[syslinux:master] chain.c: change file/sect/ hand area handling logic, add 'hptr' option
syslinux-bot for Michal Soltys
soltys at ziu.info
Mon Mar 26 15:03:13 PDT 2012
Commit-ID: b7aa5fbdee4d97c9a91a6ec04e073b2486bbd3db
Gitweb: http://www.syslinux.org/commit/b7aa5fbdee4d97c9a91a6ec04e073b2486bbd3db
Author: Michal Soltys <soltys at ziu.info>
AuthorDate: Sat, 21 Aug 2010 19:33:42 +0200
Committer: Michal Soltys <soltys at ziu.info>
CommitDate: Tue, 28 Sep 2010 09:32:52 +0200
chain.c: change file/sect/hand area handling logic, add 'hptr' option
The logic behind file/sect/hand area handling is more flexible
now. Furthermore, a user can explicitly control where ds:si/ds:bp
should point during chainloading.
Other misc. changes:
- registry setup is more conservative
- 'if' style
Signed-off-by: Michal Soltys <soltys at ziu.info>
---
com32/chain/chain.c | 168 +++++++++++++++++++++++++++-----------------------
1 files changed, 91 insertions(+), 77 deletions(-)
diff --git a/com32/chain/chain.c b/com32/chain/chain.c
index 8a96da9..dc76e05 100644
--- a/com32/chain/chain.c
+++ b/com32/chain/chain.c
@@ -63,6 +63,7 @@ static struct options {
bool grldr;
bool maps;
bool hand;
+ bool hptr;
bool swap;
bool hide;
bool sethid;
@@ -173,12 +174,12 @@ static int find_by_guid(const struct guid *gpt_guid,
continue;
}
/* Check for a matching GPT disk guid */
- if(!memcmp(&boot_part->sub.gpt.disk_guid, gpt_guid, sizeof(*gpt_guid))) {
+ if (!memcmp(&boot_part->sub.gpt.disk_guid, gpt_guid, sizeof(*gpt_guid))) {
goto ok;
}
/* disk guid doesn't match, maybe partition guid will */
while (pi_next(&boot_part)) {
- if(!memcmp(&boot_part->sub.gpt.part_guid, gpt_guid, sizeof(*gpt_guid)))
+ if (!memcmp(&boot_part->sub.gpt.part_guid, gpt_guid, sizeof(*gpt_guid)))
goto ok;
}
}
@@ -449,9 +450,9 @@ static int soi_s2n(char *ptr, unsigned int *seg,
char *p;
segval = strtoul(ptr, &p, 0);
- if(*p == ':')
+ if (*p == ':')
offval = strtoul(p+1, &p, 0);
- if(*p == ':')
+ if (*p == ':')
ipval = strtoul(p+1, NULL, 0);
val = (segval << 4) + offval;
@@ -468,11 +469,11 @@ static int soi_s2n(char *ptr, unsigned int *seg,
goto bail;
}
- if(seg)
+ if (seg)
*seg = segval;
- if(off)
+ if (off)
*off = offval;
- if(ip)
+ if (ip)
*ip = ipval;
return 0;
@@ -505,7 +506,8 @@ Usage:\n\
- <o> defaults to 0x24\n\
- only 0x24 and 0x40 are accepted\n\
nosave Write adjusted sector back to disk\n\
- hand Prepare handover data\n\
+ hand Prepare handover area\n\
+ hptr Force ds:{si,bp} to always point to handover area\n\
noswap Swap drive numbers, if bootdisk is not fd0/hd0\n\
nohide Hide primary partitions, except selected partition\n\
