[lttng-dev] [PATCH] disable_channels.c improvements and fixes
David Goulet
dgoulet at efficios.com
Wed Feb 1 13:01:46 EST 2012
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On 12-01-31 03:15 PM, Thibault, Daniel wrote:
> From 21f0eb1a7db1704645554d2f273bf80235be8240 Tue, 31 Jan 2012 15:13:29 -0500
> From: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
> Date: Tue, 31 Jan 2012 15:13:19 -0500
> Subject: [PATCH] disable_channels.c improvements and fixes * Improve usage() printout * Document and enforce return values * Send --help to stdout * Issue CMD_WARNING for bad channel name(s) or an empty list of channel names * Fix a memory leak
>
> Signed-off-by: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
>
> diff --git a/src/bin/lttng/commands/disable_channels.c b/src/bin/lttng/commands/disable_channels.c
> index bdbb657..4202963 100644
> --- a/src/bin/lttng/commands/disable_channels.c
> +++ b/src/bin/lttng/commands/disable_channels.c
> @@ -70,25 +70,29 @@
> fprintf(ofp, "\n");
> fprintf(ofp, " -h, --help Show this help\n");
> fprintf(ofp, " --list-options Simple listing of options\n");
> - fprintf(ofp, " -s, --session Apply on session name\n");
> - fprintf(ofp, " -k, --kernel Apply for the kernel tracer\n");
> + fprintf(ofp, " -s, --session Apply to session name\n");
> + fprintf(ofp, " -k, --kernel Apply to the kernel tracer\n");
> #if 0
> - fprintf(ofp, " -u, --userspace [CMD] Apply for the user-space tracer\n");
> + fprintf(ofp, " -u, --userspace [CMD] Apply to the user-space tracer\n");
> fprintf(ofp, " If no CMD, the domain used is UST global\n");
> - fprintf(ofp, " or else the domain is UST EXEC_NAME\n");
> + fprintf(ofp, " otherwise the domain is UST EXEC_NAME\n");
> + fprintf(ofp, " (--kernel preempts --userspace)\n");
> fprintf(ofp, " -p, --pid PID If -u, apply to specific PID (domain: UST PID)\n");
> #else
> - fprintf(ofp, " -u, --userspace Apply for the user-space tracer\n");
> + fprintf(ofp, " -u, --userspace Apply to the user-space tracer\n");
> + fprintf(ofp, " (--kernel preempts --userspace)\n");
> #endif
> fprintf(ofp, "\n");
> }
>
> /*
> - * Disabling channel using the lttng API.
> + * Disabling channel(s) using the lttng API.
> + * session_name must not be NULL.
> + * Returns one of the CMD_* result values.
> */
> static int disable_channels(char *session_name)
> {
> - int ret = CMD_SUCCESS;
> + int warn = 0, ret;
> char *channel_name;
> struct lttng_domain dom;
>
> @@ -105,19 +109,25 @@
>
> handle = lttng_create_handle(session_name, &dom);
> if (handle == NULL) {
> - ret = -1;
> + ret = CMD_ERROR;
> goto error;
> }
>
> /* Strip channel list */
> channel_name = strtok(opt_channels, ",");
> + /* Default to a warning in case opt_channels is empty */
> + ret = CMD_WARNING;
Actually, at this point, opt_channels *can not* be empty. There is a check
before calling this function.
So, if ret is cmd_success by default, only warn==1 will be enough after this
loop. Am I missing something ?
Thanks
David
> while (channel_name != NULL) {
> DBG("Disabling channel %s", channel_name);
>
> ret = lttng_disable_channel(handle, channel_name);
> if (ret < 0) {
> - goto error;
> + warn = 1;
> + ERR("%s channel %s unrecognised for session %s",
> + opt_kernel ? "Kernel" : "UST", channel_name,
> + session_name);
> } else {
> + ret = CMD_SUCCESS;
> MSG("%s channel %s disabled for session %s",
> opt_kernel ? "Kernel" : "UST", channel_name,
> session_name);
> @@ -125,6 +135,13 @@
>
> /* Next channel */
> channel_name = strtok(NULL, ",");
> + }
> + if (ret == CMD_WARNING) {
> + ERR("No %s channel specified for session %s",
> + opt_kernel ? "kernel" : "UST", session_name);
> + }
> + if (warn) {
> + ret = CMD_WARNING;
> }
>
> error:
> @@ -134,13 +151,13 @@
> }
>
> /*
> - * cmd_disable_channels
> - *
> - * Disable channel to trace session
> + * Disable channel(s) of a trace session.
> + * Bad channel names or an empty list of channels will yield a warning.
> + * Returns a CMD_* result value.
> */
> int cmd_disable_channels(int argc, const char **argv)
> {
> - int opt, ret;
> + int opt, ret = CMD_SUCCESS;
> static poptContext pc;
> char *session_name = NULL;
>
> @@ -150,15 +167,13 @@
> while ((opt = poptGetNextOpt(pc)) != -1) {
> switch (opt) {
> case OPT_HELP:
> - usage(stderr);
> - ret = CMD_SUCCESS;
> + usage(stdout);
> goto end;
> case OPT_USERSPACE:
> opt_userspace = 1;
> break;
> case OPT_LIST_OPTIONS:
> list_cmd_options(stdout, long_options);
> - ret = CMD_SUCCESS;
> goto end;
> default:
> usage(stderr);
> @@ -171,22 +186,23 @@
> if (opt_channels == NULL) {
> ERR("Missing channel name(s).\n");
> usage(stderr);
> - ret = CMD_SUCCESS;
> + ret = CMD_ERROR;
> goto end;
> }
>
> - if (!opt_session_name) {
> - session_name = get_session_name();
> - if (session_name == NULL) {
> - ret = -1;
> - goto end;
> - }
> - } else {
> - session_name = opt_session_name;
> + session_name = (opt_session_name ? opt_session_name : get_session_name() );
> + if (session_name == NULL) {
> + ret = CMD_ERROR;
> + goto cleanup;
> }
>
> ret = disable_channels(session_name);
>
> +cleanup:
> + if (opt_session_name == NULL) {
> + free(session_name);
> + }
> +
> end:
> return ret;
> }
> ------------------------------
>
> Daniel U. Thibault
> R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
> Système de systèmes (SdS) / System of Systems (SoS)
> Solutions informatiques et expérimentations (SIE) / Computing Solutions and Experimentations (CSE)
> 2459 Boul. Pie XI Nord
> Québec, QC G3J 1X5
> CANADA
> Vox : (418) 844-4000 x4245
> Fax : (418) 844-4538
> NAC: 918V QSDJ
> Gouvernement du Canada / Government of Canada
> <http://www.valcartier.drdc-rddc.gc.ca/>
>
> _______________________________________________
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> lttng-dev at lists.lttng.org
> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>
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