[PATCH] tools/xentop: add option to display dom0 first

[Cyril Rébert <slack@xxxxxxxxx>]

Add a command line option to xentop to be able to display dom0 first, on top of 
the list.
This is unconditional, so sorting domains with the S option will also ignore 
dom0.

Signed-off-by: Cyril Rébert (zithro) <slack@xxxxxxxxx>
---
 tools/xentop/xentop.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/tools/xentop/xentop.c b/tools/xentop/xentop.c
index 950e8935c4..9068c53fd2 100644
--- a/tools/xentop/xentop.c
+++ b/tools/xentop/xentop.c
@@ -211,6 +211,7 @@ int show_networks = 0;
 int show_vbds = 0;
 int repeat_header = 0;
 int show_full_name = 0;
+int dom0_first = -1;
 #define PROMPT_VAL_LEN 80
 const char *prompt = NULL;
 char prompt_val[PROMPT_VAL_LEN];
@@ -240,6 +241,7 @@ static void usage(const char *program)
               "-b, --batch          output in batch mode, no user input 
accepted\n"
               "-i, --iterations     number of iterations before exiting\n"
               "-f, --full-name      output the full domain name (not 
truncated)\n"
+              "-z, --dom0-first     display dom0 first (ignore sorting)\n"
               "\n" XENTOP_BUGSTO,
               program);
        return;
@@ -1162,7 +1164,8 @@ void do_vbd(xenstat_domain *domain)
 static void top(void)
 {
        xenstat_domain **domains;
-       unsigned int i, num_domains = 0;
+       unsigned int i, num_domains, sort_start, sort_count = 0;
+       int dom0_index = -1;
 
        /* Now get the node information */
        if (prev_node != NULL)
@@ -1183,11 +1186,27 @@ static void top(void)
        if(domains == NULL)
                fail("Failed to allocate memory\n");
 
-       for (i=0; i < num_domains; i++)
+       for (i=0; i < num_domains; i++) {
                domains[i] = xenstat_node_domain_by_index(cur_node, i);
+               if ( strcmp(xenstat_domain_name(domains[i]), "Domain-0") == 0 )
+                       dom0_index = i;
+       }
+
+       /* Handle dom0 position, not for dom0-less */
+       if ( dom0_first == 1 && dom0_index != -1 ){
+               /* if dom0 is not first in domains, swap it there */
+               if ( dom0_index != 0 ){
+                       xenstat_domain *tmp;
+                       tmp = domains[0];
+                       domains[0] = domains[dom0_index];
+                       domains[dom0_index] = tmp;
+               }
+               sort_start = 1;
+               sort_count = 1;
+       }
 
        /* Sort */
-       qsort(domains, num_domains, sizeof(xenstat_domain *),
+       qsort((domains+sort_start), (num_domains-sort_count), 
sizeof(xenstat_domain *),
              (int(*)(const void *, const void *))compare_domains);
 
        if(first_domain_index >= num_domains)
@@ -1242,9 +1261,10 @@ int main(int argc, char **argv)
                { "batch",         no_argument,       NULL, 'b' },
                { "iterations",    required_argument, NULL, 'i' },
                { "full-name",     no_argument,       NULL, 'f' },
+               { "dom0-first",    no_argument,       NULL, 'z' },
                { 0, 0, 0, 0 },
        };
-       const char *sopts = "hVnxrvd:bi:f";
+       const char *sopts = "hVnxrvd:bi:fz";
 
        if (atexit(cleanup) != 0)
                fail("Failed to install cleanup handler.\n");
@@ -1286,6 +1306,9 @@ int main(int argc, char **argv)
                case 'f':
                        show_full_name = 1;
                        break;
+               case 'z':
+                       dom0_first = 1;
+                       break;
                }
        }
 
-- 
2.39.2