Language/OS - Multiplatform Resource Library/LANGUAGE OS.iso/oper_sys/kerberos/pc/krb_src.lha/KUSER/KERBMEM.C

C/C++ Source or Header | 1991-07-24 | 4.6 KB | 198 lines

/***********************************************
    mk_tkt.c    Peter Tan
        used to create the "ticket file" in    RAM.
        sets TKT_ENV env variable to point
        to the segment where the ticket file exists.

***********************************************/

#include <conf.h>
#include <stdio.h>
#include <string.h>
#include <dos.h>
#include <stdlib.h>
#include <krb.h>

#define TKT_FIL_SZ 64U     /* Number of paragraphs */
#define TKT_FIL_MIN 16U    /* Minimum number of paragraphs */

extern char far *nxtevar (char far*vptr);
extern char far *mstenvp (void);
extern int envsiz (char far*envptr);

char far *menv;
char far *rest;
char far *lstbyt;
char vname[512], *txtptr;
int free_env,nmlen;
char *progname;

void findvar(char *varnam)
{
    nmlen=strlen(varnam);
    txtptr=NULL;
    while (*menv) {
        rest=nxtevar(menv);
        sprintf(vname,"%Fs",menv);
        if (vname[nmlen]=='=') {    /* possible match */
            vname[nmlen]='\0';
            if (stricmp(vname,varnam)==0) {
                txtptr=&vname[nmlen+1];
                vname[nmlen]='=';
                return;        /* found it, leave now */
            }
        }
        menv=rest;    /* try again with next */
    }
}

void putenvbak()
{
    char * locptr;
    int i,save_size;

    save_size=FP_OFF(lstbyt)-FP_OFF(rest) +1;
    locptr=(char*)malloc(save_size);

    for (i=0; i<save_size;i++)    /* save trailing data */
        locptr[i]=rest[i];
    for (i=0; vname[i];i++)        /* copy new env setting */
        *menv++=vname[i];
    if (vname[0])        /* if not deleting */
        *menv++='\0';    /* ... add end of string */
    for (i=0;i<save_size;i++)
        *menv++=locptr[i];
    free(locptr);
}

void setvar(char *varnam,char *value)
{
    int i;
    menv=mstenvp();
    free_env=envsiz(menv);
    findvar(varnam);
    for (lstbyt=menv;*lstbyt;)
        lstbyt=nxtevar(lstbyt);    /* find last byte */
    if (lstbyt[1]==1 && lstbyt[2]==0) {
        lstbyt+=3;        /* skip loadfile name */
        while (*lstbyt)
            lstbyt++;
    }
    lstbyt++;
    free_env -= FP_OFF(lstbyt);        /* what's left is free */
    if (txtptr==NULL) { /* Name not found */
        free_env-=nmlen+1;     /* take out free space
        if (free_env < strlen(value)) {
            printf("%s : Not enough environment space",progname);
            exit(1);
        }
        /* add the environment variable */
        for (i=0;i<nmlen;i++)    /* force uppercase */
            vname[i]=(char)toupper(varnam[i]);
        vname[nmlen]='=';
        vname[nmlen+1]='\0';
        txtptr=&vname[nmlen+1];
    }
    if (value)
        strcpy(txtptr,value);
    else
        vname[0]=0;        /* delete this variable */
    putenvbak();
}

void remove_memory()
{
    tkt_header far *hdr;
    char *value;
    unsigned segment;

    if ((value=getenv(TKT_ENV))==NULL) {
        printf("%s : Ticket memory not reserved\n",progname);
        exit(0);
    }
    sscanf(value,"%u",&segment);
    if (segment==0) {
        printf("%s : Environment variable corrupt\n",progname);
        exit(0);
    }
    setvar(TKT_ENV,NULL);
    hdr=(char far *)((unsigned long)segment<<16|0UL);
#ifdef __BORLANDC__
    freemem(segment);
#else
    _dos_freemem(segment);
#endif
    printf("%s : Ticket memory freed OK\n",progname);
    exit(0);
}

void clear_sema()
{
    tkt_header far *hdr;
    char *value;
    unsigned segment;

    if ((value=getenv(TKT_ENV))==NULL) {
        printf("%s : Ticket memory not reserved\n",progname);
        exit(0);
    }
    sscanf(value,"%u",&segment);
    if (segment==0) {
        printf("%s : Environment variable corrupt\n",progname);
        exit(0);
    }
    hdr=(char far *)((unsigned long)segment<<16|0UL);
    hdr->sema=0;
    printf("%s : Ticket file semaphore reset\n",progname);
    exit(0);
}

main(int argc,char **argv)
{
    tkt_header far *hdr;
    char value[12];
    unsigned buffer_size;

    progname=argv[0];

    if (strchr(argv[1],'?')) {
        printf("Usage : kerbmem [-u] [nnn]\n"
               "-u : Uinstall memory\n"
               "-c : Clear reference count/semaphore\n"
               "nnn : Number of paragraphs to reserve.\n");
        exit(1);
    }

    if (!strcmp(argv[1],"-u"))
        remove_memory();

    if (!strcmp(argv[1],"-c"))
        clear_sema();

    if ((buffer_size=atoi(argv[1]))<TKT_FIL_MIN)
        buffer_size=TKT_FIL_SZ;

    if (getenv(TKT_ENV)) {
        printf("%s : Kerberos ticket memory already installed\n",progname);
        exit(0);
    }
    sprintf(value,"%u",(unsigned)_psp);
    setvar(TKT_ENV,value);

    hdr=(char far *)((unsigned long)_psp<<16|0UL);
    hdr->buf_size=buffer_size*16;        /* size of segment */
    hdr->eof_ptr=sizeof(tkt_header);    /* pointer to EOF */
    hdr->sema=0;                        /* start with unlocked file */
    printf("%s : Kerberos ticket memory \n"
        "%d paragraphs installed OK\n",progname,buffer_size);
            /* free environment */
#ifdef __BORLANDC__
    freemem(*(unsigned far *)((char far *)hdr+0x2c));
    keep(0,buffer_size);
#else
    _dos_freemem(*(unsigned far *)((char far *)hdr+0x2c));
    _dos_keep(0,buffer_size);
#endif
}