Index: usr.sbin/newsyslog/newsyslog.c
===================================================================
--- usr.sbin/newsyslog/newsyslog.c
+++ usr.sbin/newsyslog/newsyslog.c
@@ -87,27 +87,6 @@
 #include "extern.h"
 
 /*
- * Compression suffixes
- */
-#ifndef	COMPRESS_SUFFIX_GZ
-#define	COMPRESS_SUFFIX_GZ	".gz"
-#endif
-
-#ifndef	COMPRESS_SUFFIX_BZ2
-#define	COMPRESS_SUFFIX_BZ2	".bz2"
-#endif
-
-#ifndef	COMPRESS_SUFFIX_XZ
-#define	COMPRESS_SUFFIX_XZ	".xz"
-#endif
-
-#ifndef	COMPRESS_SUFFIX_ZST
-#define	COMPRESS_SUFFIX_ZST	".zst"
-#endif
-
-#define	COMPRESS_SUFFIX_MAXLEN	MAX(MAX(MAX(sizeof(COMPRESS_SUFFIX_GZ),sizeof(COMPRESS_SUFFIX_BZ2)),sizeof(COMPRESS_SUFFIX_XZ)),sizeof(COMPRESS_SUFFIX_ZST))
-
-/*
  * Compression types
  */
 #define	COMPRESS_TYPES  5	/* Number of supported compression types */
@@ -148,28 +127,32 @@
 
 #define	MAX_OLDLOGS 65536	/* Default maximum number of old logfiles */
 
+#define	COMPRESS_SUFFIX_MAXLEN 3
+
 struct compress_types {
 	const char *flag;	/* Flag in configuration file */
-	const char *suffix;	/* Compression suffix */
+	const char suffix[COMPRESS_SUFFIX_MAXLEN+1];	/* Compression suffix */
 	const char *path;	/* Path to compression program */
-	char **args;		/* Compression program arguments */
+	const char **args;	/* Compression program arguments */
 	int nargs;		/* Program argument count */
 };
 
-static char f_arg[] = "-f";
-static char q_arg[] = "-q";
-static char rm_arg[] = "--rm";
-static char *gz_args[] = { NULL, f_arg, NULL, NULL };
-#define bz2_args gz_args
-#define xz_args gz_args
-static char *zstd_args[] = { NULL, q_arg, rm_arg, NULL, NULL };
+/*
+ * The args arrays need three more entries in addition to the compression
+ * flags themselves: one at the beginning for the command, one at the end
+ * for the filename to compress, and the trailing NULL needed by execv.
+ */
+static const char *gzip_args[] = { NULL, "-f", NULL, NULL };
+#define bzip2_args gzip_args
+#define xz_args gzip_args
+static const char *zstd_args[] = { NULL, "-q", "--rm", NULL, NULL };
 
 static const struct compress_types compress_type[COMPRESS_TYPES] = {
-	{ "", "", "", NULL, 0},
-	{ "Z", COMPRESS_SUFFIX_GZ, _PATH_GZIP, gz_args, nitems(gz_args) },
-	{ "J", COMPRESS_SUFFIX_BZ2, _PATH_BZIP2, bz2_args, nitems(bz2_args) },
-	{ "X", COMPRESS_SUFFIX_XZ, _PATH_XZ, xz_args, nitems(xz_args) },
-	{ "Y", COMPRESS_SUFFIX_ZST, _PATH_ZSTD, zstd_args, nitems(zstd_args) }
+	{ "", "", "", NULL, 0 },
+	{ "Z", ".gz", _PATH_GZIP, gzip_args, nitems(gzip_args) },
+	{ "J", ".bz2", _PATH_BZIP2, bzip2_args, nitems(bzip2_args) },
+	{ "X", ".xz", _PATH_XZ, xz_args, nitems(xz_args) },
+	{ "Y", ".zst", _PATH_ZSTD, zstd_args, nitems(zstd_args) }
 };
 
 struct conf_entry {
@@ -2027,31 +2010,26 @@
 	char zresult[MAXPATHLEN];
 	char command[BUFSIZ];
 	char **args;
-	int c, i, nargs;
+	int c, nargs;
 
 	assert(zwork != NULL);
 	pgm_path = NULL;
 	strlcpy(zresult, zwork->zw_fname, sizeof(zresult));
 	if (zwork->zw_conf != NULL &&
-	    zwork->zw_conf->compress > COMPRESS_NONE)
-		for (c = 1; c < COMPRESS_TYPES; c++) {
-			if (zwork->zw_conf->compress == c) {
-				nargs = compress_type[c].nargs;
-				args = calloc(nargs, sizeof(*args));
-				if (args == NULL)
-					err(1, "calloc()");
-				pgm_path = compress_type[c].path;
-				(void) strlcat(zresult,
-				    compress_type[c].suffix, sizeof(zresult));
-				/* the first argument is always NULL, skip it */
-				for (i = 1; i < nargs; i++) {
-					if (compress_type[c].args[i] == NULL)
-						break;
-					args[i] = compress_type[c].args[i];
-				}
-				break;
-			}
+	    zwork->zw_conf->compress > COMPRESS_NONE) {
+		nargs = compress_type[zwork->zw_conf->compress].nargs;
+		args = calloc(nargs, sizeof(*args));
+		if (args == NULL)
+			err(1, "calloc()");
+		pgm_path = compress_type[zwork->zw_conf->compress].path;
+		(void) strlcat(zresult,
+		    compress_type[zwork->zw_conf->compress].suffix,
+		    sizeof(zresult));
+		for (c = 0; c < nargs; c++) {
+			args[c] = __DECONST(char *,
+			    compress_type[zwork->zw_conf->compress].args[c]);
 		}
+	}
 	if (pgm_path == NULL) {
 		warnx("invalid entry for %s in do_zipwork", zwork->zw_fname);
 		return;