source: trunk/third/xntp/xntpd/ntp_filegen.c @ 10832

/*
 * ntp_filegen.c,v 3.12 1994/01/25 19:06:11 kardel Exp
 *
 *  implements file generations support for NTP
 *  logfiles and statistic files
 *
 *
 * Copyright (C) 1992, 1996 by Rainer Pruy
 * Friedrich-Alexander Universität Erlangen-Nürnberg, Germany
 *
 * This code may be modified and used freely
 * provided credits remain intact.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_string.h"
#include "ntp_calendar.h"
#include "ntp_filegen.h"
#include "ntp_stdlib.h"

/*
 * NTP is intended to run long periods of time without restart.
 * Thus log and statistic files generated by NTP will grow large.
 *
 * this set of routines provides a central interface 
 * to generating files using file generations
 *
 * the generation of a file is changed according to file generation type
 */


/*
 * to check reason on open failure
 */
#ifndef SYS_WINNT
extern int errno;
#endif /* SYS_WINNT */

/*
 * imported from timer
 */
extern u_long current_time;

/*
 * redefine this if your system dislikes filename suffixes like
 * X.19910101 or X.1992W50 or ....
 */
#define SUFFIX_SEP '.'

/*
 * other constants
 */
#define FGEN_AGE_SECS   (24*60*60) /* life time of FILEGEN_AGE in seconds */

#ifdef DEBUG
extern int debug;
#endif

static  void    filegen_open    P((FILEGEN *, u_long));
static  int     valid_fileref   P((char *, char *));
#ifdef  UNUSED
static  FILEGEN *filegen_unregister P((char *));
#endif  /* UNUSED */

/*
 * open a file generation according to the current settings of gen
 * will also provide a link to basename if requested to do so
 */

static void
filegen_open(gen, newid)
  FILEGEN *gen;
  u_long  newid;
{
        char *filename;
        char *basename;
        u_int len;
        FILE *fp;
        struct calendar cal;

        len = strlen(gen->prefix) + strlen(gen->basename) + 1;
        basename = emalloc(len);
        sprintf(basename, "%s%s", gen->prefix, gen->basename);
  
        switch(gen->type) {
        default:
                msyslog(LOG_ERR, "unsupported file generations type %d for \"%s\" - reverting to FILEGEN_NONE",
                       gen->type, basename);
                gen->type = FILEGEN_NONE;
      
                /*FALLTHROUGH*/
        case FILEGEN_NONE:
                filename = emalloc(len);
                sprintf(filename,"%s", basename);
                break;

        case FILEGEN_PID:
                filename = emalloc(len + 1 + 1 + 10);
                sprintf(filename,"%s%c#%ld", basename, SUFFIX_SEP, newid);
                break;
      
        case FILEGEN_DAY:
                /* You can argue here in favor of using MJD, but
                 * I would assume it to be easier for humans to interpret dates
                 * in a format they are used to in everyday life.
                 */
                caljulian(newid,&cal);
                filename = emalloc(len + 1 + 4 + 2 + 2);
                sprintf(filename, "%s%c%04d%02d%02d",
                        basename, SUFFIX_SEP, cal.year, cal.month, cal.monthday);
                break;
      
        case FILEGEN_WEEK:
                /*
                 * This is still a hack
                 * - the term week is not correlated to week as it is used
                 *   normally - it just refers to a period of 7 days
                 *   starting at Jan 1 - 'weeks' are counted starting from zero
                 */
                caljulian(newid,&cal);
                filename = emalloc(len + 1 + 4 + 1 + 2);
                sprintf(filename, "%s%c%04dw%02d",
                        basename, SUFFIX_SEP, cal.year, cal.yearday / 7);
                break;

        case FILEGEN_MONTH:
                caljulian(newid,&cal);
                filename = emalloc(len + 1 + 4 + 2);
                sprintf(filename, "%s%c%04d%02d",
                        basename, SUFFIX_SEP, cal.year, cal.month);
                break;

