From: Jakub Jirutka <jakub@jirutka.cz>
Date: Mon, 20 Dec 2021 18:52:00 +0100
Subject: [PATCH] Add support for utmps

Allow to link programs that use utmpx.h with utmps by passing relevant -I
and -l flags via variable UTMPX_CFLAGS and UTMPX_LIBS, respectively.
The following programs use utmpx.h: last, login, lslogins, agetty, wall, write.

Programs 'su' and 'runuser' include utmpx.h, but use only btmp which is not
supported on Alpine.

'utmpdump' includes utmpx.h, but doesn't log anything, just parses utmp/wtmp
files, so doesn't need to be linked with utmps.

--- a/include/pathnames.h
+++ b/include/pathnames.h
@@ -214,5 +214,13 @@
 #define _PATH_DEV_RFKILL	"/dev/rfkill"
 #define _PATH_SYS_RFKILL	"/sys/class/rfkill"
 
+#ifdef UTMPS_UTMPX_H
+/* override stub paths from <paths.h> with ones for utmps */
+# undef _PATH_UTMP
+# define _PATH_UTMP		UTMPX_FILE
+# undef _PATH_WTMP
+# define _PATH_WTMP		"/var/log/wtmp"
+#endif
+
 
 #endif /* PATHNAMES_H */
--- a/login-utils/Makemodule.am
+++ b/login-utils/Makemodule.am
@@ -5,7 +5,8 @@
 dist_noinst_DATA += login-utils/last.1.adoc
 MANLINKS += login-utils/lastb.1
 last_SOURCES = login-utils/last.c lib/monotonic.c
-last_LDADD = $(LDADD) libcommon.la $(REALTIME_LIBS)
+last_CFLAGS = $(AM_CFLAGS) $(UTMPX_CFLAGS)
+last_LDADD = $(LDADD) libcommon.la $(UTMPX_LIBS) $(REALTIME_LIBS)
 
 install-exec-hook-last:
 	cd $(DESTDIR)$(usrbin_execdir) && ln -sf last lastb
@@ -61,7 +62,9 @@
 	login-utils/login.c \
 	login-utils/logindefs.c \
 	login-utils/logindefs.h
-login_LDADD = $(LDADD) libcommon.la -lpam
+login_CFLAGS = $(AM_CFLAGS) $(UTMPX_CFLAGS)
+login_LDADD = $(LDADD) libcommon.la $(UTMPX_LIBS) -lpam
+
 if HAVE_LINUXPAM
 login_LDADD += -lpam_misc
 endif
@@ -237,8 +242,8 @@
 	login-utils/lslogins.c \
 	login-utils/logindefs.c \
 	login-utils/logindefs.h
-lslogins_LDADD = $(LDADD) libcommon.la libsmartcols.la
-lslogins_CFLAGS = $(AM_CFLAGS) -I$(ul_libsmartcols_incdir)
+lslogins_LDADD = $(LDADD) libcommon.la libsmartcols.la $(UTMPX_LIBS)
+lslogins_CFLAGS = $(AM_CFLAGS) $(UTMPX_CFLAGS) -I$(ul_libsmartcols_incdir)
 if HAVE_SELINUX
 lslogins_LDADD += -lselinux
 endif
--- a/term-utils/Makemodule.am
+++ b/term-utils/Makemodule.am
@@ -47,10 +47,11 @@
 MANPAGES += term-utils/agetty.8
 dist_noinst_DATA += term-utils/agetty.8.adoc
 agetty_SOURCES = term-utils/agetty.c
+agetty_CFLAGS = $(AM_CFLAGS) $(UTMPX_CFLAGS)
 if USE_PLYMOUTH_SUPPORT
 agetty_SOURCES += lib/plymouth-ctrl.c
 endif
-agetty_LDADD = $(LDADD) libcommon.la
+agetty_LDADD = $(LDADD) libcommon.la $(UTMPX_LIBS)
 if BSD
 agetty_LDADD += -lutil
 endif
@@ -91,9 +92,9 @@
 	term-utils/ttymsg.h
 MANPAGES += term-utils/wall.1
 dist_noinst_DATA += term-utils/wall.1.adoc
-wall_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS)
+wall_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS) $(UTMPX_CFLAGS)
 wall_LDFLAGS = $(SUID_LDFLAGS) $(AM_LDFLAGS)
-wall_LDADD = $(LDADD) libcommon.la
+wall_LDADD = $(LDADD) libcommon.la $(UTMPX_LIBS)
 if USE_TTY_GROUP
 if MAKEINSTALL_DO_CHOWN
 install-exec-hook-wall::
@@ -111,9 +112,9 @@
 MANPAGES += term-utils/write.1
 dist_noinst_DATA += term-utils/write.1.adoc
 write_SOURCES = term-utils/write.c
-write_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS)
+write_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS) $(UTMPX_CFLAGS)
 write_LDFLAGS = $(SUID_LDFLAGS) $(AM_LDFLAGS)
-write_LDADD = $(LDADD) libcommon.la
+write_LDADD = $(LDADD) libcommon.la $(UTMPX_LIBS)
 
 if USE_TTY_GROUP
 if MAKEINSTALL_DO_CHOWN