nwho: Output is now sorted as specified by command-line options

diff --git a/nwho.c b/nwho.c
index b7c932c3b3487c6d9f4684a4b3d7e206eb5652af..7e89b652ec318b8be8a8aa54d3a4d0d9c24e2de0 100644 (file)
--- a/nwho.c
+++ b/nwho.c
@@ -12,10 +12,10 @@
 #include <dirent.h>
 #include <time.h>
 #include <netinet/in.h>
+#include <getopt.h>
 
 #include "nwho.h"
 
-static int is_uptime;
 static time_t now;
 
 struct out_host {
@@ -80,6 +80,43 @@ new_user(struct out_host *host, struct userinfo *ui)
   };
 }
 
+static int
+cmp_users_by_hosts(const void *va, const void *vb)
+{
+  const struct out_user *a = va;
+  const struct out_user *b = vb;
+  return strcmp(a->host->name, b->host->name);
+}
+
+static int
+cmp_users_by_names(const void *va, const void *vb)
+{
+  const struct out_user *a = va;
+  const struct out_user *b = vb;
+  return strcmp(a->user->name, b->user->name);
+}
+
+static void
+sort_users(int by_hosts)
+{
+  qsort(user_array, num_users, sizeof(user_array[0]),
+    (by_hosts ? cmp_users_by_hosts : cmp_users_by_names));
+}
+
+static int
+cmp_hosts(const void *va, const void *vb)
+{
+  const struct out_host * const *a = va;
+  const struct out_host * const *b = vb;
+  return strcmp((*a)->name, (*b)->name);
+}
+
+static void
+sort_hosts(void)
+{
+  qsort(host_array, num_hosts, sizeof(host_array[0]), cmp_hosts);
+}
+
 static void
 puttime(int s)
 {
@@ -202,6 +239,20 @@ scan(void)
   closedir(d);
 }
 
+static void
+usage(void)
+{
+  printf("\
+Usage: nwho <options>\n\
+   or: nuptime <options>\n\
+\n\
+Options:\n\
+-h     Sort user list by hosts (default: by users)\n\
+-u     Display host uptimes (default if called as `nuptime')\n\
+");
+  exit(0);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -210,13 +261,30 @@ main(int argc, char **argv)
       printf("nwho " STRINGIFY(VERSION) "\n");
       return 0;
     }
+  if (argc == 2 && !strcmp(argv[1], "--help"))
+    usage();
+
+  int opt;
+  int uptime_mode = !!strstr(argv[0], "uptime");
+  int want_sort_by_hosts = 0;
 
-  if (strstr(argv[0], "uptime"))
-    is_uptime = 1;
-  if (argc != 1)
+  while ((opt = getopt(argc, argv, "hu")) >= 0)
+    switch (opt)
+      {
+      case 'h':
+       want_sort_by_hosts = 1;
+       break;
+      case 'u':
+       uptime_mode = 1;
+       break;
+      default:
+       fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
+       exit(1);
+      }
+  if (optind < argc)
     {
-      fprintf(stderr, "Usage: %s\n", argv[0]);
-      return 1;
+      fprintf(stderr, "This program does not need any arguments. Try `%s --help' for more information.\n", argv[0]);
+      exit(1);
     }
 
   now = time(NULL);
@@ -227,9 +295,15 @@ main(int argc, char **argv)
       return 0;
     }
 
-  if (!is_uptime)
-    show_users();
+  if (!uptime_mode)
+    {
+      sort_users(want_sort_by_hosts);
+      show_users();
+    }
   else
-    show_uptime();
+    {
+      sort_hosts();
+      show_uptime();
+    }
   return 0;
 }