initial commit, 4.5 stable

thirdparty/sdl/stdlib/SDL_getenv.c

@@ -0,0 +1,616 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 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 "SDL_getenv_c.h"
+
+#if defined(SDL_PLATFORM_WINDOWS)
+#include "../core/windows/SDL_windows.h"
+#endif
+
+#ifdef SDL_PLATFORM_ANDROID
+#include "../core/android/SDL_android.h"
+#endif
+
+#if defined(SDL_PLATFORM_WINDOWS)
+#define HAVE_WIN32_ENVIRONMENT
+#elif defined(HAVE_GETENV) && \
+      (defined(HAVE_SETENV) || defined(HAVE_PUTENV)) && \
+      (defined(HAVE_UNSETENV) || defined(HAVE_PUTENV))
+#define HAVE_LIBC_ENVIRONMENT
+#if defined(SDL_PLATFORM_MACOS)
+#include <crt_externs.h>
+#define environ (*_NSGetEnviron())
+#elif defined(SDL_PLATFORM_FREEBSD)
+#include <dlfcn.h>
+#define environ ((char **)dlsym(RTLD_DEFAULT, "environ"))
+#else
+extern char **environ;
+#endif
+#else
+#define HAVE_LOCAL_ENVIRONMENT
+static char **environ;
+#endif
+
+#if defined(SDL_PLATFORM_LINUX) || defined(SDL_PLATFORM_MACOS) || defined(SDL_PLATFORM_FREEBSD)
+#include <stdlib.h>
+#endif
+
+struct SDL_Environment
+{
+    SDL_Mutex *lock;   // !!! FIXME: reuse SDL_HashTable's lock.
+    SDL_HashTable *strings;
+};
+static SDL_Environment *SDL_environment;
+
+SDL_Environment *SDL_GetEnvironment(void)
+{
+    if (!SDL_environment) {
+        SDL_environment = SDL_CreateEnvironment(true);
+    }
+    return SDL_environment;
+}
+
+bool SDL_InitEnvironment(void)
+{
+    return (SDL_GetEnvironment() != NULL);
+}
+
+void SDL_QuitEnvironment(void)
+{
+    SDL_Environment *env = SDL_environment;
+
+    if (env) {
+        SDL_environment = NULL;
+        SDL_DestroyEnvironment(env);
+    }
+}
+
+SDL_Environment *SDL_CreateEnvironment(bool populated)
+{
+    SDL_Environment *env = SDL_calloc(1, sizeof(*env));
+    if (!env) {
+        return NULL;
+    }
+
+    env->strings = SDL_CreateHashTable(0, false, SDL_HashString, SDL_KeyMatchString, SDL_DestroyHashKey, NULL);
+    if (!env->strings) {
+        SDL_free(env);
+        return NULL;
+    }
+
+    // Don't fail if we can't create a mutex (e.g. on a single-thread environment)  // !!! FIXME: single-threaded environments should still return a non-NULL, do-nothing object here. Check for failure!
+    env->lock = SDL_CreateMutex();
+
+    if (populated) {
+#ifdef SDL_PLATFORM_WINDOWS
+        LPWCH strings = GetEnvironmentStringsW();
+        if (strings) {
+            for (LPWCH string = strings; *string; string += SDL_wcslen(string) + 1) {
+                char *variable = WIN_StringToUTF8W(string);
+                if (!variable) {
+                    continue;
+                }
+
+                char *value = SDL_strchr(variable, '=');
+                if (!value || value == variable) {
+                    SDL_free(variable);
+                    continue;
+                }
+                *value++ = '\0';
+
+                SDL_InsertIntoHashTable(env->strings, variable, value, true);
+            }
+            FreeEnvironmentStringsW(strings);
+        }
+#else
+#ifdef SDL_PLATFORM_ANDROID
+        // Make sure variables from the application manifest are available
+        Android_JNI_GetManifestEnvironmentVariables();
+#endif
+        char **strings = environ;
+        if (strings) {
+            for (int i = 0; strings[i]; ++i) {
+                char *variable = SDL_strdup(strings[i]);
+                if (!variable) {
+                    continue;
+                }
+
+                char *value = SDL_strchr(variable, '=');
+                if (!value || value == variable) {
+                    SDL_free(variable);
+                    continue;
+                }
+                *value++ = '\0';
+
+                SDL_InsertIntoHashTable(env->strings, variable, value, true);
+            }
+        }
+#endif // SDL_PLATFORM_WINDOWS
+    }
+
+    return env;
+}
+
+const char *SDL_GetEnvironmentVariable(SDL_Environment *env, const char *name)
+{
+#if defined(SDL_PLATFORM_LINUX) || defined(SDL_PLATFORM_MACOS) || defined(SDL_PLATFORM_FREEBSD)
+    return getenv(name);
+#else
+    const char *result = NULL;
+
+    if (!env) {
+        return NULL;
+    } else if (!name || *name == '\0') {
+        return NULL;
+    }
+
+    SDL_LockMutex(env->lock);
+    {
+        const char *value;
+
+        if (SDL_FindInHashTable(env->strings, name, (const void **)&value)) {
+            result = SDL_GetPersistentString(value);
+        }
+    }
+    SDL_UnlockMutex(env->lock);
+
+    return result;
+#endif
+}
+
+typedef struct CountEnvStringsData
+{
+    size_t count;
+    size_t length;
+} CountEnvStringsData;
+
+static bool SDLCALL CountEnvStrings(void *userdata, const SDL_HashTable *table, const void *key, const void *value)
+{
+    CountEnvStringsData *data = (CountEnvStringsData *) userdata;
+    data->length += SDL_strlen((const char *) key) + 1 + SDL_strlen((const char *) value) + 1;
+    data->count++;
+    return true;  // keep iterating.
