>From c297ddf1295b316d1133a49bc8d2fa08f115dcdc Tue, 31 Jan 2012 16:32:47 -0500
From: Daniel U. Thibault <[email protected]>
Date: Tue, 31 Jan 2012 16:32:33 -0500
Subject: [PATCH] disable_channels.c : * Also use the enable_channels.c channel 
name length filter enable_channels.c : * Improve usage() printout * Document 
and enforce return values * Send --help to stdout * Return CMD_WARNING for bad 
channel name(s) * Fix session_name memory leak * Use LTTNG_SYMBOL_NAME_LEN 
instead of NAME_MAX for chan.name * Replace atol/atoi with strtol (because the 
former's behaviour is undefined for bad input) (this required including 
errno.h) * Change private function enable_channel() to enable_channels() to be 
consistent with disable_channels.c

Signed-off-by: Daniel U. Thibault <[email protected]>

diff --git a/src/bin/lttng/commands/disable_channels.c 
b/src/bin/lttng/commands/disable_channels.c
index 4202963..f6929e6 100644
--- a/src/bin/lttng/commands/disable_channels.c
+++ b/src/bin/lttng/commands/disable_channels.c
@@ -94,6 +94,8 @@
 {
        int warn = 0, ret;
        char *channel_name;
+       char chan_name[LTTNG_SYMBOL_NAME_LEN];
+
        struct lttng_domain dom;
 
        /* Create lttng domain */
@@ -120,16 +122,20 @@
        while (channel_name != NULL) {
                DBG("Disabling channel %s", channel_name);
 
-               ret = lttng_disable_channel(handle, channel_name);
+               /* Copy channel name and normalize it */
+               strncpy(chan_name, channel_name, LTTNG_SYMBOL_NAME_LEN - 1);
+               chan_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
+
+               ret = lttng_disable_channel(handle, chan_name);
                if (ret < 0) {
                        warn = 1;
                        ERR("%s channel %s unrecognised for session %s",
-                                       opt_kernel ? "Kernel" : "UST", 
channel_name,
+                                       opt_kernel ? "Kernel" : "UST", 
chan_name,
                                        session_name);
                } else {
                        ret = CMD_SUCCESS;
                        MSG("%s channel %s disabled for session %s",
-                                       opt_kernel ? "Kernel" : "UST", 
channel_name,
+                                       opt_kernel ? "Kernel" : "UST", 
chan_name,
                                        session_name);
                }
 
diff --git a/src/bin/lttng/commands/enable_channels.c 
b/src/bin/lttng/commands/enable_channels.c
index 03de524..7bebf76 100644
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -84,15 +85,17 @@
        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 on 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");
        fprintf(ofp, "Channel options:\n");
@@ -100,7 +103,7 @@
                DEFAULT_CHANNEL_OVERWRITE ? "" : " (default)");
        fprintf(ofp, "      --overwrite          Flight recorder mode%s\n",
                DEFAULT_CHANNEL_OVERWRITE ? " (default)" : "");
-       fprintf(ofp, "      --subbuf-size        Subbuffer size in bytes\n");
+       fprintf(ofp, "      --subbuf-size        Subbuffer size (in bytes)\n");
        fprintf(ofp, "                               (default: %u, kernel 
default: %u)\n",
                DEFAULT_CHANNEL_SUBBUF_SIZE,
                DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE);
@@ -118,14 +121,16 @@
 /*
  * Set default attributes depending on those already defined from the command
  * line.
+ * The domain argument must not be NULL.
  */
 static void set_default_attr(struct lttng_domain *dom)
 {
        struct lttng_channel_attr default_attr;
 
-       /* Set attributes */
+       /* Recover default attributes */
        lttng_channel_set_default_attr(dom, &default_attr);
 
+       /* Set attributes */
        if (chan.attr.overwrite == -1) {
                chan.attr.overwrite = default_attr.overwrite;
        }
@@ -147,11 +152,13 @@
 }
 
 /*
- * Adding channel using the lttng API.
+ * Enables channel(s) using the lttng API.
+ * Channel names which are too long will be truncated.
+ * Returns one of the CMD_* result values.
  */
-static int enable_channel(char *session_name)
+static int enable_channels(char *session_name)
 {
-       int ret = CMD_SUCCESS;
+       int warn = 0, ret;
        char *channel_name;
        struct lttng_domain dom;
 
@@ -170,23 +177,29 @@
 
        handle = lttng_create_handle(session_name, &dom);
        if (handle == NULL) {
-               ret = -1;
+               ret = CMD_FATAL;
                goto error;
        }
 
