Hi guys,
As I mentioned, we are working in a project that introduces a hook for QEMU.
And when someone installs the RPM/DEB package with this hook,
we need to restart the libvirtd service everytime. It is really
annoying for users.
In my opinion, we can include an #if and #else to compile with inotify support.
But, I don't see any good reason to add.
Julio Cesar Faracco
2016-09-12 21:21 GMT-03:00 Julio Faracco <jcfaracco@xxxxxxxxx>:
> Libvirtd only support hooks when the daemon is started. Hooks cannot be
> loaded when the daemon is already running. So, to load a hook you need to
> restart the service everytime. Now, the inotify support enables the option
> of create a hook and run it even if libvirtd was started.
>
> Cc: Carlos Castilho <ccasti@xxxxxxxxxx>
> Signed-off-by: Julio Faracco <jcfaracco@xxxxxxxxx>
> ---
> daemon/libvirtd.c | 1 +
> src/libvirt_private.syms | 1 +
> src/util/virhook.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++-
> src/util/virhook.h | 10 +++
> 4 files changed, 175 insertions(+), 2 deletions(-)
>
> diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c
> index 95c1b1c..56175d1 100644
> --- a/daemon/libvirtd.c
> +++ b/daemon/libvirtd.c
> @@ -1622,6 +1622,7 @@ int main(int argc, char **argv) {
> 0, "shutdown", NULL, NULL);
>
> cleanup:
> + virHookCleanUp();
> virNetlinkEventServiceStopAll();
> virObjectUnref(remoteProgram);
> virObjectUnref(lxcProgram);
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 6a77e46..c8ad816 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1648,6 +1648,7 @@ virHashValueFree;
> virHookCall;
> virHookInitialize;
> virHookPresent;
> +virHookCleanUp;
>
>
> # util/virhostdev.h
> diff --git a/src/util/virhook.c b/src/util/virhook.c
> index facd74a..d5fc928 100644
> --- a/src/util/virhook.c
> +++ b/src/util/virhook.c
> @@ -26,6 +26,7 @@
> #include <sys/types.h>
> #include <sys/wait.h>
> #include <sys/stat.h>
> +#include <sys/inotify.h>
> #include <unistd.h>
> #include <stdlib.h>
> #include <stdio.h>
> @@ -45,6 +46,10 @@ VIR_LOG_INIT("util.hook");
>
> #define LIBVIRT_HOOK_DIR SYSCONFDIR "/libvirt/hooks"
>
> +#define virHookInstall(driver) virHooksFound |= (1 << driver);
> +
> +#define virHookUninstall(driver) virHooksFound ^= (1 << driver);
> +
> VIR_ENUM_DECL(virHookDriver)
> VIR_ENUM_DECL(virHookDaemonOp)
> VIR_ENUM_DECL(virHookSubop)
> @@ -109,6 +114,8 @@ VIR_ENUM_IMPL(virHookLibxlOp, VIR_HOOK_LIBXL_OP_LAST,
>
> static int virHooksFound = -1;
>
> +static virHookInotifyPtr virHooksInotify = NULL;
> +
> /**
> * virHookCheck:
> * @driver: the driver name "daemon", "qemu", "lxc"...
> @@ -153,6 +160,121 @@ virHookCheck(int no, const char *driver)
> return ret;
> }
>
> +/**
> + * virHookInotifyEvent:
> + * @fd: inotify file descriptor.
> + *
> + * Identifies file events at libvirt's hook directory.
> + * Install or uninstall hooks on demand. Acording file manipulation.
> + */
> +static void
> +virHookInotifyEvent(int watch ATTRIBUTE_UNUSED,
> + int fd,
> + int events ATTRIBUTE_UNUSED,
> + void *data ATTRIBUTE_UNUSED)
> +{
> + char buf[1024];
> + struct inotify_event *e;
> + int got;
> + int driver;
> + char *tmp, *name;
> +
> + VIR_DEBUG("inotify event in virHookInotify()");
> +
> +reread:
> + got = read(fd, buf, sizeof(buf));
> + if (got == -1) {
> + if (errno == EINTR)
> + goto reread;
> + return;
> + }
> +
> + tmp = buf;
> + while (got) {
> + if (got < sizeof(struct inotify_event))
> + return;
> +
> + VIR_WARNINGS_NO_CAST_ALIGN
> + e = (struct inotify_event *)tmp;
> + VIR_WARNINGS_RESET
> +
> + tmp += sizeof(struct inotify_event);
> + got -= sizeof(struct inotify_event);
> +
> + if (got < e->len)
> + return;
> +
> + tmp += e->len;
> + got -= e->len;
> +
> + name = (char *)&(e->name);
> +
> + /* Removing hook file. */
> + if (e->mask & (IN_DELETE | IN_MOVED_FROM)) {
> + if ((driver = virHookDriverTypeFromString(name)) < 0) {
> + VIR_DEBUG("Invalid hook name for %s", name);
> + return;
> + }
> +
> + virHookUninstall(driver);
> + }
> +
> + /* Creating hook file. */
> + if (e->mask & (IN_CREATE | IN_CLOSE_WRITE | IN_MOVED_TO)) {
> + if ((driver = virHookDriverTypeFromString(name)) < 0) {
> + VIR_DEBUG("Invalid hook name for %s", name);
> + return;
> + }
> +
> + virHookInstall(driver);
> + }
> + }
> +}
> +
> +/**
> + * virHookInotifyInit:
> + *
> + * Initialize inotify hooks support.
