/*
 * smtpconvo - hold an SMTP conversation
 *
 * smtpconvo [-v] [-raw] [-helo helo-as] server[/[port]] envelope-sender
 *	envelope-recipient [envelope-recipient ...] body-file
 *
 * body-file is expected to be already formatted as an 822/2822
 *  message; it should not have had the hidden-dot algorithm applied -
 *  smtpconvo will do hidden-dots.  body-file may use CRLF or NL line
 *  breaks; smtpconvo will convert to CRLF for transmission if
 *  necessary.  (-raw suppresses the conversion to CRLF.)
 */

#include <stdio.h>
#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/param.h>
#include <sys/socket.h>

extern const char *__progname;

static int verbose = 0;
static int rawflag = 0;
static const char *helo_as = 0;

static struct addrinfo *servaddrs;
static const char *sender;
static const char * const *recips;
static int nrecip;
static const char *bodyfile;
static FILE *bodyf;
static int s;
static char *lastsmtpsend;
static unsigned char srbuf[8192];
static int srfill;
static int srptr;

static void usage(void) __attribute__((__noreturn__));
static void usage(void)
{
 printf("Usage: %s [-v] [-raw] [-helo helo-as] server[/port] sender recip [recip [recip ...]] bodyfile\n",__progname);
 exit(1);
}

static void setserver(char *arg)
{
 char *slash;
 int i;
 const char *portstr;
 struct addrinfo hints;

 slash = rindex(arg,'/');
 if (slash)
  { *slash++ = '\0';
    portstr = slash;
  }
 else
  { portstr = "smtp";
  }
 hints.ai_flags = 0;
 hints.ai_family = PF_UNSPEC;
 hints.ai_socktype = SOCK_STREAM;
 hints.ai_protocol = 0;
 hints.ai_addrlen = 0;
 hints.ai_canonname = 0;
 hints.ai_addr = 0;
 hints.ai_next = 0;
 i = getaddrinfo(arg,portstr,&hints,&servaddrs);
 if (i)
  { fprintf(stderr,"%s: %s/%s: %s\n",__progname,arg,portstr,gai_strerror(i));
    usage();
  }
}

static void setbodyfile(const char *name)
{
 bodyfile = name;
 bodyf = fopen(name,"r");
 if (bodyf == 0)
  { fprintf(stderr,"%s: %s: %s\n",__progname,name,strerror(errno));
    usage();
  }
}

static void makeconn(void)
{
 struct addrinfo *ai;
 int printederr;
 char hn[NI_MAXHOST];
 char pn[NI_MAXSERV];
 char *txt;

 printederr = 0;
 for (ai=servaddrs;ai;ai=ai->ai_next)
  { s = socket(ai->ai_family,ai->ai_socktype,ai->ai_protocol);
    if (s < 0)
     { if (errno != EPROTONOSUPPORT)
	{ fprintf(stderr,"%s: socket (af%d): %s\n",__progname,ai->ai_family,strerror(errno));
	  printederr = 1;
	}
       continue;
     }
    if (getnameinfo(ai->ai_addr,ai->ai_addrlen,&hn[0],NI_MAXHOST,&pn[0],NI_MAXSERV,NI_NUMERICHOST|NI_NUMERICSERV))
     { asprintf(&txt,"[can't get text form for af%d: %s]",ai->ai_family,strerror(errno));
     }
    else
     { asprintf(&txt,"%s/%s",&hn[0],&pn[0]);
     }
    if (verbose) printf("Connect to %s...",txt);
    if (connect(s,ai->ai_addr,ai->ai_addrlen) >= 0)
     { if (verbose) printf("success\n");
       if (printederr)
	{ fprintf(stderr,"%s: success\n",txt);
	  free(txt);
	}
       srfill = 0;
       srptr = 0;
       return;
     }
    if (verbose)
     { printf("%s\n",strerror(errno));
     }
    else
     { fprintf(stderr,"%s: connect to %s: %s\n",__progname,txt,strerror(errno));
       printederr = 1;
     }
  }
 exit(1);
}

static int srchr(void)
{
 if (srptr >= srfill)
  { srfill = read(s,&srbuf[0],sizeof(srbuf));
    if (srfill < 0)
     { fprintf(stderr,"%s: network read error: %s\n",__progname,strerror(errno));
       exit(1);
     }
    if (srfill == 0)
     { fprintf(stderr,"%s: unexpected network EOF\n",__progname);
       exit(1);
     }
    srptr = 0;
  }
 return(srbuf[srptr++]);
}

static void fprint_pref(FILE *f, const char *s, const char *pref)
{
 int atnl;

 atnl = 1;
 while (*s)
  { if ((s[0] == '\r') && (s[1] == '\n'))
     { fprintf(f,"\n");
       atnl = 1;
       s += 2;
       continue;
     }
    if (atnl) fprintf(f,"%s",pref);
    atnl = 0;
    putc(*s,f);
    s ++;
  }
 if (! atnl) fprintf(f,"\n");
}

static void getreply(void (*chk)(char *reply))
{
 int curcol;
 static char *resp = 0;
 static int ralloc = 0;
 int rlen;
 int c;
 int lastcc0;

 static void savec(int c)
  { if (rlen >= ralloc) resp = realloc(resp,ralloc=rlen+16);
    resp[rlen++] = c;
  }

 rlen = 0;
 curcol = 0;
 while (1)
  { c = srchr();
    if (curcol == 0) lastcc0 = rlen;
    savec(c);
    curcol ++;
    if ((c == '\n') && (rlen > 1) && (resp[rlen-2] == '\r'))
     { if ((rlen-lastcc0 > 4) && (resp[lastcc0+3] == ' '))
	{ savec(0);
	  if (verbose) fprint_pref(stdout,resp,"<<< ");
	  (*chk)(resp);
	  return;
	}
       curcol = 0;
     }
  }
}

