[K/N] Expose program name in runtime #5281

vonox7 · 2024-03-21T15:39:55Z

*^[KTI-54606](https://youtrack.jetbrains.com/issue/KT-54606) Fixed*

SvyatoslavScherbina · 2024-04-26T14:53:10Z

kotlin-native/backend.native/tests/build.gradle

@@ -380,6 +380,10 @@ standaloneTest("throw_from_except_constr") {
    source = "runtime/exceptions/throw_from_except_constr.kt"
 }

+standaloneTest("program_name") {
+    source = "runtime/program_name/runtime_program_name.kt"
+}


This file represents the legacy test infrastructure that we are actively trying to get rid of.

Please create a proper test class in
https://github.com/JetBrains/kotlin/tree/master/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox instead.

I ported the testcase to the new infrastructure.

SvyatoslavScherbina · 2024-04-26T14:58:47Z

kotlin-native/runtime/src/launcher/cpp/launcher.cpp

@@ -30,6 +30,8 @@ using namespace kotlin;
 //--- Setup args --------------------------------------------------------------//

 OBJ_GETTER(setupArgs, int argc, const char** argv) {
+  kotlin::programName = argv[0];


Is argv[0] guaranteed to live long enough? What will happen if some code accesses kotlin::programName after the main function finishes?
Is argv guaranteed to always have at least one element?

programName will now be set to null before argv leaves scope. I could not find a definite answer if it would be guaranteed to live long enough, so I opted for the safe choice.

Theoretically it is guaranteed by the POSIX standard. However if it has 0 arguments, the code 1 line below would have crashed. I also added a testcase for argc=0, and added support for it via std::max(0, ...). So now kotlin executables don't crash on startup when they are launched in a non posix compatible way.

SvyatoslavScherbina · 2024-04-26T15:00:53Z

kotlin-native/runtime/src/main/kotlin/kotlin/native/Platform.kt

+     * Representation of the name used to invoke the program executable.
+     */
+    public val programName: String
+        get() = Platform_getProgramName()


What will happen if the execution is never reached setupArgs, but this property is accessed? E.g. when compiling Kotlin code to a native library.

A test for that would also be nice.

Thanks for the pointer with the native library. In that case the programName doesn't even have a meaning, therefore it is now nullable. I added a test for that too using the new test infrastructure.

SvyatoslavScherbina · 2024-04-26T15:02:50Z

kotlin-native/backend.native/tests/runtime/program_name/runtime_program_name.kt

+    val programFileName = Platform.programName.substringAfterLast("/").substringBeforeLast(".")
+
+    assertEquals("program_name", programFileName)
+}


More tests are necessary. For example, the original issue mentions a nice use case:

Build multi-call binaries. For example, busybox is a single binary that contains many tools, and decides which tool to run based on how the symbolic link is called: https://busybox.net/downloads/BusyBox.html#usage (that's how it can be so small)

So checking a case with symbolic link would also be useful.

I added test for that by calling execv() in the C code. This allowed to test even more use-cases (no programName at all), while still covering the use-case of renaming/linking a binary.

# Conflicts: # kotlin-native/backend.native/tests/build.gradle

SvyatoslavScherbina · 2024-05-13T10:22:24Z

native/native.tests/build.gradle.kts

@@ -51,6 +51,7 @@ val stdlibK2Test = nativeTest("stdlibK2Test", "stdlib & frontend-fir")
 val kotlinTestLibraryTest = nativeTest("kotlinTestLibraryTest", "kotlin-test & !frontend-fir")
 val kotlinTestLibraryK2Test = nativeTest("kotlinTestLibraryK2Test", "kotlin-test & frontend-fir")
 val partialLinkageTest = nativeTest("partialLinkageTest", "partial-linkage")
+val programNameTest = nativeTest("programNameTest", "program-name")


This seems a bit redudant. I mean, running these tests separately shouldn't happen frequently, so adding a Gradle task is overkill.

