Prepping for new 2.20 version: rewrite main syslinux program to support

FAT32 and EDD, and a new cleaner installer infrastructure.

2 files changed, 526 insertions, 0 deletions

diff --git a/unix/Makefile b/unix/Makefile
new file mode 100644
index 00000000..9ba5e554
--- /dev/null
+++ b/unix/Makefile
@@ -0,0 +1,39 @@
+CC	 = gcc
+OPTFLAGS = -g -O
+INCLUDES = -I. -I.. -I../libfat
+CFLAGS	 = -W -Wall -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(INCLUDES)
+LDFLAGS	 = 
+
+SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c $(wildcard ../libfat/*.c)
+OBJS	 = $(patsubst %.c,%.o,$(notdir $(SRCS)))
+
+.SUFFIXES: .c .o .i .s .S
+
+VPATH = .:..:../libfat
+
+all: installer
+
+tidy:
+	-rm -f *.o *.i *.s *.a .*.d
+
+clean: tidy
+	-rm -f syslinux
+
+spotless: clean
+
+installer: syslinux
+
+syslinux: $(OBJS)
+	$(CC) $(LDFLAGS) -o $@ $^
+
+%.o: %.c
+	$(CC) -Wp,-MT,$@,-MMD,.$@.d $(CFLAGS) -c -o $@ $<
+%.i: %.c
+	$(CC) $(CFLAGS) -E -o $@ $<
+%.s: %.c
+	$(CC) $(CFLAGS) -S -o $@ $<
+
+-include .*.d
+
+
+
diff --git a/unix/syslinux.c b/unix/syslinux.c
new file mode 100644
index 00000000..182e1bf9
--- /dev/null
+++ b/unix/syslinux.c
@@ -0,0 +1,487 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 1998-2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux.c - Linux installer program for SYSLINUX
+ *
+ * This program ought to be portable.  I hope so, at least.
+ *
+ * This is an alternate version of the installer which doesn't require
+ * mtools, but requires root privilege.
+ */
+
+#ifdef __KLIBC__
+# define DO_DIRECT_MOUNT 1	/* Call mount(2) directly */
+#else
+# define DO_DIRECT_MOUNT 0	/* Call /bin/mount instead */
+#endif
+
+#define _GNU_SOURCE
+#define _XOPEN_SOURCE 500	/* For pread() pwrite() */
+#define _FILE_OFFSET_BITS 64
+#include <alloca.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/mount.h>
+
+#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"
+# endif
+# ifndef _PATH_UMOUNT
+#  define _PATH_UMOUNT "/bin/umount"
+# endif
+
+#endif
+
+const char *program;		/* Name of program */
+const char *device;		/* Device to install to */
+pid_t mypid;
+char *mntpath = NULL;		/* Path on which to mount */
+#if DO_DIRECT_MOUNT
+int loop_fd = -1;		/* Loop device */
+#endif
+
+void __attribute__((noreturn)) usage(void)
+{
+  fprintf(stderr, "Usage: %s [-sf] [-o offset] device\n", program);
+  exit(1);
+}
+
+void __attribute__((noreturn)) die(const char *msg)
+{
+  fprintf(stderr, "%s: %s\n", program, msg);
+
+#if DO_DIRECT_MOUNT
+  if ( loop_fd != -1 ) {
+    ioctl(loop_fd, LOOP_CLR_FD, 0); /* Free loop device */
+    close(loop_fd);
+    loop_fd = -1;
+  }
+#endif
+
+  if ( mntpath )
+    unlink(mntpath);
+
+  exit(1);
+}
+
+/*
+ * read/write wrapper functions
+ */
+ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
+{
+  ssize_t rv;
+  ssize_t done = 0;
+
+  while ( count ) {
+    rv = pread(fd, buf, count, offset);
+    if ( rv == 0 ) {
+      die("short read");
+    } else if ( rv == -1 ) {
+      if ( errno == EINTR ) {
+	continue;
+      } else {
+	perror(program);
+	exit(1);
+      }
+    } else {
+      offset += rv;
+      done += rv;
+      count -= rv;
+    }
+  }
+
+  return done;
+}
+
+ssize_t xpwrite(int fd, void *buf, size_t count, off_t offset)
+{
+  ssize_t rv;
+  ssize_t done = 0;
+
+  while ( count ) {
+    rv = pwrite(fd, buf, count, offset);
+    if ( rv == 0 ) {
+      die("short write");
+    } else if ( rv == -1 ) {
+      if ( errno == EINTR ) {
+	continue;
+      } else {
+	perror(program);
+	exit(1);
+      }
+    } else {
+      offset += rv;
+      done += rv;
+      count -= rv;
+    }
+  }
+
+  return done;
+}
+
+/*
+ * Version of the read function suitable for libfat
+ */
+int libfat_xpread(void *pp, void *buf, size_t secsize, libfat_sector_t sector)
+{
+  off_t offset = (off_t)sector * secsize;
+  return xpread((int)pp, buf, secsize, offset);
+}
+
+int main(int argc, char *argv[])
+{
+  static unsigned char sectbuf[512];
+  unsigned char *dp;
+  const unsigned char *cdp;
+  int dev_fd, fd;
+  struct stat st;
+  int nb, left;
+  int err = 0;
+  pid_t f, w;
+  int status;
+  char mntname[64], devfdname[64];
+  char *ldlinux_name, **argp, *opt;
+  int force = 0;		/* -f (force) option */
+  off_t offset = 0;		/* -o (offset) option */
+  struct libfat_filesystem *fs;
+  libfat_sector_t s, *secp, sectors[65]; /* 65 is maximum possible */
+  int32_t ldlinux_cluster;
+  int nsectors;
+
+  (void)argc;			/* Unused */
+
+  program = argv[0];
+  mypid = getpid();
+  
+  device = NULL;
+
+  umask(077);
+
+  for ( argp = argv+1 ; *argp ; argp++ ) {
+    if ( **argp == '-' ) {
+      opt = *argp + 1;
+      if ( !*opt )
+	usage();
+
+      while ( *opt ) {
+	if ( *opt == 's' ) {
+	  syslinux_make_stupid();	/* Use "safe, slow and stupid" code */
+	} else if ( *opt == 'f' ) {
+	  force = 1;		/* Force install */
+	} else if ( *opt == 'o' && argp[1] ) {
+	  offset = (off_t)strtoull(*++argp, NULL, 0); /* Byte offset */
+	} else {
+	  usage();
+	}
+	opt++;
+      }
+    } else {
+      if ( device )
+	usage();
+      device = *argp;
+    }
+  }
+
+  if ( !device )
+    usage();
+
+  /*
+   * First make sure we can open the device at all, and that we have
+   * read/write permission.
+   */
+  dev_fd = open(device, O_RDWR);
+  if ( dev_fd < 0 || fstat(dev_fd, &st) < 0 ) {
+    perror(device);
+    exit(1);
+  }
+
+  if ( !force && !S_ISBLK(st.st_mode) && !S_ISREG(st.st_mode) ) {
+    die("not a block device or regular file (use -f to override)");
+  }
+
+  if ( !force && offset != 0 && !S_ISREG(st.st_mode) ) {
+    die("not a regular file and an offset specified (use -f to override)");
+  }
+
+  xpread(dev_fd, sectbuf, 512, offset);
+  fsync(dev_fd);
+
+  /*
+   * Check to see that what we got was indeed an MS-DOS boot sector/superblock
+   */
+  if(!syslinux_check_bootsect(sectbuf,device)) {
+    exit(1);
+  }
+
+  /*
+   * Now mount the device.
+   */
+  if ( geteuid() ) {
+    die("This program needs root privilege");
+  } else {
+    int i = 0;
+    struct stat dst;
+    int rv;
+
+    /* We're root or at least setuid.
+       Make a temp dir and pass all the gunky options to mount. */
+
+    if ( chdir("/tmp") ) {
+      perror(program);
+      exit(1);
+    }
+
+#define TMP_MODE (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IWOTH|S_IXOTH|S_ISVTX)
+
+    if ( stat(".", &dst) || !S_ISDIR(dst.st_mode) ||
+	 (dst.st_mode & TMP_MODE) != TMP_MODE ) {
+      die("possibly unsafe /tmp permissions");
+    }
+
+    for ( i = 0 ; ; i++ ) {
+      snprintf(mntname, sizeof mntname, "syslinux.mnt.%lu.%d",
+	       (unsigned long)mypid, i);
+
+      if ( lstat(mntname, &dst) != -1 || errno != ENOENT )
+	continue;
+
+      rv = mkdir(mntname, 0000);
+
+      if ( rv == -1 ) {
+	if ( errno == EEXIST || errno == EINTR )
+	  continue;
+	perror(program);
+	exit(1);
+      }
+
+      if ( lstat(mntname, &dst) || dst.st_mode != (S_IFDIR|0000) ||
+	   dst.st_uid != 0 ) {
+	die("someone is trying to symlink race us!");
+      }
+      break;			/* OK, got something... */
+    }
+
+    mntpath = mntname;
+
+#if DO_DIRECT_MOUNT
+    if ( S_ISREG(st.st_mode) ) {
+      /* It's file, need to mount it loopback */
+      unsigned int n = 0;
+      struct loop_info64 loopinfo;
+
+      for ( n = 0 ; loop_fd < 0 ; n++ ) {
+	snprintf(devfdname, sizeof devfdname, "/dev/loop%u", n);
+	loop_fd = open(devfdname, O_RDWR);
+	if ( loop_fd < 0 && errno == ENOENT ) {
+	  die("no available loopback device!");
+	}
+	if ( ioctl(loop_fd, LOOP_SET_FD, (void *)dev_fd) ) {
