/*
** Package library.
** Copyright (C) 2005-2013 Mike Pall. See Copyright Notice in luajit.h
**
** Major portions taken verbatim or adapted from the Lua interpreter.
** Copyright (C) 1994-2012 Lua.org, PUC-Rio. See Copyright Notice in lua.h
*/

#define lib_package_c
#define LUA_LIB

#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"

#include "lj_obj.h"
#include "lj_err.h"
#include "lj_lib.h"

/* ------------------------------------------------------------------------ */

/* Error codes for ll_loadfunc. */
#define PACKAGE_ERR_LIB 1
#define PACKAGE_ERR_FUNC 2
#define PACKAGE_ERR_LOAD 3

/* Redefined in platform specific part. */
#define PACKAGE_LIB_FAIL "open"

/* Symbol name prefixes. */
#define SYMPREFIX_CF "luaopen_%s"
#define SYMPREFIX_BC "luaJIT_BC_%s"

/*
** {=========================================================================
** This determines the location of the executable for relative module loading
** Modified by the LuaDist project for UNIX platforms
** ==========================================================================
*/
#if defined(_WIN32) || defined(__CYGWIN__)
    #include <windows.h>
    #define _PATH_MAX MAX_PATH
#else
    #define _PATH_MAX PATH_MAX
#endif

#if defined(__linux__) || defined(__sun)
    #include <unistd.h> /* readlink */
#endif

#if defined(__APPLE__)
    #include <sys/param.h>
    #include <mach-o/dyld.h>
#endif

#if defined(__FreeBSD__)
    #include <sys/types.h>
    #include <sys/sysctl.h>
#endif

static void setprogdir(lua_State *L)
{
    char progdir[_PATH_MAX + 1];
    char *lb;
    int nsize = sizeof(progdir) / sizeof(char);
    int n;
#if defined(__CYGWIN__)
    char win_buff[_PATH_MAX + 1];
    GetModuleFileNameA(NULL, win_buff, nsize);
    cygwin_conv_to_posix_path(win_buff, progdir);
    n = strlen(progdir);
#elif defined(_WIN32)
    n = GetModuleFileNameA(NULL, progdir, nsize);
#elif defined(__linux__)
    n = readlink("/proc/self/exe", progdir, nsize);
    if (n > 0)
        progdir[n] = 0;
#elif defined(__sun)
    pid_t pid = getpid();
    char linkname[256];
    sprintf(linkname, "/proc/%d/path/a.out", pid);
    n = readlink(linkname, progdir, nsize);
    if (n > 0)
        progdir[n] = 0;
#elif defined(__FreeBSD__)
    int mib[4];
    mib[0] = CTL_KERN;
    mib[1] = KERN_PROC;
    mib[2] = KERN_PROC_PATHNAME;
    mib[3] = -1;
    size_t cb = nsize;
    sysctl(mib, 4, progdir, &cb, NULL, 0);
    n = cb;
#elif defined(__BSD__)
    n = readlink("/proc/curproc/file", progdir, nsize);
    if (n > 0)
        progdir[n] = 0;
#elif defined(__APPLE__)
    uint32_t nsize_apple = nsize;
    if (_NSGetExecutablePath(progdir, &nsize_apple) == 0)
        n = strlen(progdir);
#else
    // FALLBACK
    // Use 'lsof' ... should work on most UNIX systems (incl. OSX)
    // lsof will list open files, this captures the 1st file listed (usually the executable)
    int pid;
    FILE *fd;
    char cmd[80];
    pid = getpid();

    sprintf(
        cmd,
        "lsof -p %d | awk '{if ($5==\"REG\") { print $9 ; exit}}' 2> /dev/null",
        pid);
    fd = popen(cmd, "r");
    n = fread(progdir, 1, nsize, fd);

    // remove newline
    if (n > 1)
        progdir[--n] = '\0';
#endif
    if (n == 0 || n == nsize ||
        (lb = strrchr(progdir, (int)LUA_DIRSEP[0])) == NULL)
        luaL_error(L, "unable to get process executable path");
    else {
        *lb = '\0';

        // Replace the relative path placeholder
        luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, progdir);
        lua_remove(L, -2);
    }
}

