virinitctl: Expose fifo paths and allow caller to chose one

So far the virInitctlSetRunLevel() is fully automatic. It finds
the correct fifo to use to talk to the init and it will set the
desired runlevel. Well, callers (so far there is just one) will
need to inspect the fifo a bit just before the runlevel is set.
Therefore, expose the internal list of fifos and also allow
caller to explicitly use one.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 6b401aa5e05ed8c64815daac95ea8dce2967a5f3..67579742fda44c1fd91b96e4275c5e9bc60d0385 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2056,6 +2056,7 @@ virIdentitySetX509DName;
 
 
 # util/virinitctl.h
+virInitctlFifos;
 virInitctlSetRunLevel;
 
 

diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index f7001d2ea45b4ed3973e35a499945d29741159c1..d6be9e87574832e3784b69b12765887b9f89e6b3 100644 (file)
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -3277,7 +3277,7 @@ lxcDomainInitctlCallback(pid_t pid ATTRIBUTE_UNUSED,
                          void *opaque)
 {
     int *command = opaque;
-    return virInitctlSetRunLevel(*command);
+    return virInitctlSetRunLevel(NULL, *command);
 }
 
 

diff --git a/src/util/virinitctl.c b/src/util/virinitctl.c
index 0b06743151a66b07e71f3f999d3b3bdaf22c7cbe..bbcbbb483dcf0eed33677681e7231d3f5e5ad6a3 100644 (file)
--- a/src/util/virinitctl.c
+++ b/src/util/virinitctl.c
@@ -101,7 +101,21 @@ struct virInitctlRequest {
   verify(sizeof(struct virInitctlRequest) == 384);
 # endif
 
-/*
+
+/* List of fifos that inits are known to listen on */
+const char *virInitctlFifos[] = {
+  "/run/initctl",
+  "/dev/initctl",
+  "/etc/.initctl",
+  NULL
+};
+
+
+/**
+ * virInitctlSetRunLevel:
+ * @fifo: the path to fifo that init listens on (can be NULL for autodetection)
+ * @level: the desired runlevel
+ *
  * Send a message to init to change the runlevel. This function is
  * asynchronous-signal-safe (thus safe to use after fork of a
  * multithreaded parent) - which is good, because it should only be
@@ -110,18 +124,14 @@ struct virInitctlRequest {
  * Returns 1 on success, 0 if initctl does not exist, -1 on error
  */
 int
-virInitctlSetRunLevel(virInitctlRunLevel level)
+virInitctlSetRunLevel(const char *fifo,
+                      virInitctlRunLevel level)
 {
     struct virInitctlRequest req;
     int fd = -1;
     int ret = -1;
-    const char *initctl_fifo = NULL;
+    const int open_flags = O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY;
     size_t i = 0;
-    const char *initctl_fifos[] = {
-        "/run/initctl",
-        "/dev/initctl",
-        "/etc/.initctl",
-    };
 
     memset(&req, 0, sizeof(req));
 
@@ -131,31 +141,39 @@ virInitctlSetRunLevel(virInitctlRunLevel level)
     /* Yes it is an 'int' field, but wants a numeric character. Go figure */
     req.runlevel = '0' + level;
 
-    for (i = 0; i < ARRAY_CARDINALITY(initctl_fifos); i++) {
-        initctl_fifo = initctl_fifos[i];
-
-        if ((fd = open(initctl_fifo,
-                       O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY)) >= 0)
-            break;
-
-        if (errno != ENOENT) {
+    if (fifo) {
+        if ((fd = open(fifo, open_flags)) < 0) {
             virReportSystemError(errno,
                                  _("Cannot open init control %s"),
-                                 initctl_fifo);
+                                 fifo);
             goto cleanup;
         }
-    }
+    } else {
+        for (i = 0; virInitctlFifos[i]; i++) {
+            fifo = virInitctlFifos[i];
+
+            if ((fd = open(fifo, open_flags)) >= 0)
+                break;
+
+            if (errno != ENOENT) {
+                virReportSystemError(errno,
+                                     _("Cannot open init control %s"),
+                                     fifo);
+                goto cleanup;
+            }
+        }
 
-    /* Ensure we found a valid initctl fifo */
-    if (fd < 0) {
-        ret = 0;
-        goto cleanup;
+        /* Ensure we found a valid initctl fifo */
+        if (fd < 0) {
+            ret = 0;
+            goto cleanup;
+        }
     }
 
     if (safewrite(fd, &req, sizeof(req)) != sizeof(req)) {
         virReportSystemError(errno,
                              _("Failed to send request to init control %s"),
-                             initctl_fifo);
+                             fifo);
         goto cleanup;
     }
 
@@ -166,7 +184,8 @@ virInitctlSetRunLevel(virInitctlRunLevel level)
     return ret;
 }
 #else
-int virInitctlSetRunLevel(virInitctlRunLevel level ATTRIBUTE_UNUSED)
+int virInitctlSetRunLevel(const char *fifo ATTRIBUTE_UNUSED,
+                          virInitctlRunLevel level ATTRIBUTE_UNUSED)
 {
     virReportUnsupportedError();
     return -1;

diff --git a/src/util/virinitctl.h b/src/util/virinitctl.h
index 7ac627883a9fd021baf65c1894557ab28e29574a..14dda98b5b0969f871251bfca54ca4f3cfce2755 100644 (file)
--- a/src/util/virinitctl.h
+++ b/src/util/virinitctl.h
@@ -33,6 +33,10 @@ typedef enum {
     VIR_INITCTL_RUNLEVEL_LAST
 } virInitctlRunLevel;
 
-int virInitctlSetRunLevel(virInitctlRunLevel level);
+
+extern const char *virInitctlFifos[];
+
+int virInitctlSetRunLevel(const char *fifo,
+                          virInitctlRunLevel level);
 
 #endif /* LIBVIRT_VIRINITCTL_H */