diff options
Diffstat (limited to 'ares/m4')
| -rw-r--r-- | ares/m4/cares-functions.m4 | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/ares/m4/cares-functions.m4 b/ares/m4/cares-functions.m4 index 5117788e3..90a07846a 100644 --- a/ares/m4/cares-functions.m4 +++ b/ares/m4/cares-functions.m4 @@ -440,6 +440,81 @@ AC_DEFUN([CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_ADDR], [ ]) +dnl CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME +dnl ------------------------------------------------- +dnl verify if the ai_canonname pointer member of the addrinfo +dnl struct returned by function getaddrinfo is a pointer +dnl which can actually be free()ed or not. + +AC_DEFUN([CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME], [ + AC_REQUIRE([CARES_CHECK_FUNC_GETADDRINFO])dnl + AC_REQUIRE([CARES_INCLUDES_STRING])dnl + # + if test "$ac_cv_func_getaddrinfo" = "yes"; then + AC_MSG_CHECKING([if getaddrinfo returns unfreeable ai_canonname]) + dnl only do runtime verification when not cross-compiling + if test "x$cross_compiling" != "xyes"; then + AC_RUN_IFELSE([ + AC_LANG_PROGRAM([[ + $cares_includes_ws2tcpip + $cares_includes_stdlib + $cares_includes_sys_socket + $cares_includes_netdb + $cares_includes_string + ]],[[ + char tmp_canonname[80]; + char *ai_canonname, *freed_ptr; + struct addrinfo hints; + struct addrinfo *ai = 0; + int error; + + memset(&hints, 0, sizeof(hints)); + hints.ai_flags = AI_NUMERICHOST|AI_CANONNAME; + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_STREAM; + error = getaddrinfo("127.0.0.1", 0, &hints, &ai); + if(error || !ai) + /* should not happen, same test already succeeded, */ + /* assume that returned ai_canonname not unfreeable. */ + exit(0); + + memset(&tmp_canonname, 1, sizeof(tmp_canonname)); + /* attempt to free ai_canonname pointer */ + freed_ptr = ai_canonname = ai->ai_canonname; + /* seg-fault free'ing an unfreeable ptr would be */ + /* nice, if this happen exit code will be non-zero. */ + free(ai_canonname); + /* attempt to write free'ed memory */ + freed_ptr[0] = 'x'; + /* attempt to reuse and clear free'ed memory */ + ai_canonname = calloc(1, sizeof(tmp_canonname)); + /* attempt to read free'ed memory */ + tmp_canonname[0] = freed_ptr[0]; + /* verify if everithing has worked */ + if(tmp_canonname[0] == 'x') + /* ai_canonname might be unfreeable, ouch! */ + exit(1); + else + /* ai_canonname is certainly freeable */ + exit(0); + ]]) + ],[ + dnl exit code was zero, getaddrinfo behaves nicely. + AC_MSG_RESULT([no]) + ],[ + dnl exit code wasn't zero, getaddrinfo returns unfreeable ptr. + AC_MSG_RESULT([yes]) + AC_DEFINE_UNQUOTED(HAVE_GETADDRINFO_UNFREEABLE_AI_CANONNAME, 1, + [Define to 1 if getaddrinfo returns unfreeable ai_addr pointer.]) + ]) + else + dnl for cross-compiling a static check would be nice. + AC_MSG_RESULT([unknown]) + fi + fi +]) + + dnl CARES_CHECK_FUNC_GETHOSTNAME dnl ------------------------------------------------- dnl Verify if gethostname is available, prototyped, and |