ShowPathInfoResponseHandler.cc

// -*- mode: c++; c-basic-offset:4 -*-
//
// ShowPathInfoResponseHandler.cc
//
// This file is part of BES dap package
//
// Copyright (c) 2015v OPeNDAP, Inc.
// Author: Nathan Potter <ndp@opendap.org>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
// Please read the full copyright statement in the file COPYRIGHT_URI.
//
 
#include "config.h"
 
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
 
#include <cerrno>
#include <cstring>
 
#include <sstream>
#include <fstream>
 
#include "ShowPathInfoResponseHandler.h"
 
#include "BESDebug.h"
 
#include "BESInfoList.h"
#include "BESInfo.h"
#include "BESUtil.h"
#include "BESRequestHandlerList.h"
#include "BESRequestHandler.h"
#include "BESNames.h"
#include "BESDapNames.h"
#include "BESDataNames.h"
#include "BESCatalogList.h"
#include "BESCatalog.h"
#include "BESCatalogEntry.h"
#include "BESCatalogUtils.h"
#include "BESSyntaxUserError.h"
#include "BESForbiddenError.h"
#include "BESNotFoundError.h"
#include "BESStopWatch.h"
 
using std::endl;
using std::map;
using std::string;
using std::list;
using std::ostream;
 
#define PATH_INFO_RESPONSE "PathInfo"
#define PATH "path"
#define VALID_PATH "validPath"
#define REMAINDER  "remainder"
#define IS_DATA "isData"
#define IS_FILE "isFile"
#define IS_DIR  "isDir"
#define IS_ACCESSIBLE "access"
#define SIZE  "size"
#define LMT  "lastModified"
 
#define SPI_DEBUG_KEY "show-path-info"
#define SHOW_PATH_INFO_RESPONSE_STR "showPathInfo"
 
const auto MODULE="dap";
#define prolog string("ShowPathInfoResponseHandler::").append(__func__).append("() - ")
 
ShowPathInfoResponseHandler::ShowPathInfoResponseHandler(const string &name) :
    BESResponseHandler(name)
{
}
 
ShowPathInfoResponseHandler::~ShowPathInfoResponseHandler()
{
}

void ShowPathInfoResponseHandler::execute(BESDataHandlerInterface &dhi)
{
 
    BES_STOPWATCH_START_DHI(MODULE, prolog + "Timing", &dhi);
 
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::execute() - BEGIN ############################################################## BEGIN" << endl);
 
    BESInfo *info = BESInfoList::TheList()->build_info();
    d_response_object = info;
 
    string container = dhi.data[CONTAINER];
#if 0
    string catname;
    string defcatname = BESCatalogList::TheCatalogList()->default_catalog_name();
#endif
 
    BESCatalog *defcat = BESCatalogList::TheCatalogList()->default_catalog();
    if (!defcat)
        throw BESInternalError("Not able to find the default catalog.", __FILE__, __LINE__);
 
    // remove all of the leading slashes from the container name
    string::size_type notslash = container.find_first_not_of("/", 0);
    if (notslash != string::npos) {
        container = container.substr(notslash);
    }
 
    // see if there is a catalog name here. It's only a possible catalog name
    string catname;
    string::size_type slash = container.find_first_of("/", 0);
    if (slash != string::npos) {
        catname = container.substr(0, slash);
    }
    else {
        catname = container;
    }
 
    // see if this catalog exists. If it does, then remove the catalog
    // name from the container (node)
    BESCatalog *catobj = BESCatalogList::TheCatalogList()->find_catalog(catname);
    if (catobj) {
        if (slash != string::npos) {
            container = container.substr(slash + 1);
 
            // remove repeated slashes
            notslash = container.find_first_not_of("/", 0);
            if (notslash != string::npos) {
                container = container.substr(notslash);
            }
        }
        else {
            container = "";
        }
    }
 
    if (container.empty()) container = "/";
 
    if (container[0] != '/') container = "/" + container;
 
