Add partial name-to-mib functionality

include/jemalloc/internal/ctl.h

@@ -98,9 +98,10 @@ typedef struct ctl_arenas_s {
 int ctl_byname(tsd_t *tsd, const char *name, void *oldp, size_t *oldlenp,
     void *newp, size_t newlen);
 int ctl_nametomib(tsd_t *tsd, const char *name, size_t *mibp, size_t *miblenp);
-
 int ctl_bymib(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen);
+int ctl_mibnametomib(tsd_t *tsd, size_t *mib, size_t miblen, const char *name,
+    size_t *miblenp);
 bool ctl_boot(void);
 void ctl_prefork(tsdn_t *tsdn);
 void ctl_postfork_parent(tsdn_t *tsdn);

src/ctl.c

@@ -1528,6 +1528,36 @@ label_return:
 	return(ret);
 }
 
+int
+ctl_mibnametomib(tsd_t *tsd, size_t *mib, size_t miblen, const char *name,
+    size_t *miblenp) {
+	int ret;
+	const ctl_named_node_t *node;
+
+	if (!ctl_initialized && ctl_init(tsd)) {
+		ret = EAGAIN;
+		goto label_return;
+	}
+
+	ret = ctl_lookupbymib(tsd_tsdn(tsd), &node, mib, miblen);
+	if (ret != 0) {
+		goto label_return;
+	}
+	if (node == NULL || node->ctl != NULL) {
+		ret = ENOENT;
+		goto label_return;
+	}
+
+	assert(miblenp != NULL);
+	assert(*miblenp >= miblen);
+	*miblenp -= miblen;
+	ret = ctl_lookup(tsd_tsdn(tsd), node, name, NULL, mib + miblen,
+	    miblenp);
+	*miblenp += miblen;
+label_return:
+	return(ret);
+}
+
 bool
 ctl_boot(void) {
 	if (malloc_mutex_init(&ctl_mtx, "ctl", WITNESS_RANK_CTL,

test/unit/mallctl.c

@@ -1,5 +1,6 @@
 #include "test/jemalloc_test.h"
 
+#include "jemalloc/internal/ctl.h"
 #include "jemalloc/internal/hook.h"
 #include "jemalloc/internal/util.h"
 
@@ -131,6 +132,61 @@ TEST_BEGIN(test_mallctlnametomib_short_name) {
 }
 TEST_END
 
+TEST_BEGIN(test_mallctlmibnametomib) {
+	size_t mib[4];
+	size_t miblen = 4;
+	uint32_t result, result_ref;
+	size_t len_result = sizeof(uint32_t);
+
+	tsd_t *tsd = tsd_fetch();
+
+	/* Error cases */
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 0, "bob", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 0, "9999", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+
+	/* Valid case. */
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 0, "arenas", &miblen), 0, "");
+	assert_zu_eq(miblen, 1, "");
+	miblen = 4;
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 1, "bin", &miblen), 0, "");
+	assert_zu_eq(miblen, 2, "");
+	expect_d_eq(mallctlbymib(mib, miblen, &result, &len_result, NULL, 0),
+	    ENOENT, "mallctlbymib() should fail on partial path");
+
+	/* Error cases. */
+	miblen = 4;
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 2, "bob", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 2, "9999", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+
+	/* Valid case. */
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 2, "0", &miblen), 0, "");
+	assert_zu_eq(miblen, 3, "");
+	expect_d_eq(mallctlbymib(mib, miblen, &result, &len_result, NULL, 0),
+	    ENOENT, "mallctlbymib() should fail on partial path");
+
+	/* Error cases. */
+	miblen = 4;
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 3, "bob", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 3, "9999", &miblen), ENOENT, "");
+	assert_zu_eq(miblen, 4, "");
+
+	/* Valid case. */
+	assert_d_eq(ctl_mibnametomib(tsd, mib, 3, "nregs", &miblen), 0, "");
+	assert_zu_eq(miblen, 4, "");
+	assert_d_eq(mallctlbymib(mib, miblen, &result, &len_result, NULL, 0),
+	    0, "Unexpected mallctlbymib() failure");
+	assert_d_eq(mallctl("arenas.bin.0.nregs", &result_ref, &len_result,
+	    NULL, 0), 0, "Unexpected mallctl() failure");
+	expect_zu_eq(result, result_ref,
+	    "mallctlbymib() and mallctl() returned different result");
+}
+TEST_END
+
 TEST_BEGIN(test_mallctl_config) {
 #define TEST_MALLCTL_CONFIG(config, t) do {				\
 	t oldval;							\
@@ -1121,6 +1177,7 @@ main(void) {
 	    test_mallctl_read_write,
 	    test_mallctlnametomib_short_mib,
 	    test_mallctlnametomib_short_name,
+	    test_mallctlmibnametomib,
 	    test_mallctl_config,
 	    test_mallctl_opt,
 	    test_manpage_example,