From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 21 Mar 2018 10:57:26 +0000 (+0100)
Subject: scsi: turn "is this a SCSI device?" into a conditional hint
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=09c2c6ffda7f8f7c64869bc465c2d1715769ebae;p=qemu.git

scsi: turn "is this a SCSI device?" into a conditional hint

If the user does not have permissions to send ioctls to the device (due to
SELinux or cgroups, for example), the output can look like

qemu-kvm: -device scsi-block,drive=disk: cannot get SG_IO version number:
  Operation not permitted.  Is this a SCSI device?

but this is confusing because the ioctl was blocked _before_ the device
even received the SG_GET_VERSION_NUM ioctl.  Therefore, for EPERM errors
the suggestion should be eliminated.  To make that simpler, change the
code to use error_append_hint.

Reported-by: Ala Hino <ahino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 5b7a48f5a5..f5ab767ab5 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2607,9 +2607,10 @@ static void scsi_block_realize(SCSIDevice *dev, Error **errp)
     /* check we are using a driver managing SG_IO (version 3 and after) */
     rc = blk_ioctl(s->qdev.conf.blk, SG_GET_VERSION_NUM, &sg_version);
     if (rc < 0) {
-        error_setg(errp, "cannot get SG_IO version number: %s.  "
-                     "Is this a SCSI device?",
-                     strerror(-rc));
+        error_setg_errno(errp, -rc, "cannot get SG_IO version number");
+        if (rc != -EPERM) {
+            error_append_hint(errp, "Is this a SCSI device?\n");
+        }
         return;
     }
     if (sg_version < 30000) {
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 7414fe2d67..4753f8738f 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -500,9 +500,10 @@ static void scsi_generic_realize(SCSIDevice *s, Error **errp)
     /* check we are using a driver managing SG_IO (version 3 and after */
     rc = blk_ioctl(s->conf.blk, SG_GET_VERSION_NUM, &sg_version);
     if (rc < 0) {
-        error_setg(errp, "cannot get SG_IO version number: %s.  "
-                         "Is this a SCSI device?",
-                         strerror(-rc));
+        error_setg_errno(errp, -rc, "cannot get SG_IO version number");
+        if (rc != -EPERM) {
+            error_append_hint(errp, "Is this a SCSI device?\n");
+        }
         return;
     }
     if (sg_version < 30000) {