Jeremy Sowden <jeremy@xxxxxxxxxx> wrote:
> Instead of statting the file, and choosing the mode with which to open
> it and whether to write the PCAP header based on the result, always open
> it with mode "a" and _then_ stat it. This simplifies the flow-control
> and avoids a race between statting and opening.
>
> Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
> ---
> output/pcap/ulogd_output_PCAP.c | 42 ++++++++++++---------------------
> 1 file changed, 15 insertions(+), 27 deletions(-)
>
> diff --git a/output/pcap/ulogd_output_PCAP.c b/output/pcap/ulogd_output_PCAP.c
> index e7798f20c8fc..220fc6dec5fe 100644
> --- a/output/pcap/ulogd_output_PCAP.c
> +++ b/output/pcap/ulogd_output_PCAP.c
> @@ -220,33 +220,21 @@ static int append_create_outfile(struct ulogd_pluginstance *upi)
> {
> + struct stat st_of;
> +
> + pi->of = fopen(filename, "a");
> + if (!pi->of) {
> + ulogd_log(ULOGD_ERROR, "can't open pcap file %s: %s\n",
> + filename,
> + strerror(errno));
> + return -EPERM;
> + }
> + if (fstat(fileno(pi->of), &st_of) == 0 && st_of.st_size == 0) {
> + if (!write_pcap_header(pi)) {
> + ulogd_log(ULOGD_ERROR, "can't write pcap header: %s\n",
> + strerror(errno));
> + return -ENOSPC;
LGTM, but should that fclose() before -ENOSPC?
