path: root/src/spawn.c

#include "spawn.h"

#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "alloc.h"
#include "buffer.h"
#include "byte.h"
#include "error.h"
#include "exit.h"
#include "fd.h"
#include "open.h"
#include "select.h"
#include "sig.h"
#include "str.h"
#include "stralloc.h"
#include "wait.h"

#ifdef USE_CONFIG
  #include "fehsqm-config.h"
#else
  #include "auto_qmail.h"
  #include "auto_spawn.h"
  #include "auto_uids.h"
#endif

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;

static 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;

static 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};

static void err(char *s)
{
  char ch;

  ch = delnum;
  buffer_put(&bo, &ch, 1);
  buffer_puts(&bo, s);
  buffer_putflush(&bo, "", 1);
}

static 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];

static 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);
              }
          }
    }
  }
}