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Annotation of linux/tools/build.c, revision 1.1.1.2

1.1.1.2 ! root        1: /*
        !             2:  *  linux/tools/build.c
        !             3:  *
        !             4:  *  (C) 1991  Linus Torvalds
        !             5:  */
        !             6: 
        !             7: /*
        !             8:  * This file builds a disk-image from three different files:
        !             9:  *
        !            10:  * - bootsect: max 510 bytes of 8086 machine code, loads the rest
        !            11:  * - setup: max 4 sectors of 8086 machine code, sets up system parm
        !            12:  * - system: 80386 code for actual system
        !            13:  *
        !            14:  * It does some checking that all files are of the correct type, and
        !            15:  * just writes the result to stdout, removing headers and padding to
        !            16:  * the right amount. It also writes some system data to stderr.
        !            17:  */
        !            18: 
1.1       root       19: #include <stdio.h>     /* fprintf */
1.1.1.2 ! root       20: #include <string.h>
1.1       root       21: #include <stdlib.h>    /* contains exit */
                     22: #include <sys/types.h> /* unistd.h needs this */
1.1.1.2 ! root       23: #include <sys/stat.h>
        !            24: #include <linux/fs.h>
1.1       root       25: #include <unistd.h>    /* contains read/write */
                     26: #include <fcntl.h>
                     27: 
                     28: #define MINIX_HEADER 32
                     29: #define GCC_HEADER 1024
                     30: 
1.1.1.2 ! root       31: #define DEFAULT_MAJOR_ROOT 3
        !            32: #define DEFAULT_MINOR_ROOT 6
        !            33: 
        !            34: /* max nr of sectors of setup: don't change unless you also change
        !            35:  * bootsect etc */
        !            36: #define SETUP_SECTS 4
        !            37: 
        !            38: #define STRINGIFY(x) #x
        !            39: 
1.1       root       40: void die(char * str)
                     41: {
                     42:        fprintf(stderr,"%s\n",str);
                     43:        exit(1);
                     44: }
                     45: 
                     46: void usage(void)
                     47: {
1.1.1.2 ! root       48:        die("Usage: build bootsect setup system [> image]");
1.1       root       49: }
                     50: 
                     51: int main(int argc, char ** argv)
                     52: {
                     53:        int i,c,id;
                     54:        char buf[1024];
1.1.1.2 ! root       55:        char major_root, minor_root;
        !            56:        struct stat sb;
1.1       root       57: 
1.1.1.2 ! root       58:        if ((argc != 4) && (argc != 5))
1.1       root       59:                usage();
1.1.1.2 ! root       60:        if (argc == 5) {
        !            61:                if (strcmp(argv[4], "FLOPPY")) {
        !            62:                        if (stat(argv[4], &sb)) {
        !            63:                                perror(argv[4]);
        !            64:                                die("Couldn't stat root device.");
        !            65:                        }
        !            66:                        major_root = MAJOR(sb.st_rdev);
        !            67:                        minor_root = MINOR(sb.st_rdev);
        !            68:                } else {
        !            69:                        major_root = 0;
        !            70:                        minor_root = 0;
        !            71:                }
        !            72:        } else {
        !            73:                major_root = DEFAULT_MAJOR_ROOT;
        !            74:                minor_root = DEFAULT_MINOR_ROOT;
        !            75:        }
        !            76:        fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
        !            77:        if ((major_root != 2) && (major_root != 3) &&
        !            78:            (major_root != 0)) {
        !            79:                fprintf(stderr, "Illegal root device (major = %d)\n",
        !            80:                        major_root);
        !            81:                die("Bad root device --- major #");
        !            82:        }
1.1       root       83:        for (i=0;i<sizeof buf; i++) buf[i]=0;
                     84:        if ((id=open(argv[1],O_RDONLY,0))<0)
                     85:                die("Unable to open 'boot'");
                     86:        if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
                     87:                die("Unable to read header of 'boot'");
