libelf/common/ar.c

	ar.c revision ba7866cd2cbdf574f47d4e38a1301b90744dd677
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 *  Copyright (c) 1988 AT&T
 *    All Rights Reserved
 */

#include <ar.h>
#include <stdlib.h>
#include <memory.h>
#include <errno.h>
#include <libelf.h>
#include "decl.h"
#include "msg.h"
#include "member.h"

#define MANGLE  '\177'


/*
 * Archive processing
 *  When processing an archive member, two things can happen
 *  that are a little tricky.
 *
 * Sliding
 *  Sliding support is left in for backward compatibility and for
 *  support of Archives produced on other systems.  The bundled
 *  ar(1) produces archives with all members on a 4 byte boundry,
 *  so current archives should need no sliding.
 *
 *  Archive members that are only 2-byte aligned within the file will
 *  be slid.  To reuse the file's memory image, the library slides an
 *  archive member into its header to align the bytes.  This means
 *  the header must be disposable.
 *
 * Header reuse
 *  Because the library can trample the header, it must be preserved to
 *  avoid restrictions on archive member reuse.  That is, if the member
 *  header changes, the library may see garbage the next time it looks
 *  at the header.  After extracting the original header, the library
 *  appends it to the parents `ed_memlist' list, thus future lookups first
 *  check this list to determine if a member has previously been processed
 *  and whether sliding occured.
 */


/*
 * Size check
 *  If the header is too small, the following generates a negative
 *  subscript for x.x and fails to compile.
 *
 * The check is based on sizeof (Elf64) because that's always going
 * to be at least as big as Elf32.
 */

struct  x
{
    char    x[sizeof (struct ar_hdr) - 3 * sizeof (Elf64) - 1];
};


static const char   fmag[] = ARFMAG;


/*
 * Convert a string starting at 'p' and ending at 'end' into
 * an integer.  Base is the base of the number being converted
 * (either 8 or 10).
 *
 * Returns the converted integer of the string being scaned.
 */
unsigned long
_elf_number(char *p, char *end, int base)
{
    register unsigned   c;
    register unsigned long  n = 0;

    while (p < end) {
        if ((c = *p - '0') >= base) {
            while (*p++ == ' ')
                if (p >= end)
                    return (n);
            return (0);
        }
        n *= base;
        n += c;
        ++p;
    }
    return (n);
}


/*
 * Convert ar_hdr to Member
 *  Converts ascii file representation to the binary memory values.
 */
Member *
_elf_armem(Elf *elf, char *file, size_t fsz)
{
    register struct ar_hdr  *f = (struct ar_hdr *)file;
    register Member     *m;
    register Memlist    *l, * ol;
    register Memident   *i;

    if (fsz < sizeof (struct ar_hdr)) {
        _elf_seterr(EFMT_ARHDRSZ, 0);
        return (0);
    }

    /*
     * Determine in this member has already been processed
     */
    for (l = elf->ed_memlist, ol = l; l; ol = l, l = l->m_next)
        for (i = (Memident *)(l + 1); i < l->m_free; i++)
            if (i->m_offset == file)
                return (i->m_member);

    if (f->ar_fmag[0] != fmag[0] || f->ar_fmag[1] != fmag[1]) {
        _elf_seterr(EFMT_ARFMAG, 0);
        return (0);
    }

    /*
     * Allocate a new member structure and assign it to the next free
     * free memlist ident.
     */
    if ((m = (Member *)malloc(sizeof (Member))) == 0) {
        _elf_seterr(EMEM_ARMEM, errno);
        return (0);
    }
    if ((elf->ed_memlist == 0) || (ol->m_free == ol->m_end)) {
        if ((l = (Memlist *)malloc(sizeof (Memlist) +
            (sizeof (Memident) * MEMIDENTNO))) == 0) {
            _elf_seterr(EMEM_ARMEM, errno);
            return (0);
        }
        l->m_next = 0;
        l->m_free = (Memident *)(l + 1);
        l->m_end = (Memident *)((uintptr_t)l->m_free +
            (sizeof (Memident) * MEMIDENTNO));

        if (elf->ed_memlist == 0)
            elf->ed_memlist = l;
        else
            ol->m_next = l;
        ol = l;
    }
    ol->m_free->m_offset = file;
    ol->m_free->m_member = m;
    ol->m_free++;

    m->m_err = 0;
    (void) memcpy(m->m_name, f->ar_name, ARSZ(ar_name));
    m->m_name[ARSZ(ar_name)] = '\0';
    m->m_hdr.ar_name = m->m_name;
    (void) memcpy(m->m_raw, f->ar_name, ARSZ(ar_name));
    m->m_raw[ARSZ(ar_name)] = '\0';
    m->m_hdr.ar_rawname = m->m_raw;
    m->m_slide = 0;

