Re: [PATCH v3 2/9] perf evlist: implement control command handling functions

From: Jiri Olsa
Date: Wed May 20 2020 - 08:38:20 EST


On Wed, May 13, 2020 at 11:00:02AM +0300, Alexey Budankov wrote:

SNIP

> +
> +static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
> + char *cmd_data, size_t data_size)
> +{
> + int err;
> + char c;
> + size_t bytes_read = 0;
> +
> + memset(cmd_data, 0, data_size--);
> +
> + do {
> + err = read(evlist->ctl_fd, &c, 1);
> + if (err > 0) {
> + if (c == '\n' || c == '\0')
> + break;
> + cmd_data[bytes_read++] = c;
> + if (bytes_read == data_size)
> + break;
> + } else {
> + if (err == -1)
> + pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd);
> + break;
> + }
> + } while (1);
> +
> + pr_debug("Message from ctl_fd: \"%s%s\"\n", cmd_data,
> + bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0");
> +
> + if (err > 0) {
> + if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
> + strlen(EVLIST_CTL_CMD_ENABLE_TAG))) {
> + *cmd = EVLIST_CTL_CMD_ENABLE;
> + } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
> + strlen(EVLIST_CTL_CMD_DISABLE_TAG))) {
> + *cmd = EVLIST_CTL_CMD_DISABLE;
> + }

are there more comands comming?

jirka