[PATCH v3 1/6] xl: Return proper error codes for block-attach and block-detach

[George Dunlap <george.dunlap@eu.citrix.com>]

Return proper error codes on failure so that scripts can tell whether
the command completed properly or not.

Also while we're at it, normalize init and dispose of
libxl_device_disk structures.  This means calling init and dispose in
the actual functions where they are declared.

This in turn means changing parse_disk_config_multistring() to not
call libxl_device_disk_init.  And that in turn means changes to
callers of parse_disk_config().

It also means removing libxl_device_disk_init() from
libxl.c:libxl_vdev_to_device_disk().  This is only called from
xl_cmdimpl.c.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
---
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Konrad Wilk <konrad.wilk@oracle.com>

v3:
 - Rebased to tip

v2:
 - Restructure functions to make sure init and dispose are properly
 called.
---
 tools/libxl/libxl.c      |  2 --
 tools/libxl/xl_cmdimpl.c | 29 ++++++++++++++++++++---------
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index bd3aac8..814d056 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2738,8 +2738,6 @@ int libxl_vdev_to_device_disk(libxl_ctx *ctx, uint32_t domid,
     if (devid < 0)
         return ERROR_INVAL;
 
-    libxl_device_disk_init(disk);
-
     dompath = libxl__xs_get_dompath(gc, domid);
     if (!dompath) {
         goto out;
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 2b6371d..2ba2393 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -570,8 +570,6 @@ static void parse_disk_config_multistring(XLU_Config **config,
 {
     int e;
 
-    libxl_device_disk_init(disk);
-
     if (!*config) {
         *config = xlu_cfg_init(stderr, "command line");
         if (!*config) { perror("xlu_cfg_init"); exit(-1); }
@@ -3340,6 +3338,8 @@ static int cd_insert(uint32_t domid, const char *virtdev, char *phys)
     xasprintf(&buf, "vdev=%s,access=r,devtype=cdrom,target=%s",
               virtdev, phys ? phys : "");
 
+    libxl_device_disk_init(&disk);
+
     parse_disk_config(&config, buf, &disk);
 
     /* ATM the existence of the backing file is not checked for qdisk
@@ -6649,6 +6649,7 @@ int main_blockattach(int argc, char **argv)
     uint32_t fe_domid;
     libxl_device_disk disk;
     XLU_Config *config = 0;
+    int rc = 0;
 
     SWITCH_FOREACH_OPT(opt, "", NULL, "block-attach", 2) {
         /* No options */
@@ -6660,6 +6661,8 @@ int main_blockattach(int argc, char **argv)
     }
     optind++;
 
+    libxl_device_disk_init(&disk);
+
     parse_disk_config_multistring
         (&config, argc-optind, (const char* const*)argv + optind, &disk);
 
@@ -6668,14 +6671,17 @@ int main_blockattach(int argc, char **argv)
         printf("disk: %s\n", json);
         free(json);
         if (ferror(stdout) || fflush(stdout)) { perror("stdout"); exit(-1); }
-        return 0;
+        goto out;
     }
 
     if (libxl_device_disk_add(ctx, fe_domid, &disk, 0)) {
         fprintf(stderr, "libxl_device_disk_add failed.\n");
-        return 1;
+        rc = 1;
     }
-    return 0;
+out:
+    libxl_device_disk_dispose(&disk);
+
+    return rc;
 }
 
 int main_blocklist(int argc, char **argv)
@@ -6726,18 +6732,23 @@ int main_blockdetach(int argc, char **argv)
         /* No options */
     }
 
+    libxl_device_disk_init(&disk);
+
     domid = find_domain(argv[optind]);
 
     if (libxl_vdev_to_device_disk(ctx, domid, argv[optind+1], &disk)) {
         fprintf(stderr, "Error: Device %s not connected.\n", argv[optind+1]);
-        return 1;
+        rc = 1;
+        goto out;
     }
-    rc = libxl_device_disk_remove(ctx, domid, &disk, 0);
-    if (rc) {
+    if (libxl_device_disk_remove(ctx, domid, &disk, 0)) {
         fprintf(stderr, "libxl_device_disk_remove failed.\n");
-        return 1;
+        rc = 1;
     }
+
+out:
     libxl_device_disk_dispose(&disk);
+
     return rc;
 }
 
-- 
2.1.4