[libvirt] [PATCH] xen: ensure /usr/sbin/xend exists before checking status
With xend on the way out, installations may not even have /usr/sbin/xend, which results in the following error when the drivers are probed 2014-04-28 18:21:19.271+0000: 22129: error : virCommandWait:2426 : internal error: Child process (/usr/sbin/xend status) unexpected exit status 127: libvirt: error : cannot execute binary /usr/sbin/xend: No such file or directory Check for existence of /usr/sbin/xend before trying to run it with the 'status' option. Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_driver.c | 19 ++++++++++++------- src/xen/xen_driver.c | 13 ++++++++----- 2 files changed, 20 insertions(+), 12 deletions(-) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index e5ed0f2..8ee61c7 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -223,7 +223,6 @@ static bool libxlDriverShouldLoad(bool privileged) { bool ret = false; - virCommandPtr cmd; int status; char *output = NULL; @@ -236,7 +235,7 @@ libxlDriverShouldLoad(bool privileged) if (!virFileExists(HYPERVISOR_CAPABILITIES)) { VIR_INFO("Disabling driver as " HYPERVISOR_CAPABILITIES " does not exist"); - return false; + return ret; } /* * Don't load if not running on a Xen control domain (dom0). It is not @@ -256,14 +255,20 @@ libxlDriverShouldLoad(bool privileged) } /* Don't load if legacy xen toolstack (xend) is in use */ - cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, &status) == 0 && status == 0) { - VIR_INFO("Legacy xen tool stack seems to be in use, disabling " - "libxenlight driver."); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, &status) == 0 && status == 0) { + VIR_INFO("Legacy xen tool stack seems to be in use, disabling " + "libxenlight driver."); + } else { + ret = true; + } + virCommandFree(cmd); } else { ret = true; } - virCommandFree(cmd); return ret; } diff --git a/src/xen/xen_driver.c b/src/xen/xen_driver.c index 2ffb06b..bd51909 100644 --- a/src/xen/xen_driver.c +++ b/src/xen/xen_driver.c @@ -315,13 +315,16 @@ xenUnifiedProbe(void) static bool xenUnifiedXendProbe(void) { - virCommandPtr cmd; bool ret = false; - cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, NULL) == 0) - ret = true; - virCommandFree(cmd); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, NULL) == 0) + ret = true; + virCommandFree(cmd); + } return ret; } -- 1.8.1.4
On 04/28/2014 12:42 PM, Jim Fehlig wrote:
With xend on the way out, installations may not even have /usr/sbin/xend, which results in the following error when the drivers are probed
2014-04-28 18:21:19.271+0000: 22129: error : virCommandWait:2426 : internal error: Child process (/usr/sbin/xend status) unexpected exit status 127: libvirt: error : cannot execute binary /usr/sbin/xend: No such file or directory
Check for existence of /usr/sbin/xend before trying to run it with the 'status' option.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_driver.c | 19 ++++++++++++------- src/xen/xen_driver.c | 13 ++++++++----- 2 files changed, 20 insertions(+), 12 deletions(-)
@@ -256,14 +255,20 @@ libxlDriverShouldLoad(bool privileged) }
/* Don't load if legacy xen toolstack (xend) is in use */ - cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, &status) == 0 && status == 0) { - VIR_INFO("Legacy xen tool stack seems to be in use, disabling " - "libxenlight driver."); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, &status) == 0 && status == 0) {
Pre-patch, passing &status to virCommandRun had the effect of avoiding a log message if the command ran with non-zero status. But now that we are requiring the file to exist, and in particular, since we are already using NULL later on...
+++ b/src/xen/xen_driver.c @@ -315,13 +315,16 @@ xenUnifiedProbe(void) static bool xenUnifiedXendProbe(void) { - virCommandPtr cmd; bool ret = false;
- cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, NULL) == 0) - ret = true; - virCommandFree(cmd); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, NULL) == 0)
...here, would it make sense to use virCommandRun(cmd, NULL) instead of checking status ourselves? If the intent is still to avoid a logged message when the status is non-zero, a comment in the code might be useful (for example, see how virStorageBackendQEMUImgBackingFormat in storage_backend.c has a comment). ACK with either the code simplification or the added comment. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
Eric Blake wrote:
On 04/28/2014 12:42 PM, Jim Fehlig wrote:
With xend on the way out, installations may not even have /usr/sbin/xend, which results in the following error when the drivers are probed
2014-04-28 18:21:19.271+0000: 22129: error : virCommandWait:2426 : internal error: Child process (/usr/sbin/xend status) unexpected exit status 127: libvirt: error : cannot execute binary /usr/sbin/xend: No such file or directory
Check for existence of /usr/sbin/xend before trying to run it with the 'status' option.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_driver.c | 19 ++++++++++++------- src/xen/xen_driver.c | 13 ++++++++----- 2 files changed, 20 insertions(+), 12 deletions(-)
@@ -256,14 +255,20 @@ libxlDriverShouldLoad(bool privileged) }
/* Don't load if legacy xen toolstack (xend) is in use */ - cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, &status) == 0 && status == 0) { - VIR_INFO("Legacy xen tool stack seems to be in use, disabling " - "libxenlight driver."); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, &status) == 0 && status == 0) {
Pre-patch, passing &status to virCommandRun had the effect of avoiding a log message if the command ran with non-zero status. But now that we are requiring the file to exist, and in particular, since we are already using NULL later on...
+++ b/src/xen/xen_driver.c @@ -315,13 +315,16 @@ xenUnifiedProbe(void) static bool xenUnifiedXendProbe(void) { - virCommandPtr cmd; bool ret = false;
- cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); - if (virCommandRun(cmd, NULL) == 0) - ret = true; - virCommandFree(cmd); + if (virFileExists("/usr/sbin/xend")) { + virCommandPtr cmd; + + cmd = virCommandNewArgList("/usr/sbin/xend", "status", NULL); + if (virCommandRun(cmd, NULL) == 0)
...here, would it make sense to use virCommandRun(cmd, NULL) instead of checking status ourselves?
Yes, I think so. No harm in a log message from virCommandRun on non-zero exit.
If the intent is still to avoid a logged message when the status is non-zero, a comment in the code might be useful (for example, see how virStorageBackendQEMUImgBackingFormat in storage_backend.c has a comment).
ACK with either the code simplification or the added comment.
Code simplified and pushed. Thanks for the review. Regards, Jim
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Eric Blake -
Jim Fehlig