    /*
     * Classify file name.
     * If a name error occurs, delay until getarhdr().
     */

    if (f->ar_name[0] != '/') { /* regular name */
        register char   *p;

        p = &m->m_name[sizeof (m->m_name)];
        while (*--p != '/')
            if (p <= m->m_name)
                break;
        *p = '\0';
    } else if (f->ar_name[1] >= '0' && f->ar_name[1] <= '9') { /* strtab */
        register unsigned long  j;

        j = _elf_number(&f->ar_name[1],
            &f->ar_name[ARSZ(ar_name)], 10);
        if (j < elf->ed_arstrsz)
            m->m_hdr.ar_name = elf->ed_arstr + j;
        else {
            m->m_hdr.ar_name = 0;
            /*LINTED*/ /* MSG_INTL(EFMT_ARSTRNM) */
            m->m_err = (int)EFMT_ARSTRNM;
        }
    } else if (f->ar_name[1] == ' ')            /* "/" */
        m->m_name[1] = '\0';
    else if (f->ar_name[1] == '/' && f->ar_name[2] == ' ')  /* "//" */
        m->m_name[2] = '\0';
    else if (f->ar_name[1] == 'S' && f->ar_name[2] == 'Y' &&
        f->ar_name[3] == 'M' && f->ar_name[4] == '6' &&
        f->ar_name[5] == '4' && f->ar_name[6] == '/' &&
        f->ar_name[7] == ' ')               /* "/SYM64/" */
        m->m_name[7] = '\0';
    else {                          /* "/?" */
        m->m_hdr.ar_name = 0;
        /*LINTED*/ /* MSG_INTL(EFMT_ARUNKNM) */
        m->m_err = (int)EFMT_ARUNKNM;
    }

    m->m_hdr.ar_date = (time_t)_elf_number(f->ar_date,
        &f->ar_date[ARSZ(ar_date)], 10);
    /* LINTED */
    m->m_hdr.ar_uid = (uid_t)_elf_number(f->ar_uid,
        &f->ar_uid[ARSZ(ar_uid)], 10);
    /* LINTED */
    m->m_hdr.ar_gid = (gid_t)_elf_number(f->ar_gid,
        &f->ar_gid[ARSZ(ar_gid)], 10);
    /* LINTED */
    m->m_hdr.ar_mode = (mode_t)_elf_number(f->ar_mode,
        &f->ar_mode[ARSZ(ar_mode)], 8);
    m->m_hdr.ar_size = (off_t)_elf_number(f->ar_size,
        &f->ar_size[ARSZ(ar_size)], 10);

    return (m);
}


/*
 * Initial archive processing
 *  An archive may have two special members.
 *
 *  A symbol table, named / or /SYM64/, must be first if it is present.
 *  Both forms use the same layout differing in the width of the
 *  integer type used (32 or 64-bit respectively).
 *
 *  A long name string table, named //, must precede all "normal"
 *  members. This string table is used to hold the names of archive
 *  members with names that are longer than 15 characters. It should not
 *  be confused with the string table found at the end of the symbol
 *  table, which is used to hold symbol names.
 *
 *  This code "peeks" at headers but doesn't change them.
 *  Later processing wants original headers.
 *
 *  String table is converted, changing '/' name terminators
 *  to nulls.  The last byte in the string table, which should
 *  be '\n', is set to nil, guaranteeing null termination.  That
 *  byte should be '\n', but this code doesn't check.
 *
 *  The symbol table conversion is delayed until needed.
 */
void
_elf_arinit(Elf * elf)
{
    char                *base = elf->ed_ident;
    register char           *end = base + elf->ed_fsz;
    register struct ar_hdr      *a;
    register char           *hdr = base + SARMAG;
    register char           *mem;
    int             j;
    size_t              sz = SARMAG;

    elf->ed_status = ES_COOKED;
    elf->ed_nextoff = SARMAG;
    for (j = 0; j < 2; ++j)  {  /* 2 special members */
        unsigned long   n;

        if (((end - hdr) < sizeof (struct ar_hdr)) ||
            (_elf_vm(elf, (size_t)(SARMAG),
            sizeof (struct ar_hdr)) != OK_YES))
            return;

        a = (struct ar_hdr *)hdr;
        mem = (char *)a + sizeof (struct ar_hdr);
        n = _elf_number(a->ar_size, &a->ar_size[ARSZ(ar_size)], 10);
        if ((end - mem < n) || (a->ar_name[0] != '/') ||
            ((sz = n) != n)) {
            return;
        }

        hdr = mem + sz;
        if (a->ar_name[1] == ' ') { /* 32-bit symbol table */
            elf->ed_arsym = mem;
            elf->ed_arsymsz = sz;
            elf->ed_arsymoff = (char *)a - base;
        } else if (a->ar_name[1] == '/' && a->ar_name[2] == ' ') {
                        /* Long name string table */
            int k;

            if (_elf_vm(elf, (size_t)(mem - elf->ed_ident),
                sz) != OK_YES)
                return;
            if (elf->ed_vm == 0) {
                char    *nmem;
                if ((nmem = malloc(sz)) == 0) {
                    _elf_seterr(EMEM_ARSTR, errno);
                    return;
                }
                (void) memcpy(nmem, mem, sz);
                elf->ed_myflags |= EDF_ASTRALLOC;
                mem = nmem;
            }

            elf->ed_arstr = mem;
            elf->ed_arstrsz = sz;
            elf->ed_arstroff = (char *)a - base;
            for (k = 0; k < sz; k++) {
                if (*mem == '/')
                    *mem = '\0';
                ++mem;
            }
            *(mem - 1) = '\0';
        } else if (a->ar_name[1] == 'S' && a->ar_name[2] == 'Y' &&
            a->ar_name[3] == 'M' && a->ar_name[4] == '6' &&
            a->ar_name[5] == '4' && a->ar_name[6] == '/' &&
            a->ar_name[7] == ' ') {
                        /* 64-bit symbol table */
            elf->ed_arsym = mem;
            elf->ed_arsymsz = sz;
            elf->ed_arsymoff = (char *)a - base;
            elf->ed_myflags |= EDF_ARSYM64;
        } else {
            return;
        }
        hdr += sz & 1;
    }
}