--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mail.c	Sat Mar 03 14:59:04 2012 -0500
@@ -0,0 +1,508 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <urweb.h>
+
+struct headers {
+  uw_Basis_string from, to, cc, bcc, subject;
+};
+
+typedef struct headers *uw_Mail_headers;
+
+uw_Mail_headers uw_Mail_empty = NULL;
+
+static void header(uw_context ctx, uw_Basis_string s) {
+  if (strlen(s) > 100)
+    uw_error(ctx, FATAL, "Header value too long");
+
+  for (; *s; ++s)
+    if (*s == '\r' || *s == '\n')
+      uw_error(ctx, FATAL, "Header value contains newline");
+}
+
+static void address(uw_context ctx, uw_Basis_string s) {
+  header(ctx, s);
+
+  if (strchr(s, ','))
+    uw_error(ctx, FATAL, "E-mail address contains comma");
+}
+
+uw_Mail_headers uw_Mail_from(uw_context ctx, uw_Basis_string s, uw_Mail_headers h) {
+  // char **allowed = uw_get_global(ctx, "mail_from");
+  // Might add this policy checking (or some expanded version of it) back later.
+  uw_Mail_headers h2 = uw_malloc(ctx, sizeof(struct headers));
+
+  if (h)
+    *h2 = *h;
+  else
+    memset(h2, 0, sizeof(*h2));
+
+  if (h2->from)
+    uw_error(ctx, FATAL, "Duplicate From header");
+
+  /*
+  if (!allowed)
+    uw_error(ctx, FATAL, "No From address whitelist has been set.  Perhaps you are not authorized to send e-mail.");
+
+  if (!(allowed[0] && !strcmp(allowed[0], "*"))) {
+    for (; *allowed; ++allowed)
+      if (!strcmp(*allowed, s))
+        goto ok;
+
+    uw_error(ctx, FATAL, "From address is not in whitelist");
+  }
+
+ ok:
+  */
+  address(ctx, s);
+  h2->from = s;
+
+  return h2;
+}
+
+uw_Mail_headers uw_Mail_to(uw_context ctx, uw_Basis_string s, uw_Mail_headers h) {
+  uw_Mail_headers h2 = uw_malloc(ctx, sizeof(struct headers));
+  if (h)
+    *h2 = *h;
+  else
+    memset(h2, 0, sizeof(*h2));
+
+  address(ctx, s);
+  if (h2->to) {
+    uw_Basis_string all = uw_malloc(ctx, strlen(h2->to) + 1 + strlen(s));
+    sprintf(all, "%s,%s", h2->to, s);
+    h2->to = all;
+  } else
+    h2->to = s;
+
+  return h2;
+}
+
+uw_Mail_headers uw_Mail_cc(uw_context ctx, uw_Basis_string s, uw_Mail_headers h) {
+  uw_Mail_headers h2 = uw_malloc(ctx, sizeof(struct headers));
+  if (h)
+    *h2 = *h;
+  else
+    memset(h2, 0, sizeof(*h2));
+
+  address(ctx, s);
+  if (h2->cc) {
+    uw_Basis_string all = uw_malloc(ctx, strlen(h2->cc) + 1 + strlen(s));
+    sprintf(all, "%s,%s", h2->cc, s);
+    h2->cc = all;
+  } else
+    h2->cc = s;
+
+  return h2;
+}
+
+uw_Mail_headers uw_Mail_bcc(uw_context ctx, uw_Basis_string s, uw_Mail_headers h) {
+  uw_Mail_headers h2 = uw_malloc(ctx, sizeof(struct headers));
+  if (h)
+    *h2 = *h;
+  else
+    memset(h2, 0, sizeof(*h2));
+
+  address(ctx, s);
+  if (h2->bcc) {
+    uw_Basis_string all = uw_malloc(ctx, strlen(h2->bcc) + 1 + strlen(s));
+    sprintf(all, "%s,%s", h2->bcc, s);
+    h2->bcc = all;
+  } else
+    h2->bcc = s;
+
+  return h2;
+}
+
+uw_Mail_headers uw_Mail_subject(uw_context ctx, uw_Basis_string s, uw_Mail_headers h) {
+  uw_Mail_headers h2 = uw_malloc(ctx, sizeof(struct headers));
+
+  if (h)
+    *h2 = *h;
+  else
+    memset(h2, 0, sizeof(*h2));
+
+  if (h2->subject)
+    uw_error(ctx, FATAL, "Duplicate Subject header");
+
+  header(ctx, s);
+  h2->subject = s;
+
+  return h2;
+}
+
+typedef struct {
+  uw_context ctx;
+  uw_Mail_headers h;
+  uw_Basis_string body, xbody;
+} job;
+
+#define BUFLEN 1024
+
+static int smtp_read(uw_context ctx, int sock, char *buf, ssize_t *pos) {
+  char *s;
+
+  while (1) {
+    ssize_t recvd;
+
+    buf[*pos] = 0;
+  
+    if ((s = strchr(buf, '\n'))) {
+      int n;
+
+      *s = 0;
+
+      if (sscanf(buf, "%d ", &n) != 1) {
+        close(sock);
