refactor: Remove VLA usage in hwinfo and target (docker, k8s) modules

Author: gfieni

src/hwinfo.c

@@ -36,6 +36,19 @@
 #include "hwinfo.h"
 #include "util.h"
 
+/*
+ * SYSFS_CPU_PATH stores the path leading to the available CPUs for the system.
+ */
+#define SYSFS_CPU_PATH "/sys/bus/cpu/devices"
+
+/*
+ * CPU_ID_REGEX is the regex used to extract the CPU id from its name.
+ * CPU_ID_REGEX_EXPECTED_MATCHES is the number of expected matches from the regex. (num groups + 1)
+ */
+#define CPU_ID_REGEX "^cpu([0-9]+)$"
+#define CPU_ID_REGEX_EXPECTED_MATCHES 2
+
+
 static struct hwinfo_pkg *
 hwinfo_pkg_create(void)
 {
@@ -79,11 +92,11 @@ static int
 get_cpu_online_status(const char *cpu_dir)
 {
     int status = 1;
-    char path[256];
+    char path[PATH_MAX] = {0};
     FILE *f = NULL;
     char buffer[2]; /* boolean expected */
 
-    snprintf(path, sizeof(path), "%s/%s/online", SYSFS_CPU_PATH, cpu_dir);
+    snprintf(path, PATH_MAX, "%s/%s/online", SYSFS_CPU_PATH, cpu_dir);
 
     f = fopen(path, "r");
     if (f) {
@@ -105,11 +118,11 @@ static char *
 get_package_id(const char *cpu_dir)
 {
     FILE *f = NULL;
-    char path[256];
+    char path[PATH_MAX] = {0};
     char buffer[24]; /* log10(ULLONG_MAX) */
     char *id = NULL;
 
-    snprintf(path, sizeof(path), "%s/%s/topology/physical_package_id", SYSFS_CPU_PATH, cpu_dir);
+    snprintf(path, PATH_MAX, "%s/%s/topology/physical_package_id", SYSFS_CPU_PATH, cpu_dir);
 
     f = fopen(path, "r");
     if (f) {
@@ -126,13 +139,11 @@ static char *
 parse_cpu_id_from_name(const char *str)
 {
     regex_t re = {0};
-    const char *expr = "^cpu([0-9]+)$";
-    const size_t num_matches = 2; /* num groups + 1 */
-    regmatch_t matches[num_matches];
+    regmatch_t matches[CPU_ID_REGEX_EXPECTED_MATCHES];
     char *id = NULL;
 
-    if (!regcomp(&re, expr, REG_EXTENDED)) {
-        if (!regexec(&re, str, num_matches, matches, 0)) {
+    if (!regcomp(&re, CPU_ID_REGEX, REG_EXTENDED)) {
+        if (!regexec(&re, str, CPU_ID_REGEX_EXPECTED_MATCHES, matches, 0)) {
             id = strndup(str + matches[1].rm_so, matches[1].rm_eo - matches[1].rm_so);
         }
         regfree(&re);

src/hwinfo.h

@@ -35,10 +35,6 @@
 #include <stddef.h>
 #include <czmq.h>
 
-/*
- * SYSFS_CPU_PATH stores the path leading to the available CPUs for the system.
- */
-#define SYSFS_CPU_PATH "/sys/bus/cpu/devices"
 
 /*
  * hwinfo_pkg stores information about the package.

src/target_docker.c

@@ -38,6 +38,21 @@
 #include "target.h"
 #include "target_docker.h"
 
