/*
* ld - load code dynamically
*
* $Author: zimoch $
* $ID$
* $Date: 2015/06/29 09:47:30 $
*
* DISCLAIMER: Use at your own risc and so on. No warranty, no refund.
*/
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <dirent.h>

#include <epicsVersion.h>
#ifdef BASE_VERSION
#define EPICS_3_13
#define epicsStdoutPrintf printf
int dbLoadDatabase(char *filename, char *path, char *substitutions);
extern volatile int interruptAccept;
#else
#define EPICS_3_14
#include <iocsh.h>
#include <dbAccess.h>
epicsShareFunc int epicsShareAPI iocshCmd (const char *cmd);
#include <epicsExit.h>
#include <epicsStdio.h>
#include <epicsExport.h>
#endif

#include "require.h"

int requireDebug=0;

static int firstTime = 1;

#define DIRSEP "/"
#define PATHSEP ":"
#define PREFIX
#define INFIX

#if defined (vxWorks)

    #include <symLib.h>
    #include <sysSymTbl.h>
    #include <sysLib.h>
    #include <symLib.h>
    #include <loadLib.h>
    #include <shellLib.h>
    #include <usrLib.h>
    #include <taskLib.h>
    #include <ioLib.h>
    #include <errno.h>

    #define HMODULE MODULE_ID
    #undef  INFIX
    #define INFIX "Lib"
    #define EXT ".munch"
    
    #define getAddress(module,name) __extension__ \
        ({SYM_TYPE t; char* a=NULL; symFindByName(sysSymTbl, (name), &a, &t); a;})
        
    #define snprintf(s, n, f, args...) sprintf(s, f, ## args)

#elif defined (__unix)

    #define __USE_GNU
    #include <dlfcn.h>
    #define HMODULE void *

    #define getAddress(module,name) (dlsym(module, name))

    #ifdef CYGWIN32

        #define EXT ".dll"

    #else

        #undef  PREFIX
        #define PREFIX "lib"
        #define EXT ".so"

    #endif

#elif defined (_WIN32)

    #include <windows.h>
    #undef  DIRSEP
    #define DIRSEP "\\"
    #undef  PATHSEP
    #define PATHSEP ";"
    #define EXT ".dll"

    #define getAddress(module,name) (GetProcAddress(module, name))
#else

    #warning unknwn OS
    #define getAddress(module,name) NULL

#endif

#define toStr2(x) x
#define toStr(x) toStr2(#x) 
const char epicsRelease[] = toStr(EPICS_RELEASE);
const char targetArch[] = toStr(T_A);

/* loadlib (library)
Find a loadable library by name and load it.
*/

static HMODULE loadlib(const char* libname)
{
    HMODULE libhandle = NULL;

    if (!libname)
    {
        fprintf (stderr, "missing library name\n");
        return NULL;
    }

#if defined (__unix)
    if (!(libhandle = dlopen(libname, RTLD_NOW|RTLD_GLOBAL)))
    {
        fprintf (stderr, "Loading %s library failed: %s\n",
            libname, dlerror());
    }
#elif defined (_WIN32)
    if (!(libhandle = LoadLibrary(libname)))
    {
        LPVOID lpMsgBuf;

        FormatMessage(
            FORMAT_MESSAGE_ALLOCATE_BUFFER |
            FORMAT_MESSAGE_FROM_SYSTEM,
            NULL,
            GetLastError(),
            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
            (LPTSTR) &lpMsgBuf,
            0, NULL );
        fprintf (stderr, "Loading %s library failed: %s\n",
            libname, lpMsgBuf);
        LocalFree(lpMsgBuf);
    }
#elif defined (vxWorks)
    {
        int fd, loaderror;
        fd = open(libname, O_RDONLY, 0);
        loaderror = errno;
        if (fd >= 0)
        {
            errno = 0;
            libhandle = loadModule(fd, LOAD_GLOBAL_SYMBOLS);
            if (errno == S_symLib_SYMBOL_NOT_FOUND)
            {
                libhandle = NULL;
            }
            loaderror = errno;
            close (fd);
        }
        if (libhandle == NULL)
        {
            fprintf(stderr, "Loading %s library failed: %s\n",
                libname, strerror(loaderror));
        }
    }
#else
    fprintf (stderr, "cannot load libraries on this OS.\n");
#endif    
    return libhandle;
}

