[syslinux:master] chain.c: Restructure finding of partition/ drive to chainload.
syslinux-bot for Michal Soltys
soltys at ziu.info
Mon Mar 26 15:03:06 PDT 2012
Commit-ID: 198c05351d044708e38af799d6e98a6078678bb0
Gitweb: http://www.syslinux.org/commit/198c05351d044708e38af799d6e98a6078678bb0
Author: Michal Soltys <soltys at ziu.info>
AuthorDate: Sun, 15 Aug 2010 13:13:04 +0200
Committer: Michal Soltys <soltys at ziu.info>
CommitDate: Mon, 16 Aug 2010 00:41:44 +0200
chain.c: Restructure finding of partition/drive to chainload.
Finding drive or partition to chainload has been moved outside
main() to find_dp(). Further adjustments and fixes made to accomodate
this change.
Signed-off-by: Michal Soltys <soltys at ziu.info>
---
com32/chain/chain.c | 290 +++++++++++++++++++++++++++---------------------
com32/chain/partiter.h | 2 +-
2 files changed, 164 insertions(+), 128 deletions(-)
diff --git a/com32/chain/chain.c b/com32/chain/chain.c
index 7dc3d31..369e3a3 100644
--- a/com32/chain/chain.c
+++ b/com32/chain/chain.c
@@ -38,6 +38,8 @@
#define ADDRMAX 0x9F000
#define ADDRMIN 0x500
+static const char cmldr_signature[8] = "cmdcons";
+
static struct options {
const char *drivename;
const char *partition;
@@ -61,35 +63,37 @@ struct data_area {
addr_t size;
};
+
static inline void error(const char *msg)
{
fputs(msg, stderr);
}
-static struct disk_info diskinfo;
-
/* Search for a specific drive, based on the MBR signature; bytes 440-443 */
-static int find_by_sig(uint32_t mbr_sig)
+static int find_by_sig(uint32_t mbr_sig,
+ struct part_iter **_boot_part)
{
struct part_iter *boot_part = NULL;
+ struct disk_info diskinfo;
int drive;
for (drive = 0x80; drive <= 0xff; drive++) {
if (disk_get_params(drive, &diskinfo))
continue; /* Drive doesn't exist */
+ if (!(boot_part = pi_begin(&diskinfo)))
+ continue;
/* Check for a MBR disk */
- boot_part = pi_begin(&diskinfo);
if (boot_part->type != typedos) {
pi_del(&boot_part);
continue;
}
if (boot_part->sub.dos.disk_sig == mbr_sig) {
- pi_del(&boot_part);
goto ok;
}
}
drive = -1;
ok:
+ *_boot_part = boot_part;
return drive;
}
@@ -105,20 +109,21 @@ static int find_by_guid(const struct guid *gpt_guid,
struct part_iter **_boot_part)
{
struct part_iter *boot_part = NULL;
+ struct disk_info diskinfo;
int drive;
for (drive = 0x80; drive <= 0xff; drive++) {
if (disk_get_params(drive, &diskinfo))
continue; /* Drive doesn't exist */
+ if (!(boot_part = pi_begin(&diskinfo)))
+ continue;
/* Check for a GPT disk */
- boot_part = pi_begin(&diskinfo);
if (boot_part->type != typegpt) {
pi_del(&boot_part);
continue;
}
/* Check for a matching GPT disk guid */
if(!memcmp(&boot_part->sub.gpt.disk_guid, gpt_guid, sizeof(*gpt_guid))) {
- pi_del(&boot_part);
goto ok;
}
/* disk guid doesn't match, maybe partition guid will */
@@ -143,11 +148,14 @@ ok:
static int find_by_label(const char *label, struct part_iter **_boot_part)
{
struct part_iter *boot_part = NULL;
+ struct disk_info diskinfo;
int drive;
for (drive = 0x80; drive <= 0xff; drive++) {
if (disk_get_params(drive, &diskinfo))
continue; /* Drive doesn't exist */
+ if (!(boot_part = pi_begin(&diskinfo)))
+ continue;
/* Check for a GPT disk */
boot_part = pi_begin(&diskinfo);
if (!(boot_part->type == typegpt)) {
@@ -296,7 +304,7 @@ enomem:
return;
}
-static int hide_unhide(struct disk_dos_mbr *mbr, int part)
+static int hide_unhide(struct disk_dos_mbr *mbr, int part, const struct disk_info *di)
{
int i;
struct disk_dos_part_entry *pt;
@@ -323,7 +331,7 @@ static int hide_unhide(struct disk_dos_mbr *mbr, int part)
}
if (write_back)
- return disk_write_verify_sector(&diskinfo, 0, mbr);
