From a699513cfc3e3f318b1cd4cfb85324021864975b Mon Sep 17 00:00:00 2001
From: =?utf8?q?Holger=20Wei=C3=9F?= <holger@weiss.in-berlin.de>
Date: Thu, 1 Aug 2013 23:02:48 +0200
Subject: [PATCH] Teach the client about backslash escape sequences

Let send_nsca(8)'s "-d" and "-e" flags accept C-style escape sequences,
so that e.g. "-e '\n'" can be specified.  Octal numbers with a leading
zero and hexadecimal numbers prefixed with "0x" are also accepted.
---
 man/send_nsca.in       |  8 +++--
 src/client/send_nsca.c | 82 ++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 79 insertions(+), 11 deletions(-)

diff --git a/man/send_nsca.in b/man/send_nsca.in
index 8ed1478..bc21ca2 100644
--- a/man/send_nsca.in
+++ b/man/send_nsca.in
@@ -148,7 +148,9 @@ instead of a horizontal tab to separate the fields when parsing host or
 service check results.
 The
 .I delimiter
-must be a single character.
+must be a single character, a C-style backslash escape sequence, the
+octal value of a character with a leading zero, or the hexadecimal value
+of a character prefixed with \(lq0x\(rq.
 Any
 .SM ASCII
 character other than a backslash, newline,
@@ -170,7 +172,9 @@ instead of an
 character to separate multiple host or service check results.
 The
 .I separator
-must be a single character.
+must be a single character, a C-style backslash escape sequence, the
+octal value of a character with a leading zero, or the hexadecimal value
+of a character prefixed with \(lq0x\(rq.
 Any
 .SM ASCII
 character is allowed, but note that multiline check result messages
diff --git a/src/client/send_nsca.c b/src/client/send_nsca.c
index 1c06fe8..f986ad5 100644
--- a/src/client/send_nsca.c
+++ b/src/client/send_nsca.c
@@ -29,9 +29,11 @@
 # include <config.h>
 #endif
 
+#include <ctype.h>
 #if HAVE_INTTYPES_H
 # include <inttypes.h>
 #endif
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -69,6 +71,7 @@ int exit_code = EXIT_SUCCESS;
 
 static options *get_options(int, char **);
 static void free_options(options *);
+static int parse_backslash_escape(const char *);
 static void delay_execution(unsigned int);
 static unsigned long random_number(unsigned long);
 static void forget_config(void);
@@ -155,7 +158,9 @@ get_options(int argc, char **argv)
 		}
 	}
 
-	while ((option = getopt(argc, argv, "Cc:D:d:e:H:ho:p:SstVv")) != -1)
+	while ((option = getopt(argc, argv, "Cc:D:d:e:H:ho:p:SstVv")) != -1) {
+		int character;
+
 		switch (option) {
 		case 'C':
 			opt->raw_commands = true;
@@ -171,18 +176,19 @@ get_options(int argc, char **argv)
 				die("-D argument must be a positive integer");
 			break;
 		case 'd':
-			if (strlen(optarg) != 1)
+			if ((character = parse_backslash_escape(optarg)) == EOF)
 				die("-d argument must be a single character");
-			if (*optarg == '\27'
-			    || *optarg == '\n'
-			    || *optarg == '\\')
+			if (character == '\27'
+			    || character == '\n'
+			    || character == '\0'
+			    || character == '\\')
 				die("Illegal delimiter specified with -d");
-			opt->delimiter = *optarg;
+			opt->delimiter = (char)character;
 			break;
 		case 'e':
-			if (strlen(optarg) != 1)
+			if ((character = parse_backslash_escape(optarg)) == EOF)
 				die("-e argument must be a single character");
-			opt->separator = *optarg;
+			opt->separator = (char)character;
 			break;
 		case 'H':
 			if (opt->server != NULL)
@@ -226,7 +232,7 @@ get_options(int argc, char **argv)
 		default:
 			usage(EXIT_FAILURE);
 		}
-
+	}
 	if (opt->delimiter == opt->separator)
 		die("Field delimiter must be different from record separator");
 	if (argc - optind > 0)
@@ -248,6 +254,64 @@ free_options(options *opt)
 	free(opt);
 }
 
+static int
+parse_backslash_escape(const char *sequence)
+{
+	char numeric[6]; /* Space for "0x345". */
+
+	switch (strlen(sequence)) {
+	case 1:
+		return (unsigned char)sequence[0];
+	case 2:
+		if (sequence[0] == '\\')
+			switch (sequence[1]) {
+			case 'a':
+				return '\a';
+			case 'b':
+				return '\b';
+			case 'f':
+				return '\f';
+			case 'n':
+				return '\n';
+			case 'r':
+				return '\r';
+			case 't':
+				return '\t';
+			case 'v':
+				return '\v';
+			case 'x': /* Fall through. */
+			case '0':
+				break;
+			default:
+				return (unsigned char)sequence[1];
+			}
+		/* Otherwise, fall through. */
+	case 3: /* Fall through. */
+	case 4: /* Fall through. */
+	case 5:
+		/*
+		 * We support octal numbers with a leading zero and hexadecimal
+		 * numbers prefixed with "0x" in addition to numeric backslash
+		 * escape sequences.
+		 */
+		if (sequence[0] == '0' || sequence[0] == '\\') {
+			char *end;
+			long value;
+
+			(void)strcpy(numeric, sequence);
+			if (numeric[0] == '\\') /* \x42 -> 0x42 */
+				numeric[0] = '0';
+			value = strtol(numeric, &end, 0);
+			if (*end == '\0' && value >= 0 && value <= CHAR_MAX)
+				return (unsigned char)value;
+			/* Otherwise, fall through. */
+		}
+		/* Otherwise, fall through. */
+	default:
+		return EOF;
+	}
+}
+
 static void
 delay_execution(unsigned int max_delay)
 {
-- 
2.11.4.GIT