ae7b6414d5
CTF data from a module. On subsequent attempts to retrieve CTF data for a module, return an error if there no CTF data. This fixes a panic if you try to enable fbt probes on a module with CTF data twice. Submitted by: Paul Ambrose (ambrosehua AT gmail DOT com) MFC after: 3 days
344 lines
9.2 KiB
C
344 lines
9.2 KiB
C
/*-
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* Copyright (c) 2008 John Birrell <jb@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Note this file is included by both link_elf.c and link_elf_obj.c.
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*
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* The CTF header structure definition can't be used here because it's
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* (annoyingly) covered by the CDDL. We will just use a few bytes from
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* it as an integer array where we 'know' what they mean.
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*/
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#define CTF_HDR_SIZE 36
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#define CTF_HDR_STRTAB_U32 7
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#define CTF_HDR_STRLEN_U32 8
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#ifdef DDB_CTF
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static void *
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z_alloc(void *nil, u_int items, u_int size)
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{
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void *ptr;
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ptr = malloc(items * size, M_TEMP, M_NOWAIT);
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return ptr;
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}
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static void
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z_free(void *nil, void *ptr)
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{
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free(ptr, M_TEMP);
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}
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#endif
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static int
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link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
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{
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#ifdef DDB_CTF
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Elf_Ehdr *hdr = NULL;
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Elf_Shdr *shdr = NULL;
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caddr_t ctftab = NULL;
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caddr_t raw = NULL;
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caddr_t shstrtab = NULL;
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elf_file_t ef = (elf_file_t) lf;
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int flags;
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int i;
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int nbytes;
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int resid;
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int vfslocked;
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size_t sz;
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struct nameidata nd;
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struct thread *td = curthread;
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uint8_t ctf_hdr[CTF_HDR_SIZE];
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#endif
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int error = 0;
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if (lf == NULL || lc == NULL)
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return (EINVAL);
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/* Set the defaults for no CTF present. That's not a crime! */
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bzero(lc, sizeof(*lc));
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#ifdef DDB_CTF
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/*
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* First check if we've tried to load CTF data previously and the
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* CTF ELF section wasn't found. We flag that condition by setting
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* ctfcnt to -1. See below.
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*/
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if (ef->ctfcnt < 0)
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return (EFTYPE);
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/* Now check if we've already loaded the CTF data.. */
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if (ef->ctfcnt > 0) {
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/* We only need to load once. */
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lc->ctftab = ef->ctftab;
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lc->ctfcnt = ef->ctfcnt;
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lc->symtab = ef->ddbsymtab;
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lc->strtab = ef->ddbstrtab;
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lc->strcnt = ef->ddbstrcnt;
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lc->nsym = ef->ddbsymcnt;
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lc->ctfoffp = (uint32_t **) &ef->ctfoff;
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lc->typoffp = (uint32_t **) &ef->typoff;
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lc->typlenp = &ef->typlen;
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return (0);
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}
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/*
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* We need to try reading the CTF data. Flag no CTF data present
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* by default and if we actually succeed in reading it, we'll
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* update ctfcnt to the number of bytes read.
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*/
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ef->ctfcnt = -1;
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NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, lf->pathname, td);
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flags = FREAD;
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error = vn_open(&nd, &flags, 0, NULL);
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if (error)
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return (error);
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vfslocked = NDHASGIANT(&nd);
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NDFREE(&nd, NDF_ONLY_PNBUF);
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/* Allocate memory for the FLF header. */
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if ((hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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/* Read the ELF header. */
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if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr),
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0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid,
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td)) != 0)
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goto out;
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/* Sanity check. */
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if (!IS_ELF(*hdr)) {
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error = ENOEXEC;
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goto out;
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}
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nbytes = hdr->e_shnum * hdr->e_shentsize;
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if (nbytes == 0 || hdr->e_shoff == 0 ||
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hdr->e_shentsize != sizeof(Elf_Shdr)) {
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error = ENOEXEC;
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goto out;
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}
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/* Allocate memory for all the section headers */
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if ((shdr = malloc(nbytes, M_LINKER, M_WAITOK)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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/* Read all the section headers */
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if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes,
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hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
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&resid, td)) != 0)
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goto out;
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/*
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* We need to search for the CTF section by name, so if the
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* section names aren't present, then we can't locate the
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* .SUNW_ctf section containing the CTF data.
