[libvirt] [PATCH 08/18] vshCommandOpt: Allow caller avoiding assert()

[Martin Kletzander]

On Tue, Jan 02, 2018 at 06:12:01PM +0100, Michal Privoznik wrote:
>In the future, completer callbacks will receive partially parsed
>command (and thus possibly incomplete). However, we still want
>them to use command options fetching APIs we already have (e.g.
>vshCommandOpt*()) and at the same time don't report any errors
>(nor call any asserts).
>
>Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>---
> tools/vsh.c | 7 ++++---
> tools/vsh.h | 3 ++-
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
>diff --git a/tools/vsh.c b/tools/vsh.c
>index ebc8d9cb1..d27acb95b 100644
>--- a/tools/vsh.c
>+++ b/tools/vsh.c
>@@ -815,8 +815,8 @@ vshCommandFree(vshCmd *cmd)
>  * to the option if found, 0 with *OPT set to NULL if the name is
>  * valid and the option is not required, -1 with *OPT set to NULL if
>  * the option is required but not present, and assert if NAME is not
>- * valid (which indicates a programming error).  No error messages are
>- * issued if a value is returned.
>+ * valid (which indicates a programming error) unless cmd->skipChecks
>+ * is set. No error messages are issued if a value is returned.
>  */
> static int
> vshCommandOpt(const vshCmd *cmd, const char *name, vshCmdOpt **opt,
>@@ -829,7 +829,8 @@ vshCommandOpt(const vshCmd *cmd, const char *name, vshCmdOpt **opt,
>     /* See if option is valid and/or required.  */
>     *opt = NULL;
>     while (valid) {
>-        assert(valid->name);
>+        if (!cmd->skipChecks)
>+            assert(valid->name);

This can segfault when cmd->skipChecks == False && valid->name == NULL,
which is what the assert() guarded before.

So either STREQ_NULLABLE or another if.

>         if (STREQ(name, valid->name))
>             break;
>         valid++;
>diff --git a/tools/vsh.h b/tools/vsh.h
>index 8f7df9ff8..112b1b57d 100644
>--- a/tools/vsh.h
>+++ b/tools/vsh.h
>@@ -188,7 +188,8 @@ struct _vshCmdDef {
> struct _vshCmd {
>     const vshCmdDef *def;       /* command definition */
>     vshCmdOpt *opts;            /* list of command arguments */
>-    vshCmd *next;      /* next command */
>+    vshCmd *next;               /* next command */
>+    bool skipChecks;            /* skip validity checks when retrieving opts */
> };
>
> /*
>-- 
>2.13.6
>
>--
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>libvir-list at redhat.com
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