lslogins: return 1 on "lslogins nonexisting"

The default behavior for -l and -g is to silently ignore unknown login
names, but this is very confusing when you explicitly specify just one
login name.

Note that the current implementation also prints empty "Last log" for
nonexisting user. It seems ugly.

 # lslogins nonexisting

 Last logs:

new version:

 # lslogins nonexisting
 lt-lslogins: cannot found 'nonexisting'
 # echo $?
 1

The -l and -g behaviour has not been changed.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1614967
Signed-off-by: Karel Zak <kzak@redhat.com>

2 files changed, 15 insertions, 4 deletions

diff --git a/login-utils/lslogins.1 b/login-utils/lslogins.1
index 001ec10f7..5aa14c706 100644
--- a/login-utils/lslogins.1
+++ b/login-utils/lslogins.1
@@ -18,7 +18,8 @@ and output the desired data.
 The optional argument \fIusername\fR forces
 .BR lslogins
 to print all available details about the specified user only. In this case the
-output format is different than in case of \fB\-l\fR or \fB\-g\fR.
+output format is different than in case of \fB\-l\fR or \fB\-g\fR and unknown
+is \fIusername\fR reported as an error.
 
 .PP
 The default action is to list info about all the users in the system.
diff --git a/login-utils/lslogins.c b/login-utils/lslogins.c
index ea40ab615..e2a0d43df 100644
--- a/login-utils/lslogins.c
+++ b/login-utils/lslogins.c
@@ -269,6 +269,7 @@ struct lslogins_control {
 	const char *journal_path;
 
 	unsigned int selinux_enabled : 1,
+		     fail_on_unknown : 1,		/* fail if user does not exist */
 		     ulist_on : 1,
 		     noheadings : 1,
 		     notrunc : 1;
@@ -656,6 +657,7 @@ static struct lslogins_user *get_user_info(struct lslogins_control *ctl, const c
 	uid_t uid;
 	errno = 0;
 
+	errno = 0;
 	pwd = username ? getpwnam(username) : getpwent();
 	if (!pwd)
 		return NULL;
@@ -678,6 +680,7 @@ static struct lslogins_user *get_user_info(struct lslogins_control *ctl, const c
 		return NULL;
 	}
 
+	errno = 0;
 	grp = getgrgid(pwd->pw_gid);
 	if (!grp)
 		return NULL;
@@ -977,10 +980,16 @@ static int create_usertree(struct lslogins_control *ctl)
 
 	if (ctl->ulist_on) {
 		for (n = 0; n < ctl->ulsiz; n++) {
-			if (get_user(ctl, &user, ctl->ulist[n]))
+			int rc = get_user(ctl, &user, ctl->ulist[n]);
+
+			if (ctl->fail_on_unknown && !user) {
+				warnx(_("cannot found '%s'"), ctl->ulist[n]);
+				return -1;
+			}
+			if (rc || !user)
 				continue;
-			if (user) /* otherwise an invalid user name has probably been given */
-				tsearch(user, &ctl->usertree, cmp_uid);
+
+			tsearch(user, &ctl->usertree, cmp_uid);
 		}
 	} else {
 		while ((user = get_next_user(ctl)))
@@ -1537,6 +1546,7 @@ int main(int argc, char *argv[])
 			errx(EXIT_FAILURE, _("Only one user may be specified. Use -l for multiple users."));
 		logins = argv[optind];
 		outmode = OUT_PRETTY;
+		ctl->fail_on_unknown = 1;
 	} else if (argc != optind)
 		errx(EXIT_FAILURE, _("Only one user may be specified. Use -l for multiple users."));