// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This 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 software 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.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


// file_deleter: deletes files that are no longer needed.
//
// default operation:
// 1) enumerate N WUs and M results (N,M compile params)
//    that are ready to file-delete, and try to delete their files
// 2) if the enums didn't yield anything, sleep for K seconds
// 3) repeat from 1)
// 4) every 1 hour, enumerate everything in state FILE_DELETE_ERROR
//    and try to delete it.
// 5) after 1 hour, and every 24 hours thereafter,
//    scan for and delete all files in the upload/download directories
//    that are older than any WU in the database,
//    and were created at least one month ago.
//    This deletes files uploaded by hosts after the WU was deleted.
//
// options:
//
// -d N
//      set debug output level (1/2/3)
// -mod M R
//      handle only WUs with ID mod M == R
// -one_pass
//      instead of sleeping in 2), exit
// -dont_retry_error
//      don't do 4)
// -dont_delete_antiques
//      don't do 5)
// -preserve_result_files
//      update the DB, but don't delete output files.
//      For debugging.
// -preserve_wu_files
//      update the DB, but don't delete input files.
//      For debugging.
// -dont_delete_batches
//      don't delete anything with positive batch number

// enum sizes.  RESULT_PER_ENUM is three times larger on the
// assumption of 3-fold average redundancy.
// This balances the rate at which input and output files are deleted
//
#define WUS_PER_ENUM        500
#define RESULTS_PER_ENUM    1500

// how long to wait until delete antiques, and how often to do it
//
#define ANTIQUE_DELAY       3600
#define ANTIQUE_INTERVAL    86400

// how often to retry errors
//
#define ERROR_INTERVAL      86400

#include "config.h"
#include <list>
#include <cstring>
#include <cstdlib>
#include <ctime>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif

#include "boinc_db.h"
#include "parse.h"
#include "error_numbers.h"
#include "util.h"
#include "str_util.h"
#include "filesys.h"
#include "strings.h"

#include "sched_config.h"
#include "sched_util.h"
#include "sched_msgs.h"

using namespace std;

#define LOCKFILE "file_deleter.out"
#define PIDFILE  "file_deleter.pid"

#define SLEEP_INTERVAL 5
#define RESULTS_PER_WU 4        // an estimate of redundancy 

SCHED_CONFIG config;

int id_modulus=0, id_remainder=0;
bool dont_retry_errors = false;
bool dont_delete_antiques = false;
bool dont_delete_batches = false;

// Given a filename, find its full path in the upload directory hierarchy
// Return an error if file isn't there.
//
int get_file_path(
    const char *filename, char* upload_dir, int fanout, char* path
) {
    dir_hier_path(filename, upload_dir, fanout, path);
    if (boinc_file_exists(path)) {
        return 0;
    }
    return ERR_NOT_FOUND;
}


int wu_delete_files(WORKUNIT& wu) {
    char* p;
    char filename[256], pathname[256], buf[LARGE_BLOB_SIZE];
    bool no_delete=false;
    int count_deleted = 0, retval, mthd_retval = 0;

    if (strstr(wu.name, "nodelete")) return 0;

    safe_strcpy(buf, wu.xml_doc);
    
    p = strtok(buf, "\n");
    strcpy(filename, "");
    while (p) {
        if (parse_str(p, "<name>", filename, sizeof(filename))) {
        } else if (match_tag(p, "<file_info>")) {
            no_delete = false;
            strcpy(filename, "");
        } else if (match_tag(p, "<no_delete/>")) {
            no_delete = true;
        } else if (match_tag(p, "</file_info>")) {
            if (!no_delete) {
                retval = get_file_path(filename, config.download_dir, config.uldl_dir_fanout,
                    pathname
                );
                if (retval) {
                    log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                        "[WU#%d] get_file_path: %s: %d\n",
                        wu.id, filename, retval
                    );
                } else {
                    log_messages.printf(SCHED_MSG_LOG::MSG_NORMAL,
                        "[WU#%d] deleting %s\n", wu.id, filename
                    );
                    retval = unlink(pathname);
                    if (retval) {
                        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                            "[WU#%d] unlink %s failed: %d\n",
                            wu.id, filename, retval
                        );
                        mthd_retval = ERR_UNLINK;
                    } else {
                        count_deleted++;
                    }
                }
            }
        }
        p = strtok(0, "\n");
    }
    log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
        "[WU#%d] deleted %d file(s)\n", wu.id, count_deleted
    );
    return mthd_retval;
}

int result_delete_files(RESULT& result) {
    char* p;
    char filename[256], pathname[256], buf[LARGE_BLOB_SIZE];
    bool no_delete=false;
    int count_deleted = 0, retval, mthd_retval = 0;

