[libvirt] [PATCH v3 02/14] util: Implement virStringFilterLines()

[John Ferlan]

On 05/04/2018 04:21 PM, Stefan Berger wrote:
> Implement virStringFilterLines() that takes as an input a buffer with text
> and extracts each line that contains a given needle. The size of each re-
> turned line can be restricted and if it is restricted '...' will automa-
> tically be appended.
> 
> Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
> ---
>  src/util/virstring.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/util/virstring.h |  3 +++
>  2 files changed, 65 insertions(+)
> 

? No src/libvirt_private.syms change to add the new function?

> diff --git a/src/util/virstring.c b/src/util/virstring.c
> index 15f367a..f1d91c7 100644
> --- a/src/util/virstring.c
> +++ b/src/util/virstring.c
> @@ -1499,3 +1499,65 @@ virStringParsePort(const char *str,
>  
>      return 0;
>  }

Similar to 1/14 - 2 blank lines...

> +
> +/**
> + * virStringFilterLines:

I think this is more ExtractLines

as compared to virStringFilterChars which filters out certain chars from
a buffer and returns a buffer with those filtered out.

> + * @input: input buffer with text
> + * @needle: the needle to search in each line
> + * @maxlinelen: maximum line length of each line in output buffer;
> + *              0 to not restrict
> + *
> + * Search for a given needle in each line of the input buffer and create
> + * an output buffer that contains only these line.

Seems to be an incomplete thought, but I can adjust. So given Extract
vs. Filter:

 * Search for a given @needle in each line of the @input buffer and
 * create a return buffer that contains only those lines with the
 * @needle. Each output buffer line can be further restricted by
 * providing @maxlinelen in which case the output line would be
 * truncated @maxlinelen with "..." appended to the line to indicate
 * the truncation.
 *
 * Returns NULL on failure or a buffer with the extracted lines. It
 * is up to the caller to free the returned buffer.

> + */
> +char *
> +virStringFilterLines(char *input, const char *needle, size_t maxlinelen)

... and 1 line per argument.


> +{
> +    char *sol = input;
> +    char *eol;
> +    char *buf = NULL;
> +    size_t buflen = 1, llen;
> +    const char *dots = "...";
> +

See below [1]

+    if (!input || !needle) {
+        virReportError(VIR_ERR_INALID_ARG,
+                       _("neither input=%s nor needle=%s can be NULL"),
+                       NULLSTR(input), NULLSTR(needle));
+        return NULL;
+    }
+

> +    while (*sol) {
> +        eol = strchr(sol, '\n');
> +        if (eol)
> +            *eol = 0;
> +
> +        if (strstr(sol, needle)) {
> +            size_t additional = 0;
> +
> +            llen = strlen(sol);
> +            if (maxlinelen && llen > maxlinelen) {
> +                llen = maxlinelen;
> +                additional = strlen(dots);
> +            }
> +
> +            if (VIR_REALLOC_N(buf, buflen + llen + additional + 1) < 0) {
> +                VIR_FREE(buf);
> +                if (*eol)

Ran the patch through Coverity and it complained right here... I think
you meant "if (eol)", right?

> +                    *eol = '\n';
> +                return NULL;
> +            }
> +            strncpy(&buf[buflen - 1], sol, llen);
> +            buflen += llen;
> +
> +            if (additional) {
> +                strncpy(&buf[buflen - 1], dots, additional);
> +                buflen += additional;
> +            }
> +
> +            strcpy(&buf[buflen - 1], "\n");
> +            buflen += 1;
> +        }
> +
> +        if (eol)
> +            *eol = '\n';
> +        else
> +            break;
> +
> +        sol = eol + 1;
> +    }
> +
> +    return buf;
> +}
> diff --git a/src/util/virstring.h b/src/util/virstring.h
> index fa2ec1d..1fb9851 100644
> --- a/src/util/virstring.h
> +++ b/src/util/virstring.h
> @@ -309,4 +309,7 @@ int virStringParsePort(const char *str,
>                         unsigned int *port)
>      ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
>  
> +char *virStringFilterLines(char *input, const char *needle, size_t maxlinelen)
> +    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);

[1]
Unfortunately all this does is ensure no one calls this with (NULL,
NULL,...)... In practice, if @input or @needle is assigned to NULL, the
compiler won't catch it.


With the adjustments,

Reviewed-by: John Ferlan <jferlan at redhat.com>

But like patch 1, I do have some other concerns later in patch 7 when
this is used.

John

> +
>  #endif /* __VIR_STRING_H__ */
>