arch/alpha/boot/tools/mkbb.c

Source file repositories/reference/linux-study-clean/arch/alpha/boot/tools/mkbb.c

File Facts

System
Linux kernel
Corpus path
arch/alpha/boot/tools/mkbb.c
Extension
.c
Size
3598 bytes
Lines
154
Domain
Architecture Layer
Bucket
arch/alpha
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct disklabel {
    u32	d_magic;				/* must be DISKLABELMAGIC */
    u16	d_type, d_subtype;
    u8	d_typename[16];
    u8	d_packname[16];
    u32	d_secsize;
    u32	d_nsectors;
    u32	d_ntracks;
    u32	d_ncylinders;
    u32	d_secpercyl;
    u32	d_secprtunit;
    u16	d_sparespertrack;
    u16	d_sparespercyl;
    u32	d_acylinders;
    u16	d_rpm, d_interleave, d_trackskew, d_cylskew;
    u32	d_headswitch, d_trkseek, d_flags;
    u32	d_drivedata[5];
    u32	d_spare[5];
    u32	d_magic2;				/* must be DISKLABELMAGIC */
    u16	d_checksum;
    u16	d_npartitions;
    u32	d_bbsize, d_sbsize;
    struct d_partition {
	u32	p_size;
	u32	p_offset;
	u32	p_fsize;
	u8	p_fstype;
	u8	p_frag;
	u16	p_cpg;
    } d_partitions[MAXPARTITIONS];
};


typedef union __bootblock {
    struct {
        char			__pad1[64];
        struct disklabel	__label;
    } __u1;
    struct {
	unsigned long		__pad2[63];
	unsigned long		__checksum;
    } __u2;
    char		bootblock_bytes[512];
    unsigned long	bootblock_quadwords[64];
} bootblock;

#define	bootblock_label		__u1.__label
#define bootblock_checksum	__u2.__checksum

int main(int argc, char ** argv)
{
    bootblock		bootblock_from_disk;
    bootblock		bootloader_image;
    int			dev, fd;
    int			i;
    int			nread;

    /* Make sure of the arg count */
    if(argc != 3) {
	fprintf(stderr, "Usage: %s device lxboot\n", argv[0]);
	exit(0);
    }

    /* First, open the device and make sure it's accessible */
    dev = open(argv[1], O_RDWR);
    if(dev < 0) {
	perror(argv[1]);
	exit(0);
    }

    /* Now open the lxboot and make sure it's reasonable */
    fd = open(argv[2], O_RDONLY);
    if(fd < 0) {
	perror(argv[2]);
	close(dev);
	exit(0);
    }

    /* Read in the lxboot */
    nread = read(fd, &bootloader_image, sizeof(bootblock));
    if(nread != sizeof(bootblock)) {
	perror("lxboot read");
	fprintf(stderr, "expected %zd, got %d\n", sizeof(bootblock), nread);
	exit(0);
    }

    /* Read in the bootblock from disk. */
    nread = read(dev, &bootblock_from_disk, sizeof(bootblock));
    if(nread != sizeof(bootblock)) {
	perror("bootblock read");

Annotation

Implementation Notes