QDnsLookup: fix "Resolver functions not found" error on FreeBSD

The current code only tries to load the required functions from
LIBRESOLV_SO (if defined) and resolv, but on FreeBSD they are in libc:
https://www.freebsd.org/cgi/man.cgi?query=res_query&sektion=3&apropos=0&manpath=freebsd

This commit changes the code so that, after failing to load the
non-existent libraries, it attempts to load the functions with dlsym()
using the special handle RTLD_DEFAULT, which searches for the specified
symbol in the loaded libraries.

Task-number: QTBUG-74844
Change-Id: If97aaae233cabbfa01c30d26d9a7fb01ec3ff5c2
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Davide Beatrici 2019-04-05 18:55:24 +02:00
parent 82ad4be4a2
commit 8eeb5150ed
2 changed files with 33 additions and 14 deletions

View File

@ -38,7 +38,11 @@ qtConfig(dnslookup) {
}
unix {
!integrity:qtConfig(dnslookup): SOURCES += kernel/qdnslookup_unix.cpp
!integrity:qtConfig(dnslookup) {
SOURCES += kernel/qdnslookup_unix.cpp
qtConfig(dlopen): QMAKE_USE_PRIVATE += libdl
}
SOURCES += kernel/qhostinfo_unix.cpp
qtConfig(linux-netlink): SOURCES += kernel/qnetworkinterface_linux.cpp

View File

@ -59,6 +59,10 @@
# include <gnu/lib-names.h>
#endif
#if defined(Q_OS_FREEBSD) || QT_CONFIG(dlopen)
# include <dlfcn.h>
#endif
#include <cstring>
QT_BEGIN_NAMESPACE
@ -87,6 +91,18 @@ struct QDnsLookupStateDeleter
}
};
static QFunctionPointer resolveSymbol(QLibrary &lib, const char *sym)
{
if (lib.isLoaded())
return lib.resolve(sym);
#if defined(RTLD_DEFAULT) && (defined(Q_OS_FREEBSD) || QT_CONFIG(dlopen))
return reinterpret_cast<QFunctionPointer>(dlsym(RTLD_DEFAULT, sym));
#else
return nullptr;
#endif
}
static bool resolveLibraryInternal()
{
QLibrary lib;
@ -96,31 +112,30 @@ static bool resolveLibraryInternal()
#endif
{
lib.setFileName(QLatin1String("resolv"));
if (!lib.load())
return false;
lib.load();
}
local_dn_expand = dn_expand_proto(lib.resolve("__dn_expand"));
local_dn_expand = dn_expand_proto(resolveSymbol(lib, "__dn_expand"));
if (!local_dn_expand)
local_dn_expand = dn_expand_proto(lib.resolve("dn_expand"));
local_dn_expand = dn_expand_proto(resolveSymbol(lib, "dn_expand"));
local_res_nclose = res_nclose_proto(lib.resolve("__res_nclose"));
local_res_nclose = res_nclose_proto(resolveSymbol(lib, "__res_nclose"));
if (!local_res_nclose)
local_res_nclose = res_nclose_proto(lib.resolve("res_9_nclose"));
local_res_nclose = res_nclose_proto(resolveSymbol(lib, "res_9_nclose"));
if (!local_res_nclose)
local_res_nclose = res_nclose_proto(lib.resolve("res_nclose"));
local_res_nclose = res_nclose_proto(resolveSymbol(lib, "res_nclose"));
local_res_ninit = res_ninit_proto(lib.resolve("__res_ninit"));
local_res_ninit = res_ninit_proto(resolveSymbol(lib, "__res_ninit"));
if (!local_res_ninit)
local_res_ninit = res_ninit_proto(lib.resolve("res_9_ninit"));
local_res_ninit = res_ninit_proto(resolveSymbol(lib, "res_9_ninit"));
if (!local_res_ninit)
local_res_ninit = res_ninit_proto(lib.resolve("res_ninit"));
local_res_ninit = res_ninit_proto(resolveSymbol(lib, "res_ninit"));
local_res_nquery = res_nquery_proto(lib.resolve("__res_nquery"));
local_res_nquery = res_nquery_proto(resolveSymbol(lib, "__res_nquery"));
if (!local_res_nquery)
local_res_nquery = res_nquery_proto(lib.resolve("res_9_nquery"));
local_res_nquery = res_nquery_proto(resolveSymbol(lib, "res_9_nquery"));
if (!local_res_nquery)
local_res_nquery = res_nquery_proto(lib.resolve("res_nquery"));
local_res_nquery = res_nquery_proto(resolveSymbol(lib, "res_nquery"));
return true;
}