Re: Using "xl create" without domain config file

["W. Michael Petullo" <mike@flyn.org>]

[...]
> Thanks, this is going in the right direction I think.  Just two
> niggles:
 
>> diff -r 435493696053 tools/libxl/xl_cmdimpl.c
>> --- a/tools/libxl/xl_cmdimpl.c  Fri May 25 08:18:47 2012 +0100
>> +++ b/tools/libxl/xl_cmdimpl.c  Thu Jun 07 22:40:58 2012 -0500
>> @@ -1454,10 +1454,13 @@ static int create_domain(struct domain_c
>> 
>>      if (config_file) {
>>          free(config_data);  config_data = 0;
[...]
>> +        // /dev/null represents special case (read config. from command line)
 
> libxl coding style uses /*...*/ comments.
 
>> +        if (strcmp(config_file, "/dev/null")) {
>> +            ret = libxl_read_file_contents(&ctx, config_file,
>> +                                           &config_data, &config_len);
 
> I think this fails to set config_len to 0 in the /dev/null case, which
> it should do.  Although config_len is initialised to 0 it may have
> been set to a non-0 value from the length of the old config file if
> we're doing a restore, and in this case it needs to be rezeroed.
 
>> +            if (ret) { fprintf(stderr, "Failed to read config file: %s: %s\n",
>> +                               config_file, strerror(errno)); return ERROR_FAIL; }
>> +        }
>>          if (!restore_file && extra_config && strlen(extra_config)) {
>>              if (config_len > INT_MAX - (strlen(extra_config) + 2 + 1)) {
>>                  fprintf(stderr, "Failed to attach extra configration\n");

This version addresses the two issues above:

# HG changeset patch
# Parent 435493696053a079ec17d6e1a63e5f2be3a2c9d0
xl: Allow use of /dev/null with xl create to enable command-line definition

xm allows specifying /dev/null as the domain configuration argument to its
create option; add same functionality to xl. xl treats the configuration
argument /dev/null as a special case.  This allows specifying an entire
domain configuration on the command line.

Signed-off-by: W. Michael Petullo <mike@flyn.org>

diff -r 435493696053 tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c	Fri May 25 08:18:47 2012 +0100
+++ b/tools/libxl/xl_cmdimpl.c	Mon Jun 11 15:18:23 2012 -0500
@@ -1454,10 +1454,15 @@ static int create_domain(struct domain_c
 
     if (config_file) {
         free(config_data);  config_data = 0;
-        ret = libxl_read_file_contents(&ctx, config_file,
-                                       &config_data, &config_len);
-        if (ret) { fprintf(stderr, "Failed to read config file: %s: %s\n",
-                           config_file, strerror(errno)); return ERROR_FAIL; }
+        /* /dev/null represents special case (read config. from command line) */
+        if (!strcmp(config_file, "/dev/null")) {
+            config_len = 0;
+        } else {
+            ret = libxl_read_file_contents(&ctx, config_file,
+                                           &config_data, &config_len);
+            if (ret) { fprintf(stderr, "Failed to read config file: %s: %s\n",
+                               config_file, strerror(errno)); return ERROR_FAIL; }
+        }
         if (!restore_file && extra_config && strlen(extra_config)) {
             if (config_len > INT_MAX - (strlen(extra_config) + 2 + 1)) {
                 fprintf(stderr, "Failed to attach extra configration\n");