From fbccecb3f0c92880df33bdf6f17d482f97b4de08 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 30 Apr 2018 12:24:57 +0200
Subject: virt: simplifications

Let's simplify the code a bit. Let's reduce the number of redundant if
checks a bit, (i.e. if we want to check for equality with
VIRTUALIZATION_VM_OTHER there's no need to check for non-equality with
VIRTUALIZATION_NONE first). As a very welcome side-effect this means we
lose some lines of code and our level of indentation is reduced.

No changes in behaviour.
---
 src/basic/virt.c | 78 +++++++++++++++++++++++++-------------------------------
 1 file changed, 35 insertions(+), 43 deletions(-)

(limited to 'src/basic/virt.c')

diff --git a/src/basic/virt.c b/src/basic/virt.c
index dfa55c710..3b2f1b917 100644
--- a/src/basic/virt.c
+++ b/src/basic/virt.c
@@ -312,8 +312,8 @@ static int detect_vm_zvm(void) {
 /* Returns a short identifier for the various VM implementations */
 int detect_vm(void) {
         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
-        int r, dmi;
         bool other = false;
+        int r, dmi;
 
         if (cached_found >= 0)
                 return cached_found;
@@ -337,21 +337,19 @@ int detect_vm(void) {
         r = detect_vm_cpuid();
         if (r < 0)
                 return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
-        }
+        if (r == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (r != VIRTUALIZATION_NONE)
+                goto finish;
 
-        r = dmi;
-        if (r < 0)
-                return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
+        /* Now, let's get back to DMI */
+        if (dmi < 0)
+                return dmi;
+        if (dmi == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (dmi != VIRTUALIZATION_NONE) {
+                r = dmi;
+                goto finish;
         }
 
         /* x86 xen will most likely be detected by cpuid. If not (most likely
@@ -363,42 +361,34 @@ int detect_vm(void) {
         r = detect_vm_xen();
         if (r < 0)
                 return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
-        }
+        if (r == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (r != VIRTUALIZATION_NONE)
+                goto finish;
 
         r = detect_vm_hypervisor();
         if (r < 0)
                 return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
-        }
+        if (r == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (r != VIRTUALIZATION_NONE)
+                goto finish;
 
         r = detect_vm_device_tree();
         if (r < 0)
                 return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
-        }
+        if (r == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (r != VIRTUALIZATION_NONE)
+                goto finish;
 
         r = detect_vm_uml();
         if (r < 0)
                 return r;
-        if (r != VIRTUALIZATION_NONE) {
-                if (r == VIRTUALIZATION_VM_OTHER)
-                        other = true;
-                else
-                        goto finish;
-        }
+        if (r == VIRTUALIZATION_VM_OTHER)
+                other = true;
+        else if (r != VIRTUALIZATION_NONE)
+                goto finish;
 
         r = detect_vm_zvm();
         if (r < 0)
@@ -409,10 +399,12 @@ finish:
          * In order to detect the Dom0 as not virtualization we need to
          * double-check it */
         if (r == VIRTUALIZATION_XEN) {
-                int ret = detect_vm_xen_dom0();
-                if (ret < 0)
-                        return ret;
-                if (ret > 0)
+                int dom0;
+
+                dom0 = detect_vm_xen_dom0();
+                if (dom0 < 0)
+                        return dom0;
+                if (dom0 > 0)
                         r = VIRTUALIZATION_NONE;
         } else if (r == VIRTUALIZATION_NONE && other)
                 r = VIRTUALIZATION_VM_OTHER;
-- 
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