[ovs-dev] [PATCH v2] command-line.c: Support parsing ctl options via env variable

Ben Pfaff blp at ovn.org
Fri Oct 25 18:12:55 UTC 2019


On Thu, Oct 24, 2019 at 10:43:14PM -0700, amginwal at gmail.com wrote:
> From: Aliasgar Ginwala <aginwala at ebay.com>
> 
> Signed-off-by: Aliasgar Ginwala <aginwala at ebay.com>

To me, this looks more complicated than necessary, and thus harder to
reason about regarding correctness.  What about the following?  It does
not make me think as hard about correctness.  However, I have not tested
it.

-8<--------------------------cut here-------------------------->8--

From: Aliasgar Ginwala <aginwala at ebay.com>
Date: Thu, 24 Oct 2019 22:43:14 -0700
Subject: [PATCH] command-line.c: Support parsing ctl options via env variable

Signed-off-by: Aliasgar Ginwala <aginwala at ebay.com>
Signed-off-by: Ben Pfaff <blp at ovn.org>
---
 lib/command-line.c | 34 ++++++++++++++++++++++++++++++++++
 lib/command-line.h |  3 +++
 2 files changed, 37 insertions(+)

diff --git a/lib/command-line.c b/lib/command-line.c
index 9e000bd28d1a..fa02b49152e5 100644
--- a/lib/command-line.c
+++ b/lib/command-line.c
@@ -19,6 +19,7 @@
 #include <getopt.h>
 #include <limits.h>
 #include <stdlib.h>
+#include "svec.h"
 #include "openvswitch/dynamic-string.h"
 #include "ovs-thread.h"
 #include "util.h"
@@ -77,6 +78,39 @@ find_option_by_value(const struct option *options, int value)
     return NULL;
 }
 
+/* Parses options set using environment variable.  The caller specifies the
+ * supported options in environment variable.  On success, adds the parsed
+ * env variables in 'argv', the number of options in 'argc', and returns argv.
+ */
+char **
+ovs_cmdl_env_parse_all(int *argcp, char *argv[], const char *env_options)
+{
+    struct svec args = SVEC_EMPTY_INITIALIZER;
+
+    /* argv[0] stays in place. */
+    ovs_assert(*argcp > 0);
+    svec_add(&args, argv[0]);
+
+    /* Anything from the environment variable goes next. */
+    if (env_options) {
+        char *env_copy = xstrdup(env_options);
+        char *save_ptr = NULL;
+        for (char *option = strtok_r(env_copy, " ", &save_ptr);
+             option; option = strtok_r(NULL, " ", &save_ptr)) {
+            svec_add(&args, option);
+        }
+        free(env_copy);
+    }
+
+    /* Remaining command-line options go at the end. */
+    for (int i = 1; i < *argcp; i++) {
+        svec_add(&args, argv[i]);
+    }
+
+    *argcp = args.n;
+    return args.names;
+}
+
 /* Parses the command-line options in 'argc' and 'argv'.  The caller specifies
  * the supported options in 'options'.  On success, stores the parsed options
  * in '*pop', the number of options in '*n_pop', and returns NULL.  On failure,
diff --git a/lib/command-line.h b/lib/command-line.h
index 9d62dc2501c5..dc7ec36eae6c 100644
--- a/lib/command-line.h
+++ b/lib/command-line.h
@@ -54,6 +54,9 @@ char *ovs_cmdl_parse_all(int argc, char *argv[], const struct option *,
                          struct ovs_cmdl_parsed_option **, size_t *)
     OVS_WARN_UNUSED_RESULT;
 
+char **ovs_cmdl_env_parse_all(int *argcp, char *argv[],
+                              const char *env_options);
+
 void ovs_cmdl_print_options(const struct option *options);
 void ovs_cmdl_print_commands(const struct ovs_cmdl_command *commands);
 
-- 
2.21.0



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