97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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* This program patches a filesystem into a kernel made with MFS_ROOT
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* option.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <ufs/ffs/fs.h>
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static int force = 0; /* don't check for zeros, may corrupt kernel */
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int
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main(int argc, char **argv)
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{
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unsigned char *buf_kernel, *buf_fs, *p,*q, *prog;
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int fd_kernel, fd_fs, ch, errs=0;
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struct stat st_kernel, st_fs;
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u_long l;
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prog= *argv;
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while ((ch = getopt(argc, argv, "f")) != EOF)
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switch(ch) {
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case 'f':
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force = 1 - force;
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break;
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default:
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errs++;
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}
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argc -= optind;
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argv += optind;
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if (errs || argc != 2) {
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fprintf(stderr,"Usage:\n\t%s [-f] kernel fs\n", prog);
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exit(2);
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}
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--argv; /* original prog did not use getopt(3) */
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fd_kernel = open(argv[1],O_RDWR);
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if (fd_kernel < 0) { perror(argv[1]); exit(2); }
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fstat(fd_kernel,&st_kernel);
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fd_fs = open(argv[2],O_RDONLY);
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if (fd_fs < 0) { perror(argv[2]); exit(2); }
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fstat(fd_fs,&st_fs);
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buf_kernel = malloc(st_kernel.st_size);
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if (!buf_kernel) { perror("malloc"); exit(2); }
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buf_fs = malloc(st_fs.st_size);
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if (!buf_fs) { perror("malloc"); exit(2); }
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if (st_kernel.st_size != read(fd_kernel,buf_kernel,st_kernel.st_size))
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{ perror(argv[1]); exit(2); }
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if (st_fs.st_size != read(fd_fs,buf_fs,st_fs.st_size))
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{ perror(argv[2]); exit(2); }
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for(l=0,p=buf_kernel; l < st_kernel.st_size - st_fs.st_size ; l++,p++ )
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if(*p == 'M' && !strcmp(p,"MFS Filesystem goes here"))
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goto found;
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fprintf(stderr,"MFS filesystem signature not found in %s\n",argv[1]);
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exit(1);
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found:
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if (!force)
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for(l=0,q= p + SBOFF; l < st_fs.st_size - SBOFF ; l++,q++ )
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if (*q)
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goto fail;
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memcpy(p+SBOFF,buf_fs+SBOFF,st_fs.st_size-SBOFF);
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lseek(fd_kernel,0L,SEEK_SET);
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if (st_kernel.st_size != write(fd_kernel,buf_kernel,st_kernel.st_size))
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{ perror(argv[1]); exit(2); }
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exit(0);
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fail:
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l += SBOFF;
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fprintf(stderr,"Obstruction in kernel after %ld bytes (%ld Kbyte)\n",
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l, l/1024);
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fprintf(stderr,"Filesystem is %ld bytes (%ld Kbyte)\n",
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(u_long)st_fs.st_size, (u_long)st_fs.st_size/1024);
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exit(1);
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}
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/*
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* I added a '-f' option to force writing the image into the kernel, even when
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* there is already data (i.e. not zero) in the written area. This is useful
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* to rewrite a changed MFS-image. Beware: If the written image is larger than
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* the space reserved in the kernel (with option MFS_ROOT) then
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* THIS WILL CORRUPT THE KERNEL!
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*
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*/
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