static void smtpsend(const char *, ...)
	__attribute__((__format__(__printf__,1,2)));
static void smtpsend(const char *fmt, ...)
{
 va_list ap;
 int lsslen;
 FILE *f;

 static int wf(void *cookie __attribute__((__unused__)), const char *data, int len)
  { lastsmtpsend = realloc(lastsmtpsend,lsslen+len+1);
    bcopy(data,lastsmtpsend+lsslen,len);
    lsslen += len;
    return(write(s,data,len));
  }

 free(lastsmtpsend);
 lastsmtpsend = malloc(1);
 lsslen = 0;
 f = fwopen(0,&wf);
 va_start(ap,fmt);
 vfprintf(f,fmt,ap);
 va_end(ap);
 fprintf(f,"\r\n");
 fclose(f);
 lastsmtpsend[lsslen] = '\0';
 if (verbose) fprint_pref(stdout,lastsmtpsend,">>> ");
}

static void mustbe2xx(char *resp)
{
 if (resp[0] != '2')
  { if (verbose)
     { fprintf(stderr,"%s: SMTP error\n",__progname);
     }
    else
     { fprintf(stderr,"%s: SMTP error:\n",__progname);
       if (lastsmtpsend) fprint_pref(stderr,lastsmtpsend,">>> ");
       fprint_pref(stderr,resp,"<<< ");
     }
    exit(1);
  }
}

static void mustbe354(char *resp)
{
 if (strncmp(resp,"354",3))
  { if (verbose)
     { fprintf(stderr,"%s: SMTP error\n",__progname);
     }
    else
     { fprintf(stderr,"%s: SMTP error:\n",__progname);
       if (lastsmtpsend) fprint_pref(stderr,lastsmtpsend,">>> ");
       fprint_pref(stderr,resp,"<<< ");
     }
    exit(1);
  }
}

static void copydata(void)
{
 int c;
 int pc;
 int ppc;
 FILE *sw;

 static int wf(void *cookie __attribute__((__unused__)), const char *data, int len)
  { return(write(s,data,len));
  }

 pc = '\r';
 c = '\n';
 sw = fwopen(0,wf);
 while (1)
  { ppc = pc;
    pc = c;
    c = getc(bodyf);
    if (c == EOF) break;
    if ((c == '.') && (pc == '\n') && (ppc == '\r')) putc('.',sw);
    if ((c == '\n') && (pc != '\r') && !rawflag)
     { ppc = pc;
       pc = '\r';
       putc('\r',sw);
     }
    putc(c,sw);
  }
 if ((pc != '\n') || (ppc != '\r'))
  { putc('\r',sw);
    putc('\n',sw);
  }
 fclose(sw);
}

static void protocol(void)
{
 char hn[MAXHOSTNAMELEN];
 int i;
 int ngood;

 static void rcptchk(char *resp)
  { switch (resp[0])
     { case '2':
	  ngood ++;
	  break;
       case '4':
       case '5':
	  if (verbose)
	   { fprintf(stderr,"%s: SMTP error\n",__progname);
	   }
	  else
	   { fprintf(stderr,"%s: recipient rejected:\n",__progname);
	     if (lastsmtpsend) fprint_pref(stderr,lastsmtpsend,">>> ");
	     fprint_pref(stderr,resp,"<<< ");
	   }
	  break;
       default:
	  if (verbose)
	   { fprintf(stderr,"%s: SMTP error\n",__progname);
	   }
	  else
	   { fprintf(stderr,"%s: SMTP error:\n",__progname);
	     if (lastsmtpsend) fprint_pref(stderr,lastsmtpsend,">>> ");
	     fprint_pref(stderr,resp,"<<< ");
	   }
	  exit(1);
	  break;
     }
  }

 lastsmtpsend = 0;
 getreply(&mustbe2xx);
 if (helo_as)
  { smtpsend("HELO %s",helo_as);
  }
 else
  { gethostname(&hn[0],MAXHOSTNAMELEN);
    hn[MAXHOSTNAMELEN-1] = '\0';
    smtpsend("HELO %s",&hn[0]);
  }
 getreply(&mustbe2xx);
 smtpsend("MAIL From:<%s>",sender);
 getreply(&mustbe2xx);
 ngood = 0;
 for (i=0;i<nrecip;i++)
  { smtpsend("RCPT To:<%s>",recips[i]);
    getreply(&rcptchk);
  }
 if (ngood < 1)
  { fprintf(stderr,"%s: all recipients rejected\n",__progname);
  }
 else
  { smtpsend("DATA");
    getreply(&mustbe354);
    copydata();
    smtpsend(".");
    getreply(&mustbe2xx);
  }
 smtpsend("QUIT");
 getreply(&mustbe2xx);
}

int main(int, char **);
int main(int ac, char **av)
{
 while (1)
  { if ((ac > 1) && !strcmp(av[1],"-v"))
     { ac --;
       av ++;
       verbose = 1;
       continue;
     }
    if ((ac > 1) && !strcmp(av[1],"-raw"))
     { ac --;
       av ++;
       rawflag = 1;
       continue;
     }
    if ((ac > 2) && !strcmp(av[1],"-helo"))
     { ac -= 2;
       av += 2;
       helo_as = av[0];
       continue;
     }
    break;
  }
 if (ac < 5) usage();
 setserver(av[1]);
 sender = av[2];
 nrecip = ac - 4;
 /* XXX why is char ** incompatible with const char * const *? */
 recips = (const void *)(av+3);
 setbodyfile(av[ac-1]);
 makeconn();
 protocol();
 exit(0);
}