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Annotation of 42BSD/usr.lib/libU77/system_.c, revision 1.1.1.1

1.1       root        1: /*
                      2: char id_system[] = "@(#)system_.c      1.5";
                      3:  *
                      4:  * execute a unix command
                      5:  *
                      6:  * calling sequence:
                      7:  *     iexit = system(command)
                      8:  * where:
                      9:  *     iexit will return the exit status of the command
                     10:  *     command is a character string containing the command to be executed
                     11:  */
                     12: 
                     13: #include       "../libI77/fiodefs.h"
                     14: #include       "../libI77/f_errno.h"
                     15: #include <sys/param.h>
                     16: #ifndef        NCARGS
                     17: #define NCARGS 256
                     18: #endif
                     19: 
                     20:  
                     21: long system_(s, n)
                     22: char *s;
                     23: long n;
                     24: {
                     25:        char buf[NCARGS - 50];
                     26:        long i;
                     27: 
                     28:        if (n >= sizeof buf)
                     29:                return(-(long)(errno=F_ERARG));
                     30:        for (i = 0; i < MXUNIT; i++)
                     31:                flush_(&i);
                     32:        g_char(s, n, buf);
                     33:        return((long)system(buf));
                     34: }
                     35: 
                     36: /*
                     37:  * this is a sane version of the libc/stdio routine.
                     38:  */
                     39: 
                     40: #include       <signal.h>
                     41: 
                     42: char   *getenv();
                     43: char   *rindex();
                     44: 
                     45: system(s)
                     46: char *s;
                     47: {
                     48:        register int (*istat)(), (*qstat)();
                     49:        int status, pid, w;
                     50:        char    *shname, *shell;
                     51: 
                     52:        if ((shell = getenv("SHELL")) == NULL)
                     53:                shell = "/bin/sh";
                     54: 
                     55:        if (shname = rindex(shell, '/'))
                     56:                shname++;
                     57:        else
                     58:                shname = shell;
                     59: 
                     60:        if ((pid = fork()) == 0) {
                     61:                execl(shell, shname, "-c", s, 0);
                     62:                _exit(127);
                     63:        }
                     64:        istat = signal(SIGINT, SIG_IGN);
                     65:        qstat = signal(SIGQUIT, SIG_IGN);
                     66:        while ((w = wait(&status)) != pid && w != -1)
                     67:                ;
                     68:        if (w == -1)
                     69:                status = -1;
                     70:        signal(SIGINT, istat);
                     71:        signal(SIGQUIT, qstat);
                     72:        return(status);
                     73: }

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