[PATCH] [v2] libxl: Add API to retrieve domain console tty

[Bamvor Jian Zhang <bjzhang@suse.com>]

This api retrieve domain console from xenstore. With this new api, it is easy to implement "virsh console" command in libvirt libxl driver.

Signed-off-by: Bamvor Jian Zhang <bjzhang@suse.com>

Changes since v1:
 * Replace function libxl__sprintf with macro GSPRINTF
 * check return value and handle error for libxl__xs_read and libxl__domain_type
 * merge common code for libxl_primary_console_get_tty and
   libxl_primary_console_exec as libxl__primary_console_find
 * Reformat code to be less than 80 characters.

diff -r ab86fc0e2b45 -r d67ab7c543d5 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c	Tue May 22 11:55:02 2012 +0100
+++ b/tools/libxl/libxl.c	Wed May 23 14:27:57 2012 +0800
@@ -1188,7 +1188,8 @@ out:
     return rc;
 }
 
-int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num, libxl_console_type type)
+int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num,
+                       libxl_console_type type)
 {
     GC_INIT(ctx);
     char *p = libxl__sprintf(gc, "%s/xenconsole", libxl__private_bindir_path());
@@ -1214,24 +1215,74 @@ out:
     return ERROR_FAIL;
 }
 
-int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm)
+int libxl_console_get_tty(libxl_ctx *ctx, uint32_t domid, int cons_num, 
+                          libxl_console_type type, char **path)
+{
+    GC_INIT(ctx);
+    char *dom_path = 0;
+    char *tty_path = 0;
+    char *tty = 0;
+    int rc = 0;
+
+    dom_path = libxl__xs_get_dompath(gc, domid);
+    if (!dom_path) {
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    switch (type) {
+    case LIBXL_CONSOLE_TYPE_SERIAL:
+        tty_path = GCSPRINTF("%s/serial/0/tty", dom_path);
+        break;
+    case LIBXL_CONSOLE_TYPE_PV:
+        if (cons_num == 0)
+            tty_path = GCSPRINTF("%s/console/tty", dom_path);
+        else
+            tty_path = GCSPRINTF("%s/device/console/%d/tty", dom_path, 
+                                cons_num);
+        break;
+    default:
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    tty = libxl__xs_read(gc, XBT_NULL, tty_path);
+    if (tty) 
+        *path = strdup(tty);
+    else
+        rc = ERROR_FAIL;
+
+out:
+    GC_FREE;
+    return rc;
+}
+
+static int libxl__primary_console_find(libxl_ctx *ctx, uint32_t domid_vm, 
+                                       uint32_t *domid_out, int *cons_num_out, 
+                                       libxl_console_type *type_out)
 {
     GC_INIT(ctx);
     uint32_t stubdomid = libxl_get_stubdom_id(ctx, domid_vm);
-    int rc;
-    if (stubdomid)
-        rc = libxl_console_exec(ctx, stubdomid,
-                                STUBDOM_CONSOLE_SERIAL, LIBXL_CONSOLE_TYPE_PV);
-    else {
+    int rc = 0;
+
+    if (stubdomid) {
+        *domid_out = stubdomid;
+        *cons_num_out = STUBDOM_CONSOLE_SERIAL;
+        *type_out = LIBXL_CONSOLE_TYPE_PV;
+    } else {
         switch (libxl__domain_type(gc, domid_vm)) {
         case LIBXL_DOMAIN_TYPE_HVM:
-            rc = libxl_console_exec(ctx, domid_vm, 0, LIBXL_CONSOLE_TYPE_SERIAL);
+            *domid_out = domid_vm;
+            *cons_num_out = 0;
+            *type_out = LIBXL_CONSOLE_TYPE_SERIAL;
             break;
         case LIBXL_DOMAIN_TYPE_PV:
-            rc = libxl_console_exec(ctx, domid_vm, 0, LIBXL_CONSOLE_TYPE_PV);
+            *domid_out = domid_vm;
+            *cons_num_out = 0;
+            *type_out = LIBXL_CONSOLE_TYPE_PV;
             break;
         case -1:
-            LOG(ERROR,"unable to get domain type for domid=%"PRIu32,domid_vm);
+            LOG(ERROR,"unable to get domain type for domid=%"PRIu32, domid_vm);
             rc = ERROR_FAIL;
             break;
         default:
@@ -1242,6 +1293,33 @@ int libxl_primary_console_exec(libxl_ctx
     return rc;
 }
 
+int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm)
+{
+    uint32_t domid_out;
+    int cons_num_out;
+    libxl_console_type type_out;
+    int rc;
+
+    rc = libxl__primary_console_find(ctx, domid_vm, &domid_out, &cons_num_out, 
+                                     &type_out);
+    if ( rc ) return rc;
+    return libxl_console_exec(ctx, domid_out, cons_num_out, type_out);
+}
+
+int libxl_primary_console_get_tty(libxl_ctx *ctx, uint32_t domid_vm,
+                                  char **path)
+{
+    uint32_t domid_out;
+    int cons_num_out;
+    libxl_console_type type_out;
+    int rc;
+
+    rc = libxl__primary_console_find(ctx, domid_vm, &domid_out, &cons_num_out, 
+                                     &type_out);
+    if ( rc ) return rc;
+    return libxl_console_get_tty(ctx, domid_out, cons_num_out, type_out, path);
+}
+
 int libxl_vncviewer_exec(libxl_ctx *ctx, uint32_t domid, int autopass)
 {
     GC_INIT(ctx);
diff -r ab86fc0e2b45 -r d67ab7c543d5 tools/libxl/libxl.h
--- a/tools/libxl/libxl.h	Tue May 22 11:55:02 2012 +0100
+++ b/tools/libxl/libxl.h	Wed May 23 14:27:57 2012 +0800
@@ -601,6 +601,16 @@ int libxl_console_exec(libxl_ctx *ctx, u
  * case of HVM guests, and before libxl_run_bootloader in case of PV
  * guests using pygrub. */
 int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm);
+/* libxl_console_get_tty retrieves the specified domain's console tty path
+ * and stores it in path. Caller is responsible for freeing the memory.
+ */
+int libxl_console_get_tty(libxl_ctx *ctx, uint32_t domid, int cons_num, 
+                          libxl_console_type type, char **path);
+/* libxl_primary_console_get_tty retrieves the specified domain's primary 
+ * console tty path and stores it in path. Caller is responsible for freeing
+ * the memory.
+ */
+int libxl_primary_console_get_tty(libxl_ctx *ctx, uint32_t domid_vm, char **path);
 
 /* May be called with info_r == NULL to check for domain's existance */
 int libxl_domain_info(libxl_ctx*, libxl_dominfo *info_r,