Messages in this thread |  | | | Date | Thu, 14 Feb 2002 08:48:55 -0800 (PST) | | From | "Randy.Dunlap" <> | | Subject | Re: How to check the kernel compile options ? |
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On Wed, 13 Feb 2002, Bill Davidsen wrote:
| On Wed, 13 Feb 2002, Ben Greear wrote: | [snippage] | | No, but there's no reason to have it part of the kernel image as the only | solution. It works as a module, it works as a flat text data file in the | modules directory (except for those who can't match kernel to modules), | and ther's no reason why this can't exist somewhere which has no impact on | the size of the kernel image.
I agree, if I understand you correctly.
I don't see a need for a CONFIG_SAVE_CONFIG option with value 'm'. kbuild in 2.5 (or any script like 'installkernel') can do that by copying the current .config file to the modules install directory or the /boot directory.
I was hoping that (e)grep could search a (b)zImage file for a binary pattern like the gzip header, but I couldn't make it work. I ended up writing a binary pattern search tool that returns the offset of the located pattern, and then I feed that value to tail | gunzip > strings | grep to get the CONFIG text that was saved by the code that I posted yesterday. I still plan to make this a config/build option (y/n) and remove the leading "CONFIG_" parts of the strings.
binoffset.c and extract-config (script) attached.
-- ~Randy
#! /bin/bash # extracts .config info from a [b]zImage file # uses binoffset (new), tail, gunzip, strings, and grep # $arg1 is [b]zImage filename
gziphdr=`binoffset $1 0x1f 0x8b 0x08 0x0` # increment by 1 since tail offsets are 1-based, not 0-based gziphdr=$((gziphdr + 1))
tail -c +$gziphdr $1 | gunzip > $1.tmp strings $1.tmp | grep CONFIG_ > $1.old.config rm $1.tmp/*************************************************************************** * binoffset.c * (C) 2002 Randy Dunlap <rddunlap@osdl.org> # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
# binoffset.c: # - searches a (binary) file for a specified (binary) pattern # - returns the offset of the located pattern or ~0 if not found # - exits with exit status 0 normally or non-0 if pattern is not found # or any other error occurs.
****************************************************************/ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #define VERSION "0.1" #define BUF_SIZE (16 * 1024) #define PAT_SIZE 100 char *progname; char *inputname; int inputfd; int bix; /* buf index */ unsigned char patterns [PAT_SIZE] = {0}; /* byte-sized pattern array */ int pat_len; /* actual number of pattern bytes */ unsigned char *madr; /* mmap address */ size_t filesize; int num_matches = 0; off_t firstloc = 0; void usage (void) { fprintf (stderr, "%s ver. %s\n", progname, VERSION); fprintf (stderr, "usage: %s filename pattern_bytes\n", progname); fprintf (stderr, " [prints location of pattern_bytes in file]\n"); exit (1); } int get_pattern (int pat_count, char *pats []) { int ix, err, tmp; #ifdef DEBUG fprintf (stderr,"get_pattern: count = %d\n", pat_count); for (ix = 0; ix < pat_count; ix++) fprintf (stderr, " pat # %d: [%s]\n", ix, pats[ix]); #endif for (ix = 0; ix < pat_count; ix++) { tmp = 0; err = sscanf (pats[ix], "%5i", &tmp); if (err != 1 || tmp > 0xff) { fprintf (stderr, "pattern or value error in pattern # %d [%s]\n", ix, pats[ix]); usage (); } patterns [ix] = tmp; } pat_len = pat_count; } int search_pattern (void) { for (bix = 0; bix < filesize; bix++) { if (madr[bix] == patterns[0]) { if (memcmp (&madr[bix], patterns, pat_len) == 0) { if (num_matches == 0) firstloc = bix; num_matches++; } } } } #ifdef NOTDEF size_t get_filesize (int fd) { off_t end_off = lseek (fd, 0, SEEK_END); lseek (fd, 0, SEEK_SET); return (size_t) end_off; } #endif size_t get_filesize (int fd) { int err; struct stat stat; err = fstat (fd, &stat); fprintf (stderr, "filesize: %d\n", err < 0 ? err : stat.st_size); if (err < 0) return err; return (size_t) stat.st_size; } int main (int argc, char *argv []) { progname = argv[0]; if (argc < 3) usage (); get_pattern (argc - 2, argv + 2); inputname = argv[1]; inputfd = open (inputname, O_RDONLY); if (inputfd == -1) { fprintf (stderr, "%s: cannot open '%s'\n", progname, inputname); exit (3); } filesize = get_filesize (inputfd); madr = mmap (0, filesize, PROT_READ, MAP_PRIVATE, inputfd, 0); if (madr == MAP_FAILED) { fprintf (stderr, "mmap error = %d\n", errno); close (inputfd); exit (4); } search_pattern (); if (munmap (madr, filesize)) fprintf (stderr, "munmap error = %d\n", errno); if (close (inputfd)) fprintf (stderr, "%s: error %d closing '%s'\n", progname, errno, inputname); fprintf (stderr, "number of pattern matches = %d\n", num_matches); if (num_matches == 0) firstloc = ~0; printf ("%d\n", firstloc); fprintf (stderr, "%d\n", firstloc); exit (num_matches ? 0 : 2); } /* end binoffset.c */ |  |