scuffed-code/icu4c/source/common/icuplug.c

/*
******************************************************************************
*
*   Copyright (C) 2009-2010, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
******************************************************************************
*
*  FILE NAME : icuplug.c
*
*   Date         Name        Description
*   10/29/2009   sl          New.
******************************************************************************
*/

#include "unicode/icuplug.h"
#include "icuplugimp.h"
#include "cstring.h"
#include "cmemory.h"
#include "putilimp.h"
#include "ucln.h"
#include <stdio.h>

#ifndef UPLUG_TRACE
#define UPLUG_TRACE 0
#endif

#if UPLUG_TRACE
#include <stdio.h>
#define DBG(x) printf("%s:%d: ",__FILE__,__LINE__); printf x; 
#else
#define DBG(x)
#endif

/**
 * Internal structure of an ICU plugin. 
 */

struct UPlugData {
    UPlugEntrypoint  *entrypoint; /**< plugin entrypoint */
    uint32_t structSize;    /**< initialized to the size of this structure */
    uint32_t token;         /**< must be U_PLUG_TOKEN */
    void *lib;              /**< plugin library, or NULL */
	char libName[UPLUG_NAME_MAX];   /**< library name */
    char sym[UPLUG_NAME_MAX];        /**< plugin symbol, or NULL */
    char config[UPLUG_NAME_MAX];     /**< configuration data */
    void *context;          /**< user context data */
    char name[UPLUG_NAME_MAX];   /**< name of plugin */
    UPlugLevel  level; /**< level of plugin */
    UBool   awaitingLoad; /**< TRUE if the plugin is awaiting a load call */
    UBool   dontUnload; /**< TRUE if plugin must stay resident (leak plugin and lib) */
    UErrorCode pluginStatus; /**< status code of plugin */
};



#define UPLUG_LIBRARY_INITIAL_COUNT 8
#define UPLUG_PLUGIN_INITIAL_COUNT 12


/*
 - have a callback to determine HIGH or LOW level
 - automatically run all LOW level then HIGH level plugins in order
- have icuinfo give diagnostics and info
 - have icuinfo give sample config file and location.
 
  */



/**
 * Remove an item
 * @param list the full list
 * @param listSize the number of entries in the list
 * @param memberSize the size of one member
 * @param itemToRemove the item number of the member
 * @return the new listsize 
 */
static int32_t uplug_removeEntryAt(void *list, int32_t listSize, int32_t memberSize, int32_t itemToRemove) {
    uint8_t *bytePtr = (uint8_t *)list;
    
    /* get rid of some bad cases first */
    if(listSize<1) {
        return listSize;
    }
    
    /* is there anything to move? */
    if(listSize > itemToRemove+1) {
        memmove(bytePtr+(itemToRemove*memberSize), bytePtr+((itemToRemove+1)*memberSize), memberSize);
    }
    
    return listSize-1;
}




#if U_ENABLE_DYLOAD
/**
 * Library management. Internal. 
 * @internal
 */
struct UPlugLibrary;

/**
 * Library management. Internal. 
 * @internal
 */
typedef struct UPlugLibrary {
    void *lib;                           /**< library ptr */
    char name[UPLUG_NAME_MAX]; /**< library name */
    uint32_t ref;                        /**< reference count */
} UPlugLibrary;

UPlugLibrary   staticLibraryList[UPLUG_LIBRARY_INITIAL_COUNT];
UPlugLibrary * libraryList = staticLibraryList;
int32_t libraryCount = 0;
int32_t libraryMax = UPLUG_LIBRARY_INITIAL_COUNT;

/**
 * Search for a library. Doesn't lock
 * @param libName libname to search for
 * @return the library's struct
 */
static int32_t searchForLibraryName(const char *libName) {
    int32_t i;
    
    for(i=0;i<libraryCount;i++) {
        if(!uprv_strcmp(libName, libraryList[i].name)) {
            return i;
        }
    }
    return -1;
}

static int32_t searchForLibrary(void *lib) {
    int32_t i;
    
    for(i=0;i<libraryCount;i++) {
        if(lib==libraryList[i].lib) {
            return i;
        }
    }
    return -1;
}