#if LJ_TARGET_DLOPEN

    #include <dlfcn.h>

static void ll_unloadlib(void *lib) { dlclose(lib); }

static void *ll_load(lua_State *L, const char *path, int gl)
{
    void *lib = dlopen(path, RTLD_NOW | (gl ? RTLD_GLOBAL : RTLD_LOCAL));
    if (lib == NULL)
        lua_pushstring(L, dlerror());
    return lib;
}

static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
    lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
    if (f == NULL)
        lua_pushstring(L, dlerror());
    return f;
}

static const char *ll_bcsym(void *lib, const char *sym)
{
    #if defined(RTLD_DEFAULT)
    if (lib == NULL)
        lib = RTLD_DEFAULT;
    #elif LJ_TARGET_OSX || LJ_TARGET_BSD
    if (lib == NULL)
        lib = (void *)(intptr_t)-2;
    #endif
    return (const char *)dlsym(lib, sym);
}

#elif LJ_TARGET_WINDOWS

    #define WIN32_LEAN_AND_MEAN
    #ifndef WINVER
        #define WINVER 0x0500
    #endif
    #include <windows.h>

    #ifndef GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
        #define GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS 4
        #define GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT 2
BOOL WINAPI GetModuleHandleExA(DWORD, LPCSTR, HMODULE *);
    #endif

static void pusherror(lua_State *L)
{
    DWORD error = GetLastError();
    char buffer[128];
    if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS |
                           FORMAT_MESSAGE_FROM_SYSTEM,
                       NULL, error, 0, buffer, sizeof(buffer), NULL))
        lua_pushstring(L, buffer);
    else
        lua_pushfstring(L, "system error %d\n", error);
}

static void ll_unloadlib(void *lib) { FreeLibrary((HINSTANCE)lib); }

static void *ll_load(lua_State *L, const char *path, int gl)
{
    HINSTANCE lib = LoadLibraryA(path);
    if (lib == NULL)
        pusherror(L);
    UNUSED(gl);
    return lib;
}

static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
    lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
    if (f == NULL)
        pusherror(L);
    return f;
}

static const char *ll_bcsym(void *lib, const char *sym)
{
    if (lib) {
        return (const char *)GetProcAddress((HINSTANCE)lib, sym);
    }
    else {
        HINSTANCE h = GetModuleHandleA(NULL);
        const char *p = (const char *)GetProcAddress(h, sym);
        if (p == NULL &&
            GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
                                   GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
                               (const char *)ll_bcsym, &h))
            p = (const char *)GetProcAddress(h, sym);
        return p;
    }
}

#else

    #undef PACKAGE_LIB_FAIL
    #define PACKAGE_LIB_FAIL "absent"

    #define DLMSG "dynamic libraries not enabled; no support for target OS"

static void ll_unloadlib(void *lib) { UNUSED(lib); }

static void *ll_load(lua_State *L, const char *path, int gl)
{
    UNUSED(path);
    UNUSED(gl);
    lua_pushliteral(L, DLMSG);
    return NULL;
}

static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
    UNUSED(lib);
    UNUSED(sym);
    lua_pushliteral(L, DLMSG);
    return NULL;
}

static const char *ll_bcsym(void *lib, const char *sym)
{
    UNUSED(lib);
    UNUSED(sym);
    return NULL;
}

#endif

/* ------------------------------------------------------------------------ */

static void **ll_register(lua_State *L, const char *path)
{
    void **plib;
    lua_pushfstring(L, "LOADLIB: %s", path);
    lua_gettable(L, LUA_REGISTRYINDEX); /* check library in registry? */
    if (!lua_isnil(L, -1)) {            /* is there an entry? */
        plib = (void **)lua_touserdata(L, -1);
    }
    else { /* no entry yet; create one */
        lua_pop(L, 1);
        plib = (void **)lua_newuserdata(L, sizeof(void *));
        *plib = NULL;
        luaL_getmetatable(L, "_LOADLIB");
        lua_setmetatable(L, -2);
        lua_pushfstring(L, "LOADLIB: %s", path);
        lua_pushvalue(L, -2);
        lua_settable(L, LUA_REGISTRYINDEX);
    }
    return plib;
}

static const char *mksymname(lua_State *L, const char *modname,
                             const char *prefix)
{
    const char *funcname;
    const char *mark = strchr(modname, *LUA_IGMARK);
    if (mark)
        modname = mark + 1;
    funcname = luaL_gsub(L, modname, ".", "_");
    funcname = lua_pushfstring(L, prefix, funcname);
    lua_remove(L, -2); /* remove 'gsub' result */
    return funcname;
}

