Hi Collin, > I've pushed a basic test for execinfo. Since BSD needs to link to > -lexecinfo unlike glibc. Should catch any bugs that occur there or if > another system adds it as a library.
Thanks. Reading through your test, I notice that when size == 0 && symbols != NULL, the symbols pointer is not freed. So I went to look deeper. Reading through the documentation at https://www.gnu.org/software/libc/manual/html_node/Backtraces.html I found the following opportunities that can be tested in a unit test: - backtrace: "The return value is the actual number of entries of buffer that are obtained, and is at most size." This is something that can be tested. - backtrace_symbols: "The return value of backtrace_symbols is a pointer obtained via the malloc function ... The return value is NULL if sufficient memory for the strings cannot be obtained." Since in unit tests, out-of-memory can be assumed to not happen, we can check that the return value is != NULL. - backtrace_symbols: "The return value is a pointer to an array of strings, which has size entries just like the array buffer" This sounds like we can pass a too-small buffer, and the stack trace will be truncated. This can be tested as well. - The third function, backtrace_symbols_fd, is not tested. So, this is what I am committing. Note the change in the module description. If we want to verify that there is an AC_SUBST for LIB_EXECINFO, the way to do it is to write @LIB_EXECINFO@. If the AC_SUBST was missing, $(LIB_EXECINFO) would come out as empty whereas @LIB_EXECINFO@ would lead to a build failure. 2024-05-12 Bruno Haible <br...@clisp.org> execinfo tests: Strengthen tests. * tests/test-execinfo.c (test_backtrace): Add an argument. Check the return value of backtrace(). Check that backtrace_symbols_fd is defined. Check the return value of backtrace_symbols(). (main): Test also the case of a short buffer. * modules/execinfo-tests (Makefile.am): Verify that LIB_EXECINFO is defined. diff --git a/modules/execinfo-tests b/modules/execinfo-tests index 191345cd5c..5d6a28c69b 100644 --- a/modules/execinfo-tests +++ b/modules/execinfo-tests @@ -9,4 +9,4 @@ configure.ac: Makefile.am: TESTS += test-execinfo check_PROGRAMS += test-execinfo -test_execinfo_LDADD = $(LDADD) $(LIB_EXECINFO) +test_execinfo_LDADD = $(LDADD) @LIB_EXECINFO@ diff --git a/tests/test-execinfo.c b/tests/test-execinfo.c index af457c468f..5745306ed5 100644 --- a/tests/test-execinfo.c +++ b/tests/test-execinfo.c @@ -27,17 +27,28 @@ #include "macros.h" static void -test_backtrace (void) +test_backtrace (int pass) { void *buffer[10]; - char **symbols; + int max_size; int size; + char **symbols; + + max_size = (pass == 0 ? SIZEOF (buffer) : 1); + size = backtrace (buffer, max_size); + ASSERT (size >= 0 && size <= max_size); + + /* Print the backtrace to a file descriptor. */ + backtrace_symbols_fd (buffer, size, 1); + printf ("\n"); - size = backtrace (buffer, SIZEOF (buffer)); symbols = backtrace_symbols (buffer, size); + if (size > 0) + /* We have enough memory available. */ + ASSERT (symbols != NULL); /* Print the backtrace if possible. */ - if (0 < size && symbols != NULL) + if (symbols != NULL) { for (int i = 0; i < size; ++i) printf ("%s\n", symbols[i]); @@ -48,7 +59,10 @@ test_backtrace (void) int main (void) { - test_backtrace (); + printf ("Full stack trace:\n"); fflush (stdout); + test_backtrace (0); + printf ("\nTruncated stack trace:\n"); fflush (stdout); + test_backtrace (1); return 0; }
