd, kd->program, "kvm_write"); break; } /* * If ka_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 (cw == 0) break; cp += cw; kva += cw; len -= cw; } return (cp - (char *)buf); } int kvm_native(kvm_t *kd) { if (ISALIVE(kd)) return (1); return (kd->arch->ka_native(kd)); } Index: head/lib/libkvm/kvm_open.3 =================================================================== --- head/lib/libkvm/kvm_open.3 (revision 315646) +++ head/lib/libkvm/kvm_open.3 (revision 315647) @@ -1,252 +1,271 @@ .\" Copyright (c) 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. .\" 3. 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. .\" .\" @(#)kvm_open.3 8.3 (Berkeley) 4/19/94 .\" $FreeBSD$ .\" -.Dd March 19, 2017 +.Dd March 20, 2017 .Dt KVM_OPEN 3 .Os .Sh NAME .Nm kvm_open , .Nm kvm_open2 , .Nm kvm_openfiles , .Nm kvm_close .Nd initialize kernel virtual memory access .Sh LIBRARY .Lb libkvm .Sh SYNOPSIS .In fcntl.h .In kvm.h .Ft kvm_t * .Fn kvm_open "const char *execfile" "const char *corefile" "const char *swapfile" "int flags" "const char *errstr" .Ft kvm_t * .Fo kvm_open2 .Fa "const char *execfile" .Fa "const char *corefile" .Fa "int flags" .Fa "char *errbuf" .Fa "int (*resolver)(const char *name, kvaddr_t *addr)" .Fc .Ft kvm_t * .Fn kvm_openfiles "const char *execfile" "const char *corefile" "const char *swapfile" "int flags" "char *errbuf" .Ft int .Fn kvm_close "kvm_t *kd" .Sh DESCRIPTION The functions .Fn kvm_open , .Fn kvm_open2 , and .Fn kvm_openfiles return a descriptor used to access kernel virtual memory via the .Xr kvm 3 library routines. Both active kernels and crash dumps are accessible through this interface. .Pp The .Fa execfile argument is the executable image of the kernel being examined. This file must contain a symbol table. If this argument is .Dv NULL , the currently running system is assumed, as determined from .Xr getbootfile 3 . .Pp The .Fa corefile argument is the kernel memory device file. It can be either .Pa /dev/mem or a crash dump core generated by .Xr savecore 8 . If .Fa corefile is .Dv NULL , the default indicated by .Dv _PATH_MEM from .In paths.h is used. It can also be set to a special value .Pa /dev/null by utilities like .Xr ps 1 that do not directly access kernel memory. .Pp The .Fa swapfile argument is currently unused. .Pp The .Fa flags argument indicates read/write access as in .Xr open 2 and applies only to the core file. Only .Dv O_RDONLY , .Dv O_WRONLY , and .Dv O_RDWR are permitted. .Pp The .Nm kvm library provides two different error reporting mechanisms. One provides backward compatibility with the SunOS kvm library, while the other provides an improved error reporting framework. The mechanism used by a descriptor is determined by the function used to open the descriptor. .Pp The .Fn kvm_open function is the Sun kvm compatible open call. Here, the .Fa errstr argument indicates how errors should be handled. If it is .Dv NULL , no errors are reported and the application cannot know the specific nature of the failed kvm call. If it is not .Dv NULL , errors are printed to .Dv stderr with .Fa errstr prepended to the message, as in .Xr perror 3 . Normally, the name of the program is used here. The string is assumed to persist at least until the corresponding .Fn kvm_close call. .Pp The .Fn kvm_open2 and .Fn kvm_openfiles functions provide .Bx style error reporting. Here, error messages are not printed out by the library. Instead, the application obtains the error message corresponding to the most recent kvm library call using .Fn kvm_geterr (see .Xr kvm_geterr 3 ) . The results are undefined if the most recent kvm call did not produce an error. Since .Fn kvm_geterr requires a kvm descriptor, but the open routines return .Dv NULL on failure, .Fn kvm_geterr cannot be used to get the error message if open fails. Thus, .Fn kvm_open2 and .Fn kvm_openfiles will place any error message in the .Fa errbuf argument. This buffer should be _POSIX2_LINE_MAX characters large (from ). .Pp The .Fa resolver argument points to a function used by the .Nm kvm library to map symbol names to kernel virtual addresses. When the .Fa resolver function is called, .Fa name specifies the requested symbol name. If the function is able to resolve the name to an address, the address should be set in .Fa addr and the function should return zero. If the function is not able to resolve the name to an address, it should return a non-zero value. When opening a native kernel image, .Fa resolver may be set to .Dv NULL to use an internal function to resolve symbol names. Non-native kernel images .Pq such as when cross-debugging a crash dump require a valid .Fa resolver . .Sh RETURN VALUES The .Fn kvm_open , .Fn kvm_open2 , and .Fn kvm_openfiles functions return a descriptor to be used in all subsequent kvm library calls. The library is fully re-entrant. On failure, .Dv NULL is returned, in which case .Fn kvm_open2 and .Fn kvm_openfiles write the error message into .Fa errbuf . .Pp +.Rv -std kvm_close +.Sh ERRORS The .Fn kvm_close -function returns 0 on success and -1 on failure. +function may fail and set the global variable +.Va errno +for any of the errors specified for +.Xr close 2 . +.Pp +The +.Fn kvm_close +function may also fail and set +.Va errno +if: +.Bl -tag -width Er +.It Bq Er EINVAL +The value passed via +.Fa kd +was +.Dv NULL . +.El .Sh SEE ALSO +.Xr close 2 , .Xr open 2 , .Xr kvm 3 , .Xr kvm_getargv 3 , .Xr kvm_getenvv 3 , .Xr kvm_geterr 3 , .Xr kvm_getprocs 3 , .Xr kvm_native 3 , .Xr kvm_nlist 3 , .Xr kvm_read 3 , .Xr kvm_write 3 , .Xr kmem 4 , .Xr mem 4 .Sh BUGS There should not be three open calls. The ill-defined error semantics of the Sun library and the desire to have a backward-compatible library for .Bx left little choice.