tables.c

Cryptmount是对Linux系统下的文件系统以及用户设备、文档等进行加密的系统.

                fprintf(stderr, _("unrecognized option \"%s\"\n"), buff);
                *t_state = T_ERROR;
            }
            break;
        default:
            break;
    }
}


cment_t *parse_config(const char *cfgname)
    /* convert config-file into linked-list of target-structures */
{   enum { C_SPACE, C_WORD, C_COMMENT };
    FILE *fp;
    int ch,lineno=1,literal=0;
    unsigned pos=0,bufflen=0;
    unsigned c_state,t_state;
    char *buff=NULL;
    cment_t *head=NULL,**cmp=&head,*cment=NULL;

    fp = fopen(cfgname, "r");
    if (fp == NULL) {
        fprintf(stderr, "failed to open \"%s\"\n", cfgname);
        goto bail_out;
    }

    c_state = C_SPACE;
    t_state = T_IDENT;
    cment = alloc_cment();

    while (!feof(fp) && t_state != T_ERROR) {
        ch = fgetc(fp);
        if (ch == (int)'\n') ++lineno;

        if (literal && ch == (int)'\n') {    /* ignore escaped end-of-line */
            literal = 0;
            continue;
        }

        if (!literal && ch == (int)'#') c_state = C_COMMENT;
        if (!literal && ch == (int)'\\') {
            /* treat next character literally */
            literal = 1;
            continue;
        }

        switch (c_state) {
            case C_SPACE:
                if (literal || !isspace(ch)) {
                    pos = 0;
                    append((char)ch, &buff, &pos, &bufflen);
                    c_state = C_WORD;
                }
                break;
            case C_WORD:
                if (literal || !isspace(ch)) {
                    append((char)ch, &buff, &pos, &bufflen);
                } else {
                    append('\0', &buff, &pos, &bufflen);
                    read_token(buff, &t_state, cment);
                    c_state = C_SPACE;
                }
                break;
            case C_COMMENT:
                if (!literal && ch == '\n') c_state = C_SPACE;
                break;
            default:
                break;
        }

        literal = 0;
        if (t_state == T_RBRACE) {
            *cmp = cment;
            cmp = &cment->nx;
            cment = alloc_cment();
            t_state = T_IDENT;
        }
    }

    if (t_state == T_ERROR) {
        fprintf(stderr, _("configuration error near %s:%d\n"),
                cfgname, lineno);
    }

  bail_out:

    if (cment != NULL) free_cment(cment);
    if (buff != NULL) free((void*)buff);

    if (fp != NULL) fclose(fp);

    return head;
}


void free_config(cment_t **head)
    /* free all entries in target-config list */
{   cment_t *cmx;

    if (head == NULL) return;

    while ((cmx = *head) != NULL) {
        *head = cmx->nx;
        free_cment(cmx);
    }
}



tgtstat_t *alloc_tgtstatus(const struct cment *ent)
    /* create new status record for given target */
{   tgtstat_t *ts;

    ts = (tgtstat_t*)malloc(sizeof(tgtstat_t));
    ts->ident = NULL;
    ts->uid = 0;

    if (ent != NULL) {
        ts->ident = (char*)malloc((size_t)(strlen(ent->ident) + 1));
        strcpy(ts->ident, ent->ident);
    }

    return ts;
}


void free_tgtstatus(tgtstat_t *ts)
    /* free storage of target-status record */
{
    if (ts->ident != NULL) free((void*)ts->ident);
    free((void*)ts);
}


struct statfile *statfile_open(const char *fname, const char *mode)
    /* prepare status-file for reading/writing */
{   struct statfile *sf=NULL;
    char buff[256];
    FILE *fp;

    if ((fp = fopen(fname, mode)) != NULL) {
        sf = (struct statfile*)malloc(sizeof(struct statfile));
        sf->fp = fp;

        if (mode[0] == 'w') {
            sf->version = 0;        /* format-version for new files */
            fprintf(fp,"# auto-generated by cryptmount - do not edit\n");
            fprintf(fp, "%d\n", sf->version);
        } else {
            (void)fgets(buff, (int)sizeof(buff), fp);
            fscanf(fp, "%d", &sf->version);
        }
    }

