implement QHostInfo::localHostName() via getdomainname() instead of resolv

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>

CMakeLists.txt

@@ -128,9 +128,6 @@ add_feature_info(postgresql WITH_POSTGRESQL "build PostgreSQL support")
 option(WITH_MYSQL "Build MySQL database plugin" ON)
 add_feature_info(mysql WITH_MYSQL "build MySQL support")
 
-option(WITH_RESOLV "Build resolv support" ON)
-add_feature_info(resolv WITH_RESOLV "build resolv support")
-
 option(WITH_INTL "Build Intl support" ON)
 add_feature_info(intl WITH_INTL "build Intl support")
 
@@ -242,14 +239,6 @@ set_package_properties(Sqlite PROPERTIES
     TYPE REQUIRED
 )
 
-find_package(Resolv)
-set_package_properties(Resolv PROPERTIES
-    PURPOSE "Required for domain resolving support"
-    DESCRIPTION "Standard C library specific resolv implementation"
-    URL ""
-    TYPE RECOMMENDED
-)
-
 find_package(JPEG)
 set_package_properties(JPEG PROPERTIES
     PURPOSE "JPEG format handler"
@@ -383,6 +372,7 @@ katie_check_function(kevent "sys/event.h")
 katie_check_function(pipe2 "unistd.h")
 katie_check_function(accept4 "sys/socket.h")
 katie_check_function(paccept "sys/socket.h")
+katie_check_function(getdomainname "unistd.h")
 katie_check_struct(tm tm_gmtoff "time.h")
 katie_check_struct(tm tm_zone "time.h")
 katie_check_struct(sockaddr_ll sll_addr "netpacket/packet.h")
@@ -464,10 +454,6 @@ if(NOT WITH_CUPS OR NOT CUPS_FOUND)
     katie_definition(-DQT_NO_CUPS)
 endif()
 
-if(NOT WITH_RESOLV OR NOT RESOLV_FOUND)
-    katie_definition(-DQT_NO_RESOLV)
-endif()
-
 if(NOT WITH_JPEG OR NOT JPEG_FOUND)
     katie_definition(-DQT_NO_IMAGEFORMAT_JPEG)
 endif()

README

@@ -14,7 +14,7 @@ There are several things you should be aware before considering Katie:
   - QMake build system replaced with CMake
   - zlib, zstd, OpenSSL, PCRE, Freetype, ICU, X11, libpng and SQLite are
     required for building
-  - OpenSSL, D-Bus, CUPS and resolv must be linked to during build
+  - OpenSSL, D-Bus and CUPS must be linked to during build
   - QtUiTools is build as shared library by default
   - moc, uic, rcc, etc. are linked to components
   - updated bundled Harfbuzz from upstream (not Harfbuzz-NG)
@@ -51,7 +51,6 @@ There are several things you should be aware before considering Katie:
   - building with OpenSSL v1.1+ is possible
   - building with IODBC instead of unixODBC is possible
   - building with LTO is possible and supported, if the toolchain can handle it
-  - building without resolv is possible
   - alternative libc implementations support
   - additional text codecs via ICU converter
   - Unicode v5.0+ characters and partial scripts support

cmake/modules/FindResolv.cmake

@@ -1,55 +0,0 @@
-# - Try to find resolv
-# Once done this will define
-#
-#  RESOLV_FOUND - system has resolv
-#  RESOLV_INCLUDES - the resolv include directory
-#  RESOLV_LIBRARIES - the libraries needed to use resolv
-#  RESOLV_THREAD_SAFE - resolv has thread-safe functions (res_ninit/res_nclose)
-#
-# Copyright (c) 2016-2020, Ivailo Monev, <xakepa10@gmail.com>
-#
-# Redistribution and use is allowed according to the terms of the BSD license.
-
-# resolv does not provide pkg-config files
-
-include(CMakePushCheckState)
-include(FindPackageHandleStandardArgs)
-
-set(RESOLV_NAMES c resolv)
-
-find_path(RESOLV_INCLUDES
-    NAMES resolv.h
-    HINTS $ENV{RESOLVDIR}/include
-)
-
-set(RESOLV_LIBRARIES)
-foreach(name ${RESOLV_NAMES})
-    if(NOT RESOLV_LIBRARIES)
-        unset(HAVE_res_ninit CACHE)
-        cmake_reset_check_state()
-        set(CMAKE_REQUIRED_LIBRARIES ${name})
-        katie_check_defined(res_ninit "netinet/in.h;resolv.h")
-        cmake_reset_check_state()
-        if(NOT HAVE_res_ninit)
-            unset(HAVE_res_init CACHE)
-            cmake_reset_check_state()
-            set(CMAKE_REQUIRED_LIBRARIES ${name})
-            katie_check_defined(res_init "netinet/in.h;resolv.h")
-            cmake_reset_check_state()
-        endif()
-        if(HAVE_res_ninit OR HAVE_res_init)
-            find_library(RESOLV_LIBRARIES
-                NAMES ${name}
-                HINTS $ENV{RESOLVDIR}/lib
-            )
-        endif()
-    endif()
-endforeach()
-
-find_package_handle_standard_args(Resolv
-    REQUIRED_VARS RESOLV_LIBRARIES RESOLV_INCLUDES
-)
-
-set(RESOLV_THREAD_SAFE "${HAVE_res_ninit}" CACHE BOOL "resolv has thread-safe functions (res_ninit/res_nclose)")
-
-mark_as_advanced(RESOLV_INCLUDES RESOLV_LIBRARIES RESOLV_THREAD_SAFE)

src/core/global/qconfig.h.cmake

@@ -108,6 +108,7 @@
 #define QT_NO_NAS
 #define QT_NO_IMAGEFORMAT_MNG
 #define QT_NO_TEXTODFWRITER
+#define QT_NO_RESOLV
 