        case FILEGEN_YEAR:
                caljulian(newid,&cal);
                filename = emalloc(len + 1 + 4);
                sprintf(filename, "%s%c%04d", basename, SUFFIX_SEP, cal.year);
                break;

        case FILEGEN_AGE:
                filename = emalloc(len + 1 + 2 + 10);
                sprintf(filename, "%s%ca%08ld", basename, SUFFIX_SEP, newid);
                break;
        }
  
        if (gen->type != FILEGEN_NONE) {
                /*
                 * check for existence of a file with name 'basename'
                 * as we disallow such a file
                 * if FGEN_FLAG_LINK is set create a link
                 */
                struct stat stats;
                /*
                 * try to resolve name collisions
                 */
                static u_long conflicts = 0;

#ifndef S_ISREG
#define S_ISREG(mode)   (((mode) & S_IFREG) == S_IFREG)
#endif
                if (stat(basename, &stats) == 0) {
                        /* Hm, file exists... */
                        if (S_ISREG(stats.st_mode)) {
                                if (stats.st_nlink <= 1)        {
                                        /*
                                         * Oh, it is not linked - try to save it
                                         */
                                        char *savename = emalloc(len + 1 + 1 + 10 + 10);
                                        sprintf(savename, "%s%c%dC%lu",
                                                basename,
                                                SUFFIX_SEP,
                                                (int) getpid(),
                                                (u_long)conflicts++);
                                        if (rename(basename, savename) != 0)
                                                msyslog(LOG_ERR," couldn't save %s: %m", basename);
                                        free(savename);
                                } else {
                                        /*
                                         * there is at least a second link tpo this file
                                         * just remove the conflicting one
                                         */
#if !defined(VMS)
                                        if (unlink(basename) != 0)
#else
                                        if (delete(basename) != 0)
#endif
                                                msyslog(LOG_ERR, "couldn't unlink %s: %m", basename);
                                }
                        } else {
                                /*
                                 * Ehh? Not a regular file ?? strange !!!!
                                 */
                                msyslog(LOG_ERR, "expected regular file for %s (found mode 0%o)",
                                       basename, stats.st_mode);
                        }
                } else {
                        /*
                         * stat(..) failed, but it is absolutely correct for
                         * 'basename' not to exist
                         */
                        if (errno != ENOENT)
                                msyslog(LOG_ERR,"stat(%s) failed: %m", basename);
                }
        }

        /*
         * now, try to open new file generation...
         */
        fp = fopen(filename, "a");
  
#ifdef DEBUG
        if (debug > 3)
                printf("opening filegen (type=%d/id=%lu) \"%s\"\n",
                    gen->type, (u_long)newid, filename);
#endif

        if (fp == NULL) {
                /* open failed -- keep previous state
                 *
                 * If the file was open before keep the previous generation.
                 * This will cause output to end up in the 'wrong' file,
                 * but I think this is still better than loosing output
                 *
                 * ignore errors due to missing directories
                 */

                if (errno != ENOENT)
                        msyslog(LOG_ERR, "can't open %s: %m", filename);
        } else {
                if (gen->fp != NULL) {
                        fclose(gen->fp);
                }
                gen->fp = fp;
                gen->id = newid;

                if (gen->flag & FGEN_FLAG_LINK) {
                        /*
                         * need to link file to basename
                         * have to use hardlink for now as I want to allow
                         * gen->basename spanning directory levels
                         * this would make it more complex to get the correct filename
                         * for symlink
                         *
                         * Ok, it would just mean taking the part following the last '/'
                         * in the name.... Should add it later....
                         */


                        /* Windows NT does not support file links -Greg Schueman 1/18/97 */
                        
#if !defined(VMS) && !defined(SYS_WINNT) && !defined (SYS_VXWORKS)
                        if (link(filename, basename) != 0) {
                                if (errno != EEXIST)
#else

