FAT: change DOS installer to EXE; additional 32K limit fixes

Additional fixes for the 32K limits in the installers.  In the case
of the DOS installer, that means changing it from COM format to EXE
format (since COM format has a 63K hard limit); retain the name
syslinux.com for user compatibility, though (DOS doesn't care what the
extension except for pathname search; if it finds an MZ EXE header it
will use it.)

With the change to EXE means having to handle more than one segment.
Since we don't have a real DOS compiler we have to wing it a bit.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/win32/syslinux.c b/win32/syslinux.c
index 1699125b..7a0fafb2 100644
--- a/win32/syslinux.c
+++ b/win32/syslinux.c
@@ -36,7 +36,6 @@ void error(char* msg);
 
 #include <winioctl.h>
 
-#define SECTOR_SIZE 512
 #define PART_TABLE  0x1be
 #define PART_SIZE   0x10
 #define PART_COUNT  4
@@ -252,7 +251,9 @@ int main(int argc, char *argv[])
   static char ldlinux_name[] = "?:\\ldlinux.sys" ;
   const char *errmsg;
   struct libfat_filesystem *fs;
-  libfat_sector_t s, *secp, sectors[65]; /* 65 is maximum possible */
+  libfat_sector_t s, *secp;
+  libfat_sector_t *sectors;
+  int ldlinux_sectors;
   uint32_t ldlinux_cluster;
   int nsectors;
   const char *bootsecfile = NULL;
@@ -414,12 +415,14 @@ int main(int argc, char *argv[])
   }
 
   /* Map the file (is there a better way to do this?) */
+  ldlinux_sectors = (syslinux_ldlinux_len+SECTOR_SIZE-1) >> SECTOR_BITS;
+  sectors = calloc(ldlinux_sectors, sizeof *sectors);
   fs = libfat_open(libfat_readfile, (intptr_t)d_handle);
   ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
   secp = sectors;
   nsectors = 0;
   s = libfat_clustertosector(fs, ldlinux_cluster);
-  while ( s && nsectors < 65 ) {
+  while ( s && nsectors < ldlinux_sectors ) {
     *secp++ = s;
     nsectors++;
     s = libfat_nextsector(fs, s);