typedef struct moduleitem
{
    struct moduleitem* next;
    char name[100];
    char version[20];
} moduleitem;

moduleitem* loadedModules = NULL;

static void registerModule(const char* module, const char* version)
{
    moduleitem* m = (moduleitem*) calloc(sizeof (moduleitem),1);
    if (!m)
    {
        printf ("require: out of memory\n");
    }
    else
    {
        strncpy (m->name, module, sizeof(m->name));
        strncpy (m->version, version, sizeof(m->version));
        m->next = loadedModules;
        loadedModules = m;
    }
}

#if defined (vxWorks)
BOOL findLibRelease (
    char      *name,  /* symbol name       */
    int       val,    /* value of symbol   */
    SYM_TYPE  type,   /* symbol type       */
    int       arg,    /* user-supplied arg */
    UINT16    group   /* group number      */
) {
    char libname [20];
    int e;
    if (name[0] != '_') return TRUE;
    e = strlen(name) - 10;
    if (e <= 0 || e > 20) return TRUE;
    if (strcmp(name+e, "LibRelease") != 0) return TRUE;
    strncpy(libname, name+1, e-1);
    libname[e-1]=0;
    if (!getLibVersion(libname))
    {
        registerModule(libname, (char*)val);
    }
    return TRUE;
}

static void registerExternalModules()
{
    symEach(sysSymTbl, (FUNCPTR)findLibRelease, 0);
}

#elif defined (__linux)
#include <link.h>

int findLibRelease (
    struct dl_phdr_info *info, /* shared library info */
    size_t size,               /* size of info structure */
    void *data                 /* user-supplied arg */
) {
    void *handle;
    char symname [80];
    const char* p;
    char* q;
    char* version;
    
    if (!info->dlpi_name || !info->dlpi_name[0]) return 0;
    p = strrchr(info->dlpi_name, '/');
    if (p) p+=4; else p=info->dlpi_name + 3;
    symname[0] = '_';
    for (q=symname+1; *p && *p != '.' && *p != '-' && q < symname+11; p++, q++) *q=*p;
    strcpy(q, "LibRelease");
    handle = dlopen(info->dlpi_name, RTLD_NOW|RTLD_GLOBAL);
    version = dlsym(handle, symname);
    dlclose(handle);
    *q = 0;
    if (version)
    {
        registerModule(symname+1, version);
    }
    return 0;
}

static void registerExternalModules()
{
    dl_iterate_phdr(findLibRelease, NULL);
}

#elif defined (_WIN32)

static void registerExternalModules()
{
    ;
}


#else
static void registerExternalModules()
{
    ;
}
#endif


const char* getLibVersion(const char* libname)
{
    moduleitem* m;

    for (m = loadedModules; m; m=m->next)
    {
        if (strncmp(m->name, libname, sizeof(m->name)) == 0)
        {
            return m->version;
        }
    }
    return NULL;
}

int libversionShow(const char* pattern)
{
    moduleitem* m;
    
    if (firstTime)
    {
        firstTime=0;
        registerExternalModules();
    }

    for (m = loadedModules; m; m=m->next)
    {
        if (pattern && !strstr(m->name, pattern)) return 0;
        epicsStdoutPrintf("%15s %s\n", m->name, m->version);
    }
    return 0;
}

#define MISMATCH -1
#define EXACT 0
#define MATCH 1
#define COMPATIBLE 2
#define TESTVERS 3

static int compareVersions(const char* request, const char* found)
{
    int found_major, found_minor=0, found_patch=0, found_parts;
    int req_major, req_minor, req_patch, req_parts;
    
    if (!request || !*request)       return MATCH;      /* No particular version request. */
    if (strcmp(found, request) == 0) return EXACT;      /* Exact match. */

