@@ -33,7 +33,6 @@ void jl_loader_print_stderr3(const char * msg1, const char * msg2, const char *
3333/* Wrapper around dlopen(), with extra relative pathing thrown in*/
3434static void * load_library (const char * rel_path , const char * src_dir , int err ) {
3535 void * handle = NULL ;
36-
3736 // See if a handle is already open to the basename
3837 const char * basename = rel_path + strlen (rel_path );
3938 while (basename -- > rel_path )
@@ -153,6 +152,181 @@ JL_DLLEXPORT const char * jl_get_libdir()
153152 return lib_dir ;
154153}
155154
155+ #ifdef _OS_LINUX_
156+ #ifndef GLIBCXX_LEAST_VERSION_SYMBOL /* Should always be defined in the makefile. This appeases the linter. */
157+ #define GLIBCXX_LEAST_VERSION_SYMBOL "GLIBCXX_a.b.c"
158+ #endif
159+
160+ #include <link.h>
161+ #include <sys/wait.h>
162+
163+ static void write_wrapper (int fd , char * str , size_t len )
164+ {
165+ size_t written_sofar = 0 ;
166+ while (len ) {
167+ ssize_t bytes_written = write (fd , str + written_sofar , len );
168+ if (bytes_written == -1 && errno == EINTR ) continue ;
169+ if (bytes_written == -1 && errno != EINTR ) {
170+ perror ("Error in write wrapper:\nwrite" );
171+ _exit (1 );
172+ }
173+ len -= bytes_written ;
174+ written_sofar += bytes_written ;
175+ }
176+ }
177+
178+ // Where the buf passed in was malloced
179+ static void read_wrapper (int fd , char * * ret , size_t * ret_len )
180+ {
181+ // Allocate an initial buffer
182+ size_t len = JL_PATH_MAX ;
183+ char * buf = (char * )malloc (len + 1 );
184+ if (!buf ) {
185+ char err_str [] = "Error in read wrapper:\nmalloc() returned NULL.\n" ;
186+ size_t err_strlen = strlen (err_str );
187+ write_wrapper (STDERR_FILENO , err_str , err_strlen );
188+ exit (1 );
189+ }
190+
191+ // Read into it, reallocating as necessary
192+ size_t have_read = 0 ;
193+ while (1 ) {
194+ ssize_t n = read (fd , buf + have_read , len - have_read );
195+ have_read += n ;
196+ if (n == 0 ) break ;
197+ if (n == -1 && errno != EINTR ) {
198+ perror ("Error in read wrapper:\nread" );
199+ exit (1 );
200+ }
201+ if (n == -1 && errno == EINTR ) continue ;
202+ if (have_read == len ) {
203+ buf = (char * )realloc (buf , 1 + (len *= 2 ));
204+ if (!buf ) {
205+ char err_str [] = "Error in read wrapper:\nrealloc() returned NULL.\n" ;
206+ size_t err_strlen = strlen (err_str );
207+ write_wrapper (STDERR_FILENO , err_str , err_strlen );
208+ exit (1 );
209+ }
210+ }
211+ }
212+
213+ * ret = buf ;
214+ * ret_len = have_read ;
215+ }
216+
217+ // On Linux, it can happen that the system has a newer libstdc++ than the one we ship,
218+ // which can break loading of some system libraries: <https://github.com/JuliaLang/julia/issues/34276>.
219+
220+ // Return the path to the libstdcxx to load.
221+ // If the path is found, return it.
222+ // Otherwise, print the error and exit.
223+ // The path returned must be freed.
224+ static char * libstdcxxprobe (void )
225+ {
226+ // Create the pipe and child process.
227+ int fork_pipe [2 ];
228+ int ret = pipe (fork_pipe );
229+ if (ret == -1 ) {
230+ perror ("Error during libstdcxxprobe:\npipe" );
231+ exit (1 );
232+ }
233+ pid_t pid = fork ();
234+ if (pid == -1 ) {
235+ perror ("Error during libstdcxxprobe:\nfork" );
236+ exit (1 );
237+ }
238+ if (pid == (pid_t ) 0 ) { // Child process.
239+ ret = close (fork_pipe [0 ]);
240+ if (ret == -1 ) {
241+ perror ("Error during libstdcxxprobe in child process:\nclose" );
242+ _exit (1 );
243+ }
244+
245+ // Open the first available libstdc++.so.
246+ // If it can't be found, report so by exiting zero.
247+ void * handle = dlopen ("libstdc++.so.6" , RTLD_LAZY );
248+ if (!handle ) {
249+ _exit (0 );
250+ }
251+
252+ // See if the version is compatible
253+ char * dlerr = dlerror (); // clear out dlerror
254+ void * sym = dlsym (handle , GLIBCXX_LEAST_VERSION_SYMBOL );
255+ dlerr = dlerror ();
256+ if (dlerr ) {
257+ // We can't use the library that was found, so don't write anything.
258+ // The main process will see that nothing was written,
259+ // then exit the function and return null.
260+ _exit (0 );
261+ }
262+
263+ // No error means the symbol was found, we can use this library.
264+ // Get the path to it, and write it to the parent process.
