[syslinux:master] chain.c: adjust what ds:si and ds: bp point to after chainloading
syslinux-bot for Michal Soltys
soltys at ziu.info
Mon Mar 26 15:03:11 PDT 2012
Commit-ID: f10e1f74f97ff8d46b994ca27f308fbc692b77dd
Gitweb: http://www.syslinux.org/commit/f10e1f74f97ff8d46b994ca27f308fbc692b77dd
Author: Michal Soltys <soltys at ziu.info>
AuthorDate: Thu, 19 Aug 2010 10:50:28 +0200
Committer: Michal Soltys <soltys at ziu.info>
CommitDate: Sun, 22 Aug 2010 23:45:16 +0200
chain.c: adjust what ds:si and ds:bp point to after chainloading
Previously, chain module always set ds:si and ds:bp to handover
area (unless otherwise blocked). This is not necessarily valid in case
when both file and sector are being loaded - here file should receive
pointer to it's [relocated] sector, and it's unlikely interested in
mbr-like handover area at all.
Signed-off-by: Michal Soltys <soltys at ziu.info>
---
com32/chain/chain.c | 117 +++++++++++++++++++++++++++++----------------------
1 files changed, 66 insertions(+), 51 deletions(-)
diff --git a/com32/chain/chain.c b/com32/chain/chain.c
index 6a58664..4f53336 100644
--- a/com32/chain/chain.c
+++ b/com32/chain/chain.c
@@ -37,19 +37,20 @@
/* used in checks, whenever addresses supplied by user are sane */
-#define ADDRMAX 0x9EFFF
-#define ADDRMIN 0x500
+#define ADDRMAX 0x9EFFFu
+#define ADDRMIN 0x500u
static const char cmldr_signature[8] = "cmdcons";
static int fixed_cnt;
static struct options {
- uint32_t flin;
- uint16_t fseg;
- uint16_t fip;
- uint32_t slin;
- uint16_t sseg;
- uint16_t sip;
+ unsigned int fseg;
+ unsigned int foff;
+ unsigned int fip;
+ unsigned int sseg;
+ unsigned int soff;
+ unsigned int sip;
+ unsigned int drvoff;
const char *drivename;
const char *partition;
const char *loadfile;
@@ -66,7 +67,6 @@ static struct options {
bool sethid;
bool setgeo;
bool setdrv;
- uint8_t drvoff;
bool read;
bool write;
bool filebpb;
@@ -438,11 +438,13 @@ static uint32_t get_file_lba(const char *filename)
return lba;
}
-/* Convert string seg:off:ip values into numerical seg:linear:ip ones */
+/* Convert string seg:off:ip values into numerical seg:off:ip ones */
-static int soi2sli(char *ptr, uint16_t *seg, uint32_t *lin, uint16_t *ip)
+static int soi_s2n(char *ptr, unsigned int *seg,
+ unsigned int *off,
+ unsigned int *ip)
{
- uint32_t segval = 0, offval = 0, ipval = 0, val;
+ unsigned int segval = 0, offval = 0, ipval = 0, val;
char *p;
segval = strtoul(ptr, &p, 0);
@@ -451,9 +453,9 @@ static int soi2sli(char *ptr, uint16_t *seg, uint32_t *lin, uint16_t *ip)
if(*p == ':')
ipval = strtoul(p+1, NULL, 0);
- offval = (segval << 4) + offval;
+ val = (segval << 4) + offval;
- if (offval < ADDRMIN || offval > ADDRMAX) {
+ if (val < ADDRMIN || val > ADDRMAX) {
error("Invalid seg:off:* address specified..\n");
goto bail;
}
@@ -461,16 +463,16 @@ static int soi2sli(char *ptr, uint16_t *seg, uint32_t *lin, uint16_t *ip)
val = (segval << 4) + ipval;
if (ipval > 0xFFFE || val < ADDRMIN || val > ADDRMAX) {
- error("Invalid *:*:ip address specified.\n");
+ error("Invalid seg:*:ip address specified.\n");
goto bail;
}
if(seg)
- *seg = (uint16_t)segval;
- if(lin)
- *lin = offval;
+ *seg = segval;
+ if(off)
+ *off = offval;