+}
+
+typedef struct CopyEnvStringsData
+{
+    char **result;
+    char *string;
+    size_t count;
+} CopyEnvStringsData;
+
+static bool SDLCALL CopyEnvStrings(void *userdata, const SDL_HashTable *table, const void *vkey, const void *vvalue)
+{
+    CopyEnvStringsData *data = (CopyEnvStringsData *) userdata;
+    const char *key = (const char *) vkey;
+    const char *value = (const char *) vvalue;
+    size_t len;
+
+    len = SDL_strlen(key);
+    data->result[data->count] = data->string;
+    SDL_memcpy(data->string, key, len);
+    data->string += len;
+    *(data->string++) = '=';
+
+    len = SDL_strlen(value);
+    SDL_memcpy(data->string, value, len);
+    data->string += len;
+    *(data->string++) = '\0';
+    data->count++;
+
+    return true;  // keep iterating.
+}
+
+char **SDL_GetEnvironmentVariables(SDL_Environment *env)
+{
+    char **result = NULL;
+
+    if (!env) {
+        SDL_InvalidParamError("env");
+        return NULL;
+    }
+
+    SDL_LockMutex(env->lock);
+    {
+        // First pass, get the size we need for all the strings
+        CountEnvStringsData countdata = { 0, 0 };
+        SDL_IterateHashTable(env->strings, CountEnvStrings, &countdata);
+
+        // Allocate memory for the strings
+        result = (char **)SDL_malloc((countdata.count + 1) * sizeof(*result) + countdata.length);
+        if (result) {
+            // Second pass, copy the strings
+            char *string = (char *)(result + countdata.count + 1);
+            CopyEnvStringsData cpydata = { result, string, 0 };
+            SDL_IterateHashTable(env->strings, CopyEnvStrings, &cpydata);
+            SDL_assert(countdata.count == cpydata.count);
+            result[cpydata.count] = NULL;
+        }
+    }
+    SDL_UnlockMutex(env->lock);
+
+    return result;
+}
+
+bool SDL_SetEnvironmentVariable(SDL_Environment *env, const char *name, const char *value, bool overwrite)
+{
+#if defined(SDL_PLATFORM_LINUX) || defined(SDL_PLATFORM_MACOS) || defined(SDL_PLATFORM_FREEBSD)
+    return setenv(name, value, overwrite);
+#else
+    bool result = false;
+
+    if (!env) {
+        return SDL_InvalidParamError("env");
+    } else if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return SDL_InvalidParamError("name");
+    } else if (!value) {
+        return SDL_InvalidParamError("value");
+    }
+
+    SDL_LockMutex(env->lock);
+    {
+        char *string = NULL;
+        if (SDL_asprintf(&string, "%s=%s", name, value) > 0) {
+            const size_t len = SDL_strlen(name);
+            string[len] = '\0';
+            const char *origname = name;
+            name = string;
+            value = string + len + 1;
+            result = SDL_InsertIntoHashTable(env->strings, name, value, overwrite);
+            if (!result) {
+                SDL_free(string);
+                if (!overwrite) {
+                    const void *existing_value = NULL;
+                    // !!! FIXME: InsertIntoHashTable does this lookup too, maybe we should have a means to report that, to avoid duplicate work?
+                    if (SDL_FindInHashTable(env->strings, origname, &existing_value)) {
+                        result = true;  // it already existed, and we refused to overwrite it. Call it success.