nokeeppxe Keep the PXE and UNDI stacks in memory (PXELINUX)\n\
@@ -540,7 +542,7 @@ static int parse_args(int argc, char *argv[])
if (!strncmp(argv[i], "file=", 5)) {
opt.file = argv[i] + 5;
} else if (!strncmp(argv[i], "seg=", 4)) {
- if(soi_s2n(argv[i] + 4, &opt.fseg, &opt.foff, &opt.fip))
+ if (soi_s2n(argv[i] + 4, &opt.fseg, &opt.foff, &opt.fip))
goto bail;
} else if (!strncmp(argv[i], "isolinux=", 9)) {
opt.file = argv[i] + 9;
@@ -630,6 +632,10 @@ static int parse_args(int argc, char *argv[])
opt.hand = true;
} else if (!strcmp(argv[i], "nohand")) {
opt.hand = false;
+ } else if (!strcmp(argv[i], "hptr")) {
+ opt.hptr = true;
+ } else if (!strcmp(argv[i], "nohptr")) {
+ opt.hptr = false;
} else if (!strcmp(argv[i], "swap")) {
opt.swap = true;
} else if (!strcmp(argv[i], "noswap")) {
@@ -649,9 +655,9 @@ static int parse_args(int argc, char *argv[])
} else if (!strcmp(argv[i], "nosetgeo")) {
opt.setgeo = false;
} else if (!strncmp(argv[i], "setdrv",6)) {
- if(!argv[i][6])
+ if (!argv[i][6])
v = 0x24;
- else if(argv[i][6] == '@' ||
+ else if (argv[i][6] == '@' ||
argv[i][6] == '=' ||
argv[i][6] == ':')
v = strtoul(argv[i] + 7, NULL, 0);
@@ -672,7 +678,7 @@ static int parse_args(int argc, char *argv[])
if (argv[i][4]) {
if (soi_s2n(argv[i] + 5, &opt.sseg, &opt.soff, &opt.sip))
goto bail;
- if((opt.sseg << 4) + opt.soff + SECTOR - 1 > ADDRMAX) {
+ if ((opt.sseg << 4) + opt.soff + SECTOR - 1 > ADDRMAX) {
error("Arguments of 'sect=' are invalid - resulting address too big.\n");
goto bail;
}
@@ -789,7 +795,7 @@ int find_dp(struct part_iter **_iter)
}
#if 0
/* offsets match, but in case it changes in the future */
- if(sdi->c.filesystem == SYSLINUX_FS_ISOLINUX) {
+ if (sdi->c.filesystem == SYSLINUX_FS_ISOLINUX) {
drive = sdi->iso.drive_number;
fs_lba = *sdi->iso.partoffset;
} else {
@@ -843,9 +849,6 @@ int find_dp(struct part_iter **_iter)
error("WARNING: Partitions on floppy devices may not work.\n");
}
- /* DOS kernels want the drive number in BL instead of DL. Indulge them. */
- opt.regs.ebx.b[0] = opt.regs.edx.b[0] = (uint8_t)iter->di.disk;
-
*_iter = iter;
return 0;
@@ -941,7 +944,7 @@ static int manglef_grldr(const struct part_iter *iter)
/*
* Legacy grub's stage2 chainloading
*/
-static int manglef_grublegacy(const struct part_iter *iter, struct data_area *data)
+static int manglef_grub(const struct part_iter *iter, struct data_area *data)
{
/* Layout of stage2 file (from byte 0x0 to 0x270) */
struct grub_stage2_patch_area {
@@ -1091,7 +1094,7 @@ out:
return h | (s << 8) | ((c & 0x300) << 6) | ((c & 0xFF) << 16);
fallback:
- if(di->disk & 0x80)
+ if (di->disk & 0x80)
return 0x00FFFFFE; /* 1023/63/254 */
else
/* FIXME ?
