From 44bca4f83d837cc5a044af6911d6cb560962b8ae Mon Sep 17 00:00:00 2001
From: Davin McCall <davmac@davmac.org>
Date: Mon, 5 Nov 2018 11:05:47 +0000
Subject: [PATCH] shutdown: use argv 0 to determine default action.

If called as "reboot", default action is to reboot, otherwise to halt
and power down.
---
 doc/manpages/shutdown.8   | 10 ++++++----
 src/includes/dinit-util.h | 12 ++++++++++++
 src/shutdown.cc           | 26 ++++++++++++++++----------
 3 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/doc/manpages/shutdown.8 b/doc/manpages/shutdown.8
index c19e609..863646d 100644
--- a/doc/manpages/shutdown.8
+++ b/doc/manpages/shutdown.8
@@ -20,6 +20,9 @@ service manager package. See \fBdinit\fR(8).
 The shutdown, reboot and halt commands can be used to instruct the service
 manager daemon to perform a service rollback and then to shutdown the
 system. They can also perform shutdown directly, without service rollback.
+
+Note that for consistency with other packages a "halt" alias is provided,
+however it has no special significance.
 .\"
 .SH OPTIONS
 .TP
@@ -28,12 +31,11 @@ Request a shutdown followed by restart. This is the default if executed as
 \fBreboot\fR.
 .TP
 \fB\-h\fP
-Shutdown and then halt the system. This is the default if executed as
-neither \fBhalt\fR nor \fBreboot\fR.
+Shutdown and then halt the system (without powering down).
 .TP
 \fB\-p\fP
-Shutdown and then power down the system. This is the default if executed as
-\fBhalt\fR.
+Shutdown and then power down the system. This is the default unless executed
+as \fBreboot\fR.
 .TP
 \fB\-\-use\-passed\-cfd\fR
 Instead of attempting to open a socket connection to the service daemon,
diff --git a/src/includes/dinit-util.h b/src/includes/dinit-util.h
index a99e9cb..d9b689c 100644
--- a/src/includes/dinit-util.h
+++ b/src/includes/dinit-util.h
@@ -63,4 +63,16 @@ inline std::string parent_path(const std::string &p)
     return p.substr(0, spos + 1);
 }
 
+// Find the base name of a path (the name after the final '/').
+inline const char * base_name(const char *path)
+{
+    const char * basen = path;
+    const char * s = path;
+    while (*s != 0) {
+        if (*s == '/') basen = s + 1;
+        s++;
+    }
+    return basen;
+}
+
 #endif
diff --git a/src/shutdown.cc b/src/shutdown.cc
index e20858d..947896b 100644
--- a/src/shutdown.cc
+++ b/src/shutdown.cc
@@ -18,6 +18,7 @@
 #include "control-cmds.h"
 #include "service-constants.h"
 #include "dinit-client.h"
+#include "dinit-util.h"
 
 #include "dasynq.h"
 
@@ -246,6 +247,11 @@ int main(int argc, char **argv)
     bool use_passed_cfd = false;
     
     auto shutdown_type = shutdown_type_t::POWEROFF;
+
+    const char *execname = base_name(argv[0]);
+    if (strcmp(execname, "reboot")) {
+        shutdown_type = shutdown_type_t::REBOOT;
+    }
         
     for (int i = 1; i < argc; i++) {
         if (argv[i][0] == '-') {
@@ -281,16 +287,16 @@ int main(int argc, char **argv)
     }
 
     if (show_help) {
-        cout << "dinit-shutdown :   shutdown the system" << endl;
-        cout << "  --help           : show this help" << endl;
-        cout << "  -r               : reboot" << endl;
-        cout << "  -h               : halt system" << endl;
-        cout << "  -p               : power down (default)" << endl;
-        cout << "  --use-passed-cfd : use the socket file descriptor identified by the DINIT_CS_FD" << endl;
-        cout << "                     environment variable to communicate with the init daemon." << endl;
-        cout << "  --system         : perform shutdown immediately, instead of issuing shutdown" << endl;
-        cout << "                     command to the init program. Not recommended for use" << endl;
-        cout << "                     by users." << endl;
+        cout << execname << " :   shutdown the system\n"
+                "  --help           : show this help\n"
+                "  -r               : reboot\n"
+                "  -h               : halt system\n"
+                "  -p               : power down (default)\n"
+                "  --use-passed-cfd : use the socket file descriptor identified by the DINIT_CS_FD\n"
+                "                     environment variable to communicate with the init daemon.\n"
+                "  --system         : perform shutdown immediately, instead of issuing shutdown\n"
+                "                     command to the init program. Not recommended for use\n"
+                "                     by users.\n";
         return 1;
     }
     
-- 
2.25.1