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-rw-r--r--ext/libelf/libelf_ar.c481
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diff --git a/ext/libelf/libelf_ar.c b/ext/libelf/libelf_ar.c
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+/*-
+ * Copyright (c) 2006 Joseph Koshy
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <ar.h>
+#include <assert.h>
+#include <ctype.h>
+#include "libelf.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include "_libelf.h"
+
+#define LIBELF_NALLOC_SIZE 16
+
+/*
+ * `ar' archive handling.
+ *
+ * `ar' archives start with signature `ARMAG'. Each archive member is
+ * preceded by a header containing meta-data for the member. This
+ * header is described in <ar.h> (struct ar_hdr). The header always
+ * starts on an even address. File data is padded with "\n"
+ * characters to keep this invariant.
+ *
+ * Special considerations for `ar' archives:
+ *
+ * The `ar' header only has space for a 16 character file name. File
+ * names are terminated with a '/', so this effectively leaves 15
+ * characters for the actual file name. In order to accomodate longer
+ * file names, names may be stored in a separate 'string table' and
+ * referenced indirectly by a member header. The string table itself
+ * appears as an archive member with name "// ". An indirect file name
+ * in an `ar' header matches the pattern "/[0-9]*". The digits form a
+ * decimal number that corresponds to a byte offset into the string
+ * table where the actual file name of the object starts. Strings in
+ * the string table are padded to start on even addresses.
+ *
+ * Archives may also have a symbol table (see ranlib(1)), mapping
+ * program symbols to object files inside the archive. A symbol table
+ * uses a file name of "/ " in its archive header. The symbol table
+ * is structured as:
+ * - a 4-byte count of entries stored as a binary value, MSB first
+ * - 'n' 4-byte offsets, stored as binary values, MSB first
+ * - 'n' NUL-terminated strings, for ELF symbol names, stored unpadded.
+ *
+ * If the symbol table and string table are is present in an archive
+ * they must be the very first objects and in that order.
+ */
+
+/*
+ * Convert a string bounded by `start' and `start+sz' (exclusive) to a
+ * number in the specified base.
+ */
+static int
+_libelf_ar_get_number(char *s, size_t sz, int base, size_t *ret)
+{
+ int c, v;
+ size_t r;
+ char *e;
+
+ assert(base <= 10);
+
+ e = s + sz;
+
+ /* skip leading blanks */
+ for (;s < e && (c = *s) == ' '; s++)
+ ;
+
+ r = 0L;
+ for (;s < e; s++) {
+ if ((c = *s) == ' ')
+ break;
+ if (c < '0' || c > '9')
+ return (0);
+ v = c - '0';
+ if (v >= base) /* Illegal digit. */
+ break;
+ r *= base;
+ r += v;
+ }
+
+ *ret = r;
+
+ return (1);
+}
+
+/*
+ * Retrieve a string from a name field. If `rawname' is set, leave
+ * ar(1) control characters in.
+ */
+static char *
+_libelf_ar_get_string(const char *buf, size_t bufsize, int rawname)
+{
+ const char *q;
+ char *r;
+ size_t sz;
+
+ if (rawname)
+ sz = bufsize + 1;
+ else {
+ /* Skip back over trailing blanks. */
+ for (q = buf + bufsize - 1; q >= buf && *q == ' '; --q)
+ ;
+
+ if (q < buf) {
+ /*
+ * If the input buffer only had blanks in it,
+ * return a zero-length string.
+ */
+ buf = "";
+ sz = 1;
+ } else {
+ /*
+ * Remove the trailing '/' character, but only
+ * if the name isn't one of the special names
+ * "/" and "//".
+ */
+ if (q > buf + 1 ||
+ (q == (buf + 1) && *buf != '/'))
+ q--;
+
+ sz = q - buf + 2; /* Space for a trailing NUL. */
+ }
+ }
+
+ if ((r = malloc(sz)) == NULL) {
+ LIBELF_SET_ERROR(RESOURCE, 0);
+ return (NULL);
+ }
+
+ (void) strncpy(r, buf, sz);
+ r[sz - 1] = '\0';
+
+ return (r);
+}
+
+/*
+ * Retrieve the full name of the archive member.
+ */
+static char *
+_libelf_ar_get_name(char *buf, size_t bufsize, Elf *e)
+{
+ char c, *q, *r, *s;
+ size_t len;
+ size_t offset;
+
+ assert(e->e_kind == ELF_K_AR);
+
+ if (buf[0] == '/' && (c = buf[1]) >= '0' && c <= '9') {
+ /*
+ * The value in field ar_name is a decimal offset into
+ * the archive string table where the actual name
+ * resides.
