Unix installer: use Linux-native ioctls instead of libfat

Unix installer: use Linux-native ioctls instead of libfat.  This should
make it smaller, and should also make it possible to use the vfat
filesystem (need to clean up the mount code for that to work.)

2 files changed, 63 insertions, 71 deletions

diff --git a/unix/Makefile b/unix/Makefile
index 5dfc0513..021aa538 100644
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -1,10 +1,10 @@
 CC	 = gcc
 OPTFLAGS = -g -Os
-INCLUDES = -I. -I.. -I../libfat
+INCLUDES = -I. -I..
 CFLAGS	 = -W -Wall -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(INCLUDES)
 LDFLAGS	 = -s
 
-SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c $(wildcard ../libfat/*.c)
+SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c
 OBJS	 = $(patsubst %.c,%.o,$(notdir $(SRCS)))
 
 .SUFFIXES: .c .o .i .s .S
diff --git a/unix/syslinux.c b/unix/syslinux.c
index 36826a1b..308e52fd 100644
--- a/unix/syslinux.c
+++ b/unix/syslinux.c
@@ -13,7 +13,7 @@
 /*
  * syslinux.c - Linux installer program for SYSLINUX
  *
- * This program ought to be portable.  I hope so, at least.
+ * This is Linux-specific by now.
  *
  * This is an alternate version of the installer which doesn't require
  * mtools, but requires root privilege.
@@ -46,15 +46,14 @@
 #include <sys/wait.h>
 #include <sys/mount.h>
 
+#include <linux/fs.h>		/* FIGETBSZ, FIBMAP */
+#include <linux/msdos_fs.h>	/* FAT_IOCTL_SET_ATTRIBUTES, SECTOR_* */
+
 #include "syslinux.h"
-#include "libfat.h"
 
 #if DO_DIRECT_MOUNT
-
 # include <linux/loop.h>
-
 #else
-
 # include <paths.h>
 # ifndef _PATH_MOUNT
 #  define _PATH_MOUNT "/bin/mount"
@@ -62,7 +61,6 @@
 # ifndef _PATH_UMOUNT
 #  define _PATH_UMOUNT "/bin/umount"
 # endif
-
 #endif
 
 const char *program;		/* Name of program */
@@ -156,17 +154,43 @@ ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
 }
 
 /*
- * Version of the read function suitable for libfat
+ * Create a block map for ldlinux.sys
  */
-int libfat_xpread(intptr_t pp, void *buf, size_t secsize, libfat_sector_t sector)
+int make_block_map(uint32_t *sectors, int len, int dev_fd, int fd)
 {
-  off_t offset = (off_t)sector * secsize + filesystem_offset;
-  return xpread(pp, buf, secsize, offset);
+  int nsectors = 0;
+  int blocksize, nblock, block;
+  int i;
+
+  (void)dev_fd;
+
+  if (ioctl(fd, FIGETBSZ, &blocksize) < 0)
+    die("ioctl FIGETBSZ failed");
+
+  blocksize >>= SECTOR_BITS;	/* sectors/block */
+
+  nblock = 0;
+  while (len > 0) {
+    block = nblock++;
+    if (ioctl(fd, FIBMAP, &block) < 0)
+      die("ioctl FIBMAP failed");
+    
+    for (i = 0; i < blocksize; i++) {
+      if (len <= 0)
+	break;
+
+      *sectors++ = (block*blocksize)+i;
+      nsectors++;
+      len -= (1 << SECTOR_BITS);
+    }
+  }
+
+  return nsectors;
 }
 
 int main(int argc, char *argv[])
 {
-  static unsigned char sectbuf[512];
+  static unsigned char sectbuf[SECTOR_SIZE];
   unsigned char *dp;
   const unsigned char *cdp;
   int dev_fd, fd;
@@ -179,10 +203,7 @@ int main(int argc, char *argv[])
   char *ldlinux_name, **argp, *opt;
   int force = 0;		/* -f (force) option */
   const char *subdir = NULL;
-  struct libfat_filesystem *fs;
-  struct libfat_direntry dentry;
-  libfat_sector_t s, *secp, sectors[65]; /* 65 is maximum possible */
-  int32_t ldlinux_cluster;
+  uint32_t sectors[65]; /* 65 is maximum possible */
   int nsectors = 0;
   const char *errmsg;
 
@@ -243,7 +264,7 @@ int main(int argc, char *argv[])
     die("not a regular file and an offset specified (use -f to override)");
   }
 