static int ll_loadfunc(lua_State *L, const char *path, const char *name, int r)
{
    void **reg = ll_register(L, path);
    if (*reg == NULL)
        *reg = ll_load(L, path, (*name == '*'));
    if (*reg == NULL) {
        return PACKAGE_ERR_LIB; /* Unable to load library. */
    }
    else if (*name == '*') { /* Only load library into global namespace. */
        lua_pushboolean(L, 1);
        return 0;
    }
    else {
        const char *sym = r ? name : mksymname(L, name, SYMPREFIX_CF);
        lua_CFunction f = ll_sym(L, *reg, sym);
        if (f) {
            lua_pushcfunction(L, f);
            return 0;
        }
        if (!r) {
            const char *bcdata =
                ll_bcsym(*reg, mksymname(L, name, SYMPREFIX_BC));
            lua_pop(L, 1);
            if (bcdata) {
                if (luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
                    return PACKAGE_ERR_LOAD;
                return 0;
            }
        }
        return PACKAGE_ERR_FUNC; /* Unable to find function. */
    }
}

static int lj_cf_package_loadlib(lua_State *L)
{
    const char *path = luaL_checkstring(L, 1);
    const char *init = luaL_checkstring(L, 2);
    int st = ll_loadfunc(L, path, init, 1);
    if (st == 0) { /* no errors? */
        return 1;  /* return the loaded function */
    }
    else { /* error; error message is on stack top */
        lua_pushnil(L);
        lua_insert(L, -2);
        lua_pushstring(L, (st == PACKAGE_ERR_LIB) ? PACKAGE_LIB_FAIL : "init");
        return 3; /* return nil, error message, and where */
    }
}

static int lj_cf_package_unloadlib(lua_State *L)
{
    void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
    if (*lib)
        ll_unloadlib(*lib);
    *lib = NULL; /* mark library as closed */
    return 0;
}

/* ------------------------------------------------------------------------ */

static int readable(const char *filename)
{
    FILE *f = fopen(filename, "r"); /* try to open file */
    if (f == NULL)
        return 0; /* open failed */
    fclose(f);
    return 1;
}

static const char *pushnexttemplate(lua_State *L, const char *path)
{
    const char *l;
    while (*path == *LUA_PATHSEP)
        path++; /* skip separators */
    if (*path == '\0')
        return NULL;                /* no more templates */
    l = strchr(path, *LUA_PATHSEP); /* find next separator */
    if (l == NULL)
        l = path + strlen(path);
    lua_pushlstring(L, path, (size_t)(l - path)); /* template */
    return l;
}

static const char *searchpath(lua_State *L, const char *name, const char *path,
                              const char *sep, const char *dirsep)
{
    luaL_Buffer msg; /* to build error message */
    luaL_buffinit(L, &msg);
    if (*sep != '\0')                           /* non-empty separator? */
        name = luaL_gsub(L, name, sep, dirsep); /* replace it by 'dirsep' */
    while ((path = pushnexttemplate(L, path)) != NULL) {
        const char *filename =
            luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
        lua_remove(L, -2);      /* remove path template */
        if (readable(filename)) /* does file exist and is readable? */
            return filename;    /* return that file name */
        lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
        lua_remove(L, -2);   /* remove file name */
        luaL_addvalue(&msg); /* concatenate error msg. entry */
    }
    luaL_pushresult(&msg); /* create error message */
    return NULL;           /* not found */
}

static int lj_cf_package_searchpath(lua_State *L)
{
    const char *f =
        searchpath(L, luaL_checkstring(L, 1), luaL_checkstring(L, 2),
                   luaL_optstring(L, 3, "."), luaL_optstring(L, 4, LUA_DIRSEP));
    if (f != NULL) {
        return 1;
    }
    else { /* error message is on top of the stack */
        lua_pushnil(L);
        lua_insert(L, -2);
        return 2; /* return nil + error message */
    }
}

static const char *findfile(lua_State *L, const char *name, const char *pname)
{
    const char *path;
    lua_getfield(L, LUA_ENVIRONINDEX, pname);
    path = lua_tostring(L, -1);
    if (path == NULL)
        luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
    return searchpath(L, name, path, ".", LUA_DIRSEP);
}

static void loaderror(lua_State *L, const char *filename)
{
    luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
               lua_tostring(L, 1), filename, lua_tostring(L, -1));
}

static int lj_cf_package_loader_lua(lua_State *L)
{
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    filename = findfile(L, name, "path");
    if (filename == NULL)
        return 1; /* library not found in this path */
    if (luaL_loadfile(L, filename) != 0)
        loaderror(L, filename);
    return 1; /* library loaded successfully */
}