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::execute() - container: " << container << endl);
 
    info->begin_response(SHOW_PATH_INFO_RESPONSE_STR, dhi);
    //string coi = dhi.data[CATALOG_OR_INFO];
 
    map<string, string, std::less<>> pathInfoAttrs;
    pathInfoAttrs[PATH] = container;
 
    info->begin_tag(PATH_INFO_RESPONSE, &pathInfoAttrs);
 
    string validPath, remainder;
    bool isFile, isDir, canRead;
    long long size, time;
 
    BESCatalogUtils *utils = BESCatalogList::TheCatalogList()->default_catalog()->get_catalog_utils();
 
    eval_resource_path(container, utils->get_root_dir(), utils->follow_sym_links(), validPath, isFile, isDir, size,
        time, canRead, remainder);
 
    // Now that we know what part of the path is actually something
    // we can access, find out if the BES sees it as a dataset
    bool isData = false;
 
    // If the valid path is an empty string then we KNOW it's not a dataset
    if (validPath.size() != 0) {
 
        // Get the catalog entry.
        BESCatalogEntry *entry = 0;
        //string coi = dhi.data[CATALOG];
        entry = defcat->show_catalog(validPath, /*coi,*/entry);
        if (!entry) {
            string err = (string) "Failed to find the validPath node " + validPath
                + " this should not be possible. Some thing BAD is happening.";
            throw BESInternalError(err, __FILE__, __LINE__);
        }
 
        // Retrieve the valid services list
        list<string> services = entry->get_service_list();
 
        // See if there's an OPENDAP_SERVICE available for the node.
        if (services.size()) {
            list<string>::const_iterator si = services.begin();
            list<string>::const_iterator se = services.end();
            for (; si != se; si++) {
                if ((*si) == OPENDAP_SERVICE) isData = true;
            }
        }
    }
 
    map<string, string, std::less<>> validPathAttrs;
    validPathAttrs[IS_DATA] = isData ? "true" : "false";
    validPathAttrs[IS_FILE] = isFile ? "true" : "false";
    validPathAttrs[IS_DIR] = isDir ? "true" : "false";
    validPathAttrs[IS_ACCESSIBLE] = canRead ? "true" : "false";
 
    // Convert size to string and add as attribute
    std::ostringstream os_size;
    os_size << size;
    validPathAttrs[SIZE] = os_size.str();
 
    // Convert lmt to string and add as attribute
    std::ostringstream os_time;
    os_time << time;
    validPathAttrs[LMT] = os_time.str();
 
    info->add_tag(VALID_PATH, validPath, &validPathAttrs);
    info->add_tag(REMAINDER, remainder);
 
    info->end_tag(PATH_INFO_RESPONSE);
 
    // end the response object
    info->end_response();
 
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::execute() - END" << endl);
}

void ShowPathInfoResponseHandler::transmit(BESTransmitter *transmitter, BESDataHandlerInterface &dhi)
{
    if (d_response_object) {
        BESInfo *info = dynamic_cast<BESInfo *>(d_response_object);
        if (!info) throw BESInternalError("cast error", __FILE__, __LINE__);
        info->transmit(transmitter, dhi);
    }
}

void ShowPathInfoResponseHandler::dump(ostream &strm) const
{
    strm << BESIndent::LMarg << "ShowPathInfoResponseHandler::dump - (" << (void *) this << ")" << std::endl;
    BESIndent::Indent();
    BESResponseHandler::dump(strm);
    BESIndent::UnIndent();
}
 
BESResponseHandler *
ShowPathInfoResponseHandler::ShowPathInfoResponseBuilder(const string &name)
{
    return new ShowPathInfoResponseHandler(name);
}

void ShowPathInfoResponseHandler::eval_resource_path(const string &resource_path, const string &catalog_root,
    const bool follow_sym_links, string &validPath, bool &isFile, bool &isDir, long long &size,
    long long &lastModifiedTime, bool &canRead, string &remainder)
{
 
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "CatalogRoot: "<< catalog_root << endl);
 
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "resourceID: "<< resource_path << endl);
 
    // nothing valid yet...
    validPath = "";
    size = -1;
    lastModifiedTime = -1;
 
    // It's all remainder at this point...
    string rem = resource_path;
    remainder = rem;
 
