Re: [libvirt PATCH 10/20] nss: convert findLeases to use json-c

On Wed, Aug 14, 2024 at 23:40:25 +0200, Ján Tomko wrote: > While the parsing is still done by 1K buffers, the results > are no longer filtered during the parsing, but the whole JSON > has to live in memory at once, which was also the case before > the NSS plugin dropped its dependency on libvirt_util. > > Also, the new parser might be more forgiving of missing elements. > > Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; > --- > tools/nss/libvirt_nss_leases.c | 339 ++++++++++----------------------- > 1 file changed, 96 insertions(+), 243 deletions(-)

> - while (1) { > - rv = read(fd, line, sizeof(line)); > + while (jerr != json_tokener_continue) { So this passes on first iteration, but ... > + rv = read(fd, line, sizeof(line) - 1); > if (rv < 0) > goto cleanup; > if (rv == 0) > break; > nreadTotal += rv; > > - if (yajl_parse(parser, (const unsigned char *)line, rv) != > - yajl_status_ok) { > - unsigned char *err = yajl_get_error(parser, 1, > - (const unsigned char*)line, rv); > - ERROR("Parse failed %s", (const char *) err); > - yajl_free_error(parser, err); > - goto cleanup; > - } > + line[rv] = 0; Why is this needed ... > + > + jobj = json_tokener_parse_ex(tok, line, rv); ... this seems to accept a length argument. > + jerr = json_tokener_get_error(tok); ... the docs state: A partial JSON string can be parsed. If the parsing is incomplete, NULL will be returned and json_tokener_get_error() will be return json_tokener_continue. json_tokener_parse_ex() can then be called with additional bytes in str to continue the parsing. So unless I'm missing something very important this will not be able to parse a file larger than 1k. > } > > - if (nreadTotal > 0 && > - yajl_complete_parse(parser) != yajl_status_ok) { > - ERROR("Parse failed %s", > - yajl_get_error(parser, 1, NULL, 0)); > + if (nreadTotal > 0 && jerr != json_tokener_success) { > + ERROR("Cannot parse %s: %s", file, json_tokener_error_desc(jerr)); > goto cleanup; > }