@@ -1188,7 +1191,7 @@ static int manglef_bpb(const struct part_iter *iter, struct data_area *data)
{
/* BPB: hidden sectors */
if (opt.sethid) {
- if(iter->start_lba < ~0u)
+ if (iter->start_lba < ~0u)
*(uint32_t *) ((char *)data->data + 0x1c) = (uint32_t)iter->start_lba;
else
/* won't really help much, but ... */
@@ -1196,10 +1199,10 @@ static int manglef_bpb(const struct part_iter *iter, struct data_area *data)
}
/* BPB: legacy geometry */
if (opt.setgeo) {
- if(iter->di.cbios)
+ if (iter->di.cbios)
*(uint32_t *)((char *)data->data + 0x18) = (uint32_t)((iter->di.head << 16) | iter->di.sect);
else {
- if(iter->di.disk & 0x80)
+ if (iter->di.disk & 0x80)
*(uint32_t *)((char *)data->data + 0x18) = 0x00FF003F;
else
*(uint32_t *)((char *)data->data + 0x18) = 0x00020012;
@@ -1214,7 +1217,7 @@ static int manglef_bpb(const struct part_iter *iter, struct data_area *data)
return 0;
}
-static int try_sector_bpb(const struct part_iter *iter, struct data_area *data)
+static int try_mangles_bpb(const struct part_iter *iter, struct data_area *data)
{
void *cmp_buf = NULL;
@@ -1264,7 +1267,6 @@ static int mangles_cmldr(struct data_area *data)
return 0;
}
-
int main(int argc, char *argv[])
{
struct part_iter *iter = NULL;
@@ -1273,8 +1275,8 @@ int main(int argc, char *argv[])
void *sect_area = NULL;
struct disk_dos_part_entry *hand_area = NULL;
- struct data_area data[3];
- int ndata = 0, fidx = -1, sidx = -1;
+ struct data_area data[3], bdata[3];
+ int ndata = 0, fidx = -1, sidx = -1, hidx = -1;
console_ansi_raw();
/* openconsole(&dev_null_r, &dev_stdcon_w);*/
@@ -1288,70 +1290,91 @@ int main(int argc, char *argv[])
opt.drivename = "boot";
/* Parse arguments */
- if(parse_args(argc, argv))
+ if (parse_args(argc, argv))
goto bail;
- /* Set initial registry values, file takes precedence */
- if(opt.file) {
- opt.regs.es = opt.regs.cs = opt.regs.ss =
- opt.regs.ds = opt.regs.fs = opt.regs.gs = (uint16_t)opt.fseg;
+ /* Set initial registry values */
+ if (opt.file) {
+ opt.regs.cs = opt.regs.ds = opt.regs.ss = (uint16_t)opt.fseg;
opt.regs.ip = (uint16_t)opt.fip;
} else {
- opt.regs.es = opt.regs.cs = opt.regs.ss =
- opt.regs.ds = opt.regs.fs = opt.regs.gs = (uint16_t)opt.sseg;
+ opt.regs.cs = opt.regs.ds = opt.regs.ss = (uint16_t)opt.sseg;
opt.regs.ip = (uint16_t)opt.sip;
}
- if(opt.regs.ip == 0x7C00 && !opt.regs.cs)
+
+ if (opt.regs.ip == 0x7C00 && !opt.regs.cs)
opt.regs.esp.l = 0x7C00;
/* Get max fixed disk number */
-
fixed_cnt = *(uint8_t *)(0x475);
/* Get disk/part iterator matching user supplied options */
- if(find_dp(&iter))
+ if (find_dp(&iter))
goto bail;
+ /* DOS kernels want the drive number in BL instead of DL. Indulge them. */
+ opt.regs.ebx.b[0] = opt.regs.edx.b[0] = (uint8_t)iter->di.disk;
+
/* Do hide / unhide if appropriate */
if (opt.hide)
hide_unhide(iter);
- /* Load file and sector */
-
+ /* Load the boot file */
if (opt.file) {
data[ndata].base = (opt.fseg << 4) + opt.foff;
+
if (loadfile(opt.file, &data[ndata].data, &data[ndata].size)) {
error("Couldn't read the boot file.\n");
goto bail;
}
+ file_area = (void *)data[ndata].data;
+
if (data[ndata].base + data[ndata].size - 1 > ADDRMAX) {
error("The boot file is too big to load at this address.\n");
goto bail;
}
- file_area = (void *)data[ndata].data;
fidx = ndata;
ndata++;
}
+ /* Load the sector */
if (opt.sect) {
data[ndata].size = SECTOR;
data[ndata].base = (opt.sseg << 4) + opt.soff;
+
if (opt.file && opt.maps && !no_ov(data + fidx, data + ndata)) {
- error("WARNING: Sector won't be loaded, as it would conflict with the boot file.\n");
