From b231e86ac9608056ea837e24d42a878927f5787a Mon Sep 17 00:00:00 2001 From: Christian Biesinger Date: Thu, 31 Oct 2019 14:41:19 -0500 Subject: [PATCH] Use strerror_r in safe_strerror if available Also stores the result in a thread-local static variable and changes the return value to a const char*. This is already important because Guile creates threads and Python can create threads, but with the patch series here: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/176 GDB itself will create threads, too. gdb/ChangeLog: 2019-10-31 Christian Biesinger * configure: Regenerate. * configure.ac: Check for strerror_r. * gdbsupport/common-utils.h (safe_strerror): Change return value to const char * and document that this function is now threadsafe. * gdbsupport/posix-strerror.c (safe_strerror): Make buf thread_local and call strerror_r, if available. * utils.c (perror_string): Update. (print_sys_errmsg): Update. Change-Id: I81048fbaf148035c221c528727f7efe58ba528eb --- gdb/ChangeLog | 11 +++++++++++ gdb/configure | 2 +- gdb/configure.ac | 2 +- gdb/gdbsupport/common-utils.h | 4 ++-- gdb/gdbsupport/posix-strerror.c | 20 +++++++++++++++----- gdb/utils.c | 11 +++-------- 6 files changed, 33 insertions(+), 17 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 7abe20ee59..b7a7d98c8a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2019-10-31 Christian Biesinger + + * configure: Regenerate. + * configure.ac: Check for strerror_r. + * gdbsupport/common-utils.h (safe_strerror): Change return value + to const char * and document that this function is now threadsafe. + * gdbsupport/posix-strerror.c (safe_strerror): Make buf + thread_local and call strerror_r, if available. + * utils.c (perror_string): Update. + (print_sys_errmsg): Update. + 2019-10-31 Luis Machado * arm-tdep.c (arm_exidx_data_key): Use bfd_key instead of diff --git a/gdb/configure b/gdb/configure index e8059039bd..018cc4ba43 100755 --- a/gdb/configure +++ b/gdb/configure @@ -13073,7 +13073,7 @@ for ac_func in getauxval getrusage getuid getgid \ sigaction sigsetmask socketpair \ ttrace wborder wresize setlocale iconvlist libiconvlist btowc \ setrlimit getrlimit posix_madvise waitpid \ - ptrace64 sigaltstack setns use_default_colors + ptrace64 sigaltstack setns use_default_colors strerror_r do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var" diff --git a/gdb/configure.ac b/gdb/configure.ac index 354bb7b4b6..987507a17d 100644 --- a/gdb/configure.ac +++ b/gdb/configure.ac @@ -1318,7 +1318,7 @@ AC_CHECK_FUNCS([getauxval getrusage getuid getgid \ sigaction sigsetmask socketpair \ ttrace wborder wresize setlocale iconvlist libiconvlist btowc \ setrlimit getrlimit posix_madvise waitpid \ - ptrace64 sigaltstack setns use_default_colors]) + ptrace64 sigaltstack setns use_default_colors strerror_r]) AM_LANGINFO_CODESET GDB_AC_COMMON diff --git a/gdb/gdbsupport/common-utils.h b/gdb/gdbsupport/common-utils.h index 23bf354a8b..89868fcf9e 100644 --- a/gdb/gdbsupport/common-utils.h +++ b/gdb/gdbsupport/common-utils.h @@ -108,9 +108,9 @@ std::string extract_string_maybe_quoted (const char **arg); /* The strerror() function can return NULL for errno values that are out of range. Provide a "safe" version that always returns a - printable string. */ + printable string. This version is also thread-safe. */ -extern char *safe_strerror (int); +extern const char *safe_strerror (int); /* Return true if the start of STRING matches PATTERN, false otherwise. */ diff --git a/gdb/gdbsupport/posix-strerror.c b/gdb/gdbsupport/posix-strerror.c index a8651b706d..34420cf537 100644 --- a/gdb/gdbsupport/posix-strerror.c +++ b/gdb/gdbsupport/posix-strerror.c @@ -21,15 +21,25 @@ /* Implementation of safe_strerror as defined in common-utils.h. */ -char * +const char * safe_strerror (int errnum) { - char *msg; - + static thread_local char buf[1024]; + + char *msg = nullptr; +#ifdef HAVE_STRERROR_R +# if !__GLIBC__ || ((_POSIX_C_SOURCE >= 200112L) && ! _GNU_SOURCE) + /* Glibc has two different, incompatible versions of strerror_r. */ + if (strerror_r (errnum, buf, sizeof (buf)) == 0) + msg = buf; +# else + msg = strerror_r (errnum, buf, sizeof (buf)); +# endif +#else msg = strerror (errnum); - if (msg == NULL) +#endif + if (msg == nullptr) { - static char buf[32]; xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum); msg = buf; diff --git a/gdb/utils.c b/gdb/utils.c index 0c133d1561..e06eeddeef 100644 --- a/gdb/utils.c +++ b/gdb/utils.c @@ -582,9 +582,7 @@ add_internal_problem_command (struct internal_problem *problem) static std::string perror_string (const char *prefix) { - char *err; - - err = safe_strerror (errno); + const char *err = safe_strerror (errno); return std::string (prefix) + ": " + err; } @@ -630,11 +628,8 @@ perror_warning_with_name (const char *string) void print_sys_errmsg (const char *string, int errcode) { - char *err; - char *combined; - - err = safe_strerror (errcode); - combined = (char *) alloca (strlen (err) + strlen (string) + 3); + const char *err = safe_strerror (errcode); + char *combined = (char *) alloca (strlen (err) + strlen (string) + 3); strcpy (combined, string); strcat (combined, ": "); strcat (combined, err); -- 2.34.1