U_INTERNAL char * U_EXPORT2
uplug_findLibrary(void *lib, UErrorCode *status) {
    int32_t libEnt;
    char *ret = NULL;
    if(U_FAILURE(*status)) {
        return NULL;
    }
    libEnt = searchForLibrary(lib);
    if(libEnt!=-1) { 
        ret = libraryList[libEnt].name;
    } else {
        *status = U_MISSING_RESOURCE_ERROR;
    }
    return ret;
}

U_INTERNAL void * U_EXPORT2
uplug_openLibrary(const char *libName, UErrorCode *status) {
    int32_t libEntry = -1;
    void *lib = NULL;
    
    DBG(("uplug_openLibrary(%s,%s)\n", libName, u_errorName(*status)))
    
    if(U_FAILURE(*status)) return NULL;

    DBG(("uplug_openLibrary(%s,%s)\n", libName, u_errorName(*status)))
    
    libEntry = searchForLibraryName(libName);
    DBG(("uplug_openLibrary(%s,%s) libEntry %d\n", libName, u_errorName(*status), libEntry))
    if(libEntry == -1) {
        libEntry = libraryCount++;
        
        /* Some operating systems don't want 
           DL operations from multiple threads. */
        libraryList[libEntry].lib = uprv_dl_open(libName, status);
        DBG(("uplug_openLibrary(%s,%s) libEntry %d, lib %p\n", libName, u_errorName(*status), libEntry, lib))
        
        if(libraryList[libEntry].lib == NULL || U_FAILURE(*status)) {
            /* cleanup. */
            libraryList[libEntry].lib = NULL; /* failure with open */
            libraryList[libEntry].name[0] = 0;
            DBG(("uplug_openLibrary(%s,%s) libEntry %d, lib %p\n", libName, u_errorName(*status), libEntry, lib))
            /* no need to free - just won't increase the count. */
            DBG(("uplug_openLibrary(%s,%s) libEntry %d, lib %p\n", libName, u_errorName(*status), libEntry, lib))
            libraryCount--;
        } else { /* is it still there? */
            /* link it in */
            strncpy(libraryList[libEntry].name,libName,UPLUG_NAME_MAX);
            libraryList[libEntry].ref=1;
            lib = libraryList[libEntry].lib;
        }

    } else {
        lib = libraryList[libEntry].lib;
        libraryList[libEntry].ref++;
    }
    DBG(("uplug_openLibrary(%s,%s) libEntry %d, lib %p, ref %d\n", libName, u_errorName(*status), libEntry, lib, libEntry?libraryList[libEntry].ref:-1))
    return lib;
}

U_INTERNAL void U_EXPORT2
uplug_closeLibrary(void *lib, UErrorCode *status) {
    int32_t i;
    
    DBG(("uplug_closeLibrary(%p,%s) list %p\n", lib, u_errorName(*status), (void*)libraryList))
    if(U_FAILURE(*status)) return;
    
    DBG(("uplug_closeLibrary(%p,%s) list %p\n", lib, u_errorName(*status), (void*)libraryList))
    for(i=0;i<libraryCount;i++) {
        if(lib==libraryList[i].lib) {
            DBG(("uplug_closeLibrary(%p,%s)  found #%d %p ref %d\n", lib, u_errorName(*status), i, (void*)&libraryList[i], libraryList[i].ref))
            if(--(libraryList[i].ref) == 0) {
                DBG(("uplug_closeLibrary(%p,%s)  entryToClose #%d %p ref %d\n", lib, u_errorName(*status), i, (void*)&libraryList[i], libraryList[i].ref))
                uprv_dl_close(libraryList[i].lib, status);
                libraryCount = uplug_removeEntryAt(libraryList, libraryCount, sizeof(*libraryList), i);
            }
            return;
        }
    }
    *status = U_INTERNAL_PROGRAM_ERROR; /* could not find the entry! */
}