    /* Numerical version compare. Format is major.minor.patch
       Numerical requests must have exact match in major and
       backward-compatible number in minor and patch
    */
    req_parts = sscanf(request, "%d.%d.%d", &req_major, &req_minor, &req_patch);
    if (req_parts == 0)              return MISMATCH;   /* Test version request not found */
    found_parts = sscanf(found, "%d.%d.%d", &found_major, &found_minor, &found_patch);
    if (found_parts == 0)            return TESTVERS;   /* Test version found */
    if (found_major != req_major)    return MISMATCH;   /* major mismatch */
    if (req_parts == 1)              return MATCH;      /* only major requested matches */
    if (found_minor < req_minor)     return MISMATCH;   /* minor too small */
    if (found_minor > req_minor)     return COMPATIBLE; /* minor larger than required */
    if (req_parts == 2)              return MATCH;      /* major and minor requested matches */
    if (found_patch < req_patch)     return MISMATCH;   /* patch level too small */
    return COMPATIBLE;                                  /* patch level higher or equal but "+" requested */
}

/* require (module)
Look if module is already loaded.
If module is already loaded check for version mismatch.
If module is not yet loaded load the library with ld,
load <module>.dbd with dbLoadDatabase (if file exists)
and call <module>_registerRecordDeviceDriver function.

If require is called from the iocsh before iocInit and fails,
it calls epicsExit to abort the application.
*/

/* wrapper to abort statup script */
static int require_priv(const char* module, const char* ver, const char* args);

int require(const char* module, const char* ver, const char* args)
{
    if (firstTime)
    {
        firstTime=0;
        registerExternalModules();
    }
    
    if (!module)
    {
        printf("Usage: require \"<module>\" [, \"<version>\"] [, \"<args>\"]\n");
        printf("Loads " PREFIX "<module>" INFIX "[-<version>]" EXT " and dbd/<libname>[-<version>].dbd\n");
#ifdef EPICS_3_14
        printf("And calls <module>_registerRecordDeviceDriver\n");
#endif
        printf("If available, runs startup script snippet or loads substitution file with args\n");
        return -1;
    }
    
    if (require_priv(module, ver, args) != 0 && !interruptAccept)
    {
        /* require failed in startup script before iocInit */
        fprintf(stderr, "Aborting startup script\n");
#ifdef vxWorks
        shellScriptAbort();
#else
        epicsExit(1);
#endif
        return -1;
    }
    return 0;
}

static int checkLoadedVersion(const char* module, const char* version)
{
    const char* loaded;

    if (requireDebug)
        printf("require: checking module %s version %s\n",
            module, vers);

    found = getLibVersion(module);
    if (loaded)
    {
        if (requireDebug)
            printf("require: %s version %s already loaded\n",
                module, found);
        /* Library already loaded. Check Version. */
        switch (compareVersions(version, loaded))
        {
            case MISMATCH:
                printf("Conflict between requested %s version %s\n"
                    "and already loaded version %s.\n",
                    module, version, loaded);
                return -1;
            case TESTVERS:
                printf("Warning: %s test version %s already loaded where %s was requested\n",
                    module, loaded, version);
                break;
            default: /* EXACT or MATCH or COMPATIBLE */
                printf ("%s %s already loaded\n", module, loaded);
        }
        /* Already loaded version is ok */
        return 0;
    }
}

static int require_priv(const char* module, const char* vers, const char* args)
{
    char version[20];
    const char* found;
    struct stat filestat;
    HMODULE libhandle;
    char* p;
    char *end; /* end of string */
    const char sep[1] = PATHSEP;
    char* driverpath;

    memset(version, 0, sizeof(version));
    if (vers) strncpy(version, vers, sizeof(version));
    
    if (checkLoadedVersion(module, version) == 0) return 0;
    

    driverpath = getenv("EPICS_DRIVER_PATH");
    if (!driverpath) driverpath = ".";

    if (requireDebug)
        printf("require: searchpath=%s\n", driverpath);