                     88:        if (((long *) buf)[0]!=0x04100301)
                     89:                die("Non-Minix header of 'boot'");
                     90:        if (((long *) buf)[1]!=MINIX_HEADER)
                     91:                die("Non-Minix header of 'boot'");
                     92:        if (((long *) buf)[3]!=0)
                     93:                die("Illegal data segment in 'boot'");
                     94:        if (((long *) buf)[4]!=0)
                     95:                die("Illegal bss in 'boot'");
                     96:        if (((long *) buf)[5] != 0)
                     97:                die("Non-Minix header of 'boot'");
                     98:        if (((long *) buf)[7] != 0)
                     99:                die("Illegal symbol table in 'boot'");
                    100:        i=read(id,buf,sizeof buf);
                    101:        fprintf(stderr,"Boot sector %d bytes.\n",i);
1.1.1.2 ! root      102:        if (i != 512)
        !           103:                die("Boot block must be exactly 512 bytes");
        !           104:        if ((*(unsigned short *)(buf+510)) != 0xAA55)
        !           105:                die("Boot block hasn't got boot flag (0xAA55)");
        !           106:        buf[508] = (char) minor_root;
        !           107:        buf[509] = (char) major_root;   
1.1       root      108:        i=write(1,buf,512);
                    109:        if (i!=512)
                    110:                die("Write call failed");
                    111:        close (id);
                    112:        
                    113:        if ((id=open(argv[2],O_RDONLY,0))<0)
1.1.1.2 ! root      114:                die("Unable to open 'setup'");
        !           115:        if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
        !           116:                die("Unable to read header of 'setup'");
        !           117:        if (((long *) buf)[0]!=0x04100301)
        !           118:                die("Non-Minix header of 'setup'");
        !           119:        if (((long *) buf)[1]!=MINIX_HEADER)
        !           120:                die("Non-Minix header of 'setup'");
        !           121:        if (((long *) buf)[3]!=0)
        !           122:                die("Illegal data segment in 'setup'");
        !           123:        if (((long *) buf)[4]!=0)
        !           124:                die("Illegal bss in 'setup'");
        !           125:        if (((long *) buf)[5] != 0)
        !           126:                die("Non-Minix header of 'setup'");
        !           127:        if (((long *) buf)[7] != 0)
        !           128:                die("Illegal symbol table in 'setup'");
        !           129:        for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
        !           130:                if (write(1,buf,c)!=c)
        !           131:                        die("Write call failed");
        !           132:        close (id);
        !           133:        if (i > SETUP_SECTS*512)
        !           134:                die("Setup exceeds " STRINGIFY(SETUP_SECTS)
        !           135:                        " sectors - rewrite build/boot/setup");
        !           136:        fprintf(stderr,"Setup is %d bytes.\n",i);
        !           137:        for (c=0 ; c<sizeof(buf) ; c++)
        !           138:                buf[c] = '\0';
        !           139:        while (i<SETUP_SECTS*512) {
        !           140:                c = SETUP_SECTS*512-i;
        !           141:                if (c > sizeof(buf))
        !           142:                        c = sizeof(buf);
        !           143:                if (write(1,buf,c) != c)
        !           144:                        die("Write call failed");
        !           145:                i += c;
        !           146:        }
        !           147:        
        !           148:        if ((id=open(argv[3],O_RDONLY,0))<0)
1.1       root      149:                die("Unable to open 'system'");
                    150:        if (read(id,buf,GCC_HEADER) != GCC_HEADER)
                    151:                die("Unable to read header of 'system'");
                    152:        if (((long *) buf)[5] != 0)
                    153:                die("Non-GCC header of 'system'");
                    154:        for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
                    155:                if (write(1,buf,c)!=c)
                    156:                        die("Write call failed");
                    157:        close(id);
1.1.1.2 ! root      158:        fprintf(stderr,"System is %d bytes.\n",i);
1.1       root      159:        return(0);
                    160: }

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