#endif

UPlugData pluginList[UPLUG_PLUGIN_INITIAL_COUNT];
int32_t pluginCount = 0;



  
static int32_t uplug_pluginNumber(UPlugData* d) {
    UPlugData *pastPlug = &pluginList[pluginCount];
    if(d<=pluginList) {
        return 0;
    } else if(d>=pastPlug) {
        return pluginCount;
    } else {
        return (d-pluginList)/sizeof(pluginList[0]);
    }
}


U_CAPI UPlugData * U_EXPORT2
uplug_nextPlug(UPlugData *prior) {
    if(prior==NULL) {
        return pluginList;
    } else {
        UPlugData *nextPlug = &prior[1];
        UPlugData *pastPlug = &pluginList[pluginCount];
    
        if(nextPlug>=pastPlug) {
            return NULL;
        } else {
            return nextPlug;
        }
    }
}



/**
 * Call the plugin with some params
 */
static void uplug_callPlug(UPlugData *plug, UPlugReason reason, UErrorCode *status) {
    UPlugTokenReturn token;
    if(plug==NULL||U_FAILURE(*status)) {
        return;
    }
    token = (*(plug->entrypoint))(plug, reason, status);
    if(token!=UPLUG_TOKEN) {
        *status = U_INTERNAL_PROGRAM_ERROR;
    }
}


static void uplug_unloadPlug(UPlugData *plug, UErrorCode *status) {
    if(plug->awaitingLoad) {  /* shouldn't happen. Plugin hasn'tbeen loaded yet.*/
        *status = U_INTERNAL_PROGRAM_ERROR;
        return; 
    }
	if(U_SUCCESS(plug->pluginStatus)) {
		/* Don't unload a plug which has a failing load status - means it didn't actually load. */
	    uplug_callPlug(plug, UPLUG_REASON_UNLOAD, status);
	}
}

static void uplug_queryPlug(UPlugData *plug, UErrorCode *status) {
    if(!plug->awaitingLoad || !(plug->level == UPLUG_LEVEL_UNKNOWN) ) {  /* shouldn't happen. Plugin hasn'tbeen loaded yet.*/
        *status = U_INTERNAL_PROGRAM_ERROR;
        return; 
    }
    plug->level = UPLUG_LEVEL_INVALID;
    uplug_callPlug(plug, UPLUG_REASON_QUERY, status);
    if(U_SUCCESS(*status)) { 
        if(plug->level == UPLUG_LEVEL_INVALID) {
            plug->pluginStatus = U_PLUGIN_DIDNT_SET_LEVEL;
            plug->awaitingLoad = FALSE;
        }
    } else {
        plug->pluginStatus = U_INTERNAL_PROGRAM_ERROR;
        plug->awaitingLoad = FALSE;
    }
}


static void uplug_loadPlug(UPlugData *plug, UErrorCode *status) {
    if(!plug->awaitingLoad || (plug->level < UPLUG_LEVEL_LOW) ) {  /* shouldn't happen. Plugin hasn'tbeen loaded yet.*/
        *status = U_INTERNAL_PROGRAM_ERROR;
        return;
    }
    uplug_callPlug(plug, UPLUG_REASON_LOAD, status);
    plug->awaitingLoad = FALSE;
    if(!U_SUCCESS(*status)) {
        plug->pluginStatus = U_INTERNAL_PROGRAM_ERROR;
    }
}

static UPlugData *uplug_allocateEmptyPlug(UErrorCode *status)
{
    UPlugData *plug = NULL;

    if(U_FAILURE(*status)) {
        return NULL;
    }

	if(pluginCount == UPLUG_PLUGIN_INITIAL_COUNT) {
		*status = U_MEMORY_ALLOCATION_ERROR;
		return NULL;
	}

    plug = &pluginList[pluginCount++];

    plug->token = UPLUG_TOKEN;
    plug->structSize = sizeof(UPlugData);
    plug->name[0]=0;
    plug->level = UPLUG_LEVEL_UNKNOWN; /* initialize to null state */
    plug->awaitingLoad = TRUE;
    plug->dontUnload = FALSE;
    plug->pluginStatus = U_ZERO_ERROR;
	plug->libName[0] = 0;
	plug->config[0]=0;
	plug->sym[0]=0;
	plug->lib=NULL;
	plug->entrypoint=NULL;


