systemctl: implement auto-pager a la git

[elogind.git] / src / systemctl.c

diff --git a/src/systemctl.c b/src/systemctl.c
index 0948e619ce3cb0124983ded400f4bea2ff38a5b4..585f1dc5fee1d56670a9c0089187a78ead227013 100644 (file)
--- a/src/systemctl.c
+++ b/src/systemctl.c
@@ -65,6 +65,7 @@ static bool arg_user = false;
 static bool arg_global = false;
 static bool arg_immediate = false;
 static bool arg_no_block = false;
+static bool arg_no_pager = false;
 static bool arg_no_wtmp = false;
 static bool arg_no_sync = false;
 static bool arg_no_wall = false;
@@ -2338,7 +2339,7 @@ static int print_property(const char *name, DBusMessageIter *iter) {
         return 0;
 }
 
-static int show_one(DBusConnection *bus, const char *path, bool show_properties, bool *new_line) {
+static int show_one(const char *verb, DBusConnection *bus, const char *path, bool show_properties, bool *new_line) {
         DBusMessage *m = NULL, *reply = NULL;
         const char *interface = "";
         int r;
@@ -2438,7 +2439,8 @@ static int show_one(DBusConnection *bus, const char *path, bool show_properties,
                 print_status_info(&info);
 
         if (!streq_ptr(info.active_state, "active") &&
-            !streq_ptr(info.active_state, "reloading"))
+            !streq_ptr(info.active_state, "reloading") &&
+            streq(verb, "status"))
                 /* According to LSB: "program not running" */
                 r = 3;
 
@@ -2477,7 +2479,7 @@ static int show(DBusConnection *bus, char **args, unsigned n) {
                 /* If not argument is specified inspect the manager
                  * itself */
 
-                ret = show_one(bus, "/org/freedesktop/systemd1", show_properties, &new_line);
+                ret = show_one(args[0], bus, "/org/freedesktop/systemd1", show_properties, &new_line);
                 goto finish;
         }
 
@@ -2611,7 +2613,7 @@ static int show(DBusConnection *bus, char **args, unsigned n) {
                         goto finish;
                 }
 
-                if ((r = show_one(bus, path, show_properties, &new_line)) != 0)
+                if ((r = show_one(args[0], bus, path, show_properties, &new_line)) != 0)
                         ret = r;
 
                 dbus_message_unref(m);
@@ -4109,6 +4111,7 @@ static int systemctl_help(void) {
                "                      pending\n"
                "  -q --quiet          Suppress output\n"
                "     --no-block       Do not wait until operation finished\n"
+               "     --no-pager       Do not pipe output into a pager.\n"
                "     --system         Connect to system manager\n"
                "     --user           Connect to user service manager\n"
                "     --order          When generating graph for dot, show only order\n"
@@ -4248,6 +4251,7 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                 ARG_SYSTEM,
                 ARG_GLOBAL,
                 ARG_NO_BLOCK,
+               ARG_NO_PAGER,
                 ARG_NO_WALL,
                 ARG_ORDER,
                 ARG_REQUIRE,
@@ -4271,6 +4275,7 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                 { "system",    no_argument,       NULL, ARG_SYSTEM    },
                 { "global",    no_argument,       NULL, ARG_GLOBAL    },
                 { "no-block",  no_argument,       NULL, ARG_NO_BLOCK  },
+                { "no-pager",  no_argument,       NULL, ARG_NO_PAGER  },
                 { "no-wall",   no_argument,       NULL, ARG_NO_WALL   },
                 { "quiet",     no_argument,       NULL, 'q'           },
                 { "order",     no_argument,       NULL, ARG_ORDER     },
@@ -4347,6 +4352,10 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                         arg_no_block = true;
                         break;
 
+               case ARG_NO_PAGER:
+                       arg_no_pager = true;
+                       break;
+
                 case ARG_NO_WALL:
                         arg_no_wall = true;
                         break;
@@ -5273,6 +5282,48 @@ static int runlevel_main(void) {
         return 0;
 }
 
+static void pager_open(void) {
+       pid_t pid;
+       int fd[2];
+       const char *pager = getenv("PAGER");
+
+       if (!on_tty() || arg_no_pager)
+               return;
+       if (!pager)
+               pager = "less";
+       else if (!*pager || !strcmp(pager, "cat"))
+               return;
+
+       if (pipe(fd) < 0)
+               return;
+       pid = fork();
+       if (pid < 0) {
+               close(fd[0]);
+               close(fd[1]);
+               return;
+       }
+
+       /* Return in the child */
+       if (!pid) {
+               dup2(fd[1], 1);
+               close(fd[0]);
+               close(fd[1]);
+               return;
+       }
+
+       /* The original process turns into the PAGER */
+       dup2(fd[0], 0);
+       close(fd[0]);
+       close(fd[1]);
+
+       setenv("LESS", "FRSX", 0);
+       execlp(pager, pager, NULL);
+       execl("/bin/sh", "sh", "-c", pager, NULL);
+
+       log_error("unable to execute pager '%s'", pager);
+       _exit(EXIT_FAILURE);
+}
+
 int main(int argc, char*argv[]) {
         int r, retval = EXIT_FAILURE;
         DBusConnection *bus = NULL;
@@ -5290,6 +5341,8 @@ int main(int argc, char*argv[]) {
                 goto finish;
         }
 
+       pager_open();
+
         /* /sbin/runlevel doesn't need to communicate via D-Bus, so
          * let's shortcut this */
         if (arg_action == ACTION_RUNLEVEL) {