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//config:config SUM
  16//config:       bool "sum (4 kb)"
  17//config:       default y
  18//config:       help
  19//config:       checksum and count the blocks in a file
  20
  21//applet:IF_SUM(APPLET(sum, BB_DIR_USR_BIN, BB_SUID_DROP))
  22
  23//kbuild:lib-$(CONFIG_SUM) += sum.o
  24
  25//usage:#define sum_trivial_usage
  26//usage:       "[-rs] [FILE]..."
  27//usage:#define sum_full_usage "\n\n"
  28//usage:       "Checksum and count the blocks in a file\n"
  29//usage:     "\n        -r      Use BSD sum algorithm (1K blocks)"
  30//usage:     "\n        -s      Use System V sum algorithm (512byte blocks)"
  31
  32#include "libbb.h"
  33#include "common_bufsiz.h"
  34
  35enum { SUM_BSD, PRINT_NAME, SUM_SYSV };
  36
  37/* BSD: calculate and print the rotated checksum and the size in 1K blocks
  38   The checksum varies depending on sizeof (int). */
  39/* SYSV: calculate and print the checksum and the size in 512-byte blocks */
  40/* Return 1 if successful.  */
  41static unsigned sum_file(const char *file, unsigned type)
  42{
  43        unsigned long long total_bytes = 0;
  44        int fd, r;
  45        /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
  46        unsigned s = 0;
  47
  48#define buf bb_common_bufsiz1
  49        setup_common_bufsiz();
  50
  51        fd = open_or_warn_stdin(file);
  52        if (fd == -1)
  53                return 0;
  54
  55        while (1) {
  56                size_t bytes_read = safe_read(fd, buf, COMMON_BUFSIZE);
  57
  58                if ((ssize_t)bytes_read <= 0) {
  59                        r = (fd && close(fd) != 0);
  60                        if (!bytes_read && !r)
  61                                /* no error */
  62                                break;
  63                        bb_simple_perror_msg(file);
  64                        return 0;
  65                }
  66
  67                total_bytes += bytes_read;
  68                if (type >= SUM_SYSV) {
  69                        do s += buf[--bytes_read]; while (bytes_read);
  70                } else {
  71                        r = 0;
  72                        do {
  73                                s = (s >> 1) + ((s & 1) << 15);
  74                                s += buf[r++];
  75                                s &= 0xffff; /* Keep it within bounds. */
  76                        } while (--bytes_read);
  77                }
  78        }
  79
  80        if (type < PRINT_NAME)
  81                file = "";
  82        if (type >= SUM_SYSV) {
  83                r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
  84                s = (r & 0xffff) + (r >> 16);
  85                printf("%u %llu %s\n", s, (total_bytes + 511) / 512, file);
  86        } else
  87                printf("%05u %5llu %s\n", s, (total_bytes + 1023) / 1024, file);
  88        return 1;
  89#undef buf
  90}
  91
  92int sum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  93int sum_main(int argc UNUSED_PARAM, char **argv)
  94{
  95        unsigned n;
  96        unsigned type = SUM_BSD;
  97
  98        n = getopt32(argv, "sr");
  99        argv += optind;
 100        if (n & 1) type = SUM_SYSV;
 101        /* give the bsd priority over sysv func */
 102        if (n & 2) type = SUM_BSD;
 103
 104        if (!argv[0]) {
 105                /* Do not print the name */
 106                n = sum_file("-", type);
 107        } else {
 108                /* Need to print the name if either
 109                 * - more than one file given
 110                 * - doing sysv */
 111                type += (argv[1] || type == SUM_SYSV);
 112                n = 1;
 113                do {
 114                        n &= sum_file(*argv, type);
 115                } while (*++argv);
 116        }
 117        return !n;
 118}
 119