	return plug;
}

static UPlugData *uplug_allocatePlug(UPlugEntrypoint *entrypoint, const char *config, void *lib, const char *symName,
                            UErrorCode *status) {
	UPlugData *plug;

    if(U_FAILURE(*status)) {
        return NULL;
    }

	plug = uplug_allocateEmptyPlug(status);
    if(config!=NULL) {
        strncpy(plug->config, config, UPLUG_NAME_MAX);
    } else {
        plug->config[0] = 0;
    }
    
    if(symName!=NULL) {
        strncpy(plug->sym, symName, UPLUG_NAME_MAX);
    } else {
        plug->sym[0] = 0;
    }
    
    plug->entrypoint = entrypoint;
    plug->lib = lib;
    uplug_queryPlug(plug, status);
    
    return plug;
}

static void uplug_deallocatePlug(UPlugData *plug, UErrorCode *status) {
    UErrorCode subStatus = U_ZERO_ERROR;
    if(!plug->dontUnload) {
#if U_ENABLE_DYLOAD
        uplug_closeLibrary(plug->lib, &subStatus);
#endif
    }
    plug->lib = NULL;
    if(U_SUCCESS(*status) && U_FAILURE(subStatus)) {
        *status = subStatus;
    }
    /* shift plugins up and decrement count. */
	if(U_SUCCESS(*status)) {
		/* all ok- remove. */
	    pluginCount = uplug_removeEntryAt(pluginList, pluginCount, sizeof(plug[0]), uplug_pluginNumber(plug));
	} else {
		/* not ok- leave as a message. */
		plug->awaitingLoad=FALSE;
		plug->entrypoint=0;
		plug->dontUnload=TRUE;
	}
}

static void uplug_doUnloadPlug(UPlugData *plugToRemove, UErrorCode *status) {
    if(plugToRemove != NULL) {
        uplug_unloadPlug(plugToRemove, status);
        uplug_deallocatePlug(plugToRemove, status);
    }
}

U_CAPI void U_EXPORT2
uplug_removePlug(UPlugData *plug, UErrorCode *status)  {
    UPlugData *cursor = NULL;
    UPlugData *plugToRemove = NULL;
    if(U_FAILURE(*status)) return;
    
    for(cursor=pluginList;cursor!=NULL;) {
        if(cursor==plug) {
            plugToRemove = plug;
            cursor=NULL;
        } else {
            cursor = uplug_nextPlug(cursor);
        }
    }
    
    uplug_doUnloadPlug(plugToRemove, status);
}




U_CAPI void U_EXPORT2 
uplug_setPlugNoUnload(UPlugData *data, UBool dontUnload)
{
    data->dontUnload = dontUnload;
}


U_CAPI void U_EXPORT2
uplug_setPlugLevel(UPlugData *data, UPlugLevel level) {
    data->level = level;
}


U_CAPI UPlugLevel U_EXPORT2
uplug_getPlugLevel(UPlugData *data) {
    return data->level;
}


U_CAPI void U_EXPORT2
uplug_setPlugName(UPlugData *data, const char *name) {
    strncpy(data->name, name, UPLUG_NAME_MAX);
}


U_CAPI const char * U_EXPORT2
uplug_getPlugName(UPlugData *data) {
    return data->name;
}


U_CAPI const char * U_EXPORT2
uplug_getSymbolName(UPlugData *data) {
    return data->sym;
}

U_CAPI const char * U_EXPORT2
uplug_getLibraryName(UPlugData *data, UErrorCode *status) {
	if(data->libName[0]) {
		return data->libName;
	} else {
#if U_ENABLE_DYLOAD
	    return uplug_findLibrary(data->lib, status);
#else
	    return NULL;
#endif
	}
}

U_CAPI void * U_EXPORT2
uplug_getLibrary(UPlugData *data) {
    return data->lib;
}

