(2006-08-06) rescue-bootcd

extra/syslinux-3.09/mtools/syslinux.c

@@ -0,0 +1,294 @@
+#ident "$Id: syslinux.c,v 1.6 2005/01/04 03:27:43 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   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 now requires mtools.  It turned out to be a lot
+ * easier to deal with than dealing with needing mount privileges.
+ * We need device write permission anyway.
+ */
+
+#define _XOPEN_SOURCE 500	/* Required on glibc 2.x */
+#define _BSD_SOURCE
+#include <alloca.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <mntent.h>
+#include <paths.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include "syslinux.h"
+#include "libfat.h"
+
+char *program;			/* Name of program */
+char *device;			/* Device to install to */
+pid_t mypid;
+off_t filesystem_offset = 0;	/* Offset of filesystem */
+
+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);
+  exit(1);
+}
+
+/*
+ * read/write wrapper functions
+ */
+ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
+{
+  char *bufp = (char *)buf;
+  ssize_t rv;
+  ssize_t done = 0;
+
+  while ( count ) {
+    rv = pread(fd, bufp, count, offset);
+    if ( rv == 0 ) {
+      die("short read");
+    } else if ( rv == -1 ) {
+      if ( errno == EINTR ) {
+	continue;
+      } else {
+	die(strerror(errno));
+      }
+    } else {
+      bufp += rv;
+      offset += rv;
+      done += rv;
+      count -= rv;
+    }
+  }
+
+  return done;
+}
+
+ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+  const char *bufp = (const char *)buf;
+  ssize_t rv;
+  ssize_t done = 0;
+
+  while ( count ) {
+    rv = pwrite(fd, bufp, count, offset);
+    if ( rv == 0 ) {
+      die("short write");
+    } else if ( rv == -1 ) {
+      if ( errno == EINTR ) {
+	continue;
+      } else {
+	die(strerror(errno));
+      }
+    } else {
+      bufp += rv;
+      offset += rv;
+      done += rv;
+      count -= rv;
+    }
+  }
+
+  return done;
+}
+
+/*
+ * Version of the read function suitable for libfat
+ */
+int libfat_xpread(intptr_t pp, void *buf, size_t secsize, libfat_sector_t sector)
+{
+  off_t offset = (off_t)sector * secsize + filesystem_offset;
+  return xpread(pp, buf, secsize, offset);
+}
+
+
+int main(int argc, char *argv[])
+{
+  static unsigned char sectbuf[512];
+  int dev_fd;
+  struct stat st;
+  int status;
+  char **argp, *opt;
+  int force = 0;		/* -f (force) option */
+  char mtools_conf[] = "/tmp/syslinux-mtools-XXXXXX";
+  int mtc_fd;
+  FILE *mtc, *mtp;
+  struct libfat_filesystem *fs;
+  libfat_sector_t s, *secp, sectors[65]; /* 65 is maximum possible */
+  int32_t ldlinux_cluster;
+  int nsectors;
+  const char *errmsg;
+
+  (void)argc;			/* Unused */
+
+  mypid = getpid();
+  program = argv[0];
+  
+  device = NULL;
+
+  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] ) {
+	  filesystem_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) ) {
+    fprintf(stderr, "%s: not a block device or regular file (use -f to override)\n", device);
+    exit(1);
+  }
+
+  xpread(dev_fd, sectbuf, 512, filesystem_offset);
+  
+  /*
+   * Check to see that what we got was indeed an MS-DOS boot sector/superblock
+   */
+  if( (errmsg = syslinux_check_bootsect(sectbuf)) ) {
+    die(errmsg);
+  }
+
+  /*
+   * Create an mtools configuration file
+   */
+  mtc_fd = mkstemp(mtools_conf);
+  if ( mtc_fd < 0 || !(mtc = fdopen(mtc_fd, "w")) ) {
+    perror(program);
+    exit(1);
+  }
+  fprintf(mtc,
+	  "MTOOLS_NO_VFAT=1\n"
+	  "MTOOLS_SKIP_CHECK=1\n" /* Needed for some flash memories */
+	  "drive s:\n"
+	  "  file=\"/proc/%lu/fd/%d\"\n"
+	  "  offset=%llu\n",
+	  (unsigned long)mypid,
+	  dev_fd,
+	  (unsigned long long)filesystem_offset);
+  fclose(mtc);
+  
+  /*
+   * Run mtools to create the LDLINUX.SYS file
+   */
+  if ( setenv("MTOOLSRC", mtools_conf, 1) ) {
+    perror(program);
+    exit(1);
+  }
+
+  /* This command may fail legitimately */
+  system("mattrib -h -r -s s:ldlinux.sys 2>/dev/null");
+
+  mtp = popen("mcopy -D o -D O -o - s:ldlinux.sys", "w");
+  if ( !mtp ||
+       (fwrite(syslinux_ldlinux, 1, syslinux_ldlinux_len, mtp) 
+	!= syslinux_ldlinux_len) ||
+       (status = pclose(mtp), !WIFEXITED(status) || WEXITSTATUS(status)) ) {
+    die("failed to create ldlinux.sys");
+  }
+
+  status = system("mattrib +r +h +s s:ldlinux.sys");
+
+  if ( !WIFEXITED(status) || WEXITSTATUS(status) ) {
+    fprintf(stderr,
+	    "%s: warning: failed to set system bit on ldlinux.sys\n",
+	    program);
+  }
+
+  unlink(mtools_conf);
+
+  /*
+   * Now, use libfat to create a block map
+   */
+  fs = libfat_open(libfat_xpread, 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, filesystem_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, 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);
+
+  close(dev_fd);
+  sync();
+
+  /* Done! */
+
+  return 0;
+}