+/*
+ * CONTAINER_ID_REGEX is the regex used to extract the Docker container id from the cgroup path.
+ * CONTAINER_ID_REGEX_EXPECTED_MATCHES is the number of expected matches from the regex. (num groups + 1)
+ */
+#define CONTAINER_ID_REGEX "perf_event/docker/([a-f0-9]{64})$"
+#define CONTAINER_ID_REGEX_EXPECTED_MATCHES 2
+
+/*
+ * CONTAINER_NAME_REGEX is the regex used to extract the Docker container name from its json configuration file.
+ * CONTAINER_NAME_REGEX_EXPECTED_MATCHES is the number of expected matches from the regex. (num groups + 1)
+ */
+#define CONTAINER_NAME_REGEX "\"Name\":\"/([a-zA-Z0-9][a-zA-Z0-9_.-]+)\""
+#define CONTAINER_NAME_REGEX_EXPECTED_MATCHES 2
+
+
 int
 target_docker_validate(const char *cgroup_path)
 {
@@ -47,7 +62,7 @@ target_docker_validate(const char *cgroup_path)
     if (!cgroup_path)
         return false;
 
-    if (!regcomp(&re, TARGET_DOCKER_EXTRACT_CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE | REG_NOSUB)) {
+    if (!regcomp(&re, CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE | REG_NOSUB)) {
         if (!regexec(&re, cgroup_path, 0, NULL, 0))
             is_docker_target = true;
 
@@ -61,20 +76,18 @@ static char *
 build_container_config_path(const char *cgroup_path)
 {
     regex_t re;
-    const size_t num_matches = 2;
-    regmatch_t matches[num_matches];
-    int res;
-    char config_path_buffer[TARGET_DOCKER_CONFIG_PATH_BUFFER_SIZE];
+    regmatch_t matches[CONTAINER_ID_REGEX_EXPECTED_MATCHES];
+    regoff_t length;
+    const char *id = NULL;
+    char buffer[PATH_MAX] = {0};
     char *config_path = NULL;
 
-    if (!regcomp(&re, TARGET_DOCKER_EXTRACT_CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE)) {
-        if (!regexec(&re, cgroup_path, num_matches, matches, 0)) {
-            res = snprintf(config_path_buffer, TARGET_DOCKER_CONFIG_PATH_BUFFER_SIZE,
-                    "/var/lib/docker/containers/%.*s/config.v2.json",
-                    matches[1].rm_eo - matches[1].rm_so, cgroup_path + matches[1].rm_so);
-
-            if (res > 0 && res < TARGET_DOCKER_CONFIG_PATH_BUFFER_SIZE)
-                config_path = strdup(config_path_buffer);
+    if (!regcomp(&re, CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE)) {
+        if (!regexec(&re, cgroup_path, CONTAINER_ID_REGEX_EXPECTED_MATCHES, matches, 0)) {
+            id = cgroup_path + matches[1].rm_so;
+            length = matches[1].rm_eo - matches[1].rm_so;
+            snprintf(buffer, PATH_MAX, "/var/lib/docker/containers/%.*s/config.v2.json", length, id);
+            config_path = strdup(buffer);
         }
         regfree(&re);
     }
@@ -90,8 +103,7 @@ target_docker_resolve_name(struct target *target)
     char *json = NULL;
     size_t json_len;
     regex_t re;
-    const size_t num_matches = 2;
-    regmatch_t matches[num_matches];
+    regmatch_t matches[CONTAINER_NAME_REGEX_EXPECTED_MATCHES];
     char *target_name = NULL;
 
     config_path = build_container_config_path(target->cgroup_path);
@@ -101,8 +113,8 @@ target_docker_resolve_name(struct target *target)
     json_file = fopen(config_path, "r");
     if (json_file) {
         if (getline(&json, &json_len, json_file) != -1) {
-            if (!regcomp(&re, TARGET_DOCKER_CONFIG_EXTRACT_NAME_REGEX, REG_EXTENDED | REG_NEWLINE)) {
-                if (!regexec(&re, json, num_matches, matches, 0))
+            if (!regcomp(&re, CONTAINER_NAME_REGEX, REG_EXTENDED | REG_NEWLINE)) {
+                if (!regexec(&re, json, CONTAINER_NAME_REGEX_EXPECTED_MATCHES, matches, 0))
                     target_name = strndup(json + matches[1].rm_so, matches[1].rm_eo - matches[1].rm_so);
 
                 regfree(&re);

src/target_docker.h

@@ -34,22 +34,6 @@
 
 #include "target.h"
 