U_CAPI void * U_EXPORT2
uplug_getContext(UPlugData *data) {
    return data->context;
}


U_CAPI void U_EXPORT2
uplug_setContext(UPlugData *data, void *context) {
    data->context = context;
}

U_CAPI const char* U_EXPORT2
uplug_getConfiguration(UPlugData *data) {
    return data->config;
}

U_INTERNAL UPlugData* U_EXPORT2
uplug_getPlugInternal(int32_t n) { 
    if(n <0 || n >= pluginCount) {
        return NULL;
    } else { 
        return &(pluginList[n]);
    }
}


U_CAPI UErrorCode U_EXPORT2
uplug_getPlugLoadStatus(UPlugData *plug) {
    return plug->pluginStatus;
}




/**
 * Initialize a plugin fron an entrypoint and library - but don't load it.
 */
static UPlugData* uplug_initPlugFromEntrypointAndLibrary(UPlugEntrypoint *entrypoint, const char *config, void *lib, const char *sym,
                            UErrorCode *status) {
    UPlugData *plug = NULL;

    plug = uplug_allocatePlug(entrypoint, config, lib, sym, status);

    if(U_SUCCESS(*status)) {
        return plug;
    } else {
        uplug_deallocatePlug(plug, status);
        return NULL;
    }
}

U_CAPI UPlugData* U_EXPORT2
uplug_loadPlugFromEntrypoint(UPlugEntrypoint *entrypoint, const char *config, UErrorCode *status) {
    UPlugData* plug = uplug_initPlugFromEntrypointAndLibrary(entrypoint, config, NULL, NULL, status);
    uplug_loadPlug(plug, status);
    return plug;
}


static UPlugData* 
uplug_initErrorPlug(const char *libName, const char *sym, const char *config, const char *nameOrError, UErrorCode loadStatus, UErrorCode *status)
{
	UPlugData *plug = uplug_allocateEmptyPlug(status);
	if(U_FAILURE(*status)) return NULL;

	plug->pluginStatus = loadStatus;
	plug->awaitingLoad = FALSE; /* Won't load. */
	plug->dontUnload = TRUE; /* cannot unload. */

	if(sym!=NULL) {
        strncpy(plug->sym, sym, UPLUG_NAME_MAX);
	}

	if(libName!=NULL) {
		strncpy(plug->libName, libName, UPLUG_NAME_MAX);
	}

	if(nameOrError!=NULL) {
		strncpy(plug->name, nameOrError, UPLUG_NAME_MAX);
	}

	if(config!=NULL) {
		strncpy(plug->config, config, UPLUG_NAME_MAX);
	}

	return plug;
}

/**
 * Fetch a plugin from DLL, and then initialize it from a library- but don't load it.
 */

#if U_ENABLE_DYLOAD

static UPlugData* 
uplug_initPlugFromLibrary(const char *libName, const char *sym, const char *config, UErrorCode *status) {
    void *lib = NULL;
    UPlugData *plug = NULL;
    void *entrypoint = NULL;
    if(U_FAILURE(*status)) { return NULL; }
    lib = uplug_openLibrary(libName, status);
    if(lib!=NULL && U_SUCCESS(*status)) {
        entrypoint = uprv_dl_sym(lib, sym, status);
        
        if(entrypoint!=NULL&&U_SUCCESS(*status)) {
            /* TODO: warning on next line needs to be corrected by complex C syntax. */
            plug = uplug_initPlugFromEntrypointAndLibrary((UPlugEntrypoint*)entrypoint, config, lib, sym, status);
            if(plug!=NULL&&U_SUCCESS(*status)) {
                plug->lib = lib; /* plug takes ownership of library */
                lib = NULL; /* library is now owned by plugin. */
            }
		} else {
			UErrorCode subStatus = U_ZERO_ERROR;
			plug = uplug_initErrorPlug(libName,sym,config,"ERROR: Could not load entrypoint",(lib==NULL)?U_MISSING_RESOURCE_ERROR:*status,&subStatus);
        }
        if(lib!=NULL) { /* still need to close the lib */
            UErrorCode subStatus = U_ZERO_ERROR;
            uplug_closeLibrary(lib, &subStatus); /* don't care here */
        }
	} else {
		UErrorCode subStatus = U_ZERO_ERROR;
		plug = uplug_initErrorPlug(libName,sym,config,"ERROR: could not load library",(lib==NULL)?U_MISSING_RESOURCE_ERROR:*status,&subStatus);
    }
    return plug;
}

