On Thu, Jan 23, 2014 at 10:28:30AM +0100, Manuel VIVES wrote:
> ---
> src/libvirt_private.syms | 1 +
> src/util/virstring.c | 66 +++++++++++++++++++++++++++++++++++++++++++++-
> src/util/virstring.h | 1 +
> 3 files changed, 67 insertions(+), 1 deletion(-)
Can you also add a test case to src/virstringtest.c for this one
too. In particular test what happens when matches are exactly at
the start and end of the string so we validate proper boundary
handling.
> +
> +/*
> + virStrReplace(haystack, oldneedle, newneedle) --
> + Search haystack and replace all occurences of oldneedle with newneedle.
> + Return a string with all the replacements in case of success, NULL in case
> + of failure
> +*/
> +char *
> +virStrReplace(char *haystack,
> + const char *oldneedle, const char *newneedle)
Can we call this virStringReplace instead.
> +{
> + char *ret = NULL;
> + size_t i = strlen(haystack);
> + size_t count = 0;
> + size_t newneedle_len = strlen(newneedle);
> + size_t oldneedle_len = strlen(oldneedle);
> + int diff_len = newneedle_len - oldneedle_len;
> + size_t totalLength = 0;
> + size_t numberOfElementsToAllocate = 0;
> + if (!haystack || !oldneedle || !newneedle) {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("null value for haystack, oldneedle or newneedle"));
> + goto cleanup;
> + }
> + if (oldneedle_len == 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("oldneedle cannot be empty"));
> + goto cleanup;
> + }
> + if (diff_len == 0 && memcmp(oldneedle, newneedle, newneedle_len) == 0) {
> + ignore_value(VIR_STRDUP(ret, haystack));
> + goto cleanup;
> + }
> +
> + for (i = 0; haystack[i] != '\0'; i++) {
> + if (memcmp(&haystack[i], oldneedle, oldneedle_len) == 0) {
This looks like a out of bounds read. eg consider
haystack = "foo"
oldneedle = "baaaaaar"
You're going to be making memcmp read beyond the end of the haystack
array I believe.
> + count ++;
> + i += oldneedle_len - 1;
> + }
> + }
> + numberOfElementsToAllocate = (i + count * (newneedle_len - oldneedle_len));
> +
> + if (VIR_ALLOC_N(ret, numberOfElementsToAllocate) < 0)
> + goto cleanup;
Rather than trying to pre-caculate buffer lengths, I thin it would
probably be simpler if you just used the virBuffer APIs to construct
the new string, since that does grow-on-demand.
> +
> + totalLength = sizeof(char) * numberOfElementsToAllocate;
> + i = 0;
> + while (*haystack) {
> + if (memcmp(haystack, oldneedle, oldneedle_len) == 0) {
> + if (virStrcpy(&ret[i], newneedle, totalLength) == NULL) {
> + VIR_FREE(ret);
> + goto cleanup;
> + }
> + totalLength -= newneedle_len;
> + i += newneedle_len;
> + haystack += oldneedle_len;
> + } else {
> + ret[i++] = *haystack++;
> + totalLength --;
> + }
> + }
> + ret[i] = '\0';
> +cleanup:
> + return ret;
> +}
Daniel
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