+ return disk_write_verify_sector(di, 0, mbr);
return 0; /* ok */
}
@@ -537,163 +545,173 @@ bail:
return -1;
}
-int main(int argc, char *argv[])
+inline static int is_phys(uint8_t sdifs)
{
- struct disk_dos_mbr *mbr = NULL;
- struct part_iter *cur_part = NULL;
+ return
+ sdifs == SYSLINUX_FS_SYSLINUX ||
+ sdifs == SYSLINUX_FS_EXTLINUX ||
+ sdifs == SYSLINUX_FS_ISOLINUX;
+}
- void *sect_area = NULL;
- void *file_area = NULL;
- struct disk_dos_part_entry *hand_area = NULL;
- struct syslinux_rm_regs regs;
- int hd, drive, whichpart = 0; /* MBR by default */
- uint64_t fs_lba = 0; /* Syslinux partition */
- uint32_t file_lba = 0;
+int find_dp(struct part_iter **_iter)
+{
+ struct part_iter *iter;
+ struct disk_info diskinfo;
struct guid gpt_guid;
- unsigned char *isolinux_bin;
- uint32_t *checksum, *chkhead, *chktail;
- struct data_area data[3];
- int ndata = 0;
- addr_t load_base;
- static const char cmldr_signature[8] = "cmdcons";
-
- openconsole(&dev_null_r, &dev_stdcon_w);
-
- /* Prepare and set default values */
- memset(&opt, 0, sizeof(opt));
- opt.drivename = "boot";
+ uint64_t fs_lba;
+ int drive, hd, partition;
+ const union syslinux_derivative_info *sdi;
- /* Parse arguments */
- if(parse_args(argc, argv))
- goto bail;
+ sdi = syslinux_derivative_info();
- /* Prepare the register set */
- memset(®s, 0, sizeof regs);
-
- if (opt.seg) {
- regs.es = regs.cs = regs.ss = regs.ds = regs.fs = regs.gs = opt.seg;
- } else {
- regs.ip = regs.esp.l = 0x7c00;
- }
-
- hd = 0;
if (!strncmp(opt.drivename, "mbr", 3)) {
- drive = find_by_sig(strtoul(opt.drivename + 4, NULL, 0));
- if (drive == -1) {
- error("Unable to find requested MBR signature\n");
+ if (find_by_sig(strtoul(opt.drivename + 4, NULL, 0), &iter)) {
+ error("Unable to find requested MBR signature.\n");
goto bail;
}
+
} else if (!strncmp(opt.drivename, "guid", 4)) {
if (str_to_guid(opt.drivename + 5, &gpt_guid))
goto bail;
- drive = find_by_guid(&gpt_guid, &cur_part);
- if (drive == -1) {
- error("Unable to find requested GPT disk/partition\n");
+ if (find_by_guid(&gpt_guid, &iter)) {
+ error("Unable to find requested GPT disk or partition by guid.\n");
goto bail;
}
+
} else if (!strncmp(opt.drivename, "label", 5)) {
if (!opt.drivename[6]) {
error("No label specified.\n");
goto bail;
}
- drive = find_by_label(opt.drivename + 6, &cur_part);
- if (drive == -1) {
- error("Unable to find requested partition by label\n");
+ if (find_by_label(opt.drivename + 6, &iter)) {
+ error("Unable to find requested GPT partition by label.\n");
goto bail;
}
+
} else if ((opt.drivename[0] == 'h' || opt.drivename[0] == 'f') &&
opt.drivename[1] == 'd') {
- hd = opt.drivename[0] == 'h';
+ hd = opt.drivename[0] == 'h' ? 0x80 : 0;
opt.drivename += 2;
- drive = (hd ? 0x80 : 0) | strtoul(opt.drivename, NULL, 0);
- } else if (!strcmp(opt.drivename, "boot") || !strcmp(opt.drivename, "fs")) {
- const union syslinux_derivative_info *sdi;
+ drive = hd | strtoul(opt.drivename, NULL, 0);
+
+ if (disk_get_params(drive, &diskinfo))
+ goto bail;
+ if (!(iter = pi_begin(&diskinfo)))
+ goto bail;
- sdi = syslinux_derivative_info();
- if (sdi->c.filesystem == SYSLINUX_FS_PXELINUX)
- drive = 0x80; /* Boot drive not available */
- else
+ } else if (!strcmp(opt.drivename, "boot") || !strcmp(opt.drivename, "fs")) {
+ if (!is_phys(sdi->c.filesystem)) {
+ error("When syslinux is not booted from physical disk (or its emulation),\n"
+ "'boot' and 'fs' are meaningless.\n");
+ goto bail;
+ }
+ /* offsets match, but in case it changes in the future */
+ if(sdi->c.filesystem == SYSLINUX_FS_ISOLINUX) {