U_CAPI UPlugData* U_EXPORT2
uplug_loadPlugFromLibrary(const char *libName, const char *sym, const char *config, UErrorCode *status) { 
    UPlugData *plug = NULL;
    if(U_FAILURE(*status)) { return NULL; }
    plug = uplug_initPlugFromLibrary(libName, sym, config, status);
    uplug_loadPlug(plug, status);

    return plug;
}

#endif




U_CAPI UPlugLevel U_EXPORT2 uplug_getCurrentLevel() {
    if(cmemory_inUse()) {
        return UPLUG_LEVEL_HIGH;
    } else {
        return UPLUG_LEVEL_LOW;
    }
}

static UBool U_CALLCONV uplug_cleanup(void)
{
    int32_t i;
    
    UPlugData *pluginToRemove;
    /* cleanup plugs */
    for(i=0;i<pluginCount;i++) {
        UErrorCode subStatus = U_ZERO_ERROR;
        
        pluginToRemove = &pluginList[i];

        /* unload and deallocate */
        uplug_doUnloadPlug(pluginToRemove, &subStatus);
    }
    
    /* close other held libs? */
    return TRUE;
}



static void uplug_loadWaitingPlugs(UErrorCode *status) {
    int32_t i;
    UPlugLevel currentLevel = uplug_getCurrentLevel();
    
    DBG(( "loadWaitingPlugs. Level: %d\n", currentLevel))
    /* pass #1: low level plugs */
    for(i=0;i<pluginCount;i++) {
        UErrorCode subStatus = U_ZERO_ERROR;
        UPlugData *pluginToLoad = &pluginList[i];
        
        if(pluginToLoad->awaitingLoad) {
            if(pluginToLoad->level == UPLUG_LEVEL_LOW) {
                DBG(( "Low #%d: Awaiting load: %p. Level: %d\n", i, (void*)pluginToLoad,
                    (int32_t)currentLevel))
                if(currentLevel > UPLUG_LEVEL_LOW) {
                    pluginToLoad->pluginStatus = U_PLUGIN_TOO_HIGH;
                } else {
                    UPlugLevel newLevel;
                    uplug_loadPlug(pluginToLoad, &subStatus);
                    newLevel = uplug_getCurrentLevel();
                        if(newLevel > currentLevel) {
                        pluginToLoad->pluginStatus = U_PLUGIN_CHANGED_LEVEL_WARNING;
                        currentLevel = newLevel;
                        DBG(( "Low #%d: Level change! %p\n", i, (void*)pluginToLoad))
                    }
                }
                pluginToLoad->awaitingLoad = FALSE;
                DBG(( " %p  -> %s, %s. Level: %d\n", (void*)pluginToLoad, u_errorName(subStatus), u_errorName(pluginToLoad->pluginStatus),
                        (int32_t)currentLevel));
            } 
        }
    }
    currentLevel = uplug_getCurrentLevel();
    
    for(i=0;i<pluginCount;i++) {
        UErrorCode subStatus = U_ZERO_ERROR;
        UPlugData *pluginToLoad = &pluginList[i];
        
        if(pluginToLoad->awaitingLoad) {
            DBG(( "High #%d: Awaiting load: %p. Level: %d\n", i, (void*)pluginToLoad,
                (int32_t)currentLevel))
            if(pluginToLoad->level == UPLUG_LEVEL_INVALID) { 
                pluginToLoad->pluginStatus = U_PLUGIN_DIDNT_SET_LEVEL;
            } else if(pluginToLoad->level == UPLUG_LEVEL_UNKNOWN) {
                pluginToLoad->pluginStatus = U_INTERNAL_PROGRAM_ERROR;
            } else {
                uplug_loadPlug(pluginToLoad, &subStatus);
            }
            pluginToLoad->awaitingLoad = FALSE;
            DBG(( " %p  -> %s, %s. Level: %d\n", (void*)pluginToLoad, u_errorName(subStatus), u_errorName(pluginToLoad->pluginStatus),
                    (int32_t)currentLevel));
            