static int lj_cf_package_loader_c(lua_State *L)
{
    const char *name = luaL_checkstring(L, 1);
    const char *filename = findfile(L, name, "cpath");
    if (filename == NULL)
        return 1; /* library not found in this path */
    if (ll_loadfunc(L, filename, name, 0) != 0)
        loaderror(L, filename);
    return 1; /* library loaded successfully */
}

static int lj_cf_package_loader_croot(lua_State *L)
{
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    const char *p = strchr(name, '.');
    int st;
    if (p == NULL)
        return 0; /* is root */
    lua_pushlstring(L, name, (size_t)(p - name));
    filename = findfile(L, lua_tostring(L, -1), "cpath");
    if (filename == NULL)
        return 1; /* root not found */
    if ((st = ll_loadfunc(L, filename, name, 0)) != 0) {
        if (st != PACKAGE_ERR_FUNC)
            loaderror(L, filename); /* real error */
        lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS, name,
                        filename);
        return 1; /* function not found */
    }
    return 1;
}

static int lj_cf_package_loader_preload(lua_State *L)
{
    const char *name = luaL_checkstring(L, 1);
    lua_getfield(L, LUA_ENVIRONINDEX, "preload");
    if (!lua_istable(L, -1))
        luaL_error(L, LUA_QL("package.preload") " must be a table");
    lua_getfield(L, -1, name);
    if (lua_isnil(L, -1)) { /* Not found? */
        const char *bcname = mksymname(L, name, SYMPREFIX_BC);
        const char *bcdata = ll_bcsym(NULL, bcname);
        if (bcdata == NULL || luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
            lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
    }
    return 1;
}

/* ------------------------------------------------------------------------ */

static const int sentinel_ = 0;
#define sentinel ((void *)&sentinel_)

static int lj_cf_package_require(lua_State *L)
{
    const char *name = luaL_checkstring(L, 1);
    int i;
    lua_settop(L, 1); /* _LOADED table will be at index 2 */
    lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
    lua_getfield(L, 2, name);
    if (lua_toboolean(L, -1)) {                /* is it there? */
        if (lua_touserdata(L, -1) == sentinel) /* check loops */
            luaL_error(L, "loop or previous error loading module " LUA_QS,
                       name);
        return 1; /* package is already loaded */
    }
    /* else must load it; iterate over available loaders */
    lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
    if (!lua_istable(L, -1))
        luaL_error(L, LUA_QL("package.loaders") " must be a table");
    lua_pushliteral(L, ""); /* error message accumulator */
    for (i = 1;; i++) {
        lua_rawgeti(L, -2, i); /* get a loader */
        if (lua_isnil(L, -1))
            luaL_error(L, "module " LUA_QS " not found:%s", name,
                       lua_tostring(L, -2));
        lua_pushstring(L, name);
        lua_call(L, 1, 1);            /* call it */
        if (lua_isfunction(L, -1))    /* did it find module? */
            break;                    /* module loaded successfully */
        else if (lua_isstring(L, -1)) /* loader returned error message? */
            lua_concat(L, 2);         /* accumulate it */
        else
            lua_pop(L, 1);
    }
    lua_pushlightuserdata(L, sentinel);
    lua_setfield(L, 2, name);     /* _LOADED[name] = sentinel */
    lua_pushstring(L, name);      /* pass name as argument to module */
    lua_call(L, 1, 1);            /* run loaded module */
    if (!lua_isnil(L, -1))        /* non-nil return? */
        lua_setfield(L, 2, name); /* _LOADED[name] = returned value */
    lua_getfield(L, 2, name);
    if (lua_touserdata(L, -1) == sentinel) { /* module did not set a value? */
        lua_pushboolean(L, 1);               /* use true as result */
        lua_pushvalue(L, -1);                /* extra copy to be returned */
        lua_setfield(L, 2, name);            /* _LOADED[name] = true */
    }
    lj_lib_checkfpu(L);
    return 1;
}

/* ------------------------------------------------------------------------ */

static void setfenv(lua_State *L)
{
    lua_Debug ar;
    if (lua_getstack(L, 1, &ar) == 0 ||
        lua_getinfo(L, "f", &ar) == 0 || /* get calling function */
        lua_iscfunction(L, -1))
        luaL_error(L, LUA_QL("module") " not called from a Lua function");
    lua_pushvalue(L, -2);
    lua_setfenv(L, -2);
    lua_pop(L, 1);
}

static void dooptions(lua_State *L, int n)
{
    int i;
    for (i = 2; i <= n; i++) {
        lua_pushvalue(L, i);  /* get option (a function) */
        lua_pushvalue(L, -2); /* module */
        lua_call(L, 1, 0);
    }
}

