spawn.c

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#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "alloc.h"
#include "sig.h"
#include "wait.h"
#include "buffer.h"
#include "byte.h"
#include "str.h"
#include "stralloc.h"
#include "select.h"
#include "exit.h"
#include "fd.h"
#include "open.h"
#include "error.h"
#include "auto_qmail.h"
#include "auto_uids.h"
#include "auto_spawn.h"
 
extern int truncreport;
extern int spawn();
extern void report();
extern void initialize();
 
struct delivery
 {
  int used;
  int fdin; /* pipe input */
  int pid; /* zero if child is dead */
  int wstat; /* if !pid: status of child */
  int fdout; /* pipe output, -1 if !pid; delays eof until after death */
  stralloc output;
 }
;
 
struct delivery *d;
 
void sigchld()
{
  int wstat;
  int pid;
  int i;
 
  while ((pid = wait_nohang(&wstat)) > 0)
    for (i = 0; i < auto_spawn; ++i) 
      if (d[i].used)
        if (d[i].pid == pid) {
          close(d[i].fdout); d[i].fdout = -1;
          d[i].wstat = wstat; d[i].pid = 0;
        }
} 
 
int flagwriting = 1;
 
ssize_t okwrite(int fd,char *buf,int n)
{
  int w;
  if (!flagwriting) return n;
  w = write(fd,buf,n);
  if (w != -1) return w;
  if (errno == EINTR) return -1;
  flagwriting = 0; close(fd);
  return n;
}
 
int flagreading = 1;
char outbuf[1024]; 
buffer bo;
 
int stage = 0; /* reading 0:delnum 1:messid 2:sender 3:recip */
int flagabort = 0; /* if 1, everything except delnum is garbage */
int delnum;
stralloc messid = {0};
stralloc sender = {0};
stralloc recip = {0};
 
void err(char *s)
{
  char ch; 
 
  ch = delnum; 
  buffer_put(&bo,&ch,1);
  buffer_puts(&bo,s); 
  buffer_putflush(&bo,"",1);
}
 
void docmd()
{
  int f;
  int i;
  int j;
  int fdmess;
  int pi[2];
  struct stat st;
 
  if (flagabort) { err("Zqmail-spawn: Out of memory. (#4.3.0)\n"); return; }
  if (delnum < 0) { err("Zqmail-spawn: Internal error: delnum negative. (#4.3.5)\n"); return; }
  if (delnum >= auto_spawn) { err("Zqmail-spawn: Internal error: delnum too big. (#4.3.5)\n"); return; }
  if (d[delnum].used) { err("Zqmail-spawn: Internal error: delnum in use. (#4.3.5)\n"); return; }
 
  for (i = 0; i < messid.len; ++i)
    if (messid.s[i])
      if (!i || (messid.s[i] != '/'))
        if ((unsigned char) (messid.s[i] - '0') > 9)
          { err("Dqmail-spawn: Internal error: messid has nonnumerics. (#5.3.5)\n"); return; }
 
  if (messid.len > 100) { err("Dqmail-spawn: Internal error: messid too long. (#5.3.5)\n"); return; }
  if (!messid.s[0]) { err("Dqmail-spawn: Internal error: messid too short. (#5.3.5)\n"); return; }
 
  if (!stralloc_copys(&d[delnum].output,""))
   { err("Zqmail-spawn: Out of memory. (#4.3.0)\n"); return; }
 
  j = byte_rchr(recip.s,recip.len,'@');
  if (j >= recip.len) { err("DSorry, address must include host name. (#5.1.3)\n"); return; }
 
  fdmess = open_read(messid.s);
  if (fdmess == -1) { err("Zqmail-spawn: Unable to open message. (#4.3.0)\n"); return; }
 
  if (fstat(fdmess,&st) == -1)
    { close(fdmess); err("Zqmail-spawn: Unable to fstat message. (#4.3.0)\n"); return; }
  if ((st.st_mode & S_IFMT) != S_IFREG)
    { close(fdmess); err("ZSorry, message has wrong type. (#4.3.5)\n"); return; }
  if (st.st_uid != auto_uidq) /* aaack! qmailq has to be trusted! */
   /* your security is already toast at this point. damage control... */
    { close(fdmess); err("ZSorry, message has wrong owner. (#4.3.5)\n"); return; }
 
  if (pipe(pi) == -1) {
    if (errno == EFAULT) err("Zqmail-spawn: Unable to create pipe (wrong fildes). (#4.3.0)\n"); 
    else if (errno == EMFILE) err("Zqmail-spawn: Unable to create pipe (too many FDS). (#4.3.0)\n"); 
    else if (errno == ENFILE) err("Zqmail-spawn: Unable to create pipe (system file table full). (#4.3.0)\n"); 
    else if (errno == ENOMEM) err("Zqmail-spawn: Unable to create pipe (out of memory). (#4.3.0)\n"); 
    else err("Zqmail-spawn: Unable to create pipe (unkown reason). (#4.3.0)\n"); 
    close(fdmess); 
    return; 
  }
 
