Initial commit

.gitignore

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+build/

Makefile

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+.PHONY: all
+all: build/parent-null build/parent-ptr build/child
+
+build:
+	@mkdir -p build
+
+build/parent-null: build
+	$(CC) -o build/parent-null src/parent.c
+
+build/parent-ptr: build
+	$(CC) -o build/parent-ptr -DPTR_TO_NULL src/parent.c
+
+build/child: build
+	$(CC) -o build/child src/child.c
+
+.PHONY: test
+test: all
+	@echo "==> Testing execve with { NULL }..."
+	./build/parent-ptr ./build/child
+	@echo "==> Testing execve with NULL..."
+	./build/parent-null ./build/child
+
+.PHONY: clean
+clean:
+	@rm -fr build

README.md

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+# argv0-test
+
+Simple tester for weird execve calls.
+
+## How to use
+```
+$ make test
+```

src/child.c

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+#include <stdio.h>
+
+int
+main(int argc, char *argv[]) {
+    printf("childproc: argc == %d!\n", argc);
+    return 0;
+}

src/parent.c

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+#include <stdio.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv, char **envp)
+{
+    char *arr = NULL;
+    char **ptr = 
+#ifdef PTR_TO_NULL
+        &arr;
+    printf("%s: using &NULL as argv...\n", argv[0]);
+#else
+        NULL;
+    printf("%s: using just NULL as argv...\n", argv[0]);
+#endif
+    printf("%s: argv == %p\n", argv[0], ptr);
+    execve(argv[1], ptr, envp);
+
+    return 0;
+}