265+ struct link_map * lm ;
266+ ret = dlinfo (handle , RTLD_DI_LINKMAP , & lm );
267+ if (ret == -1 ) {
268+ char errbuf [2048 ];
269+ int err_len = snprintf (errbuf , 2048 , "Error during libstdcxxprobe in child process:\ndlinfo() - %s\n" , dlerror ());
270+ write_wrapper (STDOUT_FILENO , errbuf , (size_t )err_len );
271+ _exit (1 );
272+ }
273+ char * libpath = lm -> l_name ;
274+ write_wrapper (fork_pipe [1 ], libpath , strlen (libpath ));
275+ _exit (0 );
276+ }
277+ else { // Parent process.
278+ ret = close (fork_pipe [1 ]);
279+ if (ret == -1 ) {
280+ perror ("Error during libstdcxxprobe in parent process:\nclose" );
281+ _exit (1 );
282+ }
283+
284+ // Wait for the child to complete.
285+ while (1 ) {
286+ int wstatus ;
287+ pid_t npid = waitpid (pid , & wstatus , 0 );
288+ if (npid == -1 ) {
289+ if (errno == EINTR ) continue ;
290+ if (errno != EINTR ) {
291+ perror ("Error during libstdcxxprobe in parent process:\nwaitpid" );
292+ exit (1 );
293+ }
294+ }
295+ else if (!WIFEXITED (wstatus )) {
296+ char err_str [] = "Error during libstdcxxprobe in parent process:\n"
297+ "The child process did not exit normally.\n" ;
298+ size_t err_strlen = strlen (err_str );
299+ write_wrapper (STDERR_FILENO , err_str , err_strlen );
300+ exit (1 );
301+ }
302+ else if (WEXITSTATUS (wstatus )) {
303+ // The child has printed an error and exited, so the parent should exit too.
304+ exit (1 );
305+ }
306+ break ;
307+ }
308+
309+ // Read the absolute path to the lib from the child process.
310+ char * path ;
311+ size_t pathlen ;
312+ read_wrapper (fork_pipe [0 ], & path , & pathlen );
313+
314+ // Close the read end of the pipe
315+ ret = close (fork_pipe [0 ]);
316+ if (ret == -1 ) {
317+ perror ("Error during libstdcxxprobe in parent process:\nclose" );
318+ _exit (1 );
319+ }
320+
321+ if (!pathlen ) {
322+ free (path );
323+ return NULL ;
324+ }
325+ return path ;
326+ }
327+ }
328+ #endif
329+
156330void * libjulia_internal = NULL ;
157331__attribute__((constructor )) void jl_load_libjulia_internal (void ) {
158332 // Only initialize this once
@@ -161,11 +335,46 @@ __attribute__((constructor)) void jl_load_libjulia_internal(void) {
161335 }
162336
163337 // Introspect to find our own path
164- const char * lib_dir = jl_get_libdir ();
338+ const char * lib_dir = jl_get_libdir ();
165339
166340 // Pre-load libraries that libjulia-internal needs.
167341 int deps_len = strlen (dep_libs );
168- char * curr_dep = & dep_libs [0 ];
342+ char * curr_dep = & dep_libs [0 ];
343+
344+ void * cxx_handle ;
345+ int done_probe = 0 ;
346+ #if defined(_OS_LINUX_ )
347+ int do_probe = 1 ;
348+ char * probevar = getenv ("JULIA_PROBE_LIBSTDCXX" );
349+ if (probevar ) {
350+ if (strcmp (probevar , "1" ) == 0 || strcmp (probevar , "yes" ))
351+ do_probe = 1 ;
352+ else if (strcmp (probevar , "0" ) == 0 || strcmp (probevar , "no" ))
353+ do_probe = 0 ;
354+ }
355+ if (do_probe ) {
356+ char * cxxpath = libstdcxxprobe ();
357+ if (cxxpath ) {
358+ cxx_handle = dlopen (cxxpath , RTLD_LAZY );
359+ char * dlr = dlerror ();
360+ if (dlr ) {
361+ size_t buflen = strlen (cxxpath ) + 2048 ;
362+ char * errbuf = malloc (buflen );
363+ int err_len = snprintf (errbuf , buflen , "Error, cannot load \"%s\"\n"
364+ "dlinfo() - %s\n" , cxxpath , dlr );
365+ write_wrapper (STDOUT_FILENO , errbuf , (size_t )err_len );
366+ free (errbuf );
367+ exit (1 );
368+ }
369+ free (cxxpath );
370+ done_probe = 1 ;
371+ }
372+ }
373+ #endif
374+ // If not on linux, or the probe does not finish successfully, load the bundled version.
375+ if (!done_probe ) {
376+ load_library ("libstdc++.so" , jl_get_libdir (), 1 );
377+ }
169378
170379 // We keep track of "special" libraries names (ones whose name is prefixed with `@`)
171380 // which are libraries that we want to load in some special, custom way, such as
@@ -189,7 +398,8 @@ __attribute__((constructor)) void jl_load_libjulia_internal(void) {
189398 }
190399 special_library_names [special_idx ] = curr_dep + 1 ;
191400 special_idx += 1 ;
192- } else {
401+ }
402+ else {
193403 load_library (curr_dep , lib_dir , 1 );
194404 }
195405
@@ -278,7 +488,7 @@ JL_DLLEXPORT int jl_load_repl(int argc, char * argv[]) {
278488}
279489
280490#ifdef _OS_WINDOWS_
281- int __stdcall DllMainCRTStartup (void * instance , unsigned reason , void * reserved ) {
491+ int __stdcall DllMainCRTStartup (void * instance , unsigned reason , void * reserved ) {
282492 setup_stdio ();
283493
284494 // Because we override DllMainCRTStartup, we have to manually call our constructor methods
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