basic/cgroup-util: simplify cg_get_keyed_attribute(), add test

I didn't like the nested loop where we'd count what we have acquired already,
since we should always know that.

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 7944785bbfa0f9474b6c9be3a9c05b5a91955983..9c3905e91e10c17ade551d52fc337376768de3f7 100644 (file)
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -2042,7 +2042,7 @@ int cg_get_keyed_attribute(
         _cleanup_free_ char *filename = NULL, *contents = NULL;
         _cleanup_fclose_ FILE *f = NULL;
         const char *p;
-        size_t n, i;
+        size_t n, i, n_done = 0;
         char **v;
         int r;
 
@@ -2069,42 +2069,31 @@ int cg_get_keyed_attribute(
 
         for (p = contents; *p;) {
                 const char *w = NULL;
-                size_t n_done = 0;
 
-                for (i = 0; i < n; i++) {
-                        if (v[i])
-                                n_done ++;
-                        else {
+                for (i = 0; i < n; i++)
+                        if (!v[i]) {
                                 w = first_word(p, keys[i]);
                                 if (w)
                                         break;
                         }
-                }
 
                 if (w) {
-                        char *c;
                         size_t l;
 
                         l = strcspn(w, NEWLINE);
-                        c = strndup(w, l);
-                        if (!c) {
+                        v[i] = strndup(w, l);
+                        if (!v[i]) {
                                 r = -ENOMEM;
                                 goto fail;
                         }
 
-                        v[i] = c;
                         n_done++;
-
                         if (n_done >= n)
                                 goto done;
 
                         p = w + l;
-                } else {
-                        if (n_done >= n)
-                                goto done;
-
+                } else
                         p += strcspn(p, NEWLINE);
-                }
 
                 p += strspn(p, NEWLINE);
         }

diff --git a/src/test/test-cgroup-util.c b/src/test/test-cgroup-util.c
index 2248a306359e1d737ff56ed3766d985757b8780a..c4163fc3a973b6d41de43bf0b73882db4878fc41 100644 (file)
--- a/src/test/test-cgroup-util.c
+++ b/src/test/test-cgroup-util.c
@@ -30,6 +30,7 @@
 #include "special.h"
 #include "stat-util.h"
 #include "string-util.h"
+#include "strv.h"
 #include "test-helper.h"
 #include "user-util.h"
 #include "util.h"
@@ -404,6 +405,45 @@ static void test_cg_tests(void) {
                 assert_se(!systemd);
 }
 
+static void test_cg_get_keyed_attribute(void) {
+        _cleanup_free_ char *val = NULL;
+        char *vals3[3] = {}, *vals3a[3] = {};
+        int i;
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "no_such_file", STRV_MAKE("no_such_attr"), &val) == -ENOENT);
+        assert_se(val == NULL);
+
+        if (access("/sys/fs/cgroup/init.scope/cpu.stat", R_OK) < 0) {
+                log_info_errno(errno, "Skipping most of %s, /init.scope/cpu.stat not accessible: %m", __func__);
+                return;
+        }
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat", STRV_MAKE("no_such_attr"), &val) == -ENXIO);
+        assert_se(val == NULL);
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat", STRV_MAKE("usage_usec"), &val) == 0);
+        log_info("cpu /init.scope cpu.stat [usage_usec] → \"%s\"", val);
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat", STRV_MAKE("usage_usec", "no_such_attr"), vals3) == -ENXIO);
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat", STRV_MAKE("usage_usec", "usage_usec"), vals3) == -ENXIO);
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat",
+                                         STRV_MAKE("usage_usec", "user_usec", "system_usec"), vals3) == 0);
+        log_info("cpu /init.scope cpu.stat [usage_usec user_usec system_usec] → \"%s\", \"%s\", \"%s\"",
+                 vals3[0], vals3[1], vals3[2]);
+
+        assert_se(cg_get_keyed_attribute("cpu", "/init.scope", "cpu.stat",
+                                         STRV_MAKE("system_usec", "user_usec", "usage_usec"), vals3a) == 0);
+        log_info("cpu /init.scope cpu.stat [system_usec user_usec usage_usec] → \"%s\", \"%s\", \"%s\"",
+                 vals3a[0], vals3a[1], vals3a[2]);
+
+        for (i = 0; i < 3; i++) {
+                free(vals3[i]);
+                free(vals3a[i]);
+        }
+}
+
 int main(void) {
         log_set_max_level(LOG_DEBUG);
         log_parse_environment();
@@ -429,6 +469,7 @@ int main(void) {
         test_is_wanted_print(false); /* run twice to test caching */
         test_is_wanted();
         test_cg_tests();
+        test_cg_get_keyed_attribute();
 
         return 0;
 }