    // Rather than have two basically identical code paths for the two cases (follow and !follow symlinks)
    // We evaluate the follow_sym_links switch and use a function pointer to get the correct "stat"
    // function for the eval operation.
    int (*ye_old_stat_function)(const char *pathname, struct stat *buf);
    if (follow_sym_links) {
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "Using 'stat' function (follow_sym_links = true)" << endl);
        ye_old_stat_function = &stat;
    }
    else {
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "Using 'lstat' function (follow_sym_links = false)" << endl);
        ye_old_stat_function = &lstat;
    }
 
    // if nothing is passed in path, then the path checks out since root is
    // assumed to be valid.
    if (resource_path == "") {
        BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::"<<__func__ << "() - The resourceID is empty" << endl);
        return;
    }
 
    // make sure there are no ../ in the path, backing up in any way is
    // not allowed.
    string::size_type dotdot = resource_path.find("..");
    if (dotdot != string::npos) {
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << " ERROR: The resourceID '" << resource_path <<"' contains the substring '..' This is Forbidden." << endl);
        string s = (string) "Invalid node name '" + resource_path + "' ACCESS IS FORBIDDEN";
 
        throw BESForbiddenError(s, __FILE__, __LINE__);
    }
 
    // What I want to do is to take each part of path and check to see if it
    // is a symbolic link and it is accessible. If everything is ok, add the
    // next part of the path.
    bool done = false;
 
    // Full file system path to check
    string fullpath = catalog_root;
 
    // localId that we are checking
    string checking;
 
    isFile = false;
    isDir = false;
 
    while (!done) {
        size_t slash = rem.find('/');
        if (slash == string::npos) {
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "Checking final path component: " << rem << endl);
            fullpath = BESUtil::assemblePath(fullpath, rem, true);
            checking = BESUtil::assemblePath(validPath, rem, true);
            rem = "";
            done = true;
        }
        else {
            fullpath = BESUtil::assemblePath(fullpath, rem.substr(0, slash), true);
            checking = BESUtil::assemblePath(validPath, rem.substr(0, slash), true);
            rem = rem.substr(slash + 1, rem.size() - slash);
        }
 
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "validPath: "<< validPath << endl);
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "checking: "<< checking << endl);
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "fullpath: "<< fullpath << endl);
 
        BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "rem: "<< rem << endl);
 
        BESDEBUG(SPI_DEBUG_KEY,
            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "remainder: "<< remainder << endl);
 
        struct stat sb;
        int statret = ye_old_stat_function(fullpath.c_str(), &sb);
 
        if (statret != -1) {
            // No Error then keep chugging along.
            validPath = checking;
            remainder = rem;
        }
        else {
            int errsv = errno;
            // stat failed, so not accessible. Get the error string,
            // store in error, and throw exception
            char *s_err = strerror(errsv);
            string error = "Unable to access node " + checking + ": ";
            if (s_err) {
                error = error + s_err;
            }
            else {
                error = error + "unknown access error";
            }
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "error: "<< error << "   errno: " << errno << endl);
 
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "remainder: '" << remainder << "'" << endl);
 
            // ENOENT means that the node wasn't found. Otherwise, access
            // is denied for some reason
            if (errsv != ENOENT && errsv != ENOTDIR) {
                throw BESForbiddenError(error, __FILE__, __LINE__);
            }
 
            // Are there slashes in the remainder?
            size_t s_loc = remainder.find('/');
            if (s_loc == string::npos) {
                // if there are no more slashes, we check to see if this final path component contains "."
                string basename = remainder;
                bool moreDots = true;
                while (moreDots) {
                    // working back from end of string, drop each dot (".") suffix until file system match or string gone
                    size_t d_loc = basename.find_last_of(".");
                    if (d_loc != string::npos) {
                        basename = basename.substr(0, d_loc);
                        BESDEBUG(SPI_DEBUG_KEY,
                            "ShowPathInfoResponseHandler::" << __func__ << "() - basename: "<< basename << endl);
 
                        string candidate_remainder = remainder.substr(basename.size());
                        BESDEBUG(SPI_DEBUG_KEY,
                            "ShowPathInfoResponseHandler::" << __func__ << "() - candidate_remainder: "<< candidate_remainder << endl);
 
