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/*
# File: dialHDB.c
# Author: Daniel Hagerty , hag@eddie.mit.edu
# 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);
}
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