+ drive = sdi->iso.drive_number;
+ fs_lba = *sdi->iso.partoffset;
+ } else {
drive = sdi->disk.drive_number;
- if (!strcmp(opt.drivename, "fs")
- && (sdi->c.filesystem == SYSLINUX_FS_SYSLINUX
- || sdi->c.filesystem == SYSLINUX_FS_EXTLINUX
- || sdi->c.filesystem == SYSLINUX_FS_ISOLINUX))
- /* We should lookup the Syslinux partition number and use it */
fs_lba = *sdi->disk.partoffset;
- } else {
- error("Unparsable drive specification\n");
- goto bail;
- }
-
- /* DOS kernels want the drive number in BL instead of DL. Indulge them. */
- regs.ebx.b[0] = regs.edx.b[0] = drive;
+ }
- /* Get the disk geometry and disk access setup */
- if (disk_get_params(drive, &diskinfo)) {
- error("Cannot get disk parameters\n");
- goto bail;
- }
+ if (disk_get_params(drive, &diskinfo))
+ goto bail;
+ if (!(iter = pi_begin(&diskinfo)))
+ goto bail;
- /* Get MBR */
- if (!(mbr = disk_read_sectors(&diskinfo, 0, 1))) {
- error("Cannot read Master Boot Record or sector 0\n");
+ /* 'fs' => we should lookup the Syslinux partition number and use it */
+ if (!strcmp(opt.drivename, "fs")) {
+ while (pi_next(&iter)) {
+ if (iter->start_lba == fs_lba)
+ break;
+ }
+ /* broken part structure or other problems */
+ if (!iter) {
+ error("Can't find myself on the drive I booted from.\n");
+ goto bail;
+ }
+ }
+ } else {
+ error("Unparsable drive specification.\n");
goto bail;
}
-
- if (opt.partition)
- whichpart = strtoul(opt.partition, NULL, 0);
-
- /* "guid:" or "label:" might have specified a partition. In such case,
- * this overrides explicit partition number specification. cur-part->index
- * can't be 0 at this stage as find_by* won't export iterator at such
- * position.
+ /* main options done, only thing left is explicit parition specification
+ * if we're still at the disk stage with the iterator AND user supplied
+ * partition number (including disk).
*/
- if (cur_part)
- whichpart = cur_part->index;
-
- /* If nothing was found, try fs first */
- if (!cur_part && fs_lba) {
- cur_part = pi_begin(&diskinfo);
- /* search for matching fs_lba, must be partition */
- while (pi_next(&cur_part)) {
- if (cur_part->start_lba == fs_lba)
- break;
- }
- }
- /* If still nothing found, do standard search */
- if (!cur_part) {
- cur_part = pi_begin(&diskinfo);
+ if (!iter->index && opt.partition) {
+ partition = strtoul(opt.partition, NULL, 0);
/* search for matching part#, including disk */
do {
- if (cur_part->index == whichpart)
+ if (iter->index == partition)
break;
- } while (pi_next(&cur_part));
+ } while (pi_next(&iter));
}
- if (!cur_part) {
- error("Requested disk / partition not found!\n");
- goto bail;
+
+ if (!(iter->di.disk & 0x80) && iter->index) {
+ error("WARNING: Partitions on floppy devices may not work.\n");
}
- whichpart = cur_part->index;
+ *_iter = iter;
+ return 0;
+
+bail:
+ return -1;
+}
+
+
+int main(int argc, char *argv[])
+{
+ struct part_iter *cur_part = NULL;
+
+ struct disk_dos_mbr *mbr_area = NULL;
+ void *sect_area = NULL;
+ void *file_area = NULL;
+ struct disk_dos_part_entry *hand_area = NULL;
+
+ struct syslinux_rm_regs regs;
+ struct data_area data[3];
+ int ndata = 0;
+ addr_t load_base;
+
+ openconsole(&dev_null_r, &dev_stdcon_w);
+
+ /* Prepare and set default values */
+ memset(&opt, 0, sizeof(opt));
+ opt.drivename = "boot"; /* potential FIXME: maybe we shouldn't assume boot by default */
+
+ /* Parse arguments */
+ if(parse_args(argc, argv))
+ goto bail;
+
+ /* Prepare the register set */
+ memset(®s, 0, sizeof regs);
- if (!(drive & 0x80) && whichpart) {
- error("Warning: Partitions of floppy devices may not work\n");
