wall: new applet

text	   data	    bss	    dec	    hex	filename
     81	      0	      0	     81	     51	miscutils/wall.o

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

miscutils/Config.in

@@ -612,6 +612,12 @@ config VOLNAME
 	help
 	  Prints a CD-ROM volume name.
 
+config WALL
+	bool "wall"
+	default n
+	help
+	  Write a message to all users that are logged in.
+
 config WATCHDOG
 	bool "watchdog"
 	default n

miscutils/Kbuild

@@ -42,4 +42,5 @@ lib-$(CONFIG_TIME)        += time.o
 lib-$(CONFIG_TIMEOUT)     += timeout.o
 lib-$(CONFIG_TTYSIZE)     += ttysize.o
 lib-$(CONFIG_VOLNAME)     += volname.o
+lib-$(CONFIG_WALL)        += wall.o
 lib-$(CONFIG_WATCHDOG)    += watchdog.o

miscutils/wall.c

@@ -0,0 +1,36 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * wall - write a message to all logged-in users
+ * Copyright (c) 2009 Bernhard Reutner-Fischer
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+#include <utmp.h>
+
+int wall_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int wall_main(int argc UNUSED_PARAM, char **argv)
+{
+	struct utmp *ut;
+	char *msg;
+	int fd = argv[1] ? xopen(argv[1], O_RDONLY) : STDIN_FILENO;
+
+	msg = xmalloc_read(fd, NULL);
+	if (ENABLE_FEATURE_CLEAN_UP && argv[1])
+		close(fd);
+	setutent();
+	while ((ut = getutent()) != NULL) {
+		char *line;
+		if (ut->ut_type != USER_PROCESS)
+			continue;
+		line = concat_path_file("/dev", ut->ut_line);
+		xopen_xwrite_close(line, msg);
+		free(line);
+	}
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		endutent();
+		free(msg);
+	}
+	return EXIT_SUCCESS;
+}