cregit-Linux how code gets into the kernel

Release 4.7 arch/cris/boot/tools/build.c

/*
 *  linux/tools/build.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 * This file builds a disk-image from three different files:
 *
 * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest
 * - setup: 8086 machine code, sets up system parm
 * - system: 80386 code for actual system
 *
 * It does some checking that all files are of the correct type, and
 * just writes the result to stdout, removing headers and padding to
 * the right amount. It also writes some system data to stderr.
 */

/*
 * Changes by tytso to allow root device specification
 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
 * Cross compiling fixes by Gertjan van Wingerde, July 1996
 */

#include <stdio.h>	/* fprintf */
#include <string.h>
#include <stdlib.h>	/* contains exit */
#include <sys/types.h>	/* unistd.h needs this */
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <unistd.h>	/* contains read/write */
#include <fcntl.h>
#include <errno.h>


#define MINIX_HEADER 32


#define N_MAGIC_OFFSET 1024
#ifndef __BFD__

static int GCC_HEADER = sizeof(struct exec);
#endif

#ifdef __BIG_KERNEL__

#define SYS_SIZE 0xffff
#else

#define SYS_SIZE DEF_SYSSIZE
#endif


#define DEFAULT_MAJOR_ROOT 0

#define DEFAULT_MINOR_ROOT 0

/* max nr of sectors of setup: don't change unless you also change
 * bootsect etc */

#define SETUP_SECTS 4


#define STRINGIFY(x) #x

typedef union {
	
int i;
	
long l;
	
short s[2];
	
char b[4];
} 
conv;


long intel_long(long l) { conv t; t.b[0] = l & 0xff; l >>= 8; t.b[1] = l & 0xff; l >>= 8; t.b[2] = l & 0xff; l >>= 8; t.b[3] = l & 0xff; l >>= 8; return t.l; }

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int intel_int(int i) { conv t; t.b[0] = i & 0xff; i >>= 8; t.b[1] = i & 0xff; i >>= 8; t.b[2] = i & 0xff; i >>= 8; t.b[3] = i & 0xff; i >>= 8; return t.i; }

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short intel_short(short l) { conv t; t.b[0] = l & 0xff; l >>= 8; t.b[1] = l & 0xff; l >>= 8; return t.s[0]; }

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void die(const char * str) { fprintf(stderr,"%s\n",str); exit(1); }

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void usage(void) { die("Usage: build bootsect setup system [rootdev] [> image]"); }

