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Commit 9f49508f authored by Elliott Hughes's avatar Elliott Hughes
Browse files

Rewrite get_sched_policy_name for safety. 

This way you'll get a build time error if you make the usual mistake of
adding to the enum but not adding an entry to the array.

Also improve the unit tests, and fix get_sched_policy_name's incorrect
behavior on invalid inputs.

Bug: N/A
Test: ran tests
Change-Id: Iefcb1ec9ef66267837da7a576c8be3d0cfb16cd0
parent 419ba9e2

libcutils/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -164,6 +164,7 @@ cc_library { 


    shared_libs: ["liblog"],

    header_libs: [

        "libbase_headers",

        "libcutils_headers",

        "libutils_headers",

    ],

libcutils/sched_policy.cpp

+7 −6
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <string.h>

#include <unistd.h>



#include <android-base/macros.h>

#include <log/log.h>



/* Re-map SP_DEFAULT to the system default policy, and leave other values unchanged.
@@ -460,16 +461,16 @@ int get_sched_policy(int /*tid*/, SchedPolicy* policy) { 


#endif



const char *get_sched_policy_name(SchedPolicy policy)

{

const char* get_sched_policy_name(SchedPolicy policy) {

    policy = _policy(policy);

    static const char* const strings[SP_CNT] = {

    static const char* const kSchedPolicyNames[] = {

            [SP_BACKGROUND] = "bg", [SP_FOREGROUND] = "fg", [SP_SYSTEM] = "  ",

            [SP_AUDIO_APP] = "aa",  [SP_AUDIO_SYS] = "as",  [SP_TOP_APP] = "ta",

            [SP_RT_APP] = "rt",     [SP_RESTRICTED] = "rs",

    };

    if ((policy < SP_CNT) && (strings[policy] != NULL))

        return strings[policy];

    else

    static_assert(arraysize(kSchedPolicyNames) == SP_CNT, "missing name");

    if (policy < SP_BACKGROUND || policy >= SP_CNT) {

        return "error";

    }

    return kSchedPolicyNames[policy];

}

libcutils/tests/sched_policy_test.cpp

+12 −12
Original line number Diff line number Diff line
@@ -60,6 +60,12 @@ long long medianSleepTime() { 
    return sleepTimes[median];

}



static void AssertPolicy(SchedPolicy expected_policy) {

    SchedPolicy current_policy;

    ASSERT_EQ(0, get_sched_policy(0, &current_policy));

    EXPECT_EQ(expected_policy, current_policy);

}



TEST(SchedPolicy, set_sched_policy) {

    if (!hasCapSysNice()) {

        GTEST_LOG_(INFO) << "skipping test that requires CAP_SYS_NICE";
@@ -76,23 +82,17 @@ TEST(SchedPolicy, set_sched_policy) { 
    const unsigned int BG_FG_SLACK_FACTOR = 100;



    ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));

    AssertPolicy(SP_BACKGROUND);

    auto bgSleepTime = medianSleepTime();



    ASSERT_EQ(0, set_sched_policy(0, SP_FOREGROUND));

    AssertPolicy(SP_FOREGROUND);

    auto fgSleepTime = medianSleepTime();

    ASSERT_GT(bgSleepTime, fgSleepTime * BG_FG_SLACK_FACTOR);

}



TEST(SchedPolicy, get_sched_policy) {

    SchedPolicy policy;

    ASSERT_EQ(0, get_sched_policy(0, &policy));



    const char *policyName = get_sched_policy_name(policy);

    EXPECT_NE(nullptr, policyName);

    EXPECT_STRNE("error", policyName);



    ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));

    SchedPolicy newPolicy;

    ASSERT_EQ(0, get_sched_policy(0, &newPolicy));

    EXPECT_EQ(SP_BACKGROUND, newPolicy);

TEST(SchedPolicy, get_sched_policy_name) {

    EXPECT_STREQ("bg", get_sched_policy_name(SP_BACKGROUND));

    EXPECT_STREQ("error", get_sched_policy_name(SchedPolicy(-2)));

    EXPECT_STREQ("error", get_sched_policy_name(SP_CNT));

}