if(ip)
- *ip = (uint16_t)ipval;
+ *ip = ipval;
return 0;
@@ -537,12 +539,12 @@ static int parse_args(int argc, char *argv[])
opt.loadfile = argv[i] + 5;
} else if ((v = 4, !strncmp(argv[i], "seg=", v)) ||
(v = 5, !strncmp(argv[i], "fseg=", v))) {
- if(soi2sli(argv[i] + v, &opt.fseg, &opt.flin, &opt.fip))
+ if(soi_s2n(argv[i] + v, &opt.fseg, &opt.foff, &opt.fip))
goto bail;
} else if (!strncmp(argv[i], "sseg=", 5)) {
- if(soi2sli(argv[i] + 5, &opt.sseg, &opt.slin, &opt.sip))
+ if(soi_s2n(argv[i] + 5, &opt.sseg, &opt.soff, &opt.sip))
goto bail;
- if(opt.slin + SECTOR - 1 > ADDRMAX) {
+ if((opt.sseg << 4) + opt.soff + SECTOR - 1 > ADDRMAX) {
error("Option 'sseg' is invalid - address too big.\n");
goto bail;
}
@@ -553,7 +555,7 @@ static int parse_args(int argc, char *argv[])
opt.read = false;
} else if (!strncmp(argv[i], "ntldr=", 6)) {
opt.fseg = 0x2000; /* NTLDR wants this address */
- opt.flin = 0x20000;
+ opt.foff = 0;
opt.fip = 0;
opt.loadfile = argv[i] + 6;
opt.sethid = true;
@@ -564,7 +566,7 @@ static int parse_args(int argc, char *argv[])
opt.hand = false;
} else if (!strncmp(argv[i], "cmldr=", 6)) {
opt.fseg = 0x2000; /* CMLDR wants this address */
- opt.flin = 0x20000;
+ opt.foff = 0;
opt.fip = 0;
opt.loadfile = argv[i] + 6;
opt.cmldr = true;
@@ -576,7 +578,7 @@ static int parse_args(int argc, char *argv[])
opt.hand = false;
} else if (!strncmp(argv[i], "freedos=", 8)) {
opt.fseg = 0x60; /* FREEDOS wants this address */
- opt.flin = 0x600;
+ opt.foff = 0;
opt.fip = 0;
opt.loadfile = argv[i] + 8;
opt.sethid = true;
@@ -588,7 +590,7 @@ static int parse_args(int argc, char *argv[])
!strncmp(argv[i], "pcdos=", v)) ||
(v = 7, !strncmp(argv[i], "msdos7=", v)) ) {
opt.fseg = 0x70; /* MS-DOS 2.00 .. 6.xx wants this address */
- opt.flin = 0x700;
+ opt.foff = 0;
opt.fip = v == 7 ? 0x200 : 0; /* MS-DOS 7.0+ wants this ip */
opt.loadfile = argv[i] + v;
opt.sethid = true;
@@ -598,7 +600,7 @@ static int parse_args(int argc, char *argv[])
opt.hand = false;
} else if (!strncmp(argv[i], "drmk=", 5)) {
opt.fseg = 0x70; /* DRMK wants this address */
- opt.flin = 0x700;
+ opt.foff = 0;
opt.fip = 0;
opt.loadfile = argv[i] + 5;
opt.drmk = true;
@@ -609,7 +611,7 @@ static int parse_args(int argc, char *argv[])
opt.hand = false;
} else if (!strncmp(argv[i], "grub=", 5)) {
opt.fseg = 0x800; /* stage2 wants this address */
- opt.flin = 0x8000;
+ opt.foff = 0;
opt.fip = 0x200;
opt.loadfile = argv[i] + 5;
opt.grub = true;
@@ -666,7 +668,7 @@ static int parse_args(int argc, char *argv[])
goto bail;
}
opt.setdrv = true;
- opt.drvoff = (uint8_t)v;
+ opt.drvoff = v;
} else if (!strcmp(argv[i], "nosetdrv")) {
opt.setdrv = false;
} else if (!strcmp(argv[i], "read")) {
@@ -1053,7 +1055,7 @@ static int manglef_drmk(struct data_area *data)
}
data->size = tsize;
/* ds:[bp+28] must be 0x0000003f */
- opt.regs.ds = (uint16_t)((tsize >> 4) + (opt.fseg - 2u));
+ opt.regs.ds = (uint16_t)((tsize >> 4) + (opt.fseg - 2));
/* "Patch" into tail of the new space */
*(uint32_t *)((char*)data->data + tsize - 4) = 0x0000003f;
@@ -1085,13 +1087,16 @@ out:
fallback:
if(di->disk & 0x80)
- return 0x00FFFFFE; /* 254/63/1023 */
+ return 0x00FFFFFE; /* 1023/63/254 */
else
/* FIXME ?
