OpenStep 4.2J (Developer)/os42jdev.iso/NextDeveloper/Source/GNU/uucp/Uucp.framework/contrib/dialHDB.c

C/C++ Source or Header | 1994-01-30 | 5.0 KB | 188 lines

/*
# File:        dialHDB.c
# Author:    Daniel Hagerty , [e-mail]
#        Copyright (C) 1993
# Date:        Fri Nov 26 19:22:31 1993
# Description:    Program for using HDB dialers for dialing modems, exiting
        with 0 on success, else failure.
# Version:    1.0
# Revision History:
######
### 11/26/93 Hag - File creation
######
### 1/5/94 Hag - Finally got around to finishing this damn thing.
######
*/
/* Basic theory behind this program-
   dialHDB forks into two processes, a monitor parent, and a child
   that does the exec of the dialer. Child pretty much just execs the
   dialer program, unless there's an exec problem, in which case the
   child sends the parent a SIGUSR1 to indicate failed execution.
*/

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>

#define kUsage    "Usage:\n\t%s dialerPath device number speed\n\
%s dialer -h device speed\n"

#define kExitErrFlag    0x80    /* & in with exit code to determine error */
#define kErrorMask    0x0f    /* Mask to determine error code */

/* Error code defines as lifted from an HDB dialer */
#define    RCE_NULL    0    /* general purpose or unknown error code */
#define    RCE_INUSE    1    /* line in use */
#define    RCE_SIG        2    /* signal aborted dialer */
#define    RCE_ARGS    3    /* invalid arguments */
#define    RCE_PHNO    4    /* invalid phone number */
#define    RCE_SPEED    5    /* invalid baud rate -or- bad connect baud */
#define    RCE_OPEN    6    /* can't open line */
#define    RCE_IOCTL    7    /* ioctl error */
#define    RCE_TIMOUT    8    /* timeout */
#define    RCE_NOTONE    9    /* no dial tone */
#define    RCE_BUSY    13    /* phone is busy */
#define    RCE_NOCARR    14    /* no carrier */
#define    RCE_ANSWER    15    /* no answer */

/* Structure definition to map error codes to strings */
typedef struct
{
  int errNum;
  char *errString;
} errTable;

const errTable errors[]=
{
  { RCE_NULL,    "Unknown Error" },
  { RCE_INUSE,    "Line is being used" },
  { RCE_SIG,    "Recieved fatal signal" },
  { RCE_ARGS,    "Bad arguments" },
  { RCE_PHNO,    "Invalid phone number" },
  { RCE_SPEED,    "Invalid baud rate or bad connection" },
  { RCE_OPEN,    "Unable to open line" },
  { RCE_IOCTL,    "ioctl error" },
  { RCE_TIMOUT,    "Timed out" },
  { RCE_NOTONE,    "No dialtone" },
  { RCE_BUSY,    "Phone number is busy" },
  { RCE_NOCARR,    "No carrier" },
  { RCE_ANSWER,    "No answer" },
  { 0,NULL}
};

/* Function Prototypes */
int figureStat(int stat);
char *findInTable(int error);
void badExec(void);

char *dialerName;        /* basename of our dialer program */
char *dialerPath;        /* full path of dialer program */

main(int argc,char *argv[])
{
  int parent;            /* pid of parent process */
  int child;            /* pid of child process */
  int stat;            /* exit status of child process */
  char *temp;            /* used to get basename of dialer */

  if(argc!=5)
  {
    fprintf(stderr,kUsage,argv[0],argv[0]);
    exit(1);
  }

  dialerPath=argv[1];
  dialerName= (temp=strrchr(argv[1],'/'))!=NULL ? temp+1 : argv[1];

  parent=getpid();

  signal(SIGUSR1,badExec);    /* set up for possible failed exec */

  if((child=fork())<0)
  {
    perror("fork");
    exit(2);
  }
  if(child>0)            /* We're parent, wait for child to exit */
  {
    /* Set up to ignore signals so we can report them on stderror */
    signal(SIGHUP,SIG_IGN);
    signal(SIGINT,SIG_IGN);
    signal(SIGTERM,SIG_IGN);

    wait(&stat);        /* wait for child to exit */
    exit(figureStat(stat));    /* figure out our exit code and die */
  }
  else                /* child process */
  {
    close(0);            /* close of modem file desc, since HDB */
    close(1);            /* doesn't use them */
    dup2(2,1);            /* and remap stdout to stderr, just in case */
    if(execvp(argv[1],argv+1)<0) /* exec program with argv shifted by 1 */
    {                /* if exec fails, send SIGUSR1 to parent */
      kill(parent,SIGUSR1);
      exit(0);
    }
  }
  exit(0);
}

/* Figure out whether or not dialer ran succesfully, and return
with 0 if it worked, otherwise error */
int figureStat(int stat)
{
  int exit;
  int errFlag;
  int error;

  if(WIFSIGNALED(stat))        /* determine if exit was from signal or what */
  {
    fprintf(stderr,"Error: Dialer %s recieved signal %d.\n",dialerName,
        WTERMSIG(stat));
    return(1);
  }
  if(WIFSTOPPED(stat))
  {
    fprintf(stderr,"Error: Dialer %s recieved signal %d.\n",dialerName,
        WSTOPSIG(stat));
    return(1);
  }
  exit=WEXITSTATUS(stat);

  errFlag=exit&kExitErrFlag;    /* Is the error flag set? */
  if(errFlag)
  {
    char *errString;

    error=exit&kErrorMask;
    errString=findInTable(error); /* find it's string, print it on stderr */
    fprintf(stderr,"Error: %s - %s.\n",dialerName,errString); /* and return */
    return(1);
  }
  return(0);
}

/* Support routine, look up exit code in error table, and return pointer
to proper string */
char *findInTable(int error)
{
  int i=0;

  for(i=0;errors[i].errString!=NULL;i++)
  {
    if(errors[i].errNum==error)
      return(errors[i].errString);
  }
  /* Still here, return the top entry, for unknown error */
  return(errors[0].errString);
}

/* Called by signal if we recieve SIGUSR 1 */
void badExec(void)
{
  fprintf(stderr,"Error: %s - Execution problem.\n",dialerPath);
  exit(1);
}