[libvirt] [PATCH 1/2] Implementation deficiency in virInitctlSetRunLevel v4

[Daniel P. Berrange]

On Fri, Dec 20, 2013 at 08:24:41PM +0400, Reco wrote:
> Implement virProcessRunInMountNamespace, which runs callback of type
> virProcessNamespaceCallback in a container namespace.
> 
> Hope it'll nail it this time.
> 
> ---
>  src/libvirt_private.syms |    1 +
>  src/util/virprocess.c    |   63 ++++++++++++++++++++++++++++++++++++++++++++++
>  src/util/virprocess.h    |    6 +++++
>  3 files changed, 70 insertions(+)
> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 2dbb8f8..e210fd0 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1646,6 +1646,7 @@ virProcessGetNamespaces;
>  virProcessGetStartTime;
>  virProcessKill;
>  virProcessKillPainfully;
> +virProcessRunInMountNamespace;
>  virProcessSetAffinity;
>  virProcessSetMaxFiles;
>  virProcessSetMaxMemLock;
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index 9fc3207..7bb494e 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -31,6 +31,7 @@
>  # include <sys/resource.h>
>  #endif
>  #include <sched.h>
> +#include <stdlib.h>
>  
>  #ifdef __FreeBSD__
>  # include <sys/param.h>
> @@ -847,3 +848,65 @@ int virProcessGetStartTime(pid_t pid,
>      return 0;
>  }
>  #endif
> +
> +#ifdef HAVE_SETNS
> +int virProcessRunInMountNamespace(pid_t pid,
> +                                  virProcessNamespaceCallback cb,
> +                                  void *opaque)
> +{
> +    char* path = NULL;
> +    int ret = -1;
> +    int cpid = -1;
> +    int status = -1;
> +    int fd = -1;
> +
> +    if (virAsprintf(&path, "/proc/%llu/ns/mnt",
> +                    (unsigned long long)pid) < 0) {
> +        goto cleanup;
> +    }
> +
> +    if ((fd = open(path, O_RDONLY)) < 0) {
> +        virReportSystemError(errno, "%s",
> +                             _("Kernel does not provide mount namespace"));
> +        goto cleanup;
> +    }
> +
> +    switch (cpid = fork()) {
> +    case 0:
> +        if (setns(fd, 0) == -1) {
> +            _exit(-1);
> +        }
> +
> +        ret = cb(pid, opaque);
> +        _exit(ret);
> +        break;
> +    case -1:
> +        virReportSystemError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                             _("Fork failed"));
> +        goto cleanup;
> +    default:
> +        if (virProcessWait(cpid, &status) < 0 || status < 0) {
> +            virReportSystemError(errno,
> +                                 _("Callback failed with status %i"),
> +                                 status);
> +            ret = 1;
> +        } else {
> +            ret = 0;
> +        }
> +    }
> +
> +cleanup:
> +    VIR_FREE(path);
> +    VIR_FORCE_CLOSE(fd);
> +    return ret;
> +}
> +#else
> +int virProcessRunInMountNamespace(pid_t pid ATTRIBUTE_UNUSED,
> +                                  virProcessNamespaceCallback cb ATTRIBUTE_UNUSED,
> +                                  void *opaque ATTRIBUTE_UNUSED)
> +{
> +    virReportSystemError(ENOSYS, "%s",
> +                         _("Mount namespaces are not available on this platform"));
> +    return -1;
> +}
> +#endif
> diff --git a/src/util/virprocess.h b/src/util/virprocess.h
> index 9f77bc5..205abf7 100644
> --- a/src/util/virprocess.h
> +++ b/src/util/virprocess.h
> @@ -60,4 +60,10 @@ int virProcessSetNamespaces(size_t nfdlist,
>  int virProcessSetMaxMemLock(pid_t pid, unsigned long long bytes);
>  int virProcessSetMaxProcesses(pid_t pid, unsigned int procs);
>  int virProcessSetMaxFiles(pid_t pid, unsigned int files);
> +
> +typedef int (*virProcessNamespaceCallback)(pid_t pid, void *opaque);
> +
> +int virProcessRunInMountNamespace(pid_t pid,
> +                                  virProcessNamespaceCallback cb,
> +                                  void *opaque);
>  #endif /* __VIR_PROCESS_H__ */

ACK

Daniel
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