SvyatoslavScherbina · 2024-05-13T12:38:02Z

native/native.tests/testData/programName/kotlinPrintEntryPoint.kt

+
+fun main(args: Array<String>) {
+    // Remove path and extension (.kexe or .exe)
+    val programFileName = Platform.programName?.substringAfterLast("/")?.substringBeforeLast(".")


This test fails on Windows, because it uses \ instead of /.

SvyatoslavScherbina · 2024-05-13T13:07:19Z

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/ProgramNameTest.kt

+            val result = runProcess(cExecutable.absolutePath, binaryName, *args) {
+                timeout = 60.seconds
+            }
+            assertEquals("calling exec...\n$expected", result.stdout)


I suspect this code should be fixed to handle \r\n on Windows.

SvyatoslavScherbina · 2024-05-13T13:07:42Z

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/ProgramNameTest.kt

+
+        fun validate(expected: String, vararg args: String) {
+            val binaryName = kotlinCompilation.resultingArtifact.executableFile.path
+            val result = runProcess(cExecutable.absolutePath, binaryName, *args) {


This fails if the test target is different from the host. You can reproduce this by running this test with -Pkotlin.internal.native.test.target=<target> Gradle property.

Please use a proper executor through

kotlin/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/settings/SettingsExecutor.kt

Line 18 in 8c69667

val Settings.executor: Executor

SvyatoslavScherbina · 2024-05-13T13:08:48Z

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/ProgramNameTest.kt

+        // No program name - this would not be POSIX compliant, see https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html:
+        // "[...] requires a Strictly Conforming POSIX Application to pass at least one argument to the exec function"
+        // However, we should not crash the Kotlin runtime because of this.
+        validate("programName: null\nargs:")


On Linux, this fails for me with

java.lang.AssertionError: Expected <calling exec... programName: null args:>, actual <calling exec... programName: args:>.

Please take a look.

…ek/program-name

[K/N] Expose program name in runtime

1ff362a

*^[KTI-54606](https://youtrack.jetbrains.com/issue/KT-54606) Fixed*

ivakub added the Native label Apr 8, 2024

SvyatoslavScherbina requested changes Apr 26, 2024

View reviewed changes

vonox7 added 5 commits April 29, 2024 14:57

Merge branch 'refs/heads/master' into slawicek/program-name

05d57ee

# Conflicts: # kotlin-native/backend.native/tests/build.gradle

Move programName testcase to new test infrastructure

f73045e

Add testcase for calling Platform.getProgramName from within a library

fb67427

Execute Kotlin executable via execv to pass custom programNames

2703f15

Support argc=0

3b66b6b

vonox7 requested a review from SvyatoslavScherbina April 30, 2024 14:05

Merge branch 'JetBrains:master' into slawicek/program-name

285dd67

SvyatoslavScherbina requested changes May 13, 2024

View reviewed changes

vonox7 added 4 commits May 15, 2024 10:45

Use proper executor

69e660f

Merge remote-tracking branch 'vali/slawicek/program-name' into slawic…

a69b027

…ek/program-name

Remove unneeded gradle task

6d07cf2

Ignore different windows path & line-endings

2fcf1f0

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[K/N] Expose program name in runtime #5281

[K/N] Expose program name in runtime #5281

vonox7 commented Mar 21, 2024

SvyatoslavScherbina Apr 26, 2024

vonox7 Apr 30, 2024

SvyatoslavScherbina Apr 26, 2024

vonox7 Apr 30, 2024 •

edited

SvyatoslavScherbina Apr 26, 2024

vonox7 Apr 30, 2024

SvyatoslavScherbina Apr 26, 2024

vonox7 Apr 30, 2024

SvyatoslavScherbina May 13, 2024

SvyatoslavScherbina May 13, 2024

SvyatoslavScherbina May 13, 2024

SvyatoslavScherbina May 13, 2024

SvyatoslavScherbina May 13, 2024

[K/N] Expose program name in runtime #5281

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[K/N] Expose program name in runtime #5281

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vonox7 commented Mar 21, 2024

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vonox7 Apr 30, 2024 • edited

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vonox7 Apr 30, 2024 •

edited