+ if (opt.seg) {
+ regs.es = regs.cs = regs.ss = regs.ds = regs.fs = regs.gs = opt.seg;
+ } else {
+ regs.ip = regs.esp.l = 0x7c00;
}
- /*
- * GRLDR of GRUB4DOS wants the partition number in DH:
- * -1: whole drive (default)
- * 0-3: primary partitions
- * 4-*: logical partitions
- */
- if (opt.grldr)
- regs.edx.b[1] = whichpart - 1;
+ /* Get disk/part iterator matching user supplied options */
+
+ if(find_dp(&cur_part))
+ goto bail;
+
+ /* DOS kernels want the drive number in BL instead of DL. Indulge them. */
+ regs.ebx.b[0] = regs.edx.b[0] = cur_part->di.disk;
+
+ /* Get MBR */
+ if (!(mbr_area = disk_read_sectors(&cur_part->di, 0, 1))) {
+ error("Cannot read Master Boot Record.\n");
+ goto bail;
+ }
if (opt.hide) {
- if (whichpart < 1 || whichpart > 4)
+ if (cur_part->index < 1 || cur_part->index > 4)
error("WARNING: hide specified without a non-primary partition\n");
- if (hide_unhide(mbr, whichpart))
+ if (hide_unhide(mbr_area, cur_part->index, &cur_part->di))
error("WARNING: failed to write MBR for 'hide'\n");
}
@@ -703,7 +721,7 @@ int main(int argc, char *argv[])
if (opt.loadfile) {
fputs("Loading the boot file...\n", stdout);
if (loadfile(opt.loadfile, &data[ndata].data, &data[ndata].size)) {
- error("Failed to load the boot file\n");
+ error("Failed to load the boot file.\n");
goto bail;
}
data[ndata].base = load_base;
@@ -719,6 +737,9 @@ int main(int argc, char *argv[])
sdi = syslinux_derivative_info();
if (sdi->c.filesystem == SYSLINUX_FS_ISOLINUX) {
+ unsigned char *isolinux_bin;
+ uint32_t *checksum, *chkhead, *chktail;
+ uint32_t file_lba = 0;
/* Boot info table info (integers in little endian format)
Offset Name Size Meaning
@@ -774,6 +795,18 @@ int main(int argc, char *argv[])
}
}
+ /*
+ * GRLDR of GRUB4DOS wants the partition number in DH:
+ * -1: whole drive (default)
+ * 0-3: primary partitions
+ * 4-*: logical partitions
+ */
+ if (opt.grldr)
+ regs.edx.b[1] = cur_part->index - 1;
+
+ /*
+ * Legacy grub's stage2 chainloading
+ */
if (opt.grub) {
/* Layout of stage2 file (from byte 0x0 to 0x270) */
struct grub_stage2_patch_area {
@@ -858,7 +891,7 @@ int main(int argc, char *argv[])
* 0-3: primary partitions
* 4-*: logical partitions
*/
- stage2->install_partition.part1 = whichpart - 1;
+ stage2->install_partition.part1 = cur_part->index - 1;
/*
* Grub Legacy reserves 89 bytes (from 0x8217 to 0x826f) for the
@@ -876,6 +909,9 @@ int main(int argc, char *argv[])
}
}
+ /*
+ * Dell's DRMK chainloading.
+ */
if (opt.drmk) {
/* DRMK entry is different than MS-DOS/PC-DOS */
/*
@@ -901,10 +937,10 @@ int main(int argc, char *argv[])
if (!opt.loadfile || data[0].base >= 0x7c00 + SECTOR) {
/* Actually read the boot sector */
if (!cur_part->index) {
- data[ndata].data = mbr;
+ data[ndata].data = mbr_area;
} else
if (!(data[ndata].data =
- disk_read_sectors(&diskinfo, cur_part->start_lba, 1))) {
+ disk_read_sectors(&cur_part->di, cur_part->start_lba, 1))) {
error("Cannot read boot sector\n");
goto bail;
} else
@@ -1024,7 +1060,7 @@ int main(int argc, char *argv[])
bail:
pi_del(&cur_part);
/* Free allocated areas */
- free(mbr);
+ free(mbr_area);
free(file_area);
free(sect_area);
free(hand_area);
diff --git a/com32/chain/partiter.h b/com32/chain/partiter.h
index c2bbb44..2b95cf6 100644
--- a/com32/chain/partiter.h
+++ b/com32/chain/partiter.h
@@ -55,9 +55,9 @@ struct part_iter {
char *record;
uint64_t start_lba;
int index;
+ struct disk_info di;
/* internal */
char *data;
- struct disk_info di;
union _sub {
struct _dos {
uint32_t disk_sig;
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