* this is mostly "useful" with partitioned floppy,
* maybe stick to 2.88mb ?
*/
- return 0x004F1201; /* 1/18/79 */
+ return 0x004F1201; /* 79/18/1 */
+#if 0
+ return 0x004F2401; /* 79/36/1 */
+#endif
}
static int setup_handover(const struct part_iter *iter,
@@ -1274,10 +1279,10 @@ int main(int argc, char *argv[])
/* Prepare and set defaults */
memset(&opt, 0, sizeof(opt));
- opt.read = true; /* by def read bs / mbr */
- opt.hand = true; /* by def do prepare handover */
- opt.smap = true; /* by def map bs / mbr */
- opt.flin = opt.slin = opt.fip = opt.sip = 0x7C00;
+ opt.read = true; /* by def load sector */
+ opt.smap = true; /* by def map sector */
+ opt.hand = true; /* by def prepare handover */
+ opt.foff = opt.soff = opt.fip = opt.sip = 0x7C00;
opt.drivename = "boot";
/* Parse arguments */
@@ -1287,12 +1292,12 @@ int main(int argc, char *argv[])
/* Set initial registry values, file takes precedence */
if(opt.loadfile) {
opt.regs.es = opt.regs.cs = opt.regs.ss =
- opt.regs.ds = opt.regs.fs = opt.regs.gs = opt.fseg;
- opt.regs.ip = opt.fip;
+ opt.regs.ds = opt.regs.fs = opt.regs.gs = (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 = opt.sseg;
- opt.regs.ip = opt.sip;
+ opt.regs.ds = opt.regs.fs = opt.regs.gs = (uint16_t)opt.sseg;
+ opt.regs.ip = (uint16_t)opt.sip;
}
if(opt.regs.ip == 0x7C00 && !opt.regs.cs)
opt.regs.esp.l = 0x7C00;
@@ -1311,13 +1316,13 @@ int main(int argc, char *argv[])
/* Load file and bs/mbr */
- data[ndata].base = opt.flin;
+ data[ndata].base = (opt.fseg << 4) + opt.foff;
if (opt.loadfile) {
if (loadfile(opt.loadfile, &data[ndata].data, &data[ndata].size)) {
error("Couldn't read the boot file.\n");
goto bail;
}
- if (opt.flin + data[ndata].size - 1 > ADDRMAX) {
+ if (data[ndata].base + data[ndata].size - 1 > ADDRMAX) {
error("Can't load the boot file at this address.\n");
goto bail;
}
@@ -1331,10 +1336,10 @@ int main(int argc, char *argv[])
* in first 512 bytes.
*/
data[ndata].size = SECTOR;
- data[ndata].base = opt.slin;
+ data[ndata].base = (opt.sseg << 4) + opt.soff;
if (opt.read && (!opt.loadfile || !opt.smap || no_ov(data + fidx, data + ndata))) {
if (!(data[ndata].data = disk_read_sectors(&iter->di, iter->start_lba, 1))) {
- error("Couldn't read the bs / mbr.\n");
+ error("Couldn't read the sector.\n");
goto bail;
}
sect_area = (void *)data[ndata].data;
@@ -1344,7 +1349,7 @@ int main(int argc, char *argv[])
}
}
- /* Mangle file area */
+ /* Do file related stuff */
if (fidx >= 0) {
if (opt.isolinux && manglef_isolinux(data + fidx))
@@ -1363,7 +1368,7 @@ int main(int argc, char *argv[])
goto bail;
}
- /* Mangle bs/mbr area */
+ /* Do sector related stuff */
if (sidx >= 0) {
if (try_sector_bpb(iter, data + sidx))
@@ -1371,23 +1376,33 @@ int main(int argc, char *argv[])
if (opt.cmldr && mangles_cmldr(data + sidx))
goto bail;
+
+ if (opt.smap && 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 (skip if not at partition) */
- if (opt.hand && iter->index) {
+ /* 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.smap)) {
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 and/or the boot sector. For example, part of FreeDOS kernel
+ * 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 || no_ov(data + sidx, data + ndata)) ) {
+ ( sidx < 0 || !opt.smap || no_ov(data + sidx, data + ndata)) ) {
/* If all is fine, prep registers and inc ndata */
- opt.regs.esi.w[0] = opt.regs.ebp.w[0] = 0x7be;
+ opt.regs.esi.l = opt.regs.ebp.l = 0x7be;
opt.regs.ds = 0;
if(iter->type == typegpt)
opt.regs.eax.l = 0x54504721; /* '!GPT' */
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