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[NO-TICKET] Minor: Fix checking for dladdr in profiling #4783

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merged 1 commit into from
Jul 9, 2025
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[NO-TICKET] Minor: Fix checking for dladdr in profiling #4783

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39 changes: 19 additions & 20 deletions ext/datadog_profiling_native_extension/collectors_stack.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,13 +4,12 @@

#include "extconf.h" // This is needed for the HAVE_DLADDR and friends below

// For dladdr/dladdr1
#if defined(HAVE_DLADDR1) || defined(HAVE_DLADDR)
#if (defined(HAVE_DLADDR1) && HAVE_DLADDR1) || (defined(HAVE_DLADDR) && HAVE_DLADDR)
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <dlfcn.h>
#ifdef HAVE_DLADDR1
#if defined(HAVE_DLADDR1) && HAVE_DLADDR1
#include <link.h>
#endif
#endif
Expand Down Expand Up @@ -63,24 +62,24 @@ void collectors_stack_init(VALUE profiling_module) {

rb_define_singleton_method(testing_module, "_native_sample", _native_sample, -1);

#if defined(HAVE_DLADDR1) || defined(HAVE_DLADDR)
// To be able to detect when a frame is coming from Ruby, we record here its filename as returned by dladdr.
// We expect this same pointer to be returned by dladdr for all frames coming from Ruby.
//
// Small note: Creating/deleting the cache is a bit awkward here, but it seems like a bigger footgun to allow
// `get_or_compute_native_filename` to run without a cache, since we never expect that to happen during sampling. So it seems
// like a reasonable trade-off to force callers to always figure that out.
st_table *temporary_cache = st_init_numtable();
const char *native_filename = get_or_compute_native_filename(rb_ary_new, temporary_cache);
if (native_filename != NULL && native_filename[0] != '\0') {
ruby_native_filename = native_filename;
}
st_free_table(temporary_cache);
#if (defined(HAVE_DLADDR1) && HAVE_DLADDR1) || (defined(HAVE_DLADDR) && HAVE_DLADDR)
// To be able to detect when a frame is coming from Ruby, we record here its filename as returned by dladdr.
// We expect this same pointer to be returned by dladdr for all frames coming from Ruby.
//
// Small note: Creating/deleting the cache is a bit awkward here, but it seems like a bigger footgun to allow
// `get_or_compute_native_filename` to run without a cache, since we never expect that to happen during sampling. So it seems
// like a reasonable trade-off to force callers to always figure that out.
st_table *temporary_cache = st_init_numtable();
const char *native_filename = get_or_compute_native_filename(rb_ary_new, temporary_cache);
if (native_filename != NULL && native_filename[0] != '\0') {
ruby_native_filename = native_filename;
}
st_free_table(temporary_cache);
#endif
}

static VALUE _native_filenames_available(DDTRACE_UNUSED VALUE self) {
#if defined(HAVE_DLADDR1) || defined(HAVE_DLADDR)
#if (defined(HAVE_DLADDR1) && HAVE_DLADDR1) || (defined(HAVE_DLADDR) && HAVE_DLADDR)
return ruby_native_filename != NULL ? Qtrue : Qfalse;
#else
return Qfalse;
Expand Down Expand Up @@ -393,7 +392,7 @@ void sample_thread(
);
}

#if defined(HAVE_DLADDR1) || defined(HAVE_DLADDR)
#if (defined(HAVE_DLADDR1) && HAVE_DLADDR1) || (defined(HAVE_DLADDR) && HAVE_DLADDR)
static void set_file_info_for_cfunc(
ddog_CharSlice *filename_slice,
int *line,
Expand Down Expand Up @@ -441,12 +440,12 @@ void sample_thread(

Dl_info info;
const char *native_filename = NULL;
#ifdef HAVE_DLADDR1
#if defined(HAVE_DLADDR1) && HAVE_DLADDR1
struct link_map *extra_info = NULL;
if (dladdr1(function, &info, (void **) &extra_info, RTLD_DL_LINKMAP) != 0 && extra_info != NULL) {
native_filename = extra_info->l_name != NULL ? extra_info->l_name : info.dli_fname;
}
#elif defined(HAVE_DLADDR)
#elif defined(HAVE_DLADDR) && HAVE_DLADDR
if (dladdr(function, &info) != 0) {
native_filename = info.dli_fname;
}
Expand Down
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