Category : UNIX Files
Archive   : PC-MAIL2.ZIP
Filename : PATH.C

/*++
/* NAME
/* path 3
/* SUMMARY
/* system-dependent file name stuff
/* PROJECT
/* pc-mail
/* PACKAGE
/* general
/* SYNOPSIS
/* #include "str.h"
/* #include "path.h"
/*
/* int pathinit()
/*
/* FILE *propen()
/*
/* char *fspool(file)
/* char *file;
/* DESCRIPTION
/* The routines in this module know the system-dependent rules
/* for file names and printers.
/*
/* pathinit() extracts the values of the environment variables
/* MAILDIR, MAILPRN, MAILCMD and EDITOR, and assumes system-dependent
/* defaults for undefined environment variables. It checks for the
/* existence of the spool directory.
/*
/* Under Unix, the MAILPRN environment variable should be the name
/* of a command. Under MS-DOS, it should be the name of a device or file.
/*
/* propen() returns a stream to print to.
/*
/* fspool() constructs a path name from the spool directory and
/* the file name in its argument.
/* Real unix uses uucp spool file names of the form
/*
/* .
/*
/* This is problematic for MS-DOS and similar systems that
/* only allow three characters after the dot. Instead of building
/* a tiny file system on top of MS-DOS, the pc-mail programs
/* use a different way of spool file naming:
/*
/*
/*
/* This scheme assumes that the pc has access to exactly one unix
/* host, since the host name is not part of spool file names.
/* COMMANDS
/* lp(1) (under unix) printer spooler program
/* FILES
/* PRN under MS-DOS
/* DIAGNOSTICS
/* pathinit() returns a nonzero value (see status(5)) if one of the
/* environment variables (or defaults) are incorrect.
/*
/* File open functions return a null pointer when a file could not
/* be opened.
/* BUGS
/* pathinit() only verifies the MAILDIR name.
/*
/* fspool() returns a pointer to static memory.
/* AUTHOR(S)
/* W.Z. Venema
/* Eindhoven University of Technology
/* Department of Mathematics and Computer Science
/* Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
/* CREATION DATE
/* Sun Apr 5 15:27:37 GMT+1:00 1987
/* LAST MODIFICATION
/* 90/01/22 13:02:26
/* VERSION/RELEASE
/* 2.1
/*--*/

#include
#include
#include "defs.h"
#include "path.h"
#include "status.h"

/*
* Environment variables are loaded here. Most of them have a default; We
* only check the validity of the MAILDIR variable.
*/

public char *maildir = DEFSPOOL; /* spool directory */
public char *editor = DEFEDIT; /* editor program */
public char *mailprn = DEFPRINT; /* where to print to */
public char *mailcmd = 0; /* do this on exit */

typedef struct {
char *vname;
char **ptr;
} Environ;

static Environ env[] = {
"SPOOL", &maildir, /* backwards compatibility... */
"MAILDIR", &maildir,
"EDITOR", &editor,
"MAILPRN", &mailprn,
"MAILCMD", &mailcmd,
0, 0, /* terminator */
};

/* pathinit - consult the environment; checks existence of spool directory */

public int pathinit()
{
register char *cp;
struct stat s;
register Environ *ep;

/* load environment variables */

for (ep = env; ep->vname; ep++)
if (cp = getenv(ep->vname))
*(ep->ptr) = cp;

/* check existence of the spool directory */

return (stat(maildir, &s) || (s.st_mode & S_IFMT) != S_IFDIR ? E_NOSPOOL : 0);
}