    safe_strcpy(buf, result.xml_doc_in);
    p = strtok(buf,"\n");
    while (p) {
        if (parse_str(p, "<name>", filename, sizeof(filename))) {
        } else if (match_tag(p, "<file_info>")) {
            no_delete = false;
            strcpy(filename, "");
        } else if (match_tag(p, "<no_delete/>")) {
            no_delete = true;
        } else if (match_tag(p, "</file_info>")) {
            if (!no_delete) {
                retval = get_file_path(
                    filename, config.upload_dir, config.uldl_dir_fanout,
                    pathname
                );
                if (retval) {
                    // the fact that no result files were found is a critical
                    // error if this was a successful result, but is to be
                    // expected if the result outcome was failure, since in
                    // that case there may well be no output file produced.
                    //
                    int debug_or_crit;
                    if (RESULT_OUTCOME_SUCCESS == result.outcome) {
                        debug_or_crit=SCHED_MSG_LOG::MSG_CRITICAL;
                    } else {
                        debug_or_crit=SCHED_MSG_LOG::MSG_DEBUG;
                    }
                    log_messages.printf(debug_or_crit,
                        "[RESULT#%d] outcome=%d client_state=%d No file %s to delete\n",
                        result.id, result.outcome, result.client_state, filename
                    );
                } else {
                    retval = unlink(pathname);
                    if (retval) {
                        mthd_retval = ERR_UNLINK;
                        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                            "[RESULT#%d] unlink %s returned %d %s\n",
                            result.id, pathname, retval,
                            (retval && errno)?strerror(errno):""
                        );
                    } else {
                        count_deleted++;
                        log_messages.printf(SCHED_MSG_LOG::MSG_NORMAL,
                            "[RESULT#%d] unlinked %s\n", result.id, pathname
                        );
                    }
                }
            }
        }
        p = strtok(0, "\n");
    }

    log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
        "[RESULT#%d] deleted %d file(s)\n", result.id, count_deleted
    );
    return mthd_retval;
}

// set by corresponding command line arguments.
static bool preserve_wu_files=false;
static bool preserve_result_files=false;

// return nonzero if did anything
//
bool do_pass(bool retry_error) {
    DB_WORKUNIT wu;
    DB_RESULT result;
    bool did_something = false;
    char buf[256];
    char clause[256];
    int retval;

    check_stop_daemons();

    strcpy(clause, "");
    if (id_modulus) {
        sprintf(clause, " and id %% %d = %d ", id_modulus, id_remainder);
    }
    if (dont_delete_batches) {
        strcat(clause, " and batch <= 0 ");
    }

    sprintf(buf,
        "where file_delete_state=%d %s limit %d",
        retry_error?FILE_DELETE_ERROR:FILE_DELETE_READY,
        clause, WUS_PER_ENUM
    );

    while (!wu.enumerate(buf)) {
        did_something = true;

        retval = 0;
        if (!preserve_wu_files) {
            retval = wu_delete_files(wu);
        }
        if (retval) {
            wu.file_delete_state = FILE_DELETE_ERROR;
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "[WU#%d] update failed: %d\n", wu.id, retval
            );
        } else {
            wu.file_delete_state = FILE_DELETE_DONE;
        }
        sprintf(buf, "file_delete_state=%d", wu.file_delete_state);
        retval= wu.update_field(buf);
    }

    sprintf(buf,
        "where file_delete_state=%d %s limit %d",
        retry_error?FILE_DELETE_ERROR:FILE_DELETE_READY,
        clause, RESULTS_PER_ENUM
    );

    while (!result.enumerate(buf)) {
        did_something = true;
        retval = 0;
        if (!preserve_result_files) {
            retval = result_delete_files(result);
        }
        if (retval) {
            result.file_delete_state = FILE_DELETE_ERROR;
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "[RESULT#%d] update failed: %d\n", result.id, retval
            );
        } else {
            result.file_delete_state = FILE_DELETE_DONE;
        }
        sprintf(buf, "file_delete_state=%d", result.file_delete_state); 
        retval= result.update_field(buf);
    } 

    return did_something;
}

struct FILE_RECORD {
     string name;
     int date_modified;
};

bool operator == (const FILE_RECORD& fr1, const FILE_RECORD& fr2) {
    return (fr1.date_modified == fr2.date_modified && fr1.name == fr2.name);
}

bool operator < (const FILE_RECORD& fr1, const FILE_RECORD& fr2) {
    if (fr1.date_modified < fr2.date_modified) return true;
    if (fr1.date_modified > fr2.date_modified) return false;
    if (fr1.name < fr2.name) return true;
    return false;
}