+	  close(loop_fd); loop_fd = -1;
+	  if ( errno != EBUSY )
+	    die("cannot set up loopback device");
+	  else
+	    continue;
+	}
+	
+	if ( ioctl(loop_fd, LOOP_GET_STATUS64, &loopinfo) ||
+	     (loopinfo.lo_offset = offset,
+	      ioctl(loop_fd, LOOP_SET_STATUS64, &loopinfo)) )
+	  die("cannot set up loopback device");
+      }
+    } else {
+      snprintf(devfdname, sizeof devfdname, "/proc/%lu/fd/%d",
+	       (unsigned long)mypid, dev_fd);
+    }
+
+    if ( mount(devfdname, mntpath, "msdos",
+	       MS_NOEXEC|MS_NOSUID, "umask=077,quiet") )
+      die("could not mount filesystem");
+
+#else
+
+    snprintf(devfdname, sizeof devfdname, "/proc/%lu/fd/%d",
+	     (unsigned long)mypid, dev_fd);
+
+    f = fork();
+    if ( f < 0 ) {
+      perror(program);
+      rmdir(mntpath);
+      exit(1);
+    } else if ( f == 0 ) {
+      char mnt_opts[128];
+      if ( S_ISREG(st.st_mode) ) {
+	snprintf(mnt_opts, sizeof mnt_opts, "rw,nodev,noexec,loop,offset=%llu,umask=077,quiet",
+		 (unsigned long long)offset);
+      } else {
+	snprintf(mnt_opts, sizeof mnt_opts, "rw,nodev,noexec,umask=077,quiet");
+      }
+      execl(_PATH_MOUNT, _PATH_MOUNT, "-t", "msdos", "-o", mnt_opts,\
+	    devfdname, mntpath, NULL);
+      _exit(255);		/* execl failed */
+    }
+
+    w = waitpid(f, &status, 0);
+    if ( w != f || status ) {
+      rmdir(mntpath);
+      exit(1);			/* Mount failed */
+    }
+    
+#endif
+  }
+  
+  ldlinux_name = alloca(strlen(mntpath)+13);
+  if ( !ldlinux_name ) {
+    perror(program);
+    err = 1;
+    goto umount;
+  }
+  sprintf(ldlinux_name, "%s/ldlinux.sys", mntpath);
+
+  unlink(ldlinux_name);
+  fd = open(ldlinux_name, O_WRONLY|O_CREAT|O_TRUNC, 0444);
+  if ( fd < 0 ) {
+    perror(device);
+    err = 1;
+    goto umount;
+  }
+
+  cdp = syslinux_ldlinux;
+  left = syslinux_ldlinux_len;
+  while ( left ) {
+    nb = write(fd, cdp, left);
+    if ( nb == -1 && errno == EINTR )
+      continue;
+    else if ( nb <= 0 ) {
+      perror(device);
+      err = 1;
+      goto umount;
+    }
+
+    dp += nb;
+    left -= nb;
+  }
+
+  /*
+   * I don't understand why I need this.  Does the DOS filesystems
+   * not honour the mode passed to open()?
+   */
+  fchmod(fd, 0400);
+
+  close(fd);
+
+  sync();
+
+umount:
+#if DO_DIRECT_MOUNT
+
+  if ( umount2(mntpath, 0) )
+    die("could not umount path");
+
+  if ( loop_fd != -1 ) {
+    ioctl(loop_fd, LOOP_CLR_FD, 0); /* Free loop device */
+    close(loop_fd);
+    loop_fd = -1;
+  }
+
+#else
+
+  f = fork();
+  if ( f < 0 ) {
+    perror("fork");
+    exit(1);
+  } else if ( f == 0 ) {
+    execl(_PATH_UMOUNT, _PATH_UMOUNT, mntpath, NULL);
+  }
+
+  w = waitpid(f, &status, 0);
+  if ( w != f || status ) {
+    exit(1);
+  }
+
+#endif
+
+  sync();
+  rmdir(mntpath);
+
+  if ( err )
+    exit(err);
+
+  /*
+   * 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.
+   */
+  fs = libfat_open(libfat_xpread, (void *)dev_fd);
+  ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
+  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);
+
+  /*
+   * Patch ldlinux.sys and the boot sector
+   */
+  syslinux_patch(sectors, nsectors);
+
+  /*
+   * Write the now-patched first sector of ldlinux.sys
+   */
+  xpwrite(dev_fd, syslinux_ldlinux, 512, offset + ((off_t)sectors[0] << 9));
+
+  /*
+   * To finish up, write the boot sector
+   */
+
+  /* Read the superblock again since it might have changed while mounted */
+  xpread(dev_fd, sectbuf, 512, offset);
+
+  /* Copy the syslinux code into the boot sector */
+  syslinux_make_bootsect(sectbuf);
+
+  /* Write new boot sector */
+  xpwrite(dev_fd, sectbuf, 512, offset);
+
+  close(dev_fd);
+  sync();
+
+  /* Done! */
+
+  return 0;
+}
+