    /* NEW */

    /* Search for module in driverpath */
    for (p = driverpath; p != NULL; p = end)
    {
        char libdir[256];
        char fulllibdir[256];
        char foundlibdir[256];
        DIR* dir;
        struct dirent* dirent;

        end = strchr(p, sep[0]);
        snprintf(libdir, sizeof(libdir), "%.*s" DIRSEP "%s", 
            (int)(end?(end++-p):sizeof(libdir)), p, module);

        /* Ignore empty driverpath elements */
        if (libdir[0] == 0) continue;

        /* Does the module directory exist? */
        dir = opendir(libdir);
        if (requireDebug)
            printf("require: directory candidate %s %sfound\n", libdir, dir?"":"not ");
        if (!dir) continue;

        /* Found module directory in driverpath. Now look for versions. */
        while ((dirent = readdir(dir)) != NULL)
        {
            #ifdef _DIRENT_HAVE_D_TYPE
            if (dirent->d_type != DT_DIR && dirent->d_type != DT_UNKNOWN) continue; /* not a directories */
            #endif
            if (dirent->d_name[0] == '.') continue;  /* ignore hidden directories */

            /* Look for highest matching version. */
            if (requireDebug)
                printf("require: checking %s against %s\n",
                        dirent->d_name, version);
            switch (compareVersions(version, dirent->d_name))
            {
                int i;
                case MISMATCH:
                    if (requireDebug)
                        printf("require: %s %s does not match %s\n",
                            module, dirent->d_name, version);
                    continue;
                case MATCH:
                    snprintf(foundlibdir, sizeof(foundlibdir), "%s" DIRSEP "%n%s",
                        libdir, &i, dirent->d_name);
                    found = foundlibdir + i;
                    if (requireDebug)
                        printf("require: %s %s matches %s exactly\n",
                            module, found, version);
                    /* We are done. */
                    end = NULL;
                    break;
                case COMPATIBLE:  /* Potential version found. */
                    if (requireDebug)
                        printf("require: %s %s may match %s\n",
                            module, dirent->d_name, version);

                    /* Check if it has our EPICS version and architecture. */
                    snprintf(fulllibdir, sizeof(fulllibdir),
                        "%s" DIRSEP "%s" DIRSEP "%s" DIRSEP "lib" DIRSEP  "%s" DIRSEP,
                        libdir, dirent->d_name, epicsRelease, targetArch);
                    if (stat(fulllibdir, &filestat) == 0)
                    {
                         if (requireDebug)
                            printf("require: %s %s has no support for %s %s\n",
                                module, dirent->d_name, epicsRelease, targetArch);
                        continue;
                    }

                    /* Is it higher than the one we found before? */
                    if (compareVersions(found, dirent->d_name) == 1)
                    {
                        if (requireDebug)
                            printf("require: %s %s looks promising\n",
                                module, dirent->d_name);
                        snprintf(foundlibdir, sizeof(foundlibdir), "%s" DIRSEP "%n%s",
                            libdir, &i, dirent->d_name);
                        found = foundlibdir + i;
                    }
                    /* Keep trying */;
                    continue;
            }
            break;
        }
        closedir(dir);
        if (!found && requireDebug)
            printf("require: No matching version in %s\n", libdir);
    }
    if (found)
    {
        if (requireDebug)
            printf("require: found module in %s\n", foundlibdir);

        /* check dependencies */

        /* load library */

        /* load dbd file */

        /* call register function */

        /* load startup script */

        /* load substitution file */


        return -1;
    }
    char libname[256];
    char dbdname[256];
    char depname[256];
    char fulllibname[256];
    char fulldbdname[256];
    char fulldepname[256];
    char symbolname[256];
        
        if (requireDebug)
            printf("require: trying the old way\n");
        /* OLD */
        
        /* user may give a minimal version (e.g. "1.2.4+")
           load highest matching version (here "1.2") and check later
        */
        if (isdigit((unsigned char)version[0]) && version[strlen(version)-1] == '+')
        {
            char* p = strrchr(version, '.');
            if (!p) p = version;
            *p = 0;
        }
        