// list of antique files to delete,
// sorted by mod time (primary key) and name(secondary key)
//
std::list<FILE_RECORD> files_to_delete;

// delete files in antique files list, and empty the list.
// Returns number of files deleted, or negative for error.
//
int delete_antique_files() {
    int nfiles=0;

    while (!files_to_delete.empty()) {
        char timestamp[128];
        char pathname[1024];
        int retval;

        FILE_RECORD fr = files_to_delete.front();
        check_stop_daemons();

        retval = get_file_path(
            fr.name.c_str(), config.upload_dir,
            config.uldl_dir_fanout, pathname
        );
        if (retval) {
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "get_file_path(%s) failed: %d\n",
                fr.name.c_str(), retval
            );
            return -1;
        }

        strcpy(timestamp, time_to_string(fr.date_modified));
        log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
            "deleting [antique %s] %s\n",
            timestamp, pathname 
        );
        if (unlink(pathname)) {
            int save_error=errno;
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "unlink(%s) failed: %s\n",
                pathname, strerror(save_error)
            );
            return -1;
        } else {
            nfiles++;
            files_to_delete.pop_front();
        }
    }
    return nfiles;
}


// construct a list "file_to_delete" of old files.
// Return number of files added to list, or negative for error.
//
int add_antiques_to_list(int days) {
    char command[256];
    char single_line[1024];
    FILE *fp;
    int dirlen=strlen(config.upload_dir);
    struct passwd *apache_info=getpwnam(config.httpd_user);
    int del_time=time(0)-86400*days;
    int nfiles=0;

    if (!apache_info) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "no user named '%s' found!\n", config.httpd_user
        );
        return -1;
    }

    sprintf(command,  "find %s -type f -mtime +%d -follow", config.upload_dir, days);
    
    // Now execute the command, read output on a stream.  We could use
    // find to also exec a 'delete' command.  But we want to log all
    // file names into the log, and do lots of sanity checking, so
    // this way is better.
    //
    if (!(fp=popen(command, "r"))) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "command %s failed\n", command
        );
        return -2;
    }

    while (fgets(single_line, 1024, fp)) {
        char pathname[1024];
        char *fname_at_end=NULL;
        int nchars=strlen(single_line);
        struct stat statbuf;
        const char *err=NULL;
        FILE_RECORD fr;

        // We can interrupt this at any point.
        // pclose() is called when process exits.
        check_stop_daemons();

        // Do serious sanity checking on the path before
        // adding the file!!
        //
        if (!err && nchars > 1022) err="line too long";
        if (!err && nchars < dirlen + 1) err="path shorter than upload directory name";
        if (!err && single_line[nchars-1] != '\n') err="no newline terminator in line";
        if (!err && strncmp(config.upload_dir, single_line, dirlen)) err="upload directory not in path";
        if (!err && single_line[dirlen] != '/') err="no slash separator in path";
        if (!err) single_line[nchars-1]='\0';
        if (!err && stat(single_line, &statbuf)) err="stat failed";
        if (!err && statbuf.st_mtime > del_time) err="file too recent";
        if (!err && apache_info->pw_uid != statbuf.st_uid) err="file not owned by httpd user";
        if (!err && !(fname_at_end=rindex(single_line+dirlen, '/'))) err="no trailing filename";
        if (!err) fname_at_end++;
        if (!err && !strlen(fname_at_end)) err="trailing filename too short";

        // skip NFS file system markers of form .nfs*
        //
        if (!err && !strncmp(fname_at_end, ".nfs", 4)) {
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "Ignoring antique (stale) NFS lockfile %s\n", single_line
            );
            continue;
        }

        if (!err && get_file_path(fname_at_end, config.upload_dir, config.uldl_dir_fanout, pathname)) err="get_file_path() failed";
        if (!err && strcmp(pathname, single_line)) err="file in wrong hierarchical upload subdirectory";

        if (err) {
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "Can't list %s for deletion: %s\n",
                single_line, err
            );
            // This file deleting business is SERIOUS.  Give up at the
            // first sign of ANYTHING amiss.
            //
            pclose(fp);
            return -3;
        }

        // insert this file onto the list
        fr.date_modified = statbuf.st_mtime;
        fr.name = fname_at_end;
        files_to_delete.push_back(fr);
        nfiles++;
       
    } // while (fgets(single_line, 1024, fp)) {  
    pclose(fp);
    log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
        "Found %d antique files to delete\n",
        nfiles 
    );
    files_to_delete.sort();
    files_to_delete.unique();
    return nfiles;
}