-  xpread(dev_fd, sectbuf, 512, filesystem_offset);
+  xpread(dev_fd, sectbuf, SECTOR_SIZE, filesystem_offset);
   fsync(dev_fd);
 
   /*
@@ -370,13 +391,21 @@ int main(int argc, char *argv[])
 #endif
   }
 
-  ldlinux_name = alloca(strlen(mntpath)+14);
+  ldlinux_name = alloca(strlen(mntpath)+14+
+			(subdir ? strlen(subdir)+2 : 0));
   if ( !ldlinux_name ) {
     perror(program);
     err = 1;
     goto umount;
   }
-  sprintf(ldlinux_name, "%s//ldlinux.sys", mntpath);
+  sprintf(ldlinux_name, "%s%s%s//ldlinux.sys",
+	  subdir ? "//" : "", subdir ? subdir : "", mntpath);
+
+  if ((fd = open(ldlinux_name, O_RDONLY)) >= 0) {
+    uint32_t zero_attr = 0;
+    ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &zero_attr);
+    close(fd);
+  }
 
   unlink(ldlinux_name);
   fd = open(ldlinux_name, O_WRONLY|O_CREAT|O_TRUNC, 0444);
@@ -402,51 +431,22 @@ int main(int argc, char *argv[])
     left -= nb;
   }
 
+  fsync(fd);
   /*
-   * I don't understand why I need this.  Does the DOS filesystems
-   * not honour the mode passed to open()?
+   * Set the attributes
    */
-  fchmod(fd, 0400);
-
-  close(fd);
-
-  sync();
+  {
+    uint32_t attr = 0x07;	/* Hidden+System+Readonly */
+    ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
+  }
 
   /*
-   * Now, use libfat to create a block map.  This probably
-   * should be changed to use ioctl(...,FIBMAP,...) since
-   * this is supposed to be a simple, privileged version
-   * of the installer.
+   * Create a block map.
    */
-  fs = libfat_open(libfat_xpread, dev_fd);
-  ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", &dentry);
-  secp = sectors;
-  nsectors = 0;
-  s = libfat_clustertosector(fs, ldlinux_cluster);
-  while ( s && nsectors < 65 ) {
-    *secp++ = s;
-    nsectors++;
-    s = libfat_nextsector(fs, s);
-  }
-  libfat_close(fs);
-
-  /* Move ldlinux.sys to the desired location */
-  if (subdir) {
-    char *new_ldlinux_name = alloca(strlen(mntpath)+
-				    strlen(subdir)+15);
-    int mov_err = 1;
-
-    if ( new_ldlinux_name ) {
-      sprintf(new_ldlinux_name, "%s//%s//ldlinux.sys", mntpath, subdir);
-
-      if (!rename(ldlinux_name, new_ldlinux_name))
-	mov_err = 0;
-    }
+  nsectors = make_block_map(sectors, syslinux_ldlinux_len, dev_fd, fd);
 
-    if (mov_err)
-      fprintf(stderr, "%s: warning: unable to move ldlinux.sys: %s\n",
-	      device, strerror(errno));
-  }
+  close(fd);
+  sync();
 
 umount:
 #if DO_DIRECT_MOUNT
@@ -491,29 +491,21 @@ umount:
   /*
    * Write the now-patched first sector of ldlinux.sys
    */
-  xpwrite(dev_fd, syslinux_ldlinux, 512, filesystem_offset + ((off_t)sectors[0] << 9));
-
-  /*
-   * Patch the root directory to set attributes to
-   * HIDDEN|SYSTEM|READONLY
-   */
-  {
-    const unsigned char attrib = 0x07;
-    xpwrite(dev_fd, &attrib, 1, ((off_t)dentry.sector << 9)+dentry.offset+11);
-  }
+  xpwrite(dev_fd, syslinux_ldlinux, SECTOR_SIZE,
+	  filesystem_offset+((off_t)sectors[0] << SECTOR_BITS));
 
   /*
    * To finish up, write the boot sector
    */
 
   /* Read the superblock again since it might have changed while mounted */
-  xpread(dev_fd, sectbuf, 512, filesystem_offset);
+  xpread(dev_fd, sectbuf, SECTOR_SIZE, filesystem_offset);
 
   /* Copy the syslinux code into the boot sector */
   syslinux_make_bootsect(sectbuf);
 
   /* Write new boot sector */
-  xpwrite(dev_fd, sectbuf, 512, filesystem_offset);
+  xpwrite(dev_fd, sectbuf, SECTOR_SIZE, filesystem_offset);
 
   close(dev_fd);
   sync();