usr/src/usr.bin/uucp/port/getwd.c

#ifndef lint
static char sccsid[] = "@(#)getwd.c     5.3 (Berkeley) %G%";
#endif

#include "uucp.h"

/*
 *      get working directory
 *
 *      return codes  SUCCESS | FAIL
 */

gwd(wkdir)
register char *wkdir;
{
        register FILE *fp;
        extern FILE *rpopen();
        extern int rpclose();
        register char *c;

#ifdef BSD4_2
        if (getwd(wkdir) == 0)
                return FAIL;
#else !BSD4_2
# ifdef VMS
        getwd(wkdir);   /* Call Eunice C library version instead */
#else !VMS
        *wkdir = '\0';
        if ((fp = rpopen("PATH=/bin:/usr/bin:/usr/ucb;pwd 2>&-", "r")) == NULL)
                return FAIL;
        if (fgets(wkdir, 100, fp) == NULL) {
                rpclose(fp);
                return FAIL;
        }
        if (*(c = wkdir + strlen(wkdir) - 1) == '\n')
                *c = '\0';
        rpclose(fp);
# endif !VMS
#endif !BSD4_2
        return SUCCESS;
}

/*
 * gwd uses 'reverting' version of popen
 * which runs process with permissions of real gid/uid
 * rather than the effective gid/uid.
 */
#include <signal.h>
#define tst(a,b)        (*mode == 'r'? (b) : (a))
#define RDR     0
#define WTR     1
static  int     popen_pid[20];

FILE *
rpopen(cmd,mode)
char    *cmd;
char    *mode;
{
        int p[2];
        register myside, hisside, pid;

        if(pipe(p) < 0)
                return NULL;
        myside = tst(p[WTR], p[RDR]);
        hisside = tst(p[RDR], p[WTR]);
        if((pid = fork()) == 0) {
                /* myside and hisside reverse roles in child */
                close(myside);
                dup2(hisside, tst(0, 1));
                close(hisside);
                /* revert permissions */
                setgid(getgid());
                setuid(getuid());
                execl("/bin/sh", "sh", "-c", cmd, (char *)0);
                _exit(1);
        }
        if(pid == -1)
                return NULL;
        popen_pid[myside] = pid;
        close(hisside);
        return(fdopen(myside, mode));
}

rpclose(ptr)
FILE *ptr;
{
        register f, r, (*hstat)(), (*istat)(), (*qstat)();
        int status;

        f = fileno(ptr);
        fclose(ptr);
        istat = signal(SIGINT, SIG_IGN);
        qstat = signal(SIGQUIT, SIG_IGN);
        hstat = signal(SIGHUP, SIG_IGN);
        while((r = wait(&status)) != popen_pid[f] && r != -1)
                ;
        if(r == -1)
                status = -1;
        signal(SIGINT, istat);
        signal(SIGQUIT, qstat);
        signal(SIGHUP, hstat);
        return status;
}