From: Namhyung Kim <namhyung@kernel.org>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 05/15] perf evlist: implement control command handling functions
Date: Mon, 13 Jul 2020 12:20:59 +0900 [thread overview]
Message-ID: <CAM9d7cikDcaLaUv8+xh9fp_KVHFVQD+eRYGAR5kN4A7ppPHmBQ@mail.gmail.com> (raw)
In-Reply-To: <93e1c3b1-ee77-a94d-8806-049e0245fab7@linux.intel.com>
On Wed, Jul 8, 2020 at 4:50 PM Alexey Budankov
<alexey.budankov@linux.intel.com> wrote:
>
>
> Implement functions of initialization, finalization and processing
> of control command messages coming from control file descriptors.
> Allocate control file descriptor as descriptor at struct pollfd
> object of evsel_list for atomic poll() operation.
>
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
[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--);
I overlooked the '--' at the end and thought there might be
buffer overflow.. Care to add a comment?
> +
> + do {
> + err = read(evlist->ctl_fd.fd, &c, 1);
Maybe I missed earlier discussion, but do we really want
this 1 byte read in a loop?
Thanks
Namhyung
> + 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.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,
> + (sizeof(EVLIST_CTL_CMD_ENABLE_TAG)-1))) {
> + *cmd = EVLIST_CTL_CMD_ENABLE;
> + } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
> + (sizeof(EVLIST_CTL_CMD_DISABLE_TAG)-1))) {
> + *cmd = EVLIST_CTL_CMD_DISABLE;
> + }
> + }
> +
> + return err;
> +}
next prev parent reply other threads:[~2020-07-13 3:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 7:36 [PATCH v10 00/15] perf: support enable and disable commands in stat and record modes Alexey Budankov
2020-07-08 7:45 ` [PATCH v10 01/15] tools/libperf: avoid internal moving of fdarray fds Alexey Budankov
2020-07-08 7:46 ` [PATCH v10 02/15] tools/libperf: add flags to fdarray fds objects Alexey Budankov
2020-07-08 7:47 ` [PATCH v10 03/15] tools/libperf: avoid counting of nonfilterable fdarray fds Alexey Budankov
2020-07-08 7:47 ` [PATCH v10 04/15] perf evlist: introduce control file descriptors Alexey Budankov
2020-07-13 3:13 ` Namhyung Kim
2020-07-13 8:16 ` Alexey Budankov
2020-07-08 7:50 ` [PATCH v10 05/15] perf evlist: implement control command handling functions Alexey Budankov
2020-07-13 3:20 ` Namhyung Kim [this message]
2020-07-13 8:24 ` Alexey Budankov
2020-07-08 7:50 ` [PATCH v10 06/15] perf stat: factor out body of event handling loop for system wide Alexey Budankov
2020-07-08 7:51 ` [PATCH v10 07/15] perf stat: move target check to loop control statement Alexey Budankov
2020-07-08 7:51 ` [PATCH v10 08/15] perf stat: factor out body of event handling loop for fork case Alexey Budankov
2020-07-08 7:52 ` [PATCH v10 09/15] perf stat: factor out event handling loop into dispatch_events() Alexey Budankov
2020-07-08 7:53 ` [PATCH v10 10/15] perf stat: extend -D,--delay option with -1 value Alexey Budankov
2020-07-08 7:53 ` [PATCH v10 11/15] perf stat: implement control commands handling Alexey Budankov
2020-07-08 7:54 ` [PATCH v10 12/15] perf stat: introduce --control fd:ctl-fd[,ack-fd] options Alexey Budankov
2020-07-08 7:54 ` [PATCH v10 13/15] perf record: extend -D,--delay option with -1 value Alexey Budankov
2020-07-08 7:55 ` [PATCH v10 14/15] perf record: implement control commands handling Alexey Budankov
2020-07-08 7:55 ` [PATCH v10 15/15] perf record: introduce --control fd:ctl-fd[,ack-fd] options Alexey Budankov
2020-07-12 21:12 ` [PATCH v10 00/15] perf: support enable and disable commands in stat and record modes Jiri Olsa
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