libexec/cron/popen.c

   1 /*
   2  * Copyright (c) 1988 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software written by Ken Arnold and
   6  * published in UNIX Review, Vol. 6, No. 8.
   7  *
   8  * Redistribution and use in source and binary forms are permitted
   9  * provided that the above copyright notice and this paragraph are
  10  * duplicated in all such forms and that any documentation,
  11  * advertising materials, and other materials related to such
  12  * distribution and use acknowledge that the software was developed
  13  * by the University of California, Berkeley.  The name of the
  14  * University may not be used to endorse or promote products derived
  15  * from this software without specific prior written permission.
  16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  19  *
  20  */
  21
  22 /* this came out of the ftpd sources; it's been modified to avoid the
  23  * globbing stuff since we don't need it.  also execvp instead of execv.
  24  */
  25
  26 #ifndef lint
  27 static char rcsid[] = "$Id: popen.c,v 1.1 1994/01/05 20:40:15 jtc Exp $";
  28 static char sccsid[] = "@(#)popen.c     5.7 (Berkeley) 2/14/89";
  29 #endif /* not lint */
  30
  31 #include "cron.h"
  32 #include "externs.h"
  33 #include <sys/signal.h>
  34
  35
  36 #define WANT_GLOBBING 0
  37
  38 /*
  39  * Special version of popen which avoids call to shell.  This insures noone
  40  * may create a pipe to a hidden program as a side effect of a list or dir
  41  * command.
  42  */
  43 static int *pids;
  44 static int fds;
  45
  46 FILE *
  47 cron_popen(program, type)
  48         char *program, *type;
  49 {
  50         register char *cp;
  51         FILE *iop;
  52         int argc, pdes[2], pid;
  53         char *argv[100];
  54 #if WANT_GLOBBING
  55         char **pop, *vv[2];
  56         int gargc;
  57         char *gargv[1000];
  58         extern char **glob(), **copyblk();
  59 #endif
  60
  61         if (*type != 'r' && *type != 'w' || type[1])
  62                 return(NULL);
  63
  64         if (!pids) {
  65                 if ((fds = getdtablesize()) <= 0)
  66                         return(NULL);
  67                 if ((pids = (int *)malloc((u_int)(fds * sizeof(int)))) == NULL)
  68                         return(NULL);
  69                 bzero((char *)pids, fds * sizeof(int));
  70         }
  71         if (pipe(pdes) < 0)
  72                 return(NULL);
  73
  74         /* break up string into pieces */
  75         for (argc = 0, cp = program;; cp = NULL)
  76                 if (!(argv[argc++] = strtok(cp, " \t\n")))
  77                         break;
  78
  79 #if WANT_GLOBBING
  80         /* glob each piece */
  81         gargv[0] = argv[0];
  82         for (gargc = argc = 1; argv[argc]; argc++) {
  83                 if (!(pop = glob(argv[argc]))) {        /* globbing failed */
  84                         vv[0] = argv[argc];
  85                         vv[1] = NULL;
  86                         pop = copyblk(vv);
  87                 }
  88                 argv[argc] = (char *)pop;               /* save to free later */
  89                 while (*pop && gargc < 1000)
  90                         gargv[gargc++] = *pop++;
  91         }
  92         gargv[gargc] = NULL;
  93 #endif
  94
  95         iop = NULL;
  96         switch(pid = vfork()) {
  97         case -1:                        /* error */
  98                 (void)close(pdes[0]);
  99                 (void)close(pdes[1]);
 100                 goto pfree;
 101                 /* NOTREACHED */
 102         case 0:                         /* child */
 103                 if (*type == 'r') {
 104                         if (pdes[1] != 1) {
 105                                 dup2(pdes[1], 1);
 106                                 dup2(pdes[1], 2);       /* stderr, too! */
 107                                 (void)close(pdes[1]);
 108                         }
 109                         (void)close(pdes[0]);
 110                 } else {
 111                         if (pdes[0] != 0) {
 112                                 dup2(pdes[0], 0);
 113                                 (void)close(pdes[0]);
 114                         }
 115                         (void)close(pdes[1]);
 116                 }
 117 #if WANT_GLOBBING
 118                 execvp(gargv[0], gargv);
 119 #else
 120                 execvp(argv[0], argv);
 121 #endif
 122                 _exit(1);
 123         }
 124         /* parent; assume fdopen can't fail...  */
 125         if (*type == 'r') {
 126                 iop = fdopen(pdes[0], type);
 127                 (void)close(pdes[1]);
 128         } else {
 129                 iop = fdopen(pdes[1], type);
 130                 (void)close(pdes[0]);
 131         }
 132         pids[fileno(iop)] = pid;
 133
 134 pfree:
 135 #if WANT_GLOBBING
 136         for (argc = 1; argv[argc] != NULL; argc++) {
 137 /*              blkfree((char **)argv[argc]);   */
 138                 free((char *)argv[argc]);
 139         }
 140 #endif
 141         return(iop);
 142 }
 143
 144 int
 145 cron_pclose(iop)
 146         FILE *iop;
 147 {
 148         register int fdes;
 149         int omask;
 150         WAIT_T stat_loc;
 151         int pid;
 152
 153         /*
 154          * pclose returns -1 if stream is not associated with a
 155          * `popened' command, or, if already `pclosed'.
 156          */
 157         if (pids == 0 || pids[fdes = fileno(iop)] == 0)
 158                 return(-1);
 159         (void)fclose(iop);
 160         omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
 161         while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1)
 162                 ;
 163         (void)sigsetmask(omask);
 164         pids[fdes] = 0;
 165         return (pid == -1 ? -1 : WEXITSTATUS(stat_loc));
 166 }