- caesar(6) is not a SETGIDGAME, so we don't need to revoke any privileges.
- replaced direct POSIX read/write with stdio, which made the code simpler. - added even more error checking. - restructured the code to make each function fit on one screen (well, except one). - now the code reflects the intended purpose of the program. - return 0 instead of EXIT_FAILURE on success.
This commit is contained in:
rillig
parent
15bc25dc45
commit
d590f7d069
@ -1,4 +1,4 @@
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/* $NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $ */
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/* $NetBSD: caesar.c,v 1.16 2005/07/22 11:52:23 rillig Exp $ */
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/*
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* Copyright (c) 1989, 1993
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@ -48,7 +48,7 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
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#if 0
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static char sccsid[] = "@(#)caesar.c 8.1 (Berkeley) 5/31/93";
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#else
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__RCSID("$NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $");
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__RCSID("$NetBSD: caesar.c,v 1.16 2005/07/22 11:52:23 rillig Exp $");
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#endif
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#endif /* not lint */
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@ -60,7 +60,6 @@ __RCSID("$NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $");
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#define NCHARS (1 << CHAR_BIT)
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#define LETTERS (26)
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@ -85,7 +84,7 @@ init_rottbl(int rot)
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{
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size_t i;
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rot %= LETTERS;
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rot %= LETTERS; /* prevent integer overflow */
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for (i = 0; i < NCHARS; i++)
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rottbl[i] = (unsigned char)i;
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@ -97,51 +96,56 @@ init_rottbl(int rot)
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rottbl[lower[i]] = lower[(i + rot) % LETTERS];
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}
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static void __attribute__((__noreturn__))
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printrot(const char *arg)
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static void
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print_file(void)
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{
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int ch;
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while ((ch = getchar()) != EOF) {
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if (putchar(rottbl[ch]) == EOF) {
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err(EXIT_FAILURE, "<stdout>");
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/* NOTREACHED */
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}
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}
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}
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static void
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print_array(const unsigned char *a, size_t len)
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{
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size_t i;
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for (i = 0; i < len; i++) {
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if (putchar(rottbl[a[i]]) == EOF) {
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err(EXIT_FAILURE, "<stdout>");
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/* NOTREACHED */
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}
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}
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}
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static int
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get_rotation(const char *arg)
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{
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long rot;
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char *endp;
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errno = 0;
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rot = strtol(arg, &endp, 10);
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if (*endp != '\0') {
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if (!(errno == 0 && *endp == '\0' && 0 <= rot && rot <= INT_MAX)) {
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errx(EXIT_FAILURE, "bad rotation value: %s", arg);
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/* NOTREACHED */
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}
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if (errno == ERANGE || rot < 0 || rot > INT_MAX) {
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errx(EXIT_FAILURE, "rotation value out of range: %s", arg);
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/* NOTREACHED */
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}
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init_rottbl((int)rot);
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while ((ch = getchar()) != EOF) {
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if (putchar(rottbl[ch]) == EOF) {
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err(EXIT_FAILURE, "writing to stdout");
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/* NOTREACHED */
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}
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}
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exit(EXIT_SUCCESS);
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/* NOTREACHED */
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return (int) rot;
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}
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int
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main(int argc, char **argv)
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static void
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guess_and_rotate(void)
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{
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ssize_t i, nread, ntotal;
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double dot, winnerdot;
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int try, winner;
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unsigned char inbuf[2048];
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unsigned int obs[NCHARS];
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/* revoke setgid privileges */
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(void)setgid(getgid());
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if (argc > 1) {
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printrot(argv[1]);
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/* NOTREACHED */
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}
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size_t i, nread;
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double dot, winnerdot;
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int try, winner;
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int ch;
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/* adjust frequency table to weight low probs REAL low */
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for (i = 0; i < LETTERS; i++)
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@ -150,18 +154,13 @@ main(int argc, char **argv)
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/* zero out observation table */
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(void)memset(obs, 0, sizeof(obs));
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for (ntotal = 0; (size_t) ntotal < sizeof(inbuf); ntotal += nread) {
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nread = read(STDIN_FILENO, &inbuf[ntotal],
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sizeof(inbuf) - ntotal);
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if (nread < 0) {
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err(EXIT_FAILURE, "reading from stdin");
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/* NOTREACHED */
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}
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if (nread == 0)
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for (nread = 0; nread < sizeof(inbuf); nread++) {
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if ((ch = getchar()) == EOF)
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break;
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inbuf[nread] = (unsigned char) ch;
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}
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for (i = 0; i < ntotal; i++)
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for (i = 0; i < nread; i++)
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obs[inbuf[i]]++;
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/*
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@ -182,20 +181,36 @@ main(int argc, char **argv)
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winnerdot = dot;
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}
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}
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init_rottbl(winner);
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while (ntotal > 0) {
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for (i = 0; i < ntotal; i++) {
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if (putchar(rottbl[inbuf[i]]) == EOF) {
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err(EXIT_FAILURE, "writing to stdout");
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/* NOTREACHED */
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}
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}
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if ((ntotal = read(STDIN_FILENO, inbuf, sizeof(inbuf))) < 0) {
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err(EXIT_FAILURE, "reading from stdin");
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/* NOTREACHED */
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}
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}
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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init_rottbl(winner);
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print_array(inbuf, nread);
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print_file();
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}
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int
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main(int argc, char **argv)
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{
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if (argc == 1) {
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guess_and_rotate();
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} else if (argc == 2) {
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init_rottbl(get_rotation(argv[1]));
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print_file();
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} else {
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(void)fprintf(stderr, "usage: caesar [rot]\n");
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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}
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if (ferror(stdin)) {
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errx(EXIT_FAILURE, "<stdin>");
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/* NOTREACHED */
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}
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(void)fflush(stdout);
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if (ferror(stdout)) {
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err(EXIT_FAILURE, "<stdout>");
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/* NOTREACHED */
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}
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return 0;
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}
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