Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

src/thread/pthread/SDL_systhread.c

@@ -0,0 +1,246 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#include <pthread.h>
+
+#if HAVE_PTHREAD_NP_H
+#include <pthread_np.h>
+#endif
+
+#include <signal.h>
+
+#ifdef __LINUX__
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#endif /* __LINUX__ */
+
+#if defined(__LINUX__) || defined(__MACOSX__) || defined(__IPHONEOS__)
+#include <dlfcn.h>
+#ifndef RTLD_DEFAULT
+#define RTLD_DEFAULT NULL
+#endif
+#endif
+
+#include "SDL_platform.h"
+#include "SDL_thread.h"
+#include "SDL_hints.h"
+#include "../SDL_thread_c.h"
+#include "../SDL_systhread.h"
+#ifdef __ANDROID__
+#include "../../core/android/SDL_android.h"
+#endif
+
+#ifdef __HAIKU__
+#include <be/kernel/OS.h>
+#endif
+
+#include "SDL_assert.h"
+
+#ifndef __NACL__
+/* List of signals to mask in the subthreads */
+static const int sig_list[] = {
+    SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGWINCH,
+    SIGVTALRM, SIGPROF, 0
+};
+#endif
+
+static void *
+RunThread(void *data)
+{
+#ifdef __ANDROID__
+    Android_JNI_SetupThread();
+#endif
+    SDL_RunThread(data);
+    return NULL;
+}
+
+#if defined(__MACOSX__) || defined(__IPHONEOS__)
+static SDL_bool checked_setname = SDL_FALSE;
+static int (*ppthread_setname_np)(const char*) = NULL;
+#elif defined(__LINUX__)
+static SDL_bool checked_setname = SDL_FALSE;
+static int (*ppthread_setname_np)(pthread_t, const char*) = NULL;
+#endif
+int
+SDL_SYS_CreateThread(SDL_Thread * thread, void *args)
+{
+    pthread_attr_t type;
+    size_t ss;
+    const char *hint = SDL_GetHint(SDL_HINT_THREAD_STACK_SIZE);
+
+    /* do this here before any threads exist, so there's no race condition. */
+    #if defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__LINUX__)
+    if (!checked_setname) {
+        void *fn = dlsym(RTLD_DEFAULT, "pthread_setname_np");
+        #if defined(__MACOSX__) || defined(__IPHONEOS__)
+        ppthread_setname_np = (int(*)(const char*)) fn;
+        #elif defined(__LINUX__)
+        ppthread_setname_np = (int(*)(pthread_t, const char*)) fn;
+        #endif
+        checked_setname = SDL_TRUE;
+    }
+    #endif
+
+    /* Set the thread attributes */
+    if (pthread_attr_init(&type) != 0) {
+        return SDL_SetError("Couldn't initialize pthread attributes");
+    }
+    pthread_attr_setdetachstate(&type, PTHREAD_CREATE_JOINABLE);
+    
+    /* If the SDL_HINT_THREAD_STACK_SIZE exists and it seems to be a positive number, use it */
+    if (hint && hint[0] >= '0' && hint[0] <= '9') {
+        const size_t stacksize = (size_t) SDL_atoi(hint);
+        if (stacksize > 0) {
+            pthread_attr_setstacksize(&type, stacksize);
+        }
+    }
+    
+    pthread_attr_getstacksize(&type, &ss);
+
+    /* Create the thread and go! */
+    if (pthread_create(&thread->handle, &type, RunThread, args) != 0) {
+        return SDL_SetError("Not enough resources to create thread");
+    }
+
+    return 0;
+}
+
+void
+SDL_SYS_SetupThread(const char *name)
+{
+#if !defined(__ANDROID__) && !defined(__NACL__)
+    int i;
+    sigset_t mask;
+#endif /* !__ANDROID__ && !__NACL__ */
+
+    if (name != NULL) {
+        #if defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__LINUX__)
+        SDL_assert(checked_setname);
+        if (ppthread_setname_np != NULL) {
+            #if defined(__MACOSX__) || defined(__IPHONEOS__)
+            ppthread_setname_np(name);
+            #elif defined(__LINUX__)
+            ppthread_setname_np(pthread_self(), name);
+            #endif
+        }
+        #elif HAVE_PTHREAD_SETNAME_NP
+            pthread_setname_np(pthread_self(), name);
+        #elif HAVE_PTHREAD_SET_NAME_NP
+            pthread_set_name_np(pthread_self(), name);
+        #elif defined(__HAIKU__)
+            /* The docs say the thread name can't be longer than B_OS_NAME_LENGTH. */
+            char namebuf[B_OS_NAME_LENGTH];
+            SDL_snprintf(namebuf, sizeof (namebuf), "%s", name);
+            namebuf[sizeof (namebuf) - 1] = '\0';
+            rename_thread(find_thread(NULL), namebuf);
+        #endif
+    }
+
+   /* NativeClient does not yet support signals.*/
+#if !defined(__ANDROID__) && !defined(__NACL__)
+    /* Mask asynchronous signals for this thread */
+    sigemptyset(&mask);
+    for (i = 0; sig_list[i]; ++i) {
+        sigaddset(&mask, sig_list[i]);
+    }
+    pthread_sigmask(SIG_BLOCK, &mask, 0);
+#endif /* !__ANDROID__ && !__NACL__ */
+
+
+#ifdef PTHREAD_CANCEL_ASYNCHRONOUS
+    /* Allow ourselves to be asynchronously cancelled */
+    {
+        int oldstate;
+        pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldstate);
+    }
+#endif
+}
+
+SDL_threadID
+SDL_ThreadID(void)
+{
+    return ((SDL_threadID) pthread_self());
+}
+
+int
+SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
+{
+#if __NACL__ 
+    /* FIXME: Setting thread priority does not seem to be supported in NACL */
+    return 0;
+#elif __LINUX__
+    int value;
+
+    if (priority == SDL_THREAD_PRIORITY_LOW) {
+        value = 19;
+    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
+        value = -20;
+    } else {
+        value = 0;
+    }
+    if (setpriority(PRIO_PROCESS, syscall(SYS_gettid), value) < 0) {
+        /* Note that this fails if you're trying to set high priority
+           and you don't have root permission. BUT DON'T RUN AS ROOT!
+         */
+        return SDL_SetError("setpriority() failed");
+    }
+    return 0;
+#else
+    struct sched_param sched;
+    int policy;
+    pthread_t thread = pthread_self();
+
+    if (pthread_getschedparam(thread, &policy, &sched) < 0) {
+        return SDL_SetError("pthread_getschedparam() failed");
+    }
+    if (priority == SDL_THREAD_PRIORITY_LOW) {
+        sched.sched_priority = sched_get_priority_min(policy);
+    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
+        sched.sched_priority = sched_get_priority_max(policy);
+    } else {
+        int min_priority = sched_get_priority_min(policy);
+        int max_priority = sched_get_priority_max(policy);
+        sched.sched_priority = (min_priority + (max_priority - min_priority) / 2);
+    }
+    if (pthread_setschedparam(thread, policy, &sched) < 0) {
+        return SDL_SetError("pthread_setschedparam() failed");
+    }
+    return 0;
+#endif /* linux */
+}
+
+void
+SDL_SYS_WaitThread(SDL_Thread * thread)
+{
+    pthread_join(thread->handle, 0);
+}
+
+void
+SDL_SYS_DetachThread(SDL_Thread * thread)
+{
+    pthread_detach(thread->handle);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */