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/* $OpenBSD: ksyms.c,v 1.2 2013/08/29 20:22:14 naddy Exp $ */
/*
* Copyright (c) 2008 Miodrag Vallat.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/exec.h>
#ifdef _NLIST_DO_ELF
#include <elf_abi.h>
#endif
#include "hangman.h"
int ksyms_aout_parse();
int ksyms_elf_parse();
void
kgetword()
{
uint tries;
off_t pos;
int buflen;
char symbuf[1 + BUFSIZ], *sym, *end;
size_t symlen;
for (tries = 0; tries < MAXBADWORDS; tries++) {
pos = arc4random_uniform(ksymsize);
if (lseek(ksyms, pos + ksymoffs, SEEK_SET) == -1)
continue;
buflen = read(ksyms, symbuf, BUFSIZ);
if (buflen < 0)
continue;
/*
* The buffer is hopefully large enough to hold at least
* a complete symbol, i.e. two occurences of NUL, or
* one occurence of NUL and the buffer containing the end
* of the string table. We make sure the buffer will be
* NUL terminated in all cases.
*/
if (buflen + pos >= ksymsize)
buflen = ksymsize - pos;
*(end = symbuf + buflen) = '\0';
for (sym = symbuf; *sym != '\0'; sym++) ;
if (sym == end)
continue;
symlen = strlen(++sym);
if (symlen < MINLEN || symlen > MAXLEN)
continue;
break;
}
if (tries >= MAXBADWORDS) {
mvcur(0, COLS - 1, LINES -1, 0);
endwin();
errx(1, "can't seem a suitable kernel symbol in %s",
Dict_name);
}
strlcpy(Word, sym, sizeof Word);
strlcpy(Known, sym, sizeof Known);
for (sym = Known; *sym != '\0'; sym++) {
if (*sym == '-')
*sym = '_'; /* try not to confuse player */
if (isalpha(*sym))
*sym = '-';
}
}
int
ksetup()
{
if ((ksyms = open(Dict_name, O_RDONLY)) < 0)
return ksyms;
/*
* Relaxed header check - /dev/ksyms is either a native a.out
* binary or a native ELF binary.
*/
#ifdef _NLIST_DO_ELF
if (ksyms_elf_parse() == 0)
return 0;
#endif
#ifdef _NLIST_DO_AOUT
if (ksyms_aout_parse() == 0)
return 0;
#endif
close(ksyms);
errno = ENOEXEC;
return -1;
}
#ifdef _NLIST_DO_ELF
int
ksyms_elf_parse()
{
Elf_Ehdr eh;
Elf_Shdr sh;
uint s;
if (lseek(ksyms, 0, SEEK_SET) == -1)
return -1;
if (read(ksyms, &eh, sizeof eh) != sizeof eh)
return -1;
if (!IS_ELF(eh))
return -1;
if (lseek(ksyms, eh.e_shoff, SEEK_SET) == -1)
return -1;
ksymoffs = 0;
ksymsize = 0;
for (s = 0; s < eh.e_shnum; s++) {
if (read(ksyms, &sh, sizeof sh) != sizeof sh)
return -1;
/*
* There should be two string table sections, one with the
* name of the sections themselves, and one with the symbol
* names. Just pick the largest one.
*/
if (sh.sh_type == SHT_STRTAB) {
if (ksymsize > (off_t)sh.sh_size)
continue;
ksymoffs = (off_t)sh.sh_offset;
ksymsize = (off_t)sh.sh_size;
}
}
if (ksymsize == 0)
return -1;
return 0;
}
#endif
#ifdef _NLIST_DO_AOUT
int
ksyms_aout_parse()
{
struct exec eh;
uint32_t size;
if (lseek(ksyms, 0, SEEK_SET) == -1)
return -1;
if (read(ksyms, &eh, sizeof eh) != sizeof eh)
return -1;
if (N_BADMAG(eh))
return -1;
ksymoffs = (off_t)N_STROFF(eh);
if (lseek(ksyms, ksymoffs, SEEK_SET) == -1)
return -1;
if (read(ksyms, &size, sizeof size) != sizeof size)
return -1;
ksymoffs += sizeof size;
if (size <= sizeof size)
return -1;
ksymsize = (off_t)size - sizeof size;
return 0;
}
#endif
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