diff options
Diffstat (limited to 'contrib/syslinux-4.02/libinstaller/syslxmod.c')
| -rw-r--r-- | contrib/syslinux-4.02/libinstaller/syslxmod.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/libinstaller/syslxmod.c b/contrib/syslinux-4.02/libinstaller/syslxmod.c new file mode 100644 index 0000000..a68f19f --- /dev/null +++ b/contrib/syslinux-4.02/libinstaller/syslxmod.c @@ -0,0 +1,197 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 1998-2008 H. Peter Anvin - All Rights Reserved + * Copyright 2009-2010 Intel Corporation; author H. Peter Anvin + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, Inc., 53 Temple Place Ste 330, + * Boston MA 02111-1307, USA; either version 2 of the License, or + * (at your option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * syslxmod.c - Code to provide a SYSLINUX code set to an installer. + */ + +#define _XOPEN_SOURCE 500 /* Required on glibc 2.x */ +#define _BSD_SOURCE +#include <stdio.h> +#include <inttypes.h> +#include <string.h> +#include <stddef.h> +#include <stdlib.h> + +#include "syslinux.h" +#include "syslxint.h" + + +/* + * Generate sector extents + */ +static void generate_extents(struct syslinux_extent *ex, int nptrs, + const sector_t *sectp, int nsect) +{ + uint32_t addr = 0x7c00 + 2*SECTOR_SIZE; + uint32_t base; + sector_t sect, lba; + unsigned int len; + + len = lba = base = 0; + + memset(ex, 0, nptrs * sizeof *ex); + + while (nsect) { + sect = *sectp++; + + if (len && sect == lba + len && + ((addr ^ (base + len * SECTOR_SIZE)) & 0xffff0000) == 0) { + /* We can add to the current extent */ + len++; + goto next; + } + + if (len) { + set_64_sl(&ex->lba, lba); + set_16_sl(&ex->len, len); + ex++; + } + + base = addr; + lba = sect; + len = 1; + + next: + addr += SECTOR_SIZE; + nsect--; + } + + if (len) { + set_64_sl(&ex->lba, lba); + set_16_sl(&ex->len, len); + ex++; + } +} + +/* + * Form a pointer based on a 16-bit patcharea/epa field + */ +static inline void *ptr(void *img, uint16_t *offset_p) +{ + return (char *)img + get_16_sl(offset_p); +} + +/* + * This patches the boot sector and the beginning of ldlinux.sys + * based on an ldlinux.sys sector map passed in. Typically this is + * handled by writing ldlinux.sys, mapping it, and then overwrite it + * with the patched version. If this isn't safe to do because of + * an OS which does block reallocation, then overwrite it with + * direct access since the location is known. + * + * Returns the number of modified bytes in ldlinux.sys if successful, + * otherwise -1. + */ +#define NADV 2 + +int syslinux_patch(const sector_t *sectp, int nsectors, + int stupid, int raid_mode, + const char *subdir, const char *subvol) +{ + struct patch_area *patcharea; + struct ext_patch_area *epa; + struct syslinux_extent *ex; + uint32_t *wp; + int nsect = ((boot_image_len + SECTOR_SIZE - 1) >> SECTOR_SHIFT) + 2; + uint32_t csum; + int i, dw, nptrs; + struct boot_sector *sbs = (struct boot_sector *)boot_sector; + uint64_t *advptrs; + + if (nsectors < nsect) + return -1; /* The actual file is too small for content */ + + /* Search for LDLINUX_MAGIC to find the patch area */ + for (wp = (uint32_t *)boot_image; get_32_sl(wp) != LDLINUX_MAGIC; + wp++) + ; + patcharea = (struct patch_area *)wp; + epa = ptr(boot_image, &patcharea->epaoffset); + + /* First sector need pointer in boot sector */ + set_32(ptr(sbs, &epa->sect1ptr0), sectp[0]); + set_32(ptr(sbs, &epa->sect1ptr1), sectp[0] >> 32); + sectp++; + + /* Handle RAID mode */ + if (raid_mode) { + /* Patch in INT 18h = CD 18 */ + set_16(ptr(sbs, &epa->raidpatch), 0x18CD); + } + + /* Set up the totals */ + dw = boot_image_len >> 2; /* COMPLETE dwords, excluding ADV */ + set_16_sl(&patcharea->data_sectors, nsect - 2); /* Not including ADVs */ + set_16_sl(&patcharea->adv_sectors, 2); /* ADVs need 2 sectors */ + set_32_sl(&patcharea->dwords, dw); + + /* Handle Stupid mode */ + if (stupid) { + /* Access only one sector at a time */ + set_16_sl(&patcharea->maxtransfer, 1); + } + + /* Set the sector extents */ + ex = ptr(boot_image, &epa->secptroffset); + nptrs = get_16_sl(&epa->secptrcnt); + + if (nsect > nptrs) { + /* Not necessarily an error in this case, but a general problem */ + fprintf(stderr, "Insufficient extent space, build error!\n"); + exit(1); + } + + /* -1 for the pointer in the boot sector, -2 for the two ADVs */ + generate_extents(ex, nptrs, sectp, nsect-1-2); + + /* ADV pointers */ + advptrs = ptr(boot_image, &epa->advptroffset); + set_64_sl(&advptrs[0], sectp[nsect-1-2]); + set_64_sl(&advptrs[1], sectp[nsect-1-1]); + + /* Poke in the base directory path */ + if (subdir) { + int sublen = strlen(subdir) + 1; + if (get_16_sl(&epa->dirlen) < sublen) { + fprintf(stderr, "Subdirectory path too long... aborting install!\n"); + exit(1); + } + memcpy_to_sl(ptr(boot_image, &epa->diroffset), subdir, sublen); + } + + /* Poke in the subvolume information */ + if (subvol) { + int sublen = strlen(subvol) + 1; + if (get_16_sl(&epa->subvollen) < sublen) { + fprintf(stderr, "Subvol name too long... aborting install!\n"); + exit(1); + } + memcpy_to_sl(ptr(boot_image, &epa->subvoloffset), subvol, sublen); + } + + /* Now produce a checksum */ + set_32_sl(&patcharea->checksum, 0); + + csum = LDLINUX_MAGIC; + for (i = 0, wp = (uint32_t *)boot_image; i < dw; i++, wp++) + csum -= get_32_sl(wp); /* Negative checksum */ + + set_32_sl(&patcharea->checksum, csum); + + /* + * Assume all bytes modified. This can be optimized at the expense + * of keeping track of what the highest modified address ever was. + */ + return dw << 2; +} |