+ */
+ if (_libelf_ar_get_number(buf + 1, bufsize - 1, 10,
+ &offset) == 0) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ if (offset > e->e_u.e_ar.e_rawstrtabsz) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ s = q = e->e_u.e_ar.e_rawstrtab + offset;
+ r = e->e_u.e_ar.e_rawstrtab + e->e_u.e_ar.e_rawstrtabsz;
+
+ for (s = q; s < r && *s != '/'; s++)
+ ;
+ len = s - q + 1; /* space for the trailing NUL */
+
+ if ((s = malloc(len)) == NULL) {
+ LIBELF_SET_ERROR(RESOURCE, 0);
+ return (NULL);
+ }
+
+ (void) strncpy(s, q, len);
+ s[len - 1] = '\0';
+
+ return (s);
+ }
+
+ /*
+ * Normal 'name'
+ */
+ return (_libelf_ar_get_string(buf, bufsize, 0));
+}
+
+
+Elf_Arhdr *
+_libelf_ar_gethdr(Elf *e)
+{
+ Elf *parent;
+ struct ar_hdr *arh;
+ Elf_Arhdr *eh;
+ size_t n;
+
+ if ((parent = e->e_parent) == NULL) {
+ LIBELF_SET_ERROR(ARGUMENT, 0);
+ return (NULL);
+ }
+
+ arh = (struct ar_hdr *) ((uintptr_t) e->e_rawfile - sizeof(struct ar_hdr));
+
+ assert((uintptr_t) arh >= (uintptr_t) parent->e_rawfile + SARMAG);
+ assert((uintptr_t) arh <= (uintptr_t) parent->e_rawfile + parent->e_rawsize -
+ sizeof(struct ar_hdr));
+
+ if ((eh = malloc(sizeof(Elf_Arhdr))) == NULL) {
+ LIBELF_SET_ERROR(RESOURCE, 0);
+ return (NULL);
+ }
+
+ e->e_arhdr = eh;
+ eh->ar_name = eh->ar_rawname = NULL;
+
+ if ((eh->ar_name = _libelf_ar_get_name(arh->ar_name, sizeof(arh->ar_name),
+ parent)) == NULL)
+ goto error;
+
+ if (_libelf_ar_get_number(arh->ar_uid, sizeof(arh->ar_uid), 10, &n) == 0)
+ goto error;
+ eh->ar_uid = (uid_t) n;
+
+ if (_libelf_ar_get_number(arh->ar_gid, sizeof(arh->ar_gid), 10, &n) == 0)
+ goto error;
+ eh->ar_gid = (gid_t) n;
+
+ if (_libelf_ar_get_number(arh->ar_mode, sizeof(arh->ar_mode), 8, &n) == 0)
+ goto error;
+ eh->ar_mode = (mode_t) n;
+
+ if (_libelf_ar_get_number(arh->ar_size, sizeof(arh->ar_size), 10, &n) == 0)
+ goto error;
+ eh->ar_size = n;
+
+ if ((eh->ar_rawname = _libelf_ar_get_string(arh->ar_name,
+ sizeof(arh->ar_name), 1)) == NULL)
+ goto error;
+
+ return (eh);
+
+ error:
+ if (eh) {
+ if (eh->ar_name)
+ free(eh->ar_name);
+ if (eh->ar_rawname)
+ free(eh->ar_rawname);
+ free(eh);
+ }
+ e->e_arhdr = NULL;
+
+ return (NULL);
+}
+
+Elf *
+_libelf_ar_open_member(int fd, Elf_Cmd c, Elf *elf)
+{
+ Elf *e;
+ off_t next;
+ struct ar_hdr *arh;
+ size_t sz;
+
+ assert(elf->e_kind == ELF_K_AR);
+
+ next = elf->e_u.e_ar.e_next;
+
+ /*
+ * `next' is only set to zero by elf_next() when the last
+ * member of an archive is processed.
+ */
+ if (next == (off_t) 0)
+ return (NULL);
+
+ assert((next & 1) == 0);
+
+ arh = (struct ar_hdr *) (elf->e_rawfile + next);
+
+ if (_libelf_ar_get_number(arh->ar_size, sizeof(arh->ar_size), 10, &sz) == 0) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ assert(sz > 0);
+
+ arh++; /* skip over archive member header */
+
+ if ((e = elf_memory((char *) arh, sz)) == NULL)
+ return (NULL);
+
+ e->e_fd = fd;
+ e->e_cmd = c;
+
+ elf->e_u.e_ar.e_nchildren++;
+ e->e_parent = elf;
+
+ return (e);
+}
+
+Elf *
+_libelf_ar_open(Elf *e)
+{
+ int i;
+ char *s, *end;
+ size_t sz;
+ struct ar_hdr arh;
+
+ e->e_kind = ELF_K_AR;
+ e->e_u.e_ar.e_nchildren = 0;
+ e->e_u.e_ar.e_next = (off_t) -1;
+
+ /*
+ * Look for special members.