                        string candidate_path = BESUtil::assemblePath(validPath, basename, true);
                        BESDEBUG(SPI_DEBUG_KEY,
                            "ShowPathInfoResponseHandler::" << __func__ << "() - candidate_path: "<< candidate_path << endl);
 
                        string full_candidate_path = BESUtil::assemblePath(catalog_root, candidate_path, true);
                        BESDEBUG(SPI_DEBUG_KEY,
                            "ShowPathInfoResponseHandler::" << __func__ << "() - full_candidate_path: "<< full_candidate_path << endl);
 
                        struct stat sb1;
                        int statret1 = ye_old_stat_function(full_candidate_path.c_str(), &sb1);
                        if (statret1 != -1) {
                            validPath = candidate_path;
                            remainder = candidate_remainder;
                            moreDots = false;
                        }
                    }
                    else {
                        BESDEBUG(SPI_DEBUG_KEY,
                            "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "No dots in remainder: "<< remainder << endl);
                        moreDots = false;
                    }
                }
            }
            else {
                BESDEBUG(SPI_DEBUG_KEY,
                    "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "Remainder has slash pollution: "<< remainder << endl);
                done = true;
            }
        }
        fullpath = BESUtil::assemblePath(catalog_root, validPath, true);
 
        statret = ye_old_stat_function(fullpath.c_str(), &sb);
        if (S_ISREG(sb.st_mode)) {
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "'"<< fullpath << "' Is regular file." << endl);
            isFile = true;
            isDir = false;
        }
        else if (S_ISDIR(sb.st_mode)) {
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "'"<< fullpath << "' Is directory." << endl);
            isFile = false;
            isDir = true;
        }
        else if (S_ISLNK(sb.st_mode)) {
            BESDEBUG(SPI_DEBUG_KEY,
                "ShowPathInfoResponseHandler::"<<__func__ << "() - " << "'"<< fullpath << "' Is symbolic Link." << endl);
            string error = "Service not configured to traverse symbolic links as embodied by the node '" + checking
                + "' ACCESS IS FORBIDDEN";
            throw BESForbiddenError(error, __FILE__, __LINE__);
        }
        // sb.st_uid;
        // sb.st_uid;
 
        // Can we read le file?
        std::ifstream ifile(fullpath.c_str());
        canRead = ifile.good();
 
        size = sb.st_size;
 
        // I'm pretty sure that assigning st_mtime to a long long (when it is a time_t) is not a
        // good plan - time_t is either a 32- or 64-bit signed integer.
        //
        // But, see ESCatalogUtils::bes_get_stat_info(BESCatalogEntry *entry, struct stat &buf)
        // for code that probably does a more universal version. of this (and other things relative
        // to stat, like symbolic link following).
        //
        // I added this #if ... #endif because Linux does not have st_mtimespec in struct stat.
        // jhrg 2.24.18
#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
        // Compute LMT by converting the time to milliseconds since epoch - because OLFS is picky
        lastModifiedTime = (sb.st_mtimespec.tv_sec * 1000) + (sb.st_mtimespec.tv_nsec / 1000000);
#else
        lastModifiedTime = sb.st_mtime;
#endif
    }
 
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::" << __func__ << "() -  fullpath: " << fullpath << endl);
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::" << __func__ << "() - validPath: " << validPath << endl);
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::" << __func__ << "() - remainder: " << remainder << endl);
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::" << __func__ << "() -       rem: " << rem << endl);
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::" << __func__ << "() -    isFile: " << (isFile?"true":"false") << endl);
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::" << __func__ << "() -     isDir: " << (isDir?"true":"false") << endl);
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::" << __func__ << "() -    access: " << (canRead?"true":"false") << endl);
    BESDEBUG(SPI_DEBUG_KEY, "ShowPathInfoResponseHandler::" << __func__ << "() -      size: " << size << endl);
    BESDEBUG(SPI_DEBUG_KEY,
        "ShowPathInfoResponseHandler::" << __func__ << "() -       LMT: " << lastModifiedTime << endl);
}