                        {
#ifndef SYS_WINNT
                                        errno = 0; /* On VMS, don't support FGEN_FLAG_LINK */
#else
                                        SetLastError(0); /* On WinNT, don't support FGEN_FLAG_LINK */
#endif /* SYS_WINNT */

#endif /* VMS */
                                        msyslog(LOG_ERR, "can't link(%s, %s): %m", filename, basename);
                        }


                }               /* flags & FGEN_FLAG_LINK */
        }                       /* else fp == NULL */
        
        free(basename);
        free(filename);
        return;
}

/*
 * this function sets up gen->fp to point to the correct
 * generation of the file for the time specified by 'now'
 *
 * 'now' usually is interpreted as second part of a l_fp as is in the cal...
 * library routines
 */

void
filegen_setup(gen,now)
  FILEGEN *gen;
  u_long   now;
{
        u_long new_gen = ~ (u_long) 0;
        struct calendar cal;

        if (!(gen->flag & FGEN_FLAG_ENABLED)) {
                if (gen->fp != NULL)
                        fclose(gen->fp);
                return;
        }
        
        switch (gen->type) {
        case FILEGEN_NONE:
                if (gen->fp != NULL) return; /* file already open */
                break;
      
        case FILEGEN_PID:
                new_gen = getpid();
                break;

        case FILEGEN_DAY:
                caljulian(now, &cal);
                cal.hour = cal.minute = cal.second = 0;
                new_gen = caltontp(&cal);
                break;
      
        case FILEGEN_WEEK:
                /* Would be nice to have a calweekstart() routine */
                /* so just use a hack ... */
                /* just round time to integral 7 days period for actual year  */
                new_gen = now - (now - calyearstart(now)) % TIMES7(SECSPERDAY)
                        + 60;
                /*
                 * just to be sure -
                 * the computation above would fail in the presence of leap seconds
                 * so at least carry the date to the next day (+60 (seconds))
                 * and go back to the start of the day via calendar computations
                 */
                caljulian(new_gen, &cal);
                cal.hour = cal.minute = cal.second = 0;
                new_gen = caltontp(&cal);
                break;
      
        case FILEGEN_MONTH:
                caljulian(now, &cal);
                cal.yearday -= cal.monthday - 1;
                cal.monthday = 1;
                cal.hour = cal.minute = cal.second = 0;
                new_gen = caltontp(&cal);
                break;
      
        case FILEGEN_YEAR:
                new_gen = calyearstart(now);
                break;

        case FILEGEN_AGE:
                new_gen = current_time  - (current_time % FGEN_AGE_SECS);
                break;
        }
        /*
         * try to open file if not yet open
         * reopen new file generation file on change of generation id
         */
        if (gen->fp == NULL || gen->id != new_gen) {
                filegen_open(gen, new_gen);
        }
}


/*
 * change settings for filegen files
 */
void
filegen_config(gen,basename,type,flag)
  FILEGEN *gen;
  char    *basename;
  u_int   type;
  u_int   flag;
{
        /*
         * if nothing would be changed...
         */
        if ((basename == gen->basename || strcmp(basename,gen->basename) == 0) &&
            type == gen->type &&
            flag == gen->flag)
                return;
  
        /*
         * validate parameters
         */
        if (!valid_fileref(gen->prefix,basename))
                return;
  
        if (gen->fp != NULL)
                fclose(gen->fp);

#ifdef DEBUG
        if (debug > 2)
                printf("configuring filegen:\n\tprefix:\t%s\n\tbasename:\t%s -> %s\n\ttype:\t%d -> %d\n\tflag: %x -> %x\n",
                       gen->prefix, gen->basename, basename, gen->type, type, gen->flag, flag);
#endif
        if (gen->basename != basename || strcmp(gen->basename, basename) != 0) {
                free(gen->basename);
                gen->basename = emalloc(strlen(basename) + 1);
                strcpy(gen->basename, basename);
        }
        gen->type = type;
        gen->flag = flag;

