/* * nvidia-installer: A tool for installing NVIDIA software packages on * Unix and Linux systems. * * Copyright (C) 2003 NVIDIA Corporation * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * * crc.c - this source file contains code for generating a 32-bit * checksum. Based on the 16 bit CRC algorithm in Numerical Recipes * 2nd Ed., pp 900-901. * * For a generator, we use the polynomial: * * x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 + x^7 + * x^5 + x^4 + x^2 + x^1 + 1. * * (without bit 32) * * See the source for cksum in GNU textutils for additional * references. */ #include #include #include #include #include #include #include #include "nvidia-installer.h" #include "user-interface.h" #include "misc.h" #include "crc.h" #define BIT(x) (1 << (x)) #define CRC_GEN_MASK (BIT(26) | BIT(23) | BIT(22) | BIT(16) | BIT(12) | \ BIT(11) | BIT(10) | BIT(8) | BIT(7) | BIT(5) | \ BIT(4) | BIT(2) | BIT(1) | BIT(0)) static uint32 crc_init(uint32 crc) { int i; uint32 ans = crc; for (i=0; i < 8; i++) { if (ans & 0x80000000) { ans = (ans << 1) ^ CRC_GEN_MASK; } else { ans <<= 1; } } return ans; } /* crc_init() */ uint32 compute_crc_from_buffer(const uint8 *buf, int len) { uint32 cword = ~0; static uint32 *crctab = NULL; int i; if (!crctab) { crctab = (uint32 *) nvalloc(sizeof(uint32) * 256); for (i=0; i < 256; i++) { crctab[i] = crc_init(i << 24); } } for (i = 0; i < len; i++) { cword = crctab[buf[i] ^ (cword >> 24)] ^ (cword << 8); } return cword; } uint32 compute_crc(Options *op, const char *filename) { uint32 cword = ~0; uint8 *buf = MAP_FAILED; int success = FALSE; int fd; struct stat stat_buf; size_t len = 0; if ((fd = open(filename, O_RDONLY)) == -1) goto done; if (fstat(fd, &stat_buf) == -1) goto done; if (stat_buf.st_size == 0) { cword = 0; success = TRUE; goto done; } len = stat_buf.st_size; buf = mmap(0, len, PROT_READ, MAP_FILE | MAP_SHARED, fd, 0); if (buf == MAP_FAILED) goto done; cword = compute_crc_from_buffer(buf, len); success = TRUE; done: if (!success) { ui_warn(op, "Unable to compute CRC for file '%s' (%s).", filename, strerror(errno)); } if (buf != MAP_FAILED) { munmap(buf, len); } if (fd >= 0) { close(fd); } return cword; } /* compute_crc() */