On Tue, Feb 07, 2017 at 06:08:14PM +0100, Jean-Christophe Dubois wrote:
> When running coverity on dtc source code the following error is reported.
>
> =========================================================================
> 250 srcpos_string(struct srcpos *pos)
> 251{
> 252 const char *fname = "<no-file>";
> 253 char *pos_str;
> 254
> 1. Condition pos, taking false branch.
> 2. var_compare_op: Comparing pos to null implies that pos might be null.
> 255 if (pos)
> 256 fname = pos->file->name;
> 257
> 258
> CID 1026108 (#1 of 1): Dereference after null check (FORWARD_NULL)3. var_deref_op: Dereferencing null pointer pos.
> 259 if (pos->first_line != pos->last_line)
>
> =======================================================================
>
> Fixed the srcpos_string() function assuming the pos argument could be NULL.
>
> Fixed the fname assignement checking the name was indeed set in the
> provided pos structure.
>
> As srcpos_string() can now return NULL, fixed srcpos_verror() to handle this
> situation.
Actually, on looking at this a bit further, it looks like the post ==
NULL case just can't happen. I've instead made a change to just
remove the pos == NULL check from srcpos_string().
>
> Signed-off-by: Jean-Christophe Dubois <jcd@xxxxxxxxxxxxxxx>
> ---
> srcpos.c | 44 ++++++++++++++++++++++++++------------------
> 1 file changed, 26 insertions(+), 18 deletions(-)
>
> diff --git a/srcpos.c b/srcpos.c
> index aa3aad0..cec790c 100644
> --- a/srcpos.c
> +++ b/srcpos.c
> @@ -249,24 +249,28 @@ srcpos_copy(struct srcpos *pos)
> char *
> srcpos_string(struct srcpos *pos)
> {
> - const char *fname = "<no-file>";
> - char *pos_str;
> + char *pos_str = NULL;
>
> - if (pos)
> - fname = pos->file->name;
> + if (pos) {
> + const char *fname = "<no-file>";
>
> + if (pos->file && pos->file->name) {
> + fname = pos->file->name;
> + }
>
> - if (pos->first_line != pos->last_line)
> - xasprintf(&pos_str, "%s:%d.%d-%d.%d", fname,
> - pos->first_line, pos->first_column,
> - pos->last_line, pos->last_column);
> - else if (pos->first_column != pos->last_column)
> - xasprintf(&pos_str, "%s:%d.%d-%d", fname,
> - pos->first_line, pos->first_column,
> - pos->last_column);
> - else
> - xasprintf(&pos_str, "%s:%d.%d", fname,
> - pos->first_line, pos->first_column);
> + if (pos->first_line != pos->last_line) {
> + xasprintf(&pos_str, "%s:%d.%d-%d.%d", fname,
> + pos->first_line, pos->first_column,
> + pos->last_line, pos->last_column);
> + } else if (pos->first_column != pos->last_column) {
> + xasprintf(&pos_str, "%s:%d.%d-%d", fname,
> + pos->first_line, pos->first_column,
> + pos->last_column);
> + } else {
> + xasprintf(&pos_str, "%s:%d.%d", fname,
> + pos->first_line, pos->first_column);
> + }
> + }
>
> return pos_str;
> }
> @@ -278,11 +282,15 @@ void srcpos_verror(struct srcpos *pos, const char *prefix,
>
> srcstr = srcpos_string(pos);
>
> - fprintf(stderr, "%s: %s ", prefix, srcstr);
> + if (srcstr) {
> + fprintf(stderr, "%s: %s ", prefix, srcstr);
> + free(srcstr);
> + } else {
> + fprintf(stderr, "%s: <unknown> ", prefix);
> + }
> +
> vfprintf(stderr, fmt, va);
> fprintf(stderr, "\n");
> -
> - free(srcstr);
> }
>
> void srcpos_error(struct srcpos *pos, const char *prefix,
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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