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better check for valid backup boot sector # and add option to skip setting it

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git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/branches/UNSTABLE@1126 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Kenneth J Davis 2005-05-28 17:14:58 +00:00
parent 726b3f5af1
commit 31377051e1
2 changed files with 18 additions and 2 deletions
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1
docs/sys.txt
View File

@ -34,6 +34,7 @@ SYS [source] dest: [bootsect] [{option}]
/L segm : hex load segment to use in boot sector instead of 0x60
/B btdrv : hex BIOS # of boot drive set in bs, 0=A:, 80=1st hd,...
/FORCEDRV: force use of drive # set in bs instead of BIOS boot value
/NOBAKBS : skips copying boot sector to backup bs, FAT32 only else ignored
/SKFN filename : set KERNEL.SYS input file and /OEM:FD
/SCFN filename : sets COMMAND.COM input file
/BACKUPBS [path]filename : save current bs before overwriting

19
sys/sys.c
View File

@ -357,6 +357,7 @@ typedef struct SYSOptions {
DOSBootFiles kernel; /* file name(s) and relevant data for kernel */
BYTE defBootDrive; /* value stored in boot sector for drive, eg 0x0=A, 0x80=C */
BOOL ignoreBIOS; /* true to NOP out boot sector code to get drive# from BIOS */
BOOL skipBakBSCopy; /* true to not copy boot sector to backup boot sector */
BOOL copyKernel; /* true to copy kernel files */
BOOL copyShell; /* true to copy command interpreter */
BOOL writeBS; /* true to write boot sector to drive/partition LBA 0 */
@ -399,6 +400,7 @@ void showHelpAndExit(void)
" /L segm : hex load segment to use in boot sector instead of %02x\n"
" /B btdrv : hex BIOS # of boot drive set in bs, 0=A:, 80=1st hd,...\n"
" /FORCEDRV: force use of drive # set in bs instead of BIOS boot value\n"
" /NOBAKBS : skips copying boot sector to backup bs, FAT32 only else ignored\n"
#ifdef FDCONFIG
"%s CONFIG /help\n"
#endif
@ -501,6 +503,11 @@ void initOptions(int argc, char *argv[], SYSOptions *opts)
{
opts->ignoreBIOS = 1;
}
/* skips copying boot sector to backup bs, FAT32 only else ignored */
else if (memicmp(argp, "NOBAKBS", 7) == 0)
{
opts->skipBakBSCopy = 1;
}
else if (argno + 1 < argc) /* two part options, /SWITCH VALUE */
{
argno++;
@ -1357,7 +1364,14 @@ void put_boot(SYSOptions *opts)
if (fs == FAT32)
{
bs32 = (struct bootsectortype32 *)&newboot;
if (!bs32->bsBackupBoot) bs32->bsBackupBoot = 0x6; /* ensure set, 6 is MS defined bs size */
/* ensure appears valid, if not then force valid */
if ((bs32->bsBackupBoot < 1) || (bs32->bsBackupBoot > bs32->bsResSectors))
{
#ifdef DEBUG
printf("BPB appears to have invalid backup boot sector #, forcing to default.\n");
#endif
bs32->bsBackupBoot = 0x6; /* ensure set, 6 is MS defined bs size */
}
bs32->bsDriveNumber = opts->defBootDrive;
/* the location of the "0060" segment portion of the far pointer
@ -1500,11 +1514,12 @@ void put_boot(SYSOptions *opts)
}
/* for FAT32, we need to update the backup copy as well */
/* unless user has asked us not to, eg for better dual boot support */
/* Note: assuming sectors 1-5 & 7-11 (FSINFO+additional boot code)
are properly setup by prior format and need no modification
[technically freespace, etc. should be updated]
*/
if (fs == FAT32)
if ((fs == FAT32) && !opts->skipBakBSCopy)
{
bs32 = (struct bootsectortype32 *)&newboot;
#ifdef DEBUG