        /* Strip channel list (format: chan1,chan2,...) */
        channel_name = strtok(opt_channels, ",");
+       /* Default to a warning in case opt_channels is empty */
+       ret = CMD_WARNING;
        while (channel_name != NULL) {
-               /* Copy channel name and normalize it */
-               strncpy(chan.name, channel_name, NAME_MAX);
-               chan.name[NAME_MAX - 1] = '\0';
-
                DBG("Enabling channel %s", channel_name);
+
+               /* Copy channel name and normalize it */
+               strncpy(chan.name, channel_name, LTTNG_SYMBOL_NAME_LEN - 1);
+               chan.name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 
                ret = lttng_enable_channel(handle, &chan);
                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 enabled for session %s",
                                        opt_kernel ? "Kernel" : "UST", 
channel_name,
                                        session_name);
@@ -194,6 +207,13 @@
 
                /* Next event */
                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:
@@ -215,7 +235,8 @@
 }
 
 /*
- * Add channel to trace session
+ * Add channel(s) to trace session
+ * Returns one of the CMD_* result values.
  */
 int cmd_enable_channels(int argc, const char **argv)
 {
@@ -231,7 +252,7 @@
        while ((opt = poptGetNextOpt(pc)) != -1) {
                switch (opt) {
                case OPT_HELP:
-                       usage(stderr);
+                       usage(stdout);
                        ret = CMD_SUCCESS;
                        goto end;
                case OPT_DISCARD:
@@ -243,20 +264,44 @@
                        DBG("Channel set to overwrite");
                        break;
                case OPT_SUBBUF_SIZE:
-                       chan.attr.subbuf_size = atol(poptGetOptArg(pc));
+                       errno = 0;
+                       chan.attr.subbuf_size = strtol(poptGetOptArg(pc), (char 
**)NULL, 10);
+                       if (errno != 0) {
+                               ERR("Subbuffer size not a number");
+                               ret = CMD_ERROR;
+                               goto end;
+                       }
                        DBG("Channel subbuf size set to %" PRIu64, 
chan.attr.subbuf_size);
                        break;
                case OPT_NUM_SUBBUF:
-                       chan.attr.num_subbuf = atoi(poptGetOptArg(pc));
+                       errno = 0;
+                       chan.attr.num_subbuf = strtol(poptGetOptArg(pc), (char 
**)NULL, 10);
+                       if (errno != 0) {
+                               ERR("Number of subbuffers not a number");
+                               ret = CMD_ERROR;
+                               goto end;
+                       }
                        DBG("Channel subbuf num set to %" PRIu64, 
chan.attr.num_subbuf);
                        break;
                case OPT_SWITCH_TIMER:
-                       chan.attr.switch_timer_interval = 
atoi(poptGetOptArg(pc));
-                       DBG("Channel switch timer interval set to %d", 
chan.attr.switch_timer_interval);
+                       errno = 0;
+                       chan.attr.switch_timer_interval = 
strtol(poptGetOptArg(pc), (char **)NULL, 10);
+                       if (errno != 0) {
+                               ERR("Switch timer interval not a number");
+                               ret = CMD_ERROR;
+                               goto end;
+                       }
+                       DBG("Channel switch timer interval set to %d usec", 
chan.attr.switch_timer_interval);
                        break;
                case OPT_READ_TIMER:
-                       chan.attr.read_timer_interval = atoi(poptGetOptArg(pc));
-                       DBG("Channel read timer interval set to %d", 
chan.attr.read_timer_interval);
+                       errno = 0;
+                       chan.attr.read_timer_interval = 
strtol(poptGetOptArg(pc), (char **)NULL, 10);
+                       if (errno != 0) {
+                               ERR("Read timer interval not a number");
+                               ret = CMD_ERROR;
+                               goto end;
+                       }
+                       DBG("Channel read timer interval set to %d usec", 
chan.attr.read_timer_interval);
                        break;
                case OPT_USERSPACE:
                        opt_userspace = 1;
@@ -274,24 +319,26 @@
 
        opt_channels = (char*) poptGetArg(pc);
        if (opt_channels == NULL) {
-               ERR("Missing channel name.\n");
+               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 = enable_channel(session_name);
+       ret = enable_channels(session_name);
+
+cleanup:
+       if (opt_session_name == NULL) {
+               free(session_name);
+       }
 
 end:
        poptFreeContext(pc);
------------------------------

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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