        /* make filenames with or without version string */
        
        if (version[0])
        {
            sprintf(libname, PREFIX "%s" INFIX "-%s" EXT, module, version);
            sprintf(depname, "%s-%s.dep", module, version);
        }
        else
        {
            sprintf(libname, PREFIX "%s" INFIX EXT, module);
            sprintf(depname, "%s.dep", module);
        }
        if (requireDebug)
        {
            printf("require: libname is %s\n", libname);
            printf("require: depname is %s\n", depname);
        }

        /* search for library in driverpath */
        for (p = driverpath; p != NULL; p = end)
        {            
            end = strchr(p, sep[0]);
            if (end)
            {
                sprintf (libdir, "%.*s", (int)(end-p), p);
                end++;
            }
            else
            {
                sprintf (libdir, "%s", p);
            }
            /* ignore empty driverpath elements */
            if (libdir[0] == 0) continue;

            sprintf (fulllibname, "%s" DIRSEP "%s", libdir, libname);
            sprintf (fulldepname, "%s" DIRSEP "%s", libdir, depname);
            if (requireDebug)
                printf("require: looking for %s\n", fulllibname);
            if (stat(fulllibname, &filestat) == 0) break;
#ifdef vxWorks
            /* now without the .munch */
            fulllibname[strlen(fulllibname)-6] = 0;
            if (requireDebug)
                printf("require: looking for %s\n", fulllibname);
            if (stat(fulllibname, &filestat) == 0) break;
#endif            
            /* allow dependency without library for aliasing */
            if (requireDebug)
                printf("require: looking for %s\n", fulldepname);
            if (stat(fulldepname, &filestat) == 0) break;
        }
        if (!p)
        {
            fprintf(stderr, "Library %s not found in EPICS_DRIVER_PATH=%s\n",
                libname, driverpath);
            return -1;
        }
        if (requireDebug)
            printf("require: found in %s\n", p);
        
        /* parse dependency file if exists */
        if (stat(fulldepname, &filestat) == 0)
        {
            FILE* depfile;
            char buffer[40];
            char *rmodule; /* required module */
            char *rversion; /* required version */
            
            if (requireDebug)
                printf("require: parsing dependency file %s\n", fulldepname);
            depfile = fopen(fulldepname, "r");
            while (fgets(buffer, sizeof(buffer)-1, depfile))
            {
                rmodule = buffer;
                /* ignore leading spaces */
                while (isspace((int)*rmodule)) rmodule++;
                /* ignore empty lines and comment lines */
                if (*rmodule == 0 || *rmodule == '#') continue;
                /* rmodule at start of module name */
                rversion = rmodule;
                /* find end of module name */
                while (*rversion && !isspace((int)*rversion)) rversion++;
                /* terminate module name */
                *rversion++ = 0;
                /* ignore spaces */
                while (isspace((int)*rversion)) rversion++;
                /* rversion at start of version */
                end = rversion;
                /* find end of version */
                while (*end && !isspace((int)*end)) end++;
                /* append + to version to allow newer compaible versions */
                *end++ = '+';
                /* terminate version */
                *end = 0;
                printf("%s depends on %s %s\n", module, rmodule, rversion);
                if (require(rmodule, rversion) != 0)
                {
                    fclose(depfile);
                    return -1;
                }
            }
            fclose(depfile);
        }
        
        if (stat(fulllibname, &filestat) != 0)
        {
            /* no library, dep file was an alias */
            if (requireDebug)
                printf("require: no library to load\n");
            return 0;
        }
        
        /* load library */
        if (requireDebug)
            printf("require: loading library %s\n", fulllibname);
        if (!(libhandle = loadlib(fulllibname)))
        {
            if (requireDebug)
                printf("require: loading failed\n");
            return -1;
        }
        