+ */
+
+ s = e->e_rawfile + SARMAG;
+ end = e->e_rawfile + e->e_rawsize;
+
+ assert(e->e_rawsize > 0);
+
+ /*
+ * Look for magic names "/ " and "// " in the first two entries
+ * of the archive.
+ */
+ for (i = 0; i < 2; i++) {
+
+ if (s + sizeof(arh) > end) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ (void) memcpy(&arh, s, sizeof(arh));
+
+ if (arh.ar_fmag[0] != '`' || arh.ar_fmag[1] != '\n') {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ if (arh.ar_name[0] != '/') /* not a special symbol */
+ break;
+
+ if (_libelf_ar_get_number(arh.ar_size, sizeof(arh.ar_size), 10, &sz) == 0) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ assert(sz > 0);
+
+ s += sizeof(arh);
+
+ if (arh.ar_name[1] == ' ') { /* "/ " => symbol table */
+
+ e->e_u.e_ar.e_rawsymtab = s;
+ e->e_u.e_ar.e_rawsymtabsz = sz;
+
+ } else if (arh.ar_name[1] == '/' && arh.ar_name[2] == ' ') {
+
+ /* "// " => string table for long file names */
+ e->e_u.e_ar.e_rawstrtab = s;
+ e->e_u.e_ar.e_rawstrtabsz = sz;
+ }
+
+ sz = LIBELF_ADJUST_AR_SIZE(sz);
+
+ s += sz;
+ }
+
+ e->e_u.e_ar.e_next = (off_t) (s - e->e_rawfile);
+
+ return (e);
+}
+
+/*
+ * An ar(1) symbol table has the following layout:
+ *
+ * The first 4 bytes are a binary count of the number of entries in the
+ * symbol table, stored MSB-first.
+ *
+ * Then there are 'n' 4-byte binary offsets, also stored MSB first.
+ *
+ * Following this, there are 'n' null-terminated strings.
+ */
+
+#define GET_WORD(P, V) do { \
+ (V) = 0; \
+ (V) = (P)[0]; (V) <<= 8; \
+ (V) += (P)[1]; (V) <<= 8; \
+ (V) += (P)[2]; (V) <<= 8; \
+ (V) += (P)[3]; \
+ } while (0)
+
+#define INTSZ 4
+
+Elf_Arsym *
+_libelf_ar_process_symtab(Elf *e, size_t *count)
+{
+ size_t n, nentries, off;
+ Elf_Arsym *symtab, *sym;
+ char *p, *s, *end;
+
+ assert(e != NULL);
+ assert(count != NULL);
+
+ if (e->e_u.e_ar.e_rawsymtabsz < INTSZ) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ p = e->e_u.e_ar.e_rawsymtab;
+ end = p + e->e_u.e_ar.e_rawsymtabsz;
+
+ GET_WORD(p, nentries);
+ p += INTSZ;
+
+ if (nentries == 0 || p + nentries * INTSZ >= end) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ return (NULL);
+ }
+
+ /* Allocate space for a nentries + a sentinel. */
+ if ((symtab = malloc(sizeof(Elf_Arsym) * (nentries+1))) == NULL) {
+ LIBELF_SET_ERROR(RESOURCE, 0);
+ return (NULL);
+ }
+
+ s = p + (nentries * INTSZ); /* start of the string table. */
+
+ for (n = nentries, sym = symtab; n > 0; n--) {
+ off = 0;
+
+ GET_WORD(p, off);
+
+ sym->as_off = off;
+ sym->as_hash = elf_hash(s);
+ sym->as_name = s;
+
+ p += INTSZ;
+ sym++;
+
+ for (; s < end && *s++ != '\0';) /* skip to next string */
+ ;
+ if (s > end) {
+ LIBELF_SET_ERROR(ARCHIVE, 0);
+ free(symtab);
+ return (NULL);
+ }
+ }
+
+ /* Fill up the sentinel entry. */
+ sym->as_name = NULL;
+ sym->as_hash = ~0UL;
+ sym->as_off = (off_t) 0;
+
+ *count = e->e_u.e_ar.e_symtabsz = nentries + 1;
+ e->e_u.e_ar.e_symtab = symtab;
+
+ return (symtab);
+}
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