        /*
         * make filegen use the new settings
         * special action is only required when a generation file
         * is currently open
         * otherwise the new settings will be used anyway at the next open
         */
        if (gen->fp != NULL) {
                l_fp now;

                get_systime(&now);
                filegen_setup(gen, now.l_ui);
        }
}


/*
 * check whether concatenating prefix and basename
 * yields a legal filename
 */
static int
valid_fileref(prefix,basename)
  char *prefix, *basename;
{
        /*
         * prefix cannot be changed dynamically
         * (within the context of filegen)
         * so just reject basenames containing '..'
         *
         * ASSUMPTION:
         *              file system parts 'below' prefix may be
         *              specified without infringement of security
         *
         *              restricing prefix to legal values
         *              has to be ensured by other means
         * (however, it would be possible to perform some checks here...)
         */
        register char *p = basename;
  
        /*
         * Just to catch, dumb errors opening up the world...
         */
        if (prefix == NULL || *prefix == '\0')
                return 0;

        if (basename == NULL)
                return 0;
  
        for (p = basename; p; p = strchr(p, '/')) {
                if (*p == '.' && *(p+1) == '.' && (*(p+2) == '\0' || *(p+2) == '/'))
                        return 0;
        }
  
        return 1;
}


/*
 * filegen registry
 */


static struct filegen_entry {
        char *name;
        FILEGEN *filegen;
        struct filegen_entry *next;
} *filegen_registry = NULL;


FILEGEN *
filegen_get(name)
  char *name;
{
        struct filegen_entry *f = filegen_registry;

        while(f) {
                if (f->name == name || strcmp(name, f->name) == 0) {
#ifdef XXX      /* this gives the Alpha compiler fits */
                        if (debug > 3)
                            printf("filegen_get(\"%s\") = %x\n", name,
                            (u_int)f->filegen);
#endif
                        return f->filegen;
                }
                f = f->next;
        }
#ifdef DEBUG
        if (debug > 3)
                printf("filegen_get(\"%s\") = NULL\n", name);
#endif
        return NULL;
}

void
filegen_register(name, filegen)
  char *name;
  FILEGEN *filegen;
{
        struct filegen_entry **f = &filegen_registry;

#ifdef XXX              /* this gives the Alpha compiler fits */
        if (debug > 3)
                printf("filegen_register(\"%s\",%x)\n", name, (u_int)filegen);
#endif
        while (*f) {
                if ((*f)->name == name || strcmp(name, (*f)->name) == 0) {
#ifdef XXX       /* this gives the Alpha compiler fits */
                        if (debug > 4) {
                                printf("replacing filegen %x\n", (u_int)(*f)->filegen);
                        }
#endif
                        (*f)->filegen = filegen;
                        return;
                }
                f = &((*f)->next);
        }

        *f = (struct filegen_entry *) emalloc(sizeof(struct filegen_entry));
        if (*f) {
                (*f)->next = NULL;
                (*f)->name = emalloc(strlen(name) + 1);
                strcpy((*f)->name, name);
                (*f)->filegen = filegen;
#ifdef DEBUG
                if (debug > 5) {
                        printf("adding new filegen\n");
                }
#endif
        }
        
        return;
}

#ifdef  UNUSED
static FILEGEN *
filegen_unregister(name)
  char *name;
{
        struct filegen_entry **f = &filegen_registry;
  
#ifdef DEBUG
        if (debug > 3)
                printf("filegen_unregister(\"%s\")\n", name);
#endif

        while (*f) {
                if (strcmp((*f)->name,name) == 0) {
                        struct filegen_entry *ff = *f;
                        FILEGEN *fg;
                        
                        *f = (*f)->next;
                        fg = ff->filegen;
                        free(ff->name);
                        free(ff);
                        return fg;
                }
                f = &((*f)->next);
        }
        return NULL;
}       
#endif  /* UNUSED */