        /* now check if we got what we wanted (with original version number) */
        sprintf (symbolname, "_%sLibRelease", module);
        loaded = getAddress(libhandle, symbolname);

        if (loaded)
        {
            printf("Loading %s (version %s)\n", fulllibname, loaded);
            /* make sure we get the dbd that matches the library version */
            sprintf(dbdname, "%s-%s.dbd", module, loaded);
        }
        else
        {
            printf("Loading %s (no version)\n", fulllibname);
            sprintf(dbdname, "%s.dbd", module);
            loaded = "";
        }

        if (compareVersions(vers, loaded) == -1)
        {
            fprintf(stderr, "Requested %s version %s not available, found only %s.\n",
                module, vers, loaded);
            return -1;
        }
        
        if (requireDebug)
        {
            printf("require: dbdname is %s\n", dbdname);
        }
        /* look for dbd in . ./dbd ../dbd ../../dbd (relative to lib dir) */
        p = PATHSEP DIRSEP "dbd"
            PATHSEP DIRSEP ".." DIRSEP "dbd"
            PATHSEP DIRSEP ".." DIRSEP ".." DIRSEP "dbd";
        while (p)
        {
            end = strchr(p, sep[0]);
            if (end)
            {
                sprintf(fulldbdname, "%s%.*s" DIRSEP "%s",
                    libdir, (int)(end-p), p, dbdname);
                end++;
            }
            else
            {
                sprintf(fulldbdname, "%s%s" DIRSEP "%s",
                    libdir, p, dbdname);
            }
            if (requireDebug)
                printf("require: Looking for %s\n", fulldbdname);
            if (stat(fulldbdname, &filestat) == 0) break;
            p=end;
        }
        
        /* if dbd file exists and is not empty load it */
        if (p && filestat.st_size > 0)
        {
            printf("Loading %s\n", fulldbdname);
            if (dbLoadDatabase(fulldbdname, NULL, NULL) != 0)
            {
                fprintf (stderr, "require: can't load %s\n", fulldbdname);
                return -1;
            }
            
            /* when dbd is loaded call register function for 3.14 */
#ifdef EPICS_3_14
            sprintf (symbolname, "%s_registerRecordDeviceDriver", module);
            printf ("Calling %s function\n", symbolname);
#ifdef vxWorks
            {
                FUNCPTR f = (FUNCPTR) getAddress(NULL, symbolname);
                if (f)
                    f(pdbbase);
                else
                    fprintf (stderr, "require: can't find %s function\n", symbolname);
            }        
#else
            iocshCmd(symbolname);
#endif
#endif        
        }
        else
        {
            /* no dbd file, but that might be OK */
            printf("no dbd file %s\n", dbdname);
        }
        
        registerModule(module, loaded);
        return 0;
}

#ifdef EPICS_3_14
static const iocshArg requireArg0 = { "module", iocshArgString };
static const iocshArg requireArg1 = { "version", iocshArgString };
static const iocshArg * const requireArgs[2] = { &requireArg0, &requireArg1 };
static const iocshFuncDef requireDef = { "require", 2, requireArgs };
static void requireFunc (const iocshArgBuf *args)
{
    require(args[0].sval, args[1].sval);
}

static const iocshArg libversionShowArg0 = { "pattern", iocshArgString };
static const iocshArg * const libversionArgs[1] = { &libversionShowArg0 };
static const iocshFuncDef libversionShowDef = { "libversionShow", 1, libversionArgs };
static void libversionShowFunc (const iocshArgBuf *args)
{
    libversionShow(args[0].sval);
}

static const iocshArg ldArg0 = { "library", iocshArgString };
static const iocshArg * const ldArgs[1] = { &ldArg0 };
static const iocshFuncDef ldDef = { "ld", 1, ldArgs };
static void ldFunc (const iocshArgBuf *args)
{
    loadlib(args[0].sval);
}

static void requireRegister(void)
{
    if (firstTime) {
        firstTime = 0;
        iocshRegister (&ldDef, ldFunc);
        iocshRegister (&libversionShowDef, libversionShowFunc);
        iocshRegister (&requireDef, requireFunc);
        registerExternalModules();
    }
}

epicsExportRegistrar(requireRegister);
epicsExportAddress(int, requireDebug);
#endif