-/*
- * TARGET_DOCKER_EXTRACT_CONTAINER_ID_REGEX stores the regex used to extract the container id from of a cgroup path.
- */
-#define TARGET_DOCKER_EXTRACT_CONTAINER_ID_REGEX "perf_event/docker/([a-f0-9]{64})$"
-
-/*
- * DOCKER_CONFIG_PATH_BUFFER_SIZE stores the max length of the path to the container config file.
- * /var/lib/docker/containers/756535dc6e9ab9b560f84c85063f55952273a23192641fc2756aa9721d9d1000/config.v2.json = 106
- */
-#define TARGET_DOCKER_CONFIG_PATH_BUFFER_SIZE 128
-
-/*
- * DOCKER_CONFIG_EXTRACT_NAME_REGEX stores the regex used to extract the name of the container from its json config file.
- */
-#define TARGET_DOCKER_CONFIG_EXTRACT_NAME_REGEX "\"Name\":\"/([a-zA-Z0-9][a-zA-Z0-9_.-]+)\""
-
 /*
  * target_docker_validate check if the cgroup path lead to a valid Docker target.
  */

src/target_kubernetes.c

@@ -35,6 +35,26 @@
 #include "target.h"
 #include "target_kubernetes.h"
 
+/*
+ * CONTAINER_ID_REGEX is the regex used to extract the Docker container id from a cgroup path.
+ * CONTAINER_ID_REGEX_EXPECTED_MATCHES is the number of matches expected from the regex. (num groups + 1)
+ */
+#define CONTAINER_ID_REGEX \
+    "perf_event/kubepods/" \
+    "(besteffort/|burstable/|)" \
+    "(pod[a-zA-Z0-9][a-zA-Z0-9.-]+)/" /* Pod ID */ \
+    "([a-f0-9]{64})" /* Container ID */ \
+    "(/[a-zA-Z0-9][a-zA-Z0-9.-]+|)" /* Resource group */
+#define CONTAINER_ID_REGEX_EXPECTED_MATCHES 5
+
+/*
+ * CONTAINER_NAME_REGEX is the regex used to extract the name of the Docker container from its json configuration file.
+ * CONTAINER_NAME_REGEX_EXPECTED_MATCHES is the number of matches expected from the regex. (num groups + 1)
+ */
+#define CONTAINER_NAME_REGEX "\"Name\":\"/([a-zA-Z0-9][a-zA-Z0-9_.-]+)\""
+#define CONTAINER_NAME_REGEX_EXPECTED_MATCHES 2
+
+
 int
 target_kubernetes_validate(const char *cgroup_path)
 {
@@ -44,7 +64,7 @@ target_kubernetes_validate(const char *cgroup_path)
     if (!cgroup_path)
         return false;
 
-    if (!regcomp(&re, TARGET_KUBERNETES_EXTRACT_CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE | REG_NOSUB)) {
+    if (!regcomp(&re, CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE | REG_NOSUB)) {
         if (!regexec(&re, cgroup_path, 0, NULL, 0))
             is_kubernetes_target = true;
 
@@ -58,20 +78,18 @@ static char *
 build_container_config_path(const char *cgroup_path)
 {
     regex_t re;
-    const size_t num_matches = 5;
-    regmatch_t matches[num_matches];
-    int res;
-    char path_buffer[TARGET_KUBERNETES_CONFIG_PATH_BUFFER_SIZE];
+    regmatch_t matches[CONTAINER_ID_REGEX_EXPECTED_MATCHES];
+    regoff_t length;
+    const char *id = NULL;
+    char buffer[PATH_MAX] = {0};
     char *config_path = NULL;
 