  fd_coe(pi[0]);
 
  f = spawn(fdmess,pi[1],sender.s,recip.s,j);
  close(fdmess);
 
  if (f == -1)
    { close(pi[0]); close(pi[1]); err("Zqmail-spawn: Unable to fork. (#4.3.0)\n"); return; }
 
  d[delnum].fdin = pi[0];
  d[delnum].fdout = pi[1]; fd_coe(pi[1]);
  d[delnum].pid = f;
  d[delnum].used = 1;
}
 
char cmdbuf[1024];
 
void getcmd()
{
  int i;
  int r;
  char ch;
 
  r = read(0,cmdbuf,sizeof(cmdbuf));
  if (r == 0)
    { flagreading = 0; return; }
  if (r == -1) {
    if (errno != EINTR)
      flagreading = 0;
    return;
  }
 
  for (i = 0; i < r; ++i) {
    ch = cmdbuf[i];
    switch (stage) {
      case 0:
        delnum = (unsigned int) (unsigned char) ch;
        messid.len = 0; stage = 1; break;
      case 1:
        if (!stralloc_append(&messid,&ch)) flagabort = 1;
        if (ch) break;
        sender.len = 0; stage = 2; break;
      case 2:
        if (!stralloc_append(&sender,&ch)) flagabort = 1;
        if (ch) break;
        recip.len = 0; stage = 3; break;
      case 3:
        if (!stralloc_append(&recip,&ch)) flagabort = 1;
        if (ch) break;
        docmd();
        flagabort = 0; stage = 0; break;
    }
  }
}
 
char inbuf[128];
 
int main(int argc,char **argv)
{
  char ch;
  int i;
  int r;
  fd_set rfds;
  int nfds;
 
  if (chdir(auto_qmail) == -1) _exit(110);
  if (chdir("queue/mess") == -1) _exit(110);
  if (!stralloc_copys(&messid,"")) _exit(111);
  if (!stralloc_copys(&sender,"")) _exit(111);
  if (!stralloc_copys(&recip,"")) _exit(111);
 
  d = (struct delivery *) alloc((auto_spawn + 10) * sizeof(struct delivery));
  if (!d) _exit(111);
 
  buffer_init(&bo,okwrite,1,outbuf,sizeof(outbuf));
 
  sig_pipeignore();
  sig_childcatch(sigchld);
 
  initialize(argc,argv);
 
  ch = auto_spawn; 
  buffer_putflush(&bo,&ch,1);
 
  for (i = 0; i < auto_spawn; ++i) 
    { d[i].used = 0; d[i].output.s = 0; }
 
  for (;;) {
    if (!flagreading) {
      for (i = 0; i < auto_spawn; ++i) if (d[i].used) break;
      if (i >= auto_spawn) _exit(0);
    }
    sig_childunblock();
 
    FD_ZERO(&rfds);
    if (flagreading) FD_SET(0,&rfds);
    nfds = 1;
 
    for (i = 0; i < auto_spawn; ++i) 
      if (d[i].used) { 
        FD_SET(d[i].fdin,&rfds); 
        if (d[i].fdin >= nfds) 
          nfds = d[i].fdin + 1; 
      }
 
    r = select(nfds,&rfds,(fd_set *) 0,(fd_set *) 0,(struct timeval *) 0);
    sig_childblock();
 
    if (r != -1) {
      if (flagreading)
        if (FD_ISSET(0,&rfds)) getcmd();
      for (i = 0; i < auto_spawn; ++i) 
        if (d[i].used)
 
      if (FD_ISSET(d[i].fdin,&rfds)) {
        r = read(d[i].fdin,inbuf,128);
        if (r == -1)
           continue; /* read error on a readable pipe? be serious */
        if (r == 0) {
          ch = i; 
          buffer_put(&bo,&ch,1);
          report(&bo,d[i].wstat,d[i].output.s,d[i].output.len);
          buffer_put(&bo,"",1);
          buffer_flush(&bo);
          close(d[i].fdin); d[i].used = 0;
          continue;
        }
        while (!stralloc_readyplus(&d[i].output,r)) 
          sleep(10); /*XXX*/
        byte_copy(d[i].output.s + d[i].output.len,r,inbuf);
        d[i].output.len += r;
        if (truncreport > 100)
          if (d[i].output.len > truncreport) {
            char *truncmess = "\nError report too long, sorry.\n";
            d[i].output.len = truncreport - str_len(truncmess) - 3;
            stralloc_cats(&d[i].output,truncmess);
          }
      }
    }
  }
}