qga: Add 'guest-get-users' command

A command that will list all currently logged in users, and the time
since when they are logged in.

Examples:

virsh # qemu-agent-command F25 '{ "execute": "guest-get-users" }'
{"return":[{"login-time":1490622289.903835,"user":"root"}]}

virsh # qemu-agent-command Win2k12r2 '{ "execute": "guest-get-users" }'
{"return":[{"login-time":1490351044.670552,"domain":"LADIDA",
"user":"Administrator"}]}

Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
* make g_hash_table_contains compat func inline to avoid
  unused warnings
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 915df9ed90..ba06be4c86 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -15,6 +15,7 @@
 #include <sys/ioctl.h>
 #include <sys/wait.h>
 #include <dirent.h>
+#include <utmpx.h>
 #include "qga/guest-agent-core.h"
 #include "qga-qmp-commands.h"
 #include "qapi/qmp/qerror.h"
@@ -2517,3 +2518,62 @@ void ga_command_state_init(GAState *s, GACommandState *cs)
     ga_command_state_add(cs, NULL, guest_fsfreeze_cleanup);
 #endif
 }
+
+#define QGA_MICRO_SECOND_TO_SECOND 1000000
+
+static double ga_get_login_time(struct utmpx *user_info)
+{
+    double seconds = (double)user_info->ut_tv.tv_sec;
+    double useconds = (double)user_info->ut_tv.tv_usec;
+    useconds /= QGA_MICRO_SECOND_TO_SECOND;
+    return seconds + useconds;
+}
+
+GuestUserList *qmp_guest_get_users(Error **err)
+{
+    GHashTable *cache = NULL;
+    GuestUserList *head = NULL, *cur_item = NULL;
+    struct utmpx *user_info = NULL;
+    gpointer value = NULL;
+    GuestUser *user = NULL;
+    GuestUserList *item = NULL;
+    double login_time = 0;
+
+    cache = g_hash_table_new(g_str_hash, g_str_equal);
+    setutxent();
+
+    for (;;) {
+        user_info = getutxent();
+        if (user_info == NULL) {
+            break;
+        } else if (user_info->ut_type != USER_PROCESS) {
+            continue;
+        } else if (g_hash_table_contains(cache, user_info->ut_user)) {
+            value = g_hash_table_lookup(cache, user_info->ut_user);
+            user = (GuestUser *)value;
+            login_time = ga_get_login_time(user_info);
+            /* We're ensuring the earliest login time to be sent */
+            if (login_time < user->login_time) {
+                user->login_time = login_time;
+            }
+            continue;
+        }
+
+        item = g_new0(GuestUserList, 1);
+        item->value = g_new0(GuestUser, 1);
+        item->value->user = g_strdup(user_info->ut_user);
+        item->value->login_time = ga_get_login_time(user_info);
+
+        g_hash_table_insert(cache, item->value->user, item->value);
+
+        if (!cur_item) {
+            head = cur_item = item;
+        } else {
+            cur_item->next = item;
+            cur_item = item;
+        }
+    }
+    endutxent();
+    g_hash_table_destroy(cache);
+    return head;
+}