tfslog.c

完整的Bell实验室的嵌入式文件系统TFS

/* tfslog.c:
 *
 *  Optional facility for TFS that supports the ability to log all
 *  tfs actions that affect flash, to a log file.
 *
 *  This function is called by tfsadd(), tfsunlink() and tfsipmod() to
 *  write to a log file indicating that something in tfs has been changed.
 *  Note that the function can be called at any user level, but it must be
 *  able to modify the TFS_CHANGELOG_FILE that has "u3" flags.  The 
 *  user level must be temporarily forced to MAXUSRLEVEL for this.
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */
#include "config.h"
#include "stddefs.h"
#include "genlib.h"
#include "tfs.h"
#include "tfsprivate.h"
#include "cli.h"

#if TFS_CHANGELOG_SIZE
static int  tfsLogging;
#endif

void
tfslog(int action, char *string)
{
#if TFS_CHANGELOG_SIZE
    static char *tfslogaction[] = { "ADD", "DEL", "IPM", " ON", "OFF" };
    
    extern  void *setTmpMaxUsrLvl();
    static  char buf[TFS_CHANGELOG_SIZE];
    TFILE   *tfp;
    int     (*fptr)();
    char    *eol, *eob, *logaction, tbuf[32];
    int     newfsize, fsize, lsize, tfd, err, len, tbuflen;

    switch(action) {
        case TFSLOG_ADD:        /* Return here if logging is off,   */
        case TFSLOG_DEL:        /* or this tfslog() call is on the  */
        case TFSLOG_IPM:        /* TFS_CHANGELOG_FILE itself.       */
            if (!tfsLogging || !strcmp(string,TFS_CHANGELOG_FILE))
                return;
            break;
        case TFSLOG_ON:
            if (tfsLogging == 1)
                return;
            tfsLogging = 1;
            break;
        case TFSLOG_OFF:
            if (tfsLogging == 0)
                return;
            tfsLogging = 0;
            break;
    }

    /* Force the getUsrLvl() function to return MAX: */
    fptr = (int(*)())setTmpMaxUsrLvl();

    logaction = tfslogaction[action];
    tfp = tfsstat(TFS_CHANGELOG_FILE);
    tfsGetAtime(0,tbuf,sizeof(tbuf));
    tbuflen = strlen(tbuf); 

    if (tfp) {
        tfd = tfsopen(TFS_CHANGELOG_FILE,TFS_RDONLY,0);
        fsize = tfsread(tfd,buf,TFS_CHANGELOG_SIZE);
        tfsclose(tfd,0);

        newfsize = (fsize+strlen(logaction)+strlen(string)+3);
        if (tbuflen)
            newfsize += tbuflen + 3;

        eob = buf + fsize;

        /* If newfsize is greater than the maximum size the file is
         * allowed to grow, then keep removing the first line
         * (oldest entry) until new size is within the limit...
         */
        if (newfsize > TFS_CHANGELOG_SIZE) {
            lsize = 0;
            eol = buf;
            while ((newfsize-lsize) > TFS_CHANGELOG_SIZE) {
                while((*eol != '\r') && (*eol != '\n')) eol++;
                while((*eol == '\r') || (*eol == '\n')) eol++;
                lsize = eol-buf;
            }
            fsize -= lsize;
            newfsize -= lsize;
            eob -= lsize;
            memcpy(buf,eol,fsize);
        }
        if (tbuflen)
            sprintf(eob,"%s: %s @ %s\n",logaction,string,tbuf);
        else
            sprintf(eob,"%s: %s\n",logaction,string);
        err = _tfsunlink(TFS_CHANGELOG_FILE);
        if (err < 0)
            printf("%s: %s\n",TFS_CHANGELOG_FILE,
                (char *)tfsctrl(TFS_ERRMSG,err,0));
        err = tfsadd(TFS_CHANGELOG_FILE,0,"u3",buf,newfsize);
        if (err < 0)
            printf("%s: %s\n",TFS_CHANGELOG_FILE,
                (char *)tfsctrl(TFS_ERRMSG,err,0));
    }
    else {
        if (tbuflen)
            len = sprintf(buf,"%s: %s @ %s\n",logaction,string,tbuf);
        else
            len = sprintf(buf,"%s: %s\n",logaction,string);
        err = tfsadd(TFS_CHANGELOG_FILE,0,"u3",buf,len);
        if (err < 0)
            printf("%s: %s\n",TFS_CHANGELOG_FILE,
                (char *)tfsctrl(TFS_ERRMSG,err,0));
    }

    /* Restore the original getUsrLvl() functionality: */
    clrTmpMaxUsrLvl(fptr);
#endif
}

int
tfsLogCmd(int argc,char *argv[], int optind)
{
#if TFS_CHANGELOG_SIZE
    int status;
    int retval = 0;

    if (getUsrLvl() < MAXUSRLEVEL) {
        status = showTfsError(TFSERR_USERDENIED,0);
    }
    else {
        if (argc == optind + 3) {
            if (!strcmp(argv[optind+1],"on"))
                tfslog(TFSLOG_ON,argv[optind+2]);
            else if (!strcmp(argv[optind+1],"off"))
                tfslog(TFSLOG_OFF,argv[optind+2]);
            else
                retval = CMD_PARAM_ERROR;
        }
        else if (argc == optind + 1)
            printf("TFS logging %sabled\n",tfsLogging ? "en" : "dis");
        else
            retval = CMD_PARAM_ERROR;
    }
    return(retval);
#else
    return(CMD_FAILURE);
#endif
}