+ error("WARNING: The sector won't be loaded, as it would conflict with the boot file.\n");
} else {
if (!(data[ndata].data = disk_read_sectors(&iter->di, iter->start_lba, 1))) {
error("Couldn't read the sector.\n");
goto bail;
}
sect_area = (void *)data[ndata].data;
+
sidx = ndata;
- if(opt.maps) {
- ndata++;
- }
+ ndata++;
}
}
+ /* Prep the handover */
+ if (opt.hand && iter->index) {
+ if (setup_handover(iter, data + ndata))
+ goto bail;
+ hand_area = (void *)data[ndata].data;
+
+ /* Verify possible conflicts */
+ if ( ( fidx >= 0 && !no_ov(data + fidx, data + ndata)) ||
+ ( sidx >= 0 && opt.maps && !no_ov(data + sidx, data + ndata)) ) {
+ error("WARNING: Handover area won't be prepared,\n"
+ "as it would conflict with the boot file and/or the sector.\n");
+ } else {
+ hidx = ndata;
+ ndata++;
+ }
+ }
+
+
/* Do file related stuff */
if (fidx >= 0) {
@@ -1361,7 +1384,7 @@ int main(int argc, char *argv[])
if (opt.grldr && manglef_grldr(iter))
goto bail;
- if (opt.grub && manglef_grublegacy(iter, data + fidx))
+ if (opt.grub && manglef_grub(iter, data + fidx))
goto bail;
if (opt.drmk && manglef_drmk(data + fidx))
@@ -1374,47 +1397,38 @@ int main(int argc, char *argv[])
/* Do sector related stuff */
if (sidx >= 0) {
- if (try_sector_bpb(iter, data + sidx))
+ if (try_mangles_bpb(iter, data + sidx))
goto bail;
if (opt.cmldr && mangles_cmldr(data + sidx))
goto bail;
-
- if (opt.maps && fidx >= 0) {
- /* if we mmap bootsector for kernel to use,
- * let's point registers there
- */
- opt.regs.esi.l = opt.regs.ebp.l = opt.soff;
- opt.regs.ds = (uint16_t)opt.sseg;
- }
}
- /* Prepare handover; if both file and sector are loaded, sector must not be
- * mmapped - if it is, then registers prepared for loaded file already
- * point at the sector. */
- if (iter->index && opt.hand && (((sidx < 0) ^ (fidx < 0)) || !opt.maps)) {
- if (setup_handover(iter, data + ndata))
- goto bail;
- hand_area = data[ndata].data;
- /*
- * We have to make sure, that handover data doesn't overlap with the
- * file or the sector. For example, part of FreeDOS kernel
- * loaded at 0x600 would conflict with the handover data. Handover
- * is not critical, so we can let it pass with a warning.
- */
- if ( ( fidx < 0 || no_ov(data + fidx, data + ndata)) &&
- ( sidx < 0 || !opt.maps || no_ov(data + sidx, data + ndata)) ) {
- /* If all is fine, prep registers and inc ndata */
- opt.regs.esi.l = opt.regs.ebp.l = (uint16_t)data[ndata].base;
- opt.regs.ds = 0;
- if(iter->type == typegpt)
- opt.regs.eax.l = 0x54504721; /* '!GPT' */
- ndata++;
- } else {
- error("WARNING: Handover ignored due to overlapping regions.\n");
- }
+ /* Adjust registers - ds:si & ds:bp */
+
+ if (sidx >= 0 && fidx >= 0 && opt.maps && !opt.hptr) {
+ opt.regs.esi.l = opt.regs.ebp.l = opt.soff;
+ opt.regs.ds = (uint16_t)opt.sseg;
+ opt.regs.eax.l = 0;
+ } else if (hidx >= 0) {
+ opt.regs.esi.l = opt.regs.ebp.l = data[hidx].base;
+ opt.regs.ds = 0;
+ if (iter->type == typegpt)
+ opt.regs.eax.l = 0x54504721; /* '!GPT' */
+ else
+ opt.regs.eax.l = 0;
}
+ /* Prepare boot-time mmap data */
+
+ ndata = 0;
+ if (sidx >= 0)
+ memcpy(bdata + ndata++, data + sidx, sizeof(struct data_area));
+ if (fidx >= 0)
+ memcpy(bdata + ndata++, data + fidx, sizeof(struct data_area));
+ if (hidx >= 0)
+ memcpy(bdata + ndata++, data + hidx, sizeof(struct data_area));
+
#ifdef DEBUG
printf("iter dsk: %d\n", iter->di.disk);
printf("iter idx: %d\n", iter->index);
@@ -1425,7 +1439,7 @@ int main(int argc, char *argv[])
wait_key();
#endif
- do_boot(data, ndata);
+ do_boot(bdata, ndata);
bail:
pi_del(&iter);
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