[lttng-dev] [PATCH lttng-tools] Fix: use strcmp instead of strncmp for full match cases

Yannick Lamarre ylamarre at efficios.com
Wed Mar 20 12:33:12 EDT 2019


Except for a single case where the compared string is not ended with
'\0', strncmp was replaced by strcmp in cases where a full string match
was required. The exception was fixed with a length comparison prior
the strncmp call.

Fixes: #987
Signed-off-by: Yannick Lamarre <ylamarre at efficios.com>
---
 src/bin/lttng-sessiond/agent.c           | 3 +--
 src/bin/lttng-sessiond/cmd.c             | 2 +-
 src/bin/lttng-sessiond/snapshot.c        | 2 +-
 src/bin/lttng-sessiond/ust-registry.c    | 2 +-
 src/bin/lttng/commands/add_context.c     | 8 ++++----
 src/bin/lttng/commands/create.c          | 4 +---
 src/bin/lttng/commands/enable_channels.c | 4 ++--
 src/common/lttng-elf.c                   | 1 +
 src/common/testpoint/testpoint.c         | 4 ++--
 9 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/src/bin/lttng-sessiond/agent.c b/src/bin/lttng-sessiond/agent.c
index 3b8acd2a..af65fa9c 100644
--- a/src/bin/lttng-sessiond/agent.c
+++ b/src/bin/lttng-sessiond/agent.c
@@ -149,8 +149,7 @@ static int ht_match_event(struct cds_lfht_node *node,
 	}
 
 	if (event->filter_expression) {
-		if (strncmp(event->filter_expression, key->filter_expression,
-				strlen(event->filter_expression)) != 0) {
+		if (strcmp(event->filter_expression, key->filter_expression) != 0) {
 			goto no_match;
 		}
 	}
diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index d91869fa..52591383 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -2310,7 +2310,7 @@ static int _cmd_enable_event(struct ltt_session *session,
 		}
 
 		/* The wild card * means that everything should be enabled. */
-		if (strncmp(event->name, "*", 1) == 0 && strlen(event->name) == 1) {
+		if (!strcmp(event->name, "*")) {
 			ret = event_agent_enable_all(usess, agt, event, filter,
 					filter_expression);
 		} else {
diff --git a/src/bin/lttng-sessiond/snapshot.c b/src/bin/lttng-sessiond/snapshot.c
index 447806bf..db7cfe77 100644
--- a/src/bin/lttng-sessiond/snapshot.c
+++ b/src/bin/lttng-sessiond/snapshot.c
@@ -251,7 +251,7 @@ struct snapshot_output *snapshot_find_output_by_name(const char *name,
 
 	cds_lfht_for_each_entry(snapshot->output_ht->ht, &iter.iter, output,
 		node.node) {
-		if (!strncmp(output->name, name, strlen(name))) {
+		if (!strcmp(output->name, name)) {
 			return output;
 		}
 	}
diff --git a/src/bin/lttng-sessiond/ust-registry.c b/src/bin/lttng-sessiond/ust-registry.c
index a8db79ea..8045075a 100644
--- a/src/bin/lttng-sessiond/ust-registry.c
+++ b/src/bin/lttng-sessiond/ust-registry.c
@@ -48,7 +48,7 @@ static int ht_match_event(struct cds_lfht_node *node, const void *_key)
 	key = _key;
 
 	/* It has to be a perfect match. First, compare the event names. */
-	if (strncmp(event->name, key->name, sizeof(event->name))) {
+	if (strcmp(event->name, key->name)) {
 		goto no_match;
 	}
 
diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
index 7aef4d50..3fd1ebd0 100644
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -885,15 +885,15 @@ int find_ctx_type_perf_raw(const char *ctx, struct ctx_type *type)
 		cur_list = NULL;
 		switch (field_pos) {
 		case 0:
-			if (strncmp(next, "perf", 4) != 0) {
+			if (strcmp(next, "perf") != 0) {
 				ret = -1;
 				goto end;
 			}
 			break;
 		case 1:
-			if (strncmp(next, "cpu", 3) == 0) {
+			if (strcmp(next, "cpu") == 0) {
 				type->opt->ctx_type = CONTEXT_PERF_CPU_COUNTER;
-			} else if (strncmp(next, "thread", 4) == 0) {
+			} else if (strcmp(next, "thread") == 0) {
 				type->opt->ctx_type = CONTEXT_PERF_THREAD_COUNTER;
 			} else {
 				ret = -1;
@@ -901,7 +901,7 @@ int find_ctx_type_perf_raw(const char *ctx, struct ctx_type *type)
 			}
 			break;
 		case 2:
-			if (strncmp(next, "raw", 3) != 0) {
+			if (strcmp(next, "raw") != 0) {
 				ret = -1;
 				goto end;
 			}
diff --git a/src/bin/lttng/commands/create.c b/src/bin/lttng/commands/create.c
index d2741c37..aea02dd3 100644
--- a/src/bin/lttng/commands/create.c
+++ b/src/bin/lttng/commands/create.c
@@ -264,9 +264,7 @@ static int create_session(void)
 		 */
 		if ((strncmp(opt_session_name, DEFAULT_SESSION_NAME "-",
 					strlen(DEFAULT_SESSION_NAME) + 1) == 0) ||
-				(strncmp(opt_session_name, DEFAULT_SESSION_NAME,
-					strlen(DEFAULT_SESSION_NAME)) == 0 &&
-				strlen(opt_session_name) == strlen(DEFAULT_SESSION_NAME))) {
+				(strcmp(opt_session_name, DEFAULT_SESSION_NAME) == 0)) {
 			ERR("%s is a reserved keyword for default session(s)",
 					DEFAULT_SESSION_NAME);
 			ret = CMD_ERROR;
diff --git a/src/bin/lttng/commands/enable_channels.c b/src/bin/lttng/commands/enable_channels.c
index b4e2942c..52d18bcc 100644
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -210,9 +210,9 @@ static int enable_channel(char *session_name)
 
 	/* Setting channel output */
 	if (opt_output) {
-		if (!strncmp(output_mmap, opt_output, strlen(output_mmap))) {
+		if (!strcmp(output_mmap, opt_output)) {
 			chan_opts.attr.output = LTTNG_EVENT_MMAP;
-		} else if (!strncmp(output_splice, opt_output, strlen(output_splice))) {
+		} else if (!strcmp(output_splice, opt_output)) {
 			chan_opts.attr.output = LTTNG_EVENT_SPLICE;
 		} else {
 			ERR("Unknown output type %s. Possible values are: %s, %s\n",
diff --git a/src/common/lttng-elf.c b/src/common/lttng-elf.c
index cd10632c..2487e8bf 100644
--- a/src/common/lttng-elf.c
+++ b/src/common/lttng-elf.c
@@ -975,6 +975,7 @@ int lttng_elf_get_sdt_probe_offsets(int fd, const char *provider_name,
 		 * and go to the next 4 byte alignement.
 		 */
 		if (note_type != NOTE_STAPSDT_TYPE ||
+			name_size != strlen(NOTE_STAPSDT_NAME) ||
 			strncmp(curr_data_ptr, NOTE_STAPSDT_NAME, name_size) != 0) {
 			continue;
 		}
diff --git a/src/common/testpoint/testpoint.c b/src/common/testpoint/testpoint.c
index 8ce5b9d2..d94772bb 100644
--- a/src/common/testpoint/testpoint.c
+++ b/src/common/testpoint/testpoint.c
@@ -20,7 +20,7 @@
 #define _LGPL_SOURCE
 #include <dlfcn.h>  /* for dlsym   */
 #include <stdlib.h> /* for getenv  */
-#include <string.h> /* for strncmp */
+#include <string.h> /* for strcmp */
 
 #include "testpoint.h"
 
@@ -39,7 +39,7 @@ static void __attribute__((constructor)) lttng_testpoint_check(void)
 
 	testpoint_env_val = getenv(lttng_testpoint_env_var);
 	if (testpoint_env_val != NULL
-			&& (strncmp(testpoint_env_val, "1", 1) == 0)) {
+			&& strcmp(testpoint_env_val, "1") == 0) {
 		lttng_testpoint_activated = 1;
 	}
 }
-- 
2.11.0



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