sca_write.c

Solaris操作系统下的过滤驱动程序, C源码程序.

/*
 * Copyright (c) 1997-2003 Erez Zadok
 * Copyright (c) 2001-2003 Stony Brook University
 * Copyright (c) 1997-2000 Columbia University
 *
 * For specific licensing information, see the COPYING file distributed with
 * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
 *
 * This Copyright notice must be kept intact and distributed with all
 * fistgen sources INCLUDING sources generated by fistgen.
 */
/*
 *  $Id: sca_write.c,v 1.5 2002/12/27 20:19:02 ezk Exp $
 */
#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <errno.h>
#include <limits.h>

#include "sca_aux.h"
#include "sca_code.h"


int
encode_file(char *name)
     /* Write out a gzipfs'ed version of file <name>. Return 0 for success,
        errno for error. */
{
  char filename[MAXPATHLEN];
  struct fistfs_header hdr;
  int infd, outfd;	/* File to be read, file to be written, and
			   the index file */
  struct stat sb;
  int base = 0;			/* Unencoded length, encoded length */
  unsigned char *data = NULL;	/* For mmaping the infile */
  unsigned char *page;		/* A pointer that steps through data */
  int cnt;

  if (name == NULL)
    return(-1);

  if ((infd = open(name, O_RDONLY)) < 0)
    return(errno);
  if ((fstat(infd, &sb)) < 0)
    return(errno);
  if (S_ISDIR(sb.st_mode))
    return(EISDIR);

  sprintf(filename, "%s.sca", name);
  fprintf(stderr, "encoding %s into %s...\n", name, filename);
  if ((outfd = open(filename, O_RDWR|O_TRUNC|O_CREAT, 00600)) < 0)
    return(errno);

  sprintf(filename, "%s.idx", name);
  if(read_idx(filename, &hdr) < 0) { /* Not there, make one! */
    hdr.num_pages = 0;
    hdr.real_size = 0;
    hdr.offsets = NULL;
  }

  if ((data = mmap((void *)data, sb.st_size, PROT_READ,
		   MAP_PRIVATE, infd, 0)) == NULL)
    return(errno);

  while(base < sb.st_size) {	/* Now step through the input file */
    cnt = sb.st_size - base;	/* How much is left? */
    if (cnt > chunksize)
      cnt = chunksize;		/* Do 1 page at a time */

    page = &(data[base]);
    base += cnt;		/* base contains the position of the last
				   unencoded byte we've read */

    if (put_page(outfd, &hdr, hdr.num_pages, page, cnt) < 0) {
      return(-1);
    }
  }

  if (write_idx(filename, &hdr) < 0)
    return(-1);

  free(hdr.offsets);

  munmap(data, sb.st_size);

  close(outfd);
  close(infd);
  return(0);
}


void
usage(const char *progname)
{
  fprintf(stderr, "Usage: %s: [-c chunksize] [-f] [-d] file1 [file2 file3 ...]\n", progname);
}


int
main(int argc, char **argv)
{
  int i, rc, cnt = 0;
  int debug=0;

  if (argc < 2) {
    usage(argv[0]);
    exit(1);
  }

  while((i = getopt(argc, argv, "c:fd")) != EOF) {
    switch(i) {
    case 'c':
      chunksize = atoi(optarg);
      if (chunksize < 0) {
	fprintf(stderr, "Please use a positive chunk size\n");
	exit(1);
      }
      break;
    case 'f':
      do_fast_tails = 1;
      break;
    case 'd':
      debug=1;
      break;
    default:
      usage(argv[0]);
      exit(1);
    }
  }

  for(i=optind; i<argc; i++) {
    if ((rc = encode_file(argv[i])) < 0) {
      fprintf(stderr, "\tError encoding %s (%d)\n", argv[i], rc);
      cnt++;
    }
  }

  if (debug) {
    fprintf(stderr, "encodes: %d\n", encode_counter);
    fprintf(stderr, "decodes: %d\n", decode_counter);
    fprintf(stderr, "writes:  %d\n", write_counter);
  }
  exit(cnt);
}