-    if (!regcomp(&re, TARGET_KUBERNETES_EXTRACT_CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE)) {
-        if (!regexec(&re, cgroup_path, num_matches, matches, 0)) {
-            res = snprintf(path_buffer, TARGET_KUBERNETES_CONFIG_PATH_BUFFER_SIZE,
-                    "/var/lib/docker/containers/%.*s/config.v2.json",
-                    matches[3].rm_eo - matches[3].rm_so, cgroup_path + matches[3].rm_so);
-
-            if (res > 0 && res < TARGET_KUBERNETES_CONFIG_PATH_BUFFER_SIZE)
-                config_path = strdup(path_buffer);
+    if (!regcomp(&re, CONTAINER_ID_REGEX, REG_EXTENDED | REG_NEWLINE)) {
+        if (!regexec(&re, cgroup_path, CONTAINER_ID_REGEX_EXPECTED_MATCHES, matches, 0)) {
+            id = cgroup_path + matches[3].rm_so;
+            length = matches[3].rm_eo - matches[3].rm_so;
+            snprintf(buffer, PATH_MAX, "/var/lib/docker/containers/%.*s/config.v2.json", length, id);
+            config_path = strdup(buffer);
         }
         regfree(&re);
     }
@@ -87,8 +105,7 @@ target_kubernetes_resolve_name(struct target *target)
     char *json = NULL;
     size_t json_len;
     regex_t re;
-    const size_t num_matches = 2;
-    regmatch_t matches[num_matches];
+    regmatch_t matches[CONTAINER_NAME_REGEX_EXPECTED_MATCHES];
     char *target_name = NULL;
 
     config_path = build_container_config_path(target->cgroup_path);
@@ -98,8 +115,8 @@ target_kubernetes_resolve_name(struct target *target)
     json_file = fopen(config_path, "r");
     if (json_file) {
         if (getline(&json, &json_len, json_file) != -1) {
-            if (!regcomp(&re, TARGET_KUBERNETES_EXTRACT_CONTAINER_NAME_REGEX, REG_EXTENDED | REG_NEWLINE)) {
-                if (!regexec(&re, json, num_matches, matches, 0))
+            if (!regcomp(&re, CONTAINER_NAME_REGEX, REG_EXTENDED | REG_NEWLINE)) {
+                if (!regexec(&re, json, CONTAINER_NAME_REGEX_EXPECTED_MATCHES, matches, 0))
                     target_name = strndup(json + matches[1].rm_so, matches[1].rm_eo - matches[1].rm_so);
 
                 regfree(&re);

src/target_kubernetes.h

@@ -34,27 +34,6 @@
 
 #include "target.h"
 
-/*
- * TARGET_KUBERNETES_EXTRACT_CONTAINER_ID_REGEX stores the regex used to extract the Docker container id from a cgroup path.
- */
-#define TARGET_KUBERNETES_EXTRACT_CONTAINER_ID_REGEX \
-    "perf_event/kubepods/" \
-    "(besteffort/|burstable/|)" \
-    "(pod[a-zA-Z0-9][a-zA-Z0-9.-]+)/" /* Pod ID */ \
-    "([a-f0-9]{64})" /* Container ID */ \
-    "(/[a-zA-Z0-9][a-zA-Z0-9.-]+|)" /* Resource group */
-
-/*
- * TARGET_KUBERNETES_EXTRACT_CONTAINER_NAME_REGEX stores the regex used to extract the name of the Docker container from
- * the json configuration file.
- */
-#define TARGET_KUBERNETES_EXTRACT_CONTAINER_NAME_REGEX "\"Name\":\"/([a-zA-Z0-9][a-zA-Z0-9_.-]+)\""
-
-/*
- * TARGET_KUBERNETES_CONFIG_PATH_BUFFER_SIZE stores the buffer size for the path to the Docker config file.
- */
-#define TARGET_KUBERNETES_CONFIG_PATH_BUFFER_SIZE 128
-
 /*
  * target_kubernetes_validate check if the cgroup path lead to a valid Kubernetes target.
  */