> + * Enable hooks installation on demand.
> + *
> + * Returns 0 if inotify was successfully installed, -1 in case of failure.
> + */
> +static int
> +virHookInotifyInit(void) {
> +
> + if (VIR_ALLOC(virHooksInotify) < 0)
> + goto error;
> +
> + if ((virHooksInotify->inotifyFD = inotify_init()) < 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("cannot initialize inotify"));
> + goto error;
> + }
> +
> + if ((virHooksInotify->inotifyWatch =
> + inotify_add_watch(virHooksInotify->inotifyFD,
> + LIBVIRT_HOOK_DIR,
> + IN_CREATE | IN_MODIFY | IN_DELETE)) < 0) {
> + virReportSystemError(errno, _("Failed to create inotify watch on %s"),
> + LIBVIRT_HOOK_DIR);
> + goto error;
> + }
> +
> + if ((virHooksInotify->inotifyHandler =
> + virEventAddHandle(virHooksInotify->inotifyFD,
> + VIR_EVENT_HANDLE_READABLE,
> + virHookInotifyEvent, NULL, NULL)) < 0) {
> + VIR_DEBUG("Failed to add inotify handle in virHook.");
> + goto error;
> + }
> +
> + return 0;
> +
> +error:
> + virHookCleanUp();
> + return -1;
> +}
> +
> +
> /*
> * virHookInitialize:
> *
> @@ -174,10 +296,14 @@ virHookInitialize(void)
> return -1;
>
> if (res == 1) {
> - virHooksFound |= (1 << i);
> + virHookInstall(i);
> ret++;
> }
> }
> +
> + if (virHookInotifyInit() < 0)
> + VIR_INFO("Disabling hooks inotify support.");
> +
> return ret;
> }
>
> @@ -309,7 +435,12 @@ virHookCall(int driver,
> if (output)
> virCommandSetOutputBuffer(cmd, output);
>
> - ret = virCommandRun(cmd, NULL);
> + ret = virHookCheck(driver, virHookDriverTypeToString(driver));
> +
> + if (ret > 0) {
> + ret = virCommandRun(cmd, NULL);
> + }
> +
> if (ret < 0) {
> /* Convert INTERNAL_ERROR into known error. */
> virReportError(VIR_ERR_HOOK_SCRIPT_FAILED, "%s",
> @@ -322,3 +453,33 @@ virHookCall(int driver,
>
> return ret;
> }
> +
> +/**
> + * virHookCall:
> + *
> + * Release all structures and data used in virhooks.
> + *
> + * Returns: 0 if the execution succeeded
> + */
> +int
> +virHookCleanUp(void)
> +{
> + if (!virHooksInotify)
> + return -1;
> +
> + if ((virHooksInotify->inotifyFD >= 0) &&
> + (virHooksInotify->inotifyWatch >= 0))
> + if (inotify_rm_watch(virHooksInotify->inotifyFD,
> + virHooksInotify->inotifyWatch) < 0)
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Cannot remove inotify watcher."));
> +
> + if (virHooksInotify->inotifyHandler >= 0)
> + virEventRemoveHandle(virHooksInotify->inotifyHandler);
> +
> + VIR_FORCE_CLOSE(virHooksInotify->inotifyFD);
> + VIR_FREE(virHooksInotify);
> +
> + virHooksFound = -1;
> +
> + return 0;
> +}
> diff --git a/src/util/virhook.h b/src/util/virhook.h
> index 205249c..47a32c7 100644
> --- a/src/util/virhook.h
> +++ b/src/util/virhook.h
> @@ -100,6 +100,14 @@ typedef enum {
> VIR_HOOK_LIBXL_OP_LAST,
> } virHookLibxlOpType;
>
> +struct _virHookInotify {
> + int inotifyFD;
> + int inotifyWatch;
> + int inotifyHandler;
> +};
> +
> +typedef struct _virHookInotify *virHookInotifyPtr;
> +
> int virHookInitialize(void);
>
> int virHookPresent(int driver);
> @@ -107,4 +115,6 @@ int virHookPresent(int driver);
> int virHookCall(int driver, const char *id, int op, int sub_op,
> const char *extra, const char *input, char **output);
>
> +int virHookCleanUp(void);
> +
> #endif /* __VIR_HOOKS_H__ */
> --
> 2.7.4
>
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list