w: new applet, alias to "who -H"

function                                             old     new   delta
who_main                                             451     463     +12
packed_usage                                       31477   31485      +8
applet_main                                         1508    1512      +4
applet_names                                        2606    2608      +2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 26/0)               Total: 26 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 44 insertions, 4 deletions

diff --git a/coreutils/who.c b/coreutils/who.c
index e6179bb00..ec9d25159 100644
--- a/coreutils/who.c
+++ b/coreutils/who.c
@@ -23,6 +23,14 @@
 //config:      help
 //config:        who is used to show who is logged on.
 //config:
+// procps-ng has this variation of "who":
+//config:config W
+//config:      bool "w"
+//config:      default y
+//config:      depends on FEATURE_UTMP
+//config:      help
+//config:        w is used to show who is logged on.
+//config:
 //config:config USERS
 //config:      bool "users"
 //config:      default y
@@ -32,7 +40,8 @@
 
 //                APPLET_ODDNAME:name   main location        suid_type     help
 //applet:IF_USERS(APPLET_ODDNAME(users, who, BB_DIR_USR_BIN, BB_SUID_DROP, users))
-//applet:IF_WHO(APPLET(who, BB_DIR_USR_BIN, BB_SUID_DROP))
+//applet:IF_USERS(APPLET_ODDNAME(w,     who, BB_DIR_USR_BIN, BB_SUID_DROP, w))
+//applet:IF_WHO(  APPLET(        who,        BB_DIR_USR_BIN, BB_SUID_DROP))
 
 //kbuild:lib-$(CONFIG_USERS) += who.o
 //kbuild:lib-$(CONFIG_WHO) += who.o
@@ -44,6 +53,31 @@
 //usage:#define users_full_usage "\n\n"
 //usage:       "Print the users currently logged on"
 
+//usage:#define w_trivial_usage
+//usage:       ""
+//usage:#define w_full_usage "\n\n"
+//usage:       "Show who is logged on"
+//
+// procps-ng 3.3.10:
+//           "\n	-h, --no-header"
+//           "\n	-u, --no-current"
+//	Ignores the username while figuring out the current process
+//	and cpu times.  To demonstrate this, do a "su" and do a "w" and a "w -u".
+//           "\n	-s, --short"
+//	Short format.  Don't print the login time, JCPU or PCPU times.
+//           "\n	-f, --from"
+//	Toggle printing the from (remote hostname) field.
+//	The default is for the from field to not be printed
+//           "\n	-i, --ip-addr"
+//	Display IP address instead of hostname for from field.
+//           "\n	-o, --old-style"
+//	Old style output. Prints blank space for idle times less than one minute.
+// Example output:
+//  17:28:00 up 4 days, 22:41,  4 users,  load average: 0.84, 0.97, 0.90
+// USER     TTY        LOGIN@   IDLE   JCPU   PCPU WHAT
+// root     tty1      Thu18    4days  4:33m  0.07s /bin/sh /etc/xdg/xfce4/xinitrc -- vt
+// root     pts/1     Mon13    3:24m  1:01   0.01s w
+
 //usage:#define who_trivial_usage
 //usage:       "[-a]"
 //usage:#define who_full_usage "\n\n"
@@ -74,14 +108,17 @@ static void idle_string(char *str6, time_t t)
 int who_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int who_main(int argc UNUSED_PARAM, char **argv)
 {
+#define CNT_APPLET (ENABLE_USERS + ENABLE_W + ENABLE_WHO)
+	int do_users = (ENABLE_USERS && (CNT_APPLET == 1 || applet_name[0] == 'u'));
+	int do_w     = (ENABLE_W     && (CNT_APPLET == 1 || applet_name[1] == '\0'));
+	int do_who   = (ENABLE_WHO   && (CNT_APPLET == 1 || applet_name[1] == 'h'));
 	struct utmpx *ut;
 	unsigned opt;
-	int do_users = (ENABLE_USERS && (!ENABLE_WHO || applet_name[0] == 'u'));
 	const char *fmt = "%s";
 
 	opt_complementary = "=0";
-	opt = getopt32(argv, do_users ? "" : "aH");
-	if (opt & 2) // -H
+	opt = getopt32(argv, do_who ? "aH" : "");
+	if ((opt & 2) || do_w) /* -H or we are w */
 		puts("USER\t\tTTY\t\tIDLE\tTIME\t\t HOST");
 
 	setutxent();
@@ -115,6 +152,9 @@ int who_main(int argc UNUSED_PARAM, char **argv)
 						(int)sizeof(ut->ut_user), ut->ut_user,
 						(int)sizeof(ut->ut_line), ut->ut_line,
 						str6,
+// TODO: with LANG=en_US.UTF-8, who from coreutils 8.25 shows
+// TIME col as "2017-04-06 18:47" (the default format is "Apr  6 18:47").
+// The former format looks saner to me. Switch to it unconditionally?
 						ctime(&seconds) + 4,
 						(int)sizeof(ut->ut_host), ut->ut_host
 				);