    return sf;
}


tgtstat_t *statfile_read(struct statfile *sf)
    /* read information about next target from status-file */
{   tgtstat_t *ts=NULL;
    char *ident=NULL;
    int len;
    unsigned long uid;

    if (sf == NULL) goto bail_out;

    if (fscanf(sf->fp, "%d,", &len) != 1) goto bail_out;

    ident = (char*)malloc((size_t)(len + 1));
    if (fread((void*)ident, (size_t)(len + 1), 1, sf->fp) != 1) {
        goto bail_out;
    }
    ident[len] = '\0';

    if (fscanf(sf->fp, "%lu", &uid) != 1) goto bail_out;
    if (feof(sf->fp)) goto bail_out;

    ts = alloc_tgtstatus(NULL);
    ts->ident = ident;
    ts->uid = uid;
    ident = NULL;

  bail_out:

    if (ident != NULL) free((void*)ident);

    return ts;
}


void statfile_write(struct statfile *sf, const tgtstat_t *stat)
{
    fprintf(sf->fp, "%u,", (unsigned)strlen(stat->ident));
    fprintf(sf->fp, "%s,", stat->ident);
    fprintf(sf->fp, "%lu\n", stat->uid);
}


void statfile_close(struct statfile *sf)
{
    fclose(sf->fp);
    free((void*)sf);
}


tgtstat_t *get_tgtstatus(const cment_t *cment)
{   char *fname=NULL;
    tgtstat_t *ts=NULL;
    struct statfile *sf;
    int badlock;

    (void)cm_path(&fname, "cmstatus");
    badlock = cm_mutex_lock();
    sf = statfile_open(fname, "r");
    if (sf == NULL) goto bail_out;

    while ((ts = statfile_read(sf)) != NULL) {
        if (strcmp(cment->ident, ts->ident) == 0) break;
        else free_tgtstatus(ts);
    }

    statfile_close(sf);

  bail_out:

    if (!badlock) cm_mutex_unlock();
    if (fname != NULL) free((void*)fname);

    return ts;
}


int put_tgtstatus(const cment_t *cment, const tgtstat_t *newstat)
{   char *newfname=NULL,*oldfname=NULL;
    struct statfile *sfin,*sfout;
    tgtstat_t *ts=NULL;
    struct stat sbuff;
    int badlock,eflag=0;

    (void)cm_path(&oldfname,"cmstatus");
    (void)cm_path(&newfname,"cmstatus-temp");
    badlock = cm_mutex_lock();

    sfout = statfile_open(newfname, "w");
    if (sfout == NULL) {
        eflag = 1; goto bail_out;
    }

    if (stat(oldfname,&sbuff) == 0) {
        sfin = statfile_open(oldfname, "r");
        if (sfin == NULL) {
            statfile_close(sfout);
            unlink(newfname);
            eflag = 1; goto bail_out;
        }

        /* copy most entries from existing status-file: */
        while ((ts = statfile_read(sfin)) != NULL) {
            if (strcmp(cment->ident, ts->ident) != 0) {
                statfile_write(sfout, ts);
            }
            free_tgtstatus(ts);
        }
        statfile_close(sfin);
    }

    /* add new entry onto end of new status-file: */
    if (newstat != NULL) {
        statfile_write(sfout, newstat);
    }
    statfile_close(sfout);

    /* overwrite old status-file: */
    rename(newfname, oldfname);
    chown(oldfname, (uid_t)0, (gid_t)0);
    chmod(oldfname, S_IWUSR|S_IRUSR | S_IRGRP | S_IROTH);

  bail_out:

    if (!badlock) cm_mutex_unlock();
    if (newfname != NULL) free((void*)newfname);
    if (oldfname != NULL) free((void*)oldfname);

    return eflag;
}


/*
 *  tables.c
 *  (C)Copyright 2005-2006, RW Penney
 */