+                    }
+                }
+            }
+        }
+    }
+    SDL_UnlockMutex(env->lock);
+
+    return result;
+#endif
+}
+
+bool SDL_UnsetEnvironmentVariable(SDL_Environment *env, const char *name)
+{
+#if defined(SDL_PLATFORM_LINUX) || defined(SDL_PLATFORM_MACOS) || defined(SDL_PLATFORM_FREEBSD)
+    return unsetenv(name);
+#else
+    bool result = false;
+
+    if (!env) {
+        return SDL_InvalidParamError("env");
+    } else if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return SDL_InvalidParamError("name");
+    }
+
+    SDL_LockMutex(env->lock);
+    {
+        const void *value;
+        if (SDL_FindInHashTable(env->strings, name, &value)) {
+            result = SDL_RemoveFromHashTable(env->strings, name);
+        } else {
+            result = true;
+        }
+    }
+    SDL_UnlockMutex(env->lock);
+
+    return result;
+#endif
+}
+
+void SDL_DestroyEnvironment(SDL_Environment *env)
+{
+    if (!env || env == SDL_environment) {
+        return;
+    }
+
+    SDL_DestroyMutex(env->lock);
+    SDL_DestroyHashTable(env->strings);
+    SDL_free(env);
+}
+
+// Put a variable into the environment
+// Note: Name may not contain a '=' character. (Reference: http://www.unix.com/man-page/Linux/3/setenv/)
+#ifdef HAVE_LIBC_ENVIRONMENT
+#if defined(HAVE_SETENV)
+int SDL_setenv_unsafe(const char *name, const char *value, int overwrite)
+{
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL || !value) {
+        return -1;
+    }
+
+    SDL_SetEnvironmentVariable(SDL_GetEnvironment(), name, value, (overwrite != 0));
+
+    return setenv(name, value, overwrite);
+}
+// We have a real environment table, but no real setenv? Fake it w/ putenv.
+#else
+int SDL_setenv_unsafe(const char *name, const char *value, int overwrite)
+{
+    char *new_variable;
+
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL || !value) {
+        return -1;
+    }
+
+    SDL_SetEnvironmentVariable(SDL_GetEnvironment(), name, value, (overwrite != 0));
+
+    if (getenv(name) != NULL) {
+        if (!overwrite) {
+            return 0; // leave the existing one there.
+        }
+    }
+
+    // This leaks. Sorry. Get a better OS so we don't have to do this.
+    SDL_asprintf(&new_variable, "%s=%s", name, value);
+    if (!new_variable) {
+        return -1;
+    }
+    return putenv(new_variable);
+}
+#endif
+#elif defined(HAVE_WIN32_ENVIRONMENT)
+int SDL_setenv_unsafe(const char *name, const char *value, int overwrite)
+{
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL || !value) {
+        return -1;
+    }
+
+    SDL_SetEnvironmentVariable(SDL_GetEnvironment(), name, value, (overwrite != 0));
+
+    if (!overwrite) {
+        if (GetEnvironmentVariableA(name, NULL, 0) > 0) {
+            return 0; // asked not to overwrite existing value.
+        }
+    }
+    if (!SetEnvironmentVariableA(name, value)) {
+        return -1;
+    }
+    return 0;
+}
+#else // roll our own
+
+int SDL_setenv_unsafe(const char *name, const char *value, int overwrite)
+{
+    int added;
+    size_t len, i;
+    char **new_env;
+    char *new_variable;
+
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL || !value) {
+        return -1;
+    }
+
+    // See if it already exists
+    if (!overwrite && SDL_getenv_unsafe(name)) {
+        return 0;
+    }
+
+    SDL_SetEnvironmentVariable(SDL_GetEnvironment(), name, value, (overwrite != 0));
+
+    // Allocate memory for the variable
+    len = SDL_strlen(name) + SDL_strlen(value) + 2;
+    new_variable = (char *)SDL_malloc(len);
+    if (!new_variable) {
+        return -1;
+    }
+
+    SDL_snprintf(new_variable, len, "%s=%s", name, value);
+    value = new_variable + SDL_strlen(name) + 1;
+    name = new_variable;
+
+    // Actually put it into the environment
+    added = 0;
+    i = 0;
+    if (environ) {
+        // Check to see if it's already there...
