Add tests for usdt library probes

Adding runtime tests that ensure we can list and probe tracepoints not
present in the main binary, but rather in linked shared libraries.

tests/CMakeLists.txt

@@ -198,11 +198,14 @@ foreach(testprog ${testprogs})
   if(HAVE_SYSTEMTAP_SYS_SDT_H)
     target_compile_definitions(${bin_name} PRIVATE HAVE_SYSTEMTAP_SYS_SDT_H)
   endif(HAVE_SYSTEMTAP_SYS_SDT_H)
-  set_target_properties( ${bin_name} PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/testprogs/ COMPILE_FLAGS "-g -O0" LINK_FLAGS "-no-pie")
+  set_target_properties(${bin_name} PROPERTIES LINK_SEARCH_START_STATIC FALSE LINK_SEARCH_END_STATIC FALSE RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/testprogs/ COMPILE_FLAGS "-g -O0" LINK_FLAGS "-no-pie")
   list(APPEND compiled_testprogs ${CMAKE_CURRENT_BINARY_DIR}/testprogs/${bin_name})
 endforeach()
 add_custom_target(testprogs DEPENDS ${compiled_testprogs})
 
+target_include_directories(usdt_lib PUBLIC ${CMAKE_SOURCE_DIR}/tests/testlibs/)
+target_link_libraries(usdt_lib -shared usdt_tp)
+
 # Similarly compile all test libs
 file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/testlibs/)
 file(GLOB testlibs testlibs/*.c)
@@ -211,6 +214,9 @@ foreach(testlib_source ${testlibs})
   get_filename_component(testlib_name ${testlib_source} NAME_WE)
   add_library(${testlib_name} SHARED ${testlib_source})
   set_target_properties(${testlib_name} PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/testlibs/ COMPILE_FLAGS "-g -O0")
+  if(HAVE_SYSTEMTAP_SYS_SDT_H)
+    target_compile_definitions(${testlib_name} PRIVATE HAVE_SYSTEMTAP_SYS_SDT_H)
+  endif(HAVE_SYSTEMTAP_SYS_SDT_H)
   # clear the executable bit
   add_custom_command(TARGET ${testlib_name}
     POST_BUILD
@@ -219,6 +225,8 @@ foreach(testlib_source ${testlibs})
 endforeach()
 add_custom_target(testlibs DEPENDS ${compiled_testlibs})
 
+target_compile_options(usdt_tp PRIVATE -fPIC)
+
 configure_file(runtime-tests.sh runtime-tests.sh COPYONLY)
 file(GLOB runtime_tests runtime/*)
 list(REMOVE_ITEM runtime_tests ${CMAKE_CURRENT_SOURCE_DIR}/runtime/engine)

tests/runtime/usdt

@@ -11,6 +11,13 @@ TIMEOUT 5
 BEFORE ./testprogs/usdt_test
 REQUIRES ./testprogs/usdt_test should_not_skip
 
+NAME "usdt probes - lists linked library probes by pid"
+RUN bpftrace -l 'usdt:*' -p $(pidof usdt_lib)
+EXPECT libusdt_tp.so:tracetestlib:lib_probe_1
+TIMEOUT 5
+BEFORE ./testprogs/usdt_lib
+REQUIRES ./testprogs/usdt_lib should_not_skip
+
 NAME "usdt probes - filter probes by file on provider"
 RUN bpftrace -l 'usdt:./testprogs/usdt_test:tracetest2:*'
 EXPECT usdt:./testprogs/usdt_test:tracetest2:testprobe2
@@ -62,6 +69,13 @@ BEFORE ./testprogs/usdt_test
 REQUIRES ./testprogs/usdt_test should_not_skip
 TIMEOUT 5
 
+NAME "usdt probes - attach to fully specified library probe by pid"
+RUN bpftrace -e 'usdt:./testlibs/libusdt_tp.so.so:tracetestlib:lib_probe_1 { printf("here\n" ); exit(); }' -p $(pidof usdt_lib)
+BEFORE ./testprogs/usdt_lib
+EXPECT here
+TIMEOUT 5
+REQUIRES ./testprogs/usdt_lib should_not_skip
+
 NAME "usdt probes - all probes by wildcard and file"
 RUN bpftrace -e 'usdt:./testprogs/usdt_test:* { printf("here\n" ); exit(); }'
 EXPECT Attaching 3 probes...

tests/testlibs/usdt_tp.c

@@ -0,0 +1,19 @@
+#ifdef HAVE_SYSTEMTAP_SYS_SDT_H
+#include <sys/sdt.h>
+#else
+#define DTRACE_PROBE2(a, b, c, d) (void)0
+#endif
+#include "usdt_tp.h"
+#include <stdio.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+long myclock()
+{
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  DTRACE_PROBE2(tracetestlib, lib_probe_1, tv.tv_sec, "Hello world");
+  DTRACE_PROBE2(tracetestlib, lib_probe_1, tv.tv_sec, "Hello world2");
+  DTRACE_PROBE2(tracetestlib2, lib_probe_2, tv.tv_sec, "Hello world3");
+  return tv.tv_sec;
+}

tests/testlibs/usdt_tp.h

@@ -0,0 +1,4 @@
+#ifndef _USDTLIBX_H_
+#define _USDTLIBX_H_
+extern long myclock();
+#endif

tests/testprogs/usdt_lib.c

@@ -0,0 +1,20 @@
+#include "usdt_tp.h"
+#include <stdio.h>
+
+int main(int argc, char **argv __attribute__((unused)))
+{
+  if (argc > 1)
+  // If we don't have Systemtap headers, we should skip USDT tests. Returning 1
+  // can be used as validation in the REQUIRE
+#ifndef HAVE_SYSTEMTAP_SYS_SDT_H
+    return 1;
+#else
+    return 0;
+#endif
+
+  while (1)
+  {
+    myclock();
+  }
+  return 0;
+}