// returns number of files found & added, or negative for error.
//
int find_antique_files() {
    char buf[256];
    DB_WORKUNIT wu;

    check_stop_daemons();

    // Find the oldest workunit.  We could add
    // "where file_delete_state!=FILE_DELETE_DONE" to the query,
    // but this might create some race condition
    // with the 'regular' file delete mechanism,
    // so better to do it like this.
    //
    sprintf(buf, "order by id limit 1");
    if (!wu.enumerate(buf)) {
        // Don't ever delete files younger than a month.
        //
        int days = 1 + (time(0) - wu.create_time)/86400;
        if (days<31) days=31;

        return add_antiques_to_list(days);
    }
    return 0;
}

void do_antique_pass() {
    int retval;

    // If any problems appear in deleting antique files
    // immediately DISABLE this feature.
    //
    retval = find_antique_files();
    if (retval < 0) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "Problem 1 [%d] in antique file deletion: turning OFF -delete_antiques switch\n", retval
        );
        dont_delete_antiques = true;
        return;
    }

    retval = delete_antique_files();
    if (retval < 0) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "Problem 2 [%d] in antique file deletion: turning OFF -delete_antiques switch\n", retval
        );
        dont_delete_antiques = true;
    }
}

int main(int argc, char** argv) {
    int retval;
    bool one_pass = false;
    int i;

    check_stop_daemons();
    for (i=1; i<argc; i++) {
        if (!strcmp(argv[i], "-one_pass")) {
            one_pass = true;
        } else if (!strcmp(argv[i], "-dont_retry_errors")) {
            dont_retry_errors = true;
        } else if (!strcmp(argv[i], "-preserve_wu_files")) {
            preserve_wu_files = true;
        } else if (!strcmp(argv[i], "-preserve_result_files")) {
            preserve_result_files = true;
        } else if (!strcmp(argv[i], "-d")) {
            log_messages.set_debug_level(atoi(argv[++i]));
        } else if (!strcmp(argv[i], "-mod")) {
            id_modulus   = atoi(argv[++i]);
            id_remainder = atoi(argv[++i]);
        } else if (!strcmp(argv[i], "-dont_delete_antiques")) {
            dont_delete_antiques = true;
        } else if (!strcmp(argv[i], "-dont_delete_batches")) {
            dont_delete_batches = true;
        } else {
            log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
                "Unrecognized arg: %s\n", argv[i]
            );
        }
    }

    if (id_modulus) {
        log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
            "Using mod'ed WU/result enumeration.  mod = %d  rem = %d\n",
            id_modulus, id_remainder
        );
    }

    retval = config.parse_file("..");
    if (retval) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "Can't parse ../config.xml: %s\n", boincerror(retval)
        );
        exit(1);
    }

    log_messages.printf(SCHED_MSG_LOG::MSG_NORMAL, "Starting\n");

    retval = boinc_db.open(config.db_name, config.db_host, config.db_user, config.db_passwd);
    if (retval) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL, "can't open DB\n");
        exit(1);
    }
    retval = boinc_db.set_isolation_level(READ_UNCOMMITTED);
    if (retval) {
        log_messages.printf(SCHED_MSG_LOG::MSG_CRITICAL,
            "boinc_db.set_isolation_level: %d; %s\n", retval, boinc_db.error_string()
        );
    }
    install_stop_signal_handler();

    bool retry_errors_now = !dont_retry_errors;
    double next_error_time=0;
    double next_antique_time = dtime() + ANTIQUE_DELAY;
    while (1) {
        bool got_any = do_pass(false);
        if (retry_errors_now) {
            bool got_any_errors = do_pass(true);
            if (got_any_errors) {
                got_any = true;
            } else {
                retry_errors_now = false;
                next_error_time = dtime() + ERROR_INTERVAL;
                log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
                    "ending retry of previous errors\n"
                );
            }
        }
        if (!got_any) {
            if (one_pass) break;
            sleep(SLEEP_INTERVAL);
        }
        if (!dont_delete_antiques && (dtime() > next_antique_time)) {
            log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
                "Doing antique deletion pass\n"
            );
            do_antique_pass();
            next_antique_time = dtime() + ANTIQUE_INTERVAL;
        }
        if (!dont_retry_errors && !retry_errors_now && (dtime() > next_error_time)) {
            retry_errors_now = true;
            log_messages.printf(SCHED_MSG_LOG::MSG_DEBUG,
                "starting retry of previous errors\n"
            );
        }
    }
}

const char *BOINC_RCSID_bd0d4938a6 = "$Id$";