273 lines
6.6 KiB
C
273 lines
6.6 KiB
C
/*
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Simple utility to make a single-image install kernel with initial ramdisk
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for Sparc tftpbooting without need to set up nfs.
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Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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Pete Zaitcev <zaitcev@yahoo.com> endian fixes for cross-compiles, 2000.
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Copyright (C) 2011 Sam Ravnborg <sam@ravnborg.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include <dirent.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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/*
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* Note: run this on an a.out kernel (use elftoaout for it),
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* as PROM looks for a.out image only.
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*/
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#define AOUT_TEXT_OFFSET 32
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static int is64bit = 0;
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/* align to power-of-two size */
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static int align(int n)
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{
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if (is64bit)
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return (n + 0x1fff) & ~0x1fff;
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else
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return (n + 0xfff) & ~0xfff;
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}
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/* read two bytes as big endian */
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static unsigned short ld2(char *p)
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{
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return (p[0] << 8) | p[1];
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}
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/* save 4 bytes as big endian */
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static void st4(char *p, unsigned int x)
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{
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p[0] = x >> 24;
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p[1] = x >> 16;
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p[2] = x >> 8;
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p[3] = x;
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}
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static void die(const char *str)
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{
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perror(str);
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exit(1);
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}
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static void usage(void)
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{
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/* fs_img.gz is an image of initial ramdisk. */
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fprintf(stderr, "Usage: piggyback bits vmlinux.aout System.map fs_img.gz\n");
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fprintf(stderr, "\tKernel image will be modified in place.\n");
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exit(1);
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}
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static int start_line(const char *line)
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{
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if (strcmp(line + 10, " _start\n") == 0)
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return 1;
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else if (strcmp(line + 18, " _start\n") == 0)
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return 1;
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return 0;
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}
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static int end_line(const char *line)
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{
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if (strcmp(line + 10, " _end\n") == 0)
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return 1;
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else if (strcmp (line + 18, " _end\n") == 0)
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return 1;
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return 0;
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}
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/*
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* Find address for start and end in System.map.
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* The file looks like this:
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* f0004000 ... _start
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* f0379f79 ... _end
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* 1234567890123456
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* ^coloumn 1
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* There is support for 64 bit addresses too.
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*
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* Return 0 if either start or end is not found
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*/
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static int get_start_end(const char *filename, unsigned int *start,
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unsigned int *end)
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{
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FILE *map;
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char buffer[1024];
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*start = 0;
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*end = 0;
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map = fopen(filename, "r");
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if (!map)
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die(filename);
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while (fgets(buffer, 1024, map)) {
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if (start_line(buffer))
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*start = strtoul(buffer, NULL, 16);
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else if (end_line(buffer))
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*end = strtoul(buffer, NULL, 16);
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}
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fclose (map);
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if (*start == 0 || *end == 0)
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return 0;
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return 1;
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}
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#define LOOKBACK (128 * 4)
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#define BUFSIZE 1024
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/*
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* Find the HdrS entry from head_32/head_64.
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* We check if it is at the beginning of the file (sparc64 case)
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* and if not we search for it.
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* When we search do so in steps of 4 as HdrS is on a 4-byte aligned
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* address (it is on same alignment as sparc instructions)
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* Return the offset to the HdrS entry (as off_t)
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*/
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static off_t get_hdrs_offset(int kernelfd, const char *filename)
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{
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char buffer[BUFSIZE];
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off_t offset;
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int i;
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if (lseek(kernelfd, 0, SEEK_SET) < 0)
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die("lseek");
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if (read(kernelfd, buffer, BUFSIZE) != BUFSIZE)
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die(filename);
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if (buffer[40] == 'H' && buffer[41] == 'd' &&
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buffer[42] == 'r' && buffer[43] == 'S') {
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return 40;
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} else {
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/* Find the gokernel label */
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/* Decode offset from branch instruction */
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offset = ld2(buffer + AOUT_TEXT_OFFSET + 2) << 2;
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/* Go back 512 bytes so we do not miss HdrS */
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offset -= LOOKBACK;
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/* skip a.out header */
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offset += AOUT_TEXT_OFFSET;
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if (lseek(kernelfd, offset, SEEK_SET) < 0)
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die("lseek");
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if (read(kernelfd, buffer, BUFSIZE) != BUFSIZE)
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die(filename);
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for (i = 0; i < LOOKBACK; i += 4) {
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if (buffer[i + 0] == 'H' && buffer[i + 1] == 'd' &&
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buffer[i + 2] == 'r' && buffer[i + 3] == 'S') {
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return offset + i;
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}
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}
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}
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fprintf (stderr, "Couldn't find headers signature in %s\n", filename);
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exit(1);
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}
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int main(int argc,char **argv)
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{
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static char aout_magic[] = { 0x01, 0x03, 0x01, 0x07 };
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char buffer[1024];
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unsigned int i, start, end;
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off_t offset;
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struct stat s;
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int image, tail;
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if (argc != 5)
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usage();
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if (strcmp(argv[1], "64") == 0)
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is64bit = 1;
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if (stat (argv[4], &s) < 0)
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die(argv[4]);
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if (!get_start_end(argv[3], &start, &end)) {
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fprintf(stderr, "Could not determine start and end from %s\n",
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argv[3]);
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exit(1);
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}
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if ((image = open(argv[2], O_RDWR)) < 0)
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die(argv[2]);
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if (read(image, buffer, 512) != 512)
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die(argv[2]);
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if (memcmp(buffer, aout_magic, 4) != 0) {
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fprintf (stderr, "Not a.out. Don't blame me.\n");
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exit(1);
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}
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/*
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* We need to fill in values for
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* sparc_ramdisk_image + sparc_ramdisk_size
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* To locate these symbols search for the "HdrS" text which appear
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* in the image a little before the gokernel symbol.
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* See definition of these in init_32.S
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*/
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offset = get_hdrs_offset(image, argv[2]);
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/* skip HdrS + LINUX_VERSION_CODE + HdrS version */
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offset += 10;
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if (lseek(image, offset, 0) < 0)
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die("lseek");
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/*
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* root_flags = 0
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* root_dev = 1 (RAMDISK_MAJOR)
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* ram_flags = 0
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* sparc_ramdisk_image = "PAGE aligned address after _end")
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* sparc_ramdisk_size = size of image
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*/
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st4(buffer, 0);
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st4(buffer + 4, 0x01000000);
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st4(buffer + 8, align(end + 32));
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st4(buffer + 12, s.st_size);
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if (write(image, buffer + 2, 14) != 14)
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die(argv[2]);
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/* For sparc64 update a_text and clear a_data + a_bss */
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if (is64bit)
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{
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if (lseek(image, 4, 0) < 0)
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die("lseek");
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/* a_text */
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st4(buffer, align(end + 32 + 8191) - (start & ~0x3fffffUL) +
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s.st_size);
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/* a_data */
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st4(buffer + 4, 0);
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/* a_bss */
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st4(buffer + 8, 0);
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if (write(image, buffer, 12) != 12)
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die(argv[2]);
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}
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/* seek page aligned boundary in the image file and add boot image */
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if (lseek(image, AOUT_TEXT_OFFSET - start + align(end + 32), 0) < 0)
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die("lseek");
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if ((tail = open(argv[4], O_RDONLY)) < 0)
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die(argv[4]);
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while ((i = read(tail, buffer, 1024)) > 0)
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if (write(image, buffer, i) != i)
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die(argv[2]);
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if (close(image) < 0)
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die("close");
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if (close(tail) < 0)
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die("close");
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return 0;
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}
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