+        len = (value - name);
+        for (; environ[i]; ++i) {
+            if (SDL_strncmp(environ[i], name, len) == 0) {
+                // If we found it, just replace the entry
+                SDL_free(environ[i]);
+                environ[i] = new_variable;
+                added = 1;
+                break;
+            }
+        }
+    }
+
+    // Didn't find it in the environment, expand and add
+    if (!added) {
+        new_env = SDL_realloc(environ, (i + 2) * sizeof(char *));
+        if (new_env) {
+            environ = new_env;
+            environ[i++] = new_variable;
+            environ[i++] = (char *)0;
+            added = 1;
+        } else {
+            SDL_free(new_variable);
+        }
+    }
+    return added ? 0 : -1;
+}
+#endif // HAVE_LIBC_ENVIRONMENT
+
+#ifdef HAVE_LIBC_ENVIRONMENT
+#if defined(HAVE_UNSETENV)
+int SDL_unsetenv_unsafe(const char *name)
+{
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return -1;
+    }
+
+    SDL_UnsetEnvironmentVariable(SDL_GetEnvironment(), name);
+
+    return unsetenv(name);
+}
+// We have a real environment table, but no unsetenv? Fake it w/ putenv.
+#else
+int SDL_unsetenv_unsafe(const char *name)
+{
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return -1;
+    }
+
+    SDL_UnsetEnvironmentVariable(SDL_GetEnvironment(), name);
+
+    // Hope this environment uses the non-standard extension of removing the environment variable if it has no '='
+    return putenv(name);
+}
+#endif
+#elif defined(HAVE_WIN32_ENVIRONMENT)
+int SDL_unsetenv_unsafe(const char *name)
+{
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return -1;
+    }
+
+    SDL_UnsetEnvironmentVariable(SDL_GetEnvironment(), name);
+
+    if (!SetEnvironmentVariableA(name, NULL)) {
+        return -1;
+    }
+    return 0;
+}
+#else
+int SDL_unsetenv_unsafe(const char *name)
+{
+    size_t len, i;
+
+    // Input validation
+    if (!name || *name == '\0' || SDL_strchr(name, '=') != NULL) {
+        return -1;
+    }
+
+    SDL_UnsetEnvironmentVariable(SDL_GetEnvironment(), name);
+
+    if (environ) {
+        len = SDL_strlen(name);
+        for (i = 0; environ[i]; ++i) {
+            if ((SDL_strncmp(environ[i], name, len) == 0) &&
+                (environ[i][len] == '=')) {
+                // Just clear out this entry for now
+                *environ[i] = '\0';
+                break;
+            }
+        }
+    }
+    return 0;
+}
+#endif // HAVE_LIBC_ENVIRONMENT
+
+// Retrieve a variable named "name" from the environment
+#ifdef HAVE_LIBC_ENVIRONMENT
+const char *SDL_getenv_unsafe(const char *name)
+{
+#ifdef SDL_PLATFORM_ANDROID
+    // Make sure variables from the application manifest are available
+    Android_JNI_GetManifestEnvironmentVariables();
+#endif
+
+    // Input validation
+    if (!name || *name == '\0') {
+        return NULL;
+    }
+
+    return getenv(name);
+}
+#elif defined(HAVE_WIN32_ENVIRONMENT)
+const char *SDL_getenv_unsafe(const char *name)
+{
+    DWORD length, maxlen = 0;
+    char *string = NULL;
+    const char *result = NULL;
+
+    // Input validation
+    if (!name || *name == '\0') {
+        return NULL;
+    }
+
+    for ( ; ; ) {
+        SetLastError(ERROR_SUCCESS);
+        length = GetEnvironmentVariableA(name, string, maxlen);
+
+        if (length > maxlen) {
+            char *temp = (char *)SDL_realloc(string, length);
+            if (!temp)  {
+                return NULL;
+            }
+            string = temp;
+            maxlen = length;
+        } else {
+            if (GetLastError() != ERROR_SUCCESS) {
+                if (string) {
+                    SDL_free(string);
+                }
+                return NULL;
+            }
+            break;
+        }
+    }
+    if (string) {
+        result = SDL_GetPersistentString(string);
+        SDL_free(string);
+    }
+    return result;
+}
+#else
+const char *SDL_getenv_unsafe(const char *name)
+{
+    size_t len, i;
+    const char *value = NULL;
+
+    // Input validation
+    if (!name || *name == '\0') {
+        return NULL;
+    }
+
+    if (environ) {
+        len = SDL_strlen(name);
+        for (i = 0; environ[i]; ++i) {
+            if ((SDL_strncmp(environ[i], name, len) == 0) &&
+                (environ[i][len] == '=')) {
+                value = &environ[i][len + 1];
+                break;
+            }
+        }
+    }
+    return value;
+}
+#endif // HAVE_LIBC_ENVIRONMENT
+
+const char *SDL_getenv(const char *name)
+{
+    return SDL_GetEnvironmentVariable(SDL_GetEnvironment(), name);
+}