add compat for setproctitle

This adds a check for setproctitle and for the (linux) prctl
PR_SET_NAME.  If setproctitle is not available, on linux we provide an
implementation that use prctl (taken from tmux compat layer.)

compat/setproctitle.c

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2016 Nicholas Marriott <nicholas.marriott@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "../config.h"
+
+#if HAVE_PR_SET_NAME
+
+#include <sys/prctl.h>
+
+void
+setproctitle(const char *fmt, ...)
+{
+	char	title[16], name[16], *cp;
+	va_list	ap;
+	int	used;
+
+	va_start(ap, fmt);
+	vsnprintf(title, sizeof title, fmt, ap);
+	va_end(ap);
+
+	used = snprintf(name, sizeof name, "%s: %s", getprogname(), title);
+	if (used >= (int)sizeof name) {
+		cp = strrchr(name, ' ');
+		if (cp != NULL)
+			*cp = '\0';
+	}
+	prctl(PR_SET_NAME, name);
+}
+#else
+void
+setproctitle(const char *fmt, ...)
+{
+	(void)fmt;
+}
+#endif

configure

@@ -48,7 +48,9 @@ HAVE_EXPLICIT_BZERO=
 HAVE_GETPROGNAME=
 HAVE_LIBTLS=
 HAVE_OPENSSL=
+HAVE_PR_SET_NAME=
 HAVE_RECALLOCARRAY=
+HAVE_SETPROCTITLE=
 HAVE_STRLCAT=
 HAVE_STRLCPY=
 HAVE_STRTONUM=
@@ -219,7 +221,9 @@ runtest explicit_bzero	EXPLICIT_BZERO	|| true
 runtest getprogname	GETPROGNAME	|| true
 runtest libtls		LIBTLS		|| true
 runtest openssl		OPENSSL		|| true
+runtest pr_set_name	PR_SET_NAME	|| true
 runtest recallocarray	RECALLOCARRAY	|| true
+runtest setproctitle	SETPROCTITLE	|| true
 runtest strlcat		STRLCAT		|| true
 runtest strlcpy		STRLCPY		|| true
 runtest strtonum	STRTONUM	|| true
@@ -260,7 +264,9 @@ cat <<__HEREDOC__
 #define HAVE_ERR		${HAVE_ERR}
 #define HAVE_EXPLICIT_BZERO	${HAVE_EXPLICIT_BZERO}
 #define HAVE_GETPROGNAME	${HAVE_GETPROGNAME}
+#define HAVE_PR_SET_NAME	${HAVE_PR_SET_NAME}
 #define HAVE_RECALLOCARRAY	${HAVE_RECALLOCARRAY}
+#define HAVE_SETPROCTITLE	${SETPROCTITLE}
 #define HAVE_STRLCAT		${HAVE_STRLCAT}
 #define HAVE_STRLCPY		${HAVE_STRLCPY}
 #define HAVE_STRTONUM		${HAVE_STRTONUM}
@@ -297,6 +303,10 @@ if [ ${HAVE_RECALLOCARRAY} -eq 0 ]; then
 	echo "extern	void*	 recallocarray(void*, size_t, size_t, size_t);"
 	COMPAT="${COMPAT} compat/recallocarray.o"
 fi
+if [ ${HAVE_SETPROCTITLE} -eq 0 ]; then
+	echo "extern	void	 setproctitle(const char *fmt, ...);"
+	COMPAT="${COMPAT} compat/setproctitle.o"
+fi
 if [ ${HAVE_STRLCAT} -eq 0 ]; then
 	echo "extern	size_t	 strlcat(char*, const char*, size_t);"
 	COMPAT="${COMPAT} compat/strlcat.o"

have/pr_set_name.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/prctl.h>
+
+int
+main(void)
+{
+	prctl(PR_SET_NAME, "foo");
+}

have/setproctitle.c

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+
+int
+main(void)
+{
+	setproctitle("%s", "frobnicator");
+}