[tboot-devel] [PATCH] Ensure txt-acminfo does not print false information if msr is not loaded

[Timo J. L. <tim...@ik...>]

# HG changeset patch
# User Timo Juhani Lindfors <tim...@ik...>
# Date 1590255168 -10800
#      Sat May 23 20:32:48 2020 +0300
# Branch fix/acminfo-without-msr
# Node ID d4591fde44c08fb5a0f1d1531b6df02c7223c67e
# Parent  2ada74557b3db6c13deeda874c20c5132e40c53b
Ensure txt-acminfo does not print false information if msr is not loaded

Previously txt-acminfo would report "ACM does not match platform"
for all ACMs if the msr module was not loaded.

Signed-off-by: Timo Juhani Lindfors <tim...@ik...>

diff -r 2ada74557b3d -r d4591fde44c0 utils/txt-acminfo.c
--- a/utils/txt-acminfo.c	Fri May 15 09:59:23 2020 +0200
+++ b/utils/txt-acminfo.c	Sat May 23 20:32:48 2020 +0300
@@ -39,6 +39,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -75,15 +76,19 @@
     int fd = open("/dev/cpu/0/msr", O_RDONLY);
     if ( fd == -1 ) {
         printf("Error:  failed to open /dev/cpu/0/msr\n");
-        return 0;
+        printf("Perhaps you should modprobe msr?\n");
+        exit(1);
     }
 
     /* lseek() to MSR # */
-    if ( lseek(fd, msr, SEEK_SET) == (off_t)-1 )
+    if ( lseek(fd, msr, SEEK_SET) == (off_t)-1 ) {
         printf("Error:  failed to find MSR 0x%x\n", msr);
-    else {
-        if ( read(fd, &val, sizeof(val)) != sizeof(val) )
+        exit(1);
+    } else {
+        if ( read(fd, &val, sizeof(val)) != sizeof(val) ) {
             printf("Error:  failed to read MSR 0x%x value\n", msr);
+            exit(1);
+        }
     }
 
     close(fd);