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int main(int argc, char ** argv) { int i,c,id,sz,tmp_int; unsigned long sys_size, tmp_long; char buf[1024]; #ifndef __BFD__ struct exec *ex = (struct exec *)buf; #endif char major_root, minor_root; struct stat sb; unsigned char setup_sectors; if ((argc < 4) || (argc > 5)) usage(); if (argc > 4) { if (!strcmp(argv[4], "CURRENT")) { if (stat("/", &sb)) { perror("/"); die("Couldn't stat /"); } major_root = major(sb.st_dev); minor_root = minor(sb.st_dev); } else if (strcmp(argv[4], "FLOPPY")) { if (stat(argv[4], &sb)) { perror(argv[4]); die("Couldn't stat root device."); } major_root = major(sb.st_rdev); minor_root = minor(sb.st_rdev); } else { major_root = 0; minor_root = 0; } } else { major_root = DEFAULT_MAJOR_ROOT; minor_root = DEFAULT_MINOR_ROOT; } fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root); for (i=0;i<sizeof buf; i++) buf[i]=0; if ((id=open(argv[1],O_RDONLY,0))<0) die("Unable to open 'boot'"); if (read(id,buf,MINIX_HEADER) != MINIX_HEADER) die("Unable to read header of 'boot'"); if (((long *) buf)[0]!=intel_long(0x04100301)) die("Non-Minix header of 'boot'"); if (((long *) buf)[1]!=intel_long(MINIX_HEADER)) die("Non-Minix header of 'boot'"); if (((long *) buf)[3] != 0) die("Illegal data segment in 'boot'"); if (((long *) buf)[4] != 0) die("Illegal bss in 'boot'"); if (((long *) buf)[5] != 0) die("Non-Minix header of 'boot'"); if (((long *) buf)[7] != 0) die("Illegal symbol table in 'boot'"); i=read(id,buf,sizeof buf); fprintf(stderr,"Boot sector %d bytes.\n",i); if (i != 512) die("Boot block must be exactly 512 bytes"); if ((*(unsigned short *)(buf+510)) != (unsigned short)intel_short(0xAA55)) die("Boot block hasn't got boot flag (0xAA55)"); buf[508] = (char) minor_root; buf[509] = (char) major_root; i=write(1,buf,512); if (i!=512) die("Write call failed"); close (id); if ((id=open(argv[2],O_RDONLY,0))<0) die("Unable to open 'setup'"); if (read(id,buf,MINIX_HEADER) != MINIX_HEADER) die("Unable to read header of 'setup'"); if (((long *) buf)[0]!=intel_long(0x04100301)) die("Non-Minix header of 'setup'"); if (((long *) buf)[1]!=intel_long(MINIX_HEADER)) die("Non-Minix header of 'setup'"); if (((long *) buf)[3] != 0) die("Illegal data segment in 'setup'"); if (((long *) buf)[4] != 0) die("Illegal bss in 'setup'"); if (((long *) buf)[5] != 0) die("Non-Minix header of 'setup'"); if (((long *) buf)[7] != 0) die("Illegal symbol table in 'setup'"); for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c ) #ifdef __BIG_KERNEL__ { if (!i) { /* Working with memcpy because of alignment constraints on Sparc - Gertjan */ memcpy(&tmp_long, &buf[2], sizeof(long)); if (tmp_long != intel_long(0x53726448) ) die("Wrong magic in loader header of 'setup'"); memcpy(&tmp_int, &buf[6], sizeof(int)); if (tmp_int < intel_int(0x200)) die("Wrong version of loader header of 'setup'"); buf[0x11] = 1; /* LOADED_HIGH */ tmp_long = intel_long(0x100000); memcpy(&buf[0x14], &tmp_long, sizeof(long)); /* code32_start */ } #endif if (write(1,buf,c)!=c) die("Write call failed"); #ifdef __BIG_KERNEL__ } #endif if (c != 0) die("read-error on 'setup'"); close (id); setup_sectors = (unsigned char)((i + 511) / 512); /* for compatibility with LILO */ if (setup_sectors < SETUP_SECTS) setup_sectors = SETUP_SECTS; fprintf(stderr,"Setup is %d bytes.\n",i); for (c=0 ; c<sizeof(buf) ; c++) buf[c] = '\0'; while (i < setup_sectors * 512) { c = setup_sectors * 512 - i; if (c > sizeof(buf)) c = sizeof(buf); if (write(1,buf,c) != c) die("Write call failed"); i += c; } if ((id=open(argv[3],O_RDONLY,0))<0) die("Unable to open 'system'"); #ifndef __BFD__ if (read(id,buf,GCC_HEADER) != GCC_HEADER) die("Unable to read header of 'system'"); if (N_MAGIC(*ex) == ZMAGIC) { GCC_HEADER = N_MAGIC_OFFSET; lseek(id, GCC_HEADER, SEEK_SET); } else if (N_MAGIC(*ex) != QMAGIC) die("Non-GCC header of 'system'"); fprintf(stderr,"System is %d kB (%d kB code, %d kB data and %d kB bss)\n", (ex->a_text+ex->a_data+ex->a_bss)/1024, ex->a_text /1024, ex->a_data /1024, ex->a_bss /1024); sz = N_SYMOFF(*ex) - GCC_HEADER + 4; #else if (fstat (id, &sb)) { perror ("fstat"); die ("Unable to stat 'system'"); } sz = sb.st_size; fprintf (stderr, "System is %d kB\n", sz/1024); #endif sys_size = (sz + 15) / 16; if (sys_size > SYS_SIZE) die("System is too big"); while (sz > 0) { int l, n; l = sz; if (l > sizeof(buf)) l = sizeof(buf); if ((n=read(id, buf, l)) != l) { if (n == -1) perror(argv[1]); else fprintf(stderr, "Unexpected EOF\n"); die("Can't read 'system'"); } if (write(1, buf, l) != l) die("Write failed"); sz -= l; } close(id); if (lseek(1, 497, 0) == 497) { if (write(1, &setup_sectors, 1) != 1) die("Write of setup sectors failed"); } if (lseek(1,500,0) == 500) { buf[0] = (sys_size & 0xff); buf[1] = ((sys_size >> 8) & 0xff); if (write(1, buf, 2) != 2) die("Write failed"); } return(0); }

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linus torvaldslinus torvalds1407100.00%1100.00%
Total1407100.00%1100.00%


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Total1760100.00%1100.00%
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