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*/
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if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
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printf("%s(%d): module %s e_shstrndx is %d, sh_type is %d\n",
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__func__, __LINE__, lf->pathname, hdr->e_shstrndx,
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shdr[hdr->e_shstrndx].sh_type);
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error = EFTYPE;
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goto out;
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}
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/* Allocate memory to buffer the section header strings. */
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if ((shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER,
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M_WAITOK)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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/* Read the section header strings. */
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if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab,
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shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset,
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UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid,
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td)) != 0)
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goto out;
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/* Search for the section containing the CTF data. */
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for (i = 0; i < hdr->e_shnum; i++)
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if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0)
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break;
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/* Check if the CTF section wasn't found. */
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if (i >= hdr->e_shnum) {
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printf("%s(%d): module %s has no .SUNW_ctf section\n",
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__func__, __LINE__, lf->pathname);
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error = EFTYPE;
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goto out;
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}
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/* Read the CTF header. */
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if ((error = vn_rdwr(UIO_READ, nd.ni_vp, ctf_hdr, sizeof(ctf_hdr),
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shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
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NOCRED, &resid, td)) != 0)
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goto out;
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/* Check the CTF magic number. (XXX check for big endian!) */
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if (ctf_hdr[0] != 0xf1 || ctf_hdr[1] != 0xcf) {
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printf("%s(%d): module %s has invalid format\n",
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__func__, __LINE__, lf->pathname);
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error = EFTYPE;
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goto out;
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}
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/* Check if version 2. */
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if (ctf_hdr[2] != 2) {
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printf("%s(%d): module %s CTF format version is %d "
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"(2 expected)\n",
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__func__, __LINE__, lf->pathname, ctf_hdr[2]);
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error = EFTYPE;
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goto out;
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}
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/* Check if the data is compressed. */
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if ((ctf_hdr[3] & 0x1) != 0) {
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uint32_t *u32 = (uint32_t *) ctf_hdr;
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/*
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* The last two fields in the CTF header are the offset
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* from the end of the header to the start of the string
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* data and the length of that string data. se this
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* information to determine the decompressed CTF data
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* buffer required.
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*/
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sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] +
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sizeof(ctf_hdr);
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/*
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* Allocate memory for the compressed CTF data, including
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* the header (which isn't compressed).
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*/
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if ((raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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} else {
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/*
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* The CTF data is not compressed, so the ELF section
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* size is the same as the buffer size required.
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*/
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sz = shdr[i].sh_size;
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}
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/*
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* Allocate memory to buffer the CTF data in it's decompressed
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* form.
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*/
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if ((ctftab = malloc(sz, M_LINKER, M_WAITOK)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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/*
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* Read the CTF data into the raw buffer if compressed, or
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* directly into the CTF buffer otherwise.
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*/
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if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw,
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shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
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td->td_ucred, NOCRED, &resid, td)) != 0)
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goto out;
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/* Check if decompression is required. */
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if (raw != NULL) {
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z_stream zs;
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int ret;
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/*
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* The header isn't compressed, so copy that into the
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* CTF buffer first.
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*/
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bcopy(ctf_hdr, ctftab, sizeof(ctf_hdr));
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/* Initialise the zlib structure. */
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bzero(&zs, sizeof(zs));
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zs.zalloc = z_alloc;
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zs.zfree = z_free;
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if (inflateInit(&zs) != Z_OK) {
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error = EIO;
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goto out;
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}
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zs.avail_in = shdr[i].sh_size - sizeof(ctf_hdr);
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zs.next_in = ((uint8_t *) raw) + sizeof(ctf_hdr);
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zs.avail_out = sz - sizeof(ctf_hdr);
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zs.next_out = ((uint8_t *) ctftab) + sizeof(ctf_hdr);
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if ((ret = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
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printf("%s(%d): zlib inflate returned %d\n", __func__, __LINE__, ret);
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error = EIO;
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goto out;
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}
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}
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/* Got the CTF data! */
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ef->ctftab = ctftab;
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ef->ctfcnt = shdr[i].sh_size;
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/* We'll retain the memory allocated for the CTF data. */
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ctftab = NULL;
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/* Let the caller use the CTF data read. */
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lc->ctftab = ef->ctftab;
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lc->ctfcnt = ef->ctfcnt;
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lc->symtab = ef->ddbsymtab;
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lc->strtab = ef->ddbstrtab;
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lc->strcnt = ef->ddbstrcnt;
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lc->nsym = ef->ddbsymcnt;
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lc->ctfoffp = (uint32_t **) &ef->ctfoff;
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lc->typoffp = (uint32_t **) &ef->typoff;
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lc->typlenp = &ef->typlen;
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out:
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VOP_UNLOCK(nd.ni_vp, 0);
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vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
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VFS_UNLOCK_GIANT(vfslocked);
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if (hdr != NULL)
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free(hdr, M_LINKER);
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if (shdr != NULL)
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free(shdr, M_LINKER);
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if (shstrtab != NULL)
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free(shstrtab, M_LINKER);
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if (ctftab != NULL)
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free(ctftab, M_LINKER);
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if (raw != NULL)
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free(raw, M_LINKER);
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#else
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error = EOPNOTSUPP;
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#endif
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return (error);
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}
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