static void modinit(lua_State *L, const char *modname)
{
    const char *dot;
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "_M"); /* module._M = module */
    lua_pushstring(L, modname);
    lua_setfield(L, -2, "_NAME");
    dot = strrchr(modname, '.'); /* look for last dot in module name */
    if (dot == NULL)
        dot = modname;
    else
        dot++;
    /* set _PACKAGE as package name (full module name minus last part) */
    lua_pushlstring(L, modname, (size_t)(dot - modname));
    lua_setfield(L, -2, "_PACKAGE");
}

static int lj_cf_package_module(lua_State *L)
{
    const char *modname = luaL_checkstring(L, 1);
    int loaded = lua_gettop(L) + 1; /* index of _LOADED table */
    lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
    lua_getfield(L, loaded, modname); /* get _LOADED[modname] */
    if (!lua_istable(L, -1)) {        /* not found? */
        lua_pop(L, 1);                /* remove previous result */
        /* try global variable (and create one if it does not exist) */
        if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
            lj_err_callerv(L, LJ_ERR_BADMODN, modname);
        lua_pushvalue(L, -1);
        lua_setfield(L, loaded, modname); /* _LOADED[modname] = new table */
    }
    /* check whether table already has a _NAME field */
    lua_getfield(L, -1, "_NAME");
    if (!lua_isnil(L, -1)) { /* is table an initialized module? */
        lua_pop(L, 1);
    }
    else { /* no; initialize it */
        lua_pop(L, 1);
        modinit(L, modname);
    }
    lua_pushvalue(L, -1);
    setfenv(L);
    dooptions(L, loaded - 1);
    return 0;
}

static int lj_cf_package_seeall(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    if (!lua_getmetatable(L, 1)) {
        lua_createtable(L, 0, 1); /* create new metatable */
        lua_pushvalue(L, -1);
        lua_setmetatable(L, 1);
    }
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    lua_setfield(L, -2, "__index"); /* mt.__index = _G */
    return 0;
}

/* ------------------------------------------------------------------------ */

#define AUXMARK "\1"

static void setpath(lua_State *L, const char *fieldname, const char *envname,
                    const char *def, int noenv)
{
#if LJ_TARGET_CONSOLE
    const char *path = NULL;
    UNUSED(envname);
#else
    const char *path = getenv(envname);
#endif
    if (path == NULL || noenv) {
        lua_pushstring(L, def);
    }
    else {
        path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
                         LUA_PATHSEP AUXMARK LUA_PATHSEP);
        luaL_gsub(L, path, AUXMARK, def);
        lua_remove(L, -2);
    }
    setprogdir(L);
    lua_setfield(L, -2, fieldname);
}

static const luaL_Reg package_lib[] = {{"loadlib", lj_cf_package_loadlib},
                                       {"searchpath", lj_cf_package_searchpath},
                                       {"seeall", lj_cf_package_seeall},
                                       {NULL, NULL}};

static const luaL_Reg package_global[] = {{"module", lj_cf_package_module},
                                          {"require", lj_cf_package_require},
                                          {NULL, NULL}};

static const lua_CFunction package_loaders[] = {
    lj_cf_package_loader_preload, lj_cf_package_loader_lua,
    lj_cf_package_loader_c, lj_cf_package_loader_croot, NULL};

LUALIB_API int luaopen_package(lua_State *L)
{
    int i;
    int noenv;
    luaL_newmetatable(L, "_LOADLIB");
    lj_lib_pushcf(L, lj_cf_package_unloadlib, 1);
    lua_setfield(L, -2, "__gc");
    luaL_register(L, LUA_LOADLIBNAME, package_lib);
    lua_pushvalue(L, -1);
    lua_replace(L, LUA_ENVIRONINDEX);
    lua_createtable(L, sizeof(package_loaders) / sizeof(package_loaders[0]) - 1,
                    0);
    for (i = 0; package_loaders[i] != NULL; i++) {
        lj_lib_pushcf(L, package_loaders[i], 1);
        lua_rawseti(L, -2, i + 1);
    }
    lua_setfield(L, -2, "loaders");
    lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
    noenv = lua_toboolean(L, -1);
    lua_pop(L, 1);
    setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT, noenv);
    setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT, noenv);
    lua_pushliteral(L, LUA_PATH_CONFIG);
    lua_setfield(L, -2, "config");
    luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16);
    lua_setfield(L, -2, "loaded");
    luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
    lua_setfield(L, -2, "preload");
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    luaL_register(L, NULL, package_global);
    lua_pop(L, 1);
    return 1;
}