        }
    }
    
    DBG(( " Done Loading Plugs. Level:  Level: %d\n", (int32_t)uplug_getCurrentLevel()));
}

#if U_ENABLE_DYLOAD
static char plugin_file[2048] = "";
#endif

U_INTERNAL const char* U_EXPORT2
uplug_getPluginFile() {
#if U_ENABLE_DYLOAD
    return plugin_file;
#else
    return NULL;
#endif
}


U_CAPI void U_EXPORT2
uplug_init(UErrorCode *status) {
#if U_ENABLE_DYLOAD
    const char *plugin_dir;
    
    plugin_dir = getenv("ICU_PLUGINS");
    DBG((">> ICU_PLUGINS=%s\n", plugin_dir))

#if defined(DEFAULT_ICU_PLUGINS) 
    if(plugin_dir == NULL || !*plugin_dir) {
        plugin_dir = DEFAULT_ICU_PLUGINS;
	DBG(("  (using DEFAULT_ICU_PLUGINS)\n"))
    }
#endif

    if(plugin_dir != NULL && *plugin_dir) {
        FILE *f;
        
        
        strncpy(plugin_file, plugin_dir, 2047);
        strncat(plugin_file, U_FILE_SEP_STRING,2047);
        strncat(plugin_file, "icuplugins",2047);
        strncat(plugin_file, U_ICU_VERSION_SHORT ,2047);
        strncat(plugin_file, ".txt" ,2047);
        
        DBG((">> pluginfile [%s]\n", plugin_file))
        
        f = fopen(plugin_file, "r");

        if(f != NULL) {
            char linebuf[1024];
            char *p, *libName=NULL, *symName=NULL, *config=NULL;
			int32_t line = 0;
            
            
            while(fgets(linebuf,1023,f)) {
				line++;
				DBG(("#%d: %s",line,linebuf))

                if(!*linebuf || *linebuf=='#') {
                    continue;
                } else {
                    p = linebuf;
                    while(*p&&isspace(*p))
                        p++;
                    if(!*p || *p=='#') continue;
                    libName = p;
                    while(*p&&!isspace(*p)) {
                        p++;
                    }
                    if(!*p || *p=='#') continue; /* no tab after libname */
                    *p=0; /* end of libname */
                    p++;
                    while(*p&&isspace(*p)) {
                        p++;
                    }
                    if(!*p||*p=='#') continue; /* no symname after libname +tab */
                    symName = p;
                    while(*p&&!isspace(*p)) {
                        p++;
                    }
                    
                    if(*p) { /* has config */
                        *p=0;
                        ++p;
                        while(*p&&isspace(*p)) {
                            p++;
                        }
                        if(*p) {
                            config = p;
                        }
                    }
                    
                    /* chop whitespace at the end of the config */
                    if(config!=NULL&&*config!=0) {
                        p = config+strlen(config);
                        while(p>config&&isspace(*(--p))) {
                            *p=0;
                        }
                    }
                
                    /* OK, we're good. */
                    DBG(("PLUGIN libName=[%s], sym=[%s], config=[%s]\n", libName, symName, config))
                    
                    { 
                        UErrorCode subStatus = U_ZERO_ERROR;
                        UPlugData *plug =  uplug_initPlugFromLibrary(libName, symName, config, &subStatus);
                        DBG((" -> %p, %s\n", (void*)plug, u_errorName(subStatus)))
                    }
                }
            }
		} else {
			DBG(("Can't open plugin file %s\n", plugin_file))
        }
    }
    uplug_loadWaitingPlugs(status);
#endif /* U_ENABLE_DYLOAD */
    ucln_registerCleanup(UCLN_UPLUG, uplug_cleanup);
}