Change in flashrom[master]: Improve IO permission error messages

[Miklós Márton (Code Review)]

Miklós Márton has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/62878 )

Change subject: Improve IO permission error messages
......................................................................

Improve IO permission error messages

- Display the BSD hints only when compiled for a specific BSD
- On Linux check the user's uid to see if flashrom run with root privileges
- Add a note about the dmesg check if the flashrom run as root and have no
  IO privilege

Change-Id: I6a6f60a5f0ac8f2b51c74661f7dad30571819680
Signed-off-by: Miklós Márton 
---
M hwaccess_x86_io.c
1 file changed, 14 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/78/62878/1

diff --git a/hwaccess_x86_io.c b/hwaccess_x86_io.c
index c3ad313..ed63888 100644
--- a/hwaccess_x86_io.c
+++ b/hwaccess_x86_io.c
@@ -66,6 +66,7 @@

#if defined(__linux__) && !defined(__ANDROID__)
 #include <sys/io.h>
+#include <unistd.h>

#define IO_PORT_PERMISSION USE_IOPL
 #define IO_PORT_FUNCTION USE_LIBC_TARGET_LAST
@@ -261,13 +262,24 @@
    	register_shutdown(platform_release_io_perms, NULL);
    	return 0;
    }
+
    msg_perr("ERROR: Could not get I/O privileges (%s).\n", strerror(errno));
-	msg_perr("Make sure you are root. If you are root, your kernel may still\n"
-		 "prevent access based on security policies.\n");
+#if defined(__linux__) && !defined(__ANDROID__)
+	if (getuid() != 0) {
+		msg_perr("Make sure you are running flashrom with root privileges.\n");
+	} else {
+		msg_perr("Your kernel may prevent access based on security policies.\n"
+		 "Issue a 'dmesg | grep flashrom' for further information\n");
+	}
+#elif defined(__OpenBSD__)
    msg_perr("On OpenBSD set securelevel=-1 in /etc/rc.securelevel and\n"
    	 "reboot, or reboot into single user mode.\n");
+#elif defined(__NetBSD__)
    msg_perr("On NetBSD reboot into single user mode or make sure\n"
    	 "that your kernel configuration has the option INSECURE enabled.\n");
+#else
+	msg_perr("Make sure you are running flashrom with root privileges.\n");
+#endif
    return 1;
 }