 // Not supported, used to bootstrap
 #cmakedefine QT_NO_QOBJECT
@@ -140,7 +141,6 @@
 #cmakedefine QT_NO_FONTCONFIG
 #cmakedefine QT_NO_IMAGEFORMAT_JPEG
 #cmakedefine QT_NO_IMAGEFORMAT_TIFF
-#cmakedefine QT_NO_RESOLV
 #cmakedefine QT_NO_SESSIONMANAGER
 #cmakedefine QT_NO_TRANSLATION
 #cmakedefine QT_NO_XCURSOR

src/network/CMakeLists.txt

@@ -202,17 +202,6 @@ set(NETWORK_SOURCES
     ${CMAKE_CURRENT_SOURCE_DIR}/ssl/qsslsocket_openssl.cpp
 )
 
-if(WITH_RESOLV AND RESOLV_FOUND)
-    set(EXTRA_NETWORK_LIBS
-        ${EXTRA_NETWORK_LIBS}
-        ${RESOLV_LIBRARIES}
-    )
-    include_directories(${RESOLV_INCLUDES})
-    if(RESOLV_THREAD_SAFE)
-        add_definitions(-DQT_HAVE_RES_NINIT)
-    endif()
-endif()
-
 katie_generate_misc("${NETWORK_HEADERS}" QtNetwork)
 katie_generate_public("${NETWORK_PUBLIC_HEADERS}" QtNetwork)
 katie_generate_package(KtNetwork "KtCore")

src/network/kernel/qhostinfo_unix.cpp

@@ -47,10 +47,6 @@
 #include <netdb.h>
 #include <arpa/inet.h>
 
-#ifndef QT_NO_RESOLV
-#include <resolv.h>
-#endif // QT_NO_RESOLV
-
 QT_BEGIN_NAMESPACE
 
 #if !defined(QT_HAVE_GETADDRINFO)
@@ -67,11 +63,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
            hostName.toLatin1().constData());
 #endif
 
-#ifndef QT_NO_RESOLV
-    // If res_init is available, poll it.
-    res_init();
-#endif // QT_NO_RESOLV
-
     QHostAddress address;
     if (address.setAddress(hostName)) {
         // Reverse lookup
@@ -272,43 +263,28 @@ QString QHostInfo::localHostName()
     static long size_max = sysconf(_SC_HOST_NAME_MAX);
     if (size_max == -1)
         size_max = _POSIX_HOST_NAME_MAX;
-    char gethostbuffer[size_max];
-    if (Q_LIKELY(::gethostname(gethostbuffer, size_max) == 0)) {
-        gethostbuffer[size_max - 1] = '\0';
-        return QString::fromLocal8Bit(gethostbuffer);
+    char gethostbuff[size_max];
+    if (Q_LIKELY(::gethostname(gethostbuff, size_max) == 0)) {
+        gethostbuff[size_max - 1] = '\0';
+        return QString::fromLocal8Bit(gethostbuff);
     }
     return QString();
 }
 
 QString QHostInfo::localDomainName()
 {
-//support both thread-safe and unsafe versions
-#if !defined(QT_NO_RESOLV) && defined(QT_HAVE_RES_NINIT)
-    // using thread-safe version
-    struct __res_state state;
-    res_ninit(&state);
-    QString domainName = QUrl::fromAce(state.defdname);
-    if (domainName.isEmpty())
-        domainName = QUrl::fromAce(state.dnsrch[0]);
-    res_nclose(&state);
-
-    return domainName;
-#elif !defined(QT_NO_RESOLV)
-    // using thread-unsafe version
-
-#if !defined(QT_HAVE_GETADDRINFO)
-    // We have to call res_init to be sure that _res was initialized
-    // So, for systems without getaddrinfo (which is thread-safe), we lock the mutex too
-    QMutexLocker locker(getHostByNameMutex());
-#endif
-    res_init();
-    QString domainName = QUrl::fromAce(_res.defdname);
-    if (domainName.isEmpty())
-        domainName = QUrl::fromAce(_res.dnsrch[0]);
-    return domainName;
+#if defined(QT_HAVE_GETDOMAINNAME)
+    // thread-safe
+    static long size_max = sysconf(_SC_HOST_NAME_MAX);
+    if (size_max == -1)
+        size_max = _POSIX_HOST_NAME_MAX;
+    char getdomainbuff[size_max];
+    if (Q_LIKELY(::getdomainname(getdomainbuff, size_max) == 0)) {
+        return QUrl::fromAce(getdomainbuff);
+    }
+    return QString();
 #else
-
-    // nothing worked, try doing it by ourselves:
+    // doing it by ourselves
 #if defined(_PATH_RESCONF)
     QFile resolvconf(QFile::decodeName(_PATH_RESCONF));
 #else
@@ -335,7 +311,7 @@ QString QHostInfo::localDomainName()
 
     // return the fallen-back-to searched domain
     return domainName;
-#endif // QT_NO_RESOLV
+#endif // QT_HAVE_GETDOMAINNAME
 }
 
 QT_END_NAMESPACE