LXR busybox/coreutils/sum.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * sum -- checksum and count the blocks in a file
   4 *     Like BSD sum or SysV sum -r, except like SysV sum if -s option is given.
   5 *
   6 * Copyright (C) 86, 89, 91, 1995-2002, 2004 Free Software Foundation, Inc.
   7 * Copyright (C) 2005 by Erik Andersen <andersen@codepoet.org>
   8 * Copyright (C) 2005 by Mike Frysinger <vapier@gentoo.org>
   9 *
  10 * Written by Kayvan Aghaiepour and David MacKenzie
  11 * Taken from coreutils and turned into a busybox applet by Mike Frysinger
  12 *
  13 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  14 */
  15
  16//usage:#define sum_trivial_usage
  17//usage:       "[-rs] [FILE]..."
  18//usage:#define sum_full_usage "\n\n"
  19//usage:       "Checksum and count the blocks in a file\n"
  20//usage:     "\n        -r      Use BSD sum algorithm (1K blocks)"
  21//usage:     "\n        -s      Use System V sum algorithm (512byte blocks)"
  22
  23#include "libbb.h"
  24
  25enum { SUM_BSD, PRINT_NAME, SUM_SYSV };
  26
  27/* BSD: calculate and print the rotated checksum and the size in 1K blocks
  28   The checksum varies depending on sizeof (int). */
  29/* SYSV: calculate and print the checksum and the size in 512-byte blocks */
  30/* Return 1 if successful.  */
  31static unsigned sum_file(const char *file, unsigned type)
  32{
  33#define buf bb_common_bufsiz1
  34        unsigned long long total_bytes = 0;
  35        int fd, r;
  36        /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
  37        unsigned s = 0;
  38
  39        fd = open_or_warn_stdin(file);
  40        if (fd == -1)
  41                return 0;
  42
  43        while (1) {
  44                size_t bytes_read = safe_read(fd, buf, BUFSIZ);
  45
  46                if ((ssize_t)bytes_read <= 0) {
  47                        r = (fd && close(fd) != 0);
  48                        if (!bytes_read && !r)
  49                                /* no error */
  50                                break;
  51                        bb_simple_perror_msg(file);
  52                        return 0;
  53                }
  54
  55                total_bytes += bytes_read;
  56                if (type >= SUM_SYSV) {
  57                        do s += buf[--bytes_read]; while (bytes_read);
  58                } else {
  59                        r = 0;
  60                        do {
  61                                s = (s >> 1) + ((s & 1) << 15);
  62                                s += buf[r++];
  63                                s &= 0xffff; /* Keep it within bounds. */
  64                        } while (--bytes_read);
  65                }
  66        }
  67
  68        if (type < PRINT_NAME)
  69                file = "";
  70        if (type >= SUM_SYSV) {
  71                r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
  72                s = (r & 0xffff) + (r >> 16);
  73                printf("%u %llu %s\n", s, (total_bytes + 511) / 512, file);
  74        } else
  75                printf("%05u %5llu %s\n", s, (total_bytes + 1023) / 1024, file);
  76        return 1;
  77#undef buf
  78}
  79
  80int sum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  81int sum_main(int argc UNUSED_PARAM, char **argv)
  82{
  83        unsigned n;
  84        unsigned type = SUM_BSD;
  85
  86        n = getopt32(argv, "sr");
  87        argv += optind;
  88        if (n & 1) type = SUM_SYSV;
  89        /* give the bsd priority over sysv func */
  90        if (n & 2) type = SUM_BSD;
  91
  92        if (!argv[0]) {
  93                /* Do not print the name */
  94                n = sum_file("-", type);
  95        } else {
  96                /* Need to print the name if either
  97                 * - more than one file given
  98                 * - doing sysv */
  99                type += (argv[1] || type == SUM_SYSV);
 100                n = 1;
 101                do {
 102                        n &= sum_file(*argv, type);
 103                } while (*++argv);
 104        }
 105        return !n;
 106}
 107