+        uw_set_error_message(ctx, "Mail server response does not begin with a code.");
+        return 0;
+      }
+
+      *pos -= s - buf + 1;
+      memmove(buf, s+1, *pos);
+
+      return n;
+    }
+
+    recvd = recv(sock, buf + *pos, BUFLEN - *pos - 1, 0);
+
+    if (recvd == 0) {
+      close(sock);
+      uw_set_error_message(ctx, "Mail server response ends unexpectedly.");
+      return 0;
+    } else if (recvd < 0) {
+      close(sock);
+      uw_set_error_message(ctx, "Error reading mail server response.");
+      return 0;
+    }
+
+    *pos += recvd;
+  }
+}
+
+static int really_string(int sock, const char *s) {
+  return uw_really_send(sock, s, strlen(s));
+}
+
+static int sendAddrs(const char *kind, uw_context ctx, int sock, char *s, char *buf, ssize_t *pos) {
+  char *p;
+  char out[BUFLEN];
+
+  if (!s)
+    return 0;
+
+  for (p = strchr(s, ','); p; p = strchr(p+1, ',')) {
+    *p = 0;
+
+    snprintf(out, sizeof(out), "RCPT TO:%s\n", s);
+    out[sizeof(out)-1] = 0;
+    *p = ',';
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(ctx, "Error sending RCPT TO for %s", kind);
+      return 1;
+    }
+
+    if (smtp_read(ctx, sock, buf, pos) != 250) {
+      close(sock);
+      uw_set_error_message(ctx, "Mail server doesn't respond to %s RCPT TO with code 250.", kind);
+      return 1;
+    }
+  }
+
+  if (*s) {
+    snprintf(out, sizeof(out), "RCPT TO:%s\n", s);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(ctx, "Error sending RCPT TO for %s", kind);
+      return 1;
+    }
+
+    if (smtp_read(ctx, sock, buf, pos) != 250) {
+      close(sock);
+      uw_set_error_message(ctx, "Mail server doesn't respond to %s RCPT TO with code 250.", kind);
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+static void commit(void *data) {
+  job *j = data;
+  int sock;
+  struct sockaddr_in my_addr;
+  char buf[BUFLEN], out[BUFLEN];
+  ssize_t pos = 0;
+  char *s;
+
+  if ((sock = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
+    uw_set_error_message(j->ctx, "Can't create socket for mail server connection");
+    return;
+  }
+
+  my_addr.sin_family = AF_INET;
+  my_addr.sin_port = htons(25);
+  my_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+  memset(my_addr.sin_zero, 0, sizeof my_addr.sin_zero);
+
+  if (connect(sock, (struct sockaddr *)&my_addr, sizeof my_addr) < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error connecting to mail server");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 220) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't greet with code 220.");
+    return;
+  }
+
+  if (really_string(sock, "HELO localhost\n") < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending HELO");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 250) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't respond to HELO with code 250.");
+    return;
+  }
+
+  snprintf(out, sizeof(out), "MAIL FROM:%s\n", j->h->from);
+  out[sizeof(out)-1] = 0;
+
+  if (really_string(sock, out) < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending MAIL FROM");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 250) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't respond to MAIL FROM with code 250.");
+    return;
+  }
+
+  if (sendAddrs("To", j->ctx, sock, j->h->to, buf, &pos)) return;
+  if (sendAddrs("Cc", j->ctx, sock, j->h->cc, buf, &pos)) return;
+  if (sendAddrs("Bcc", j->ctx, sock, j->h->bcc, buf, &pos)) return;
+
+  if (really_string(sock, "DATA\n") < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending DATA");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 354) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't respond to DATA with code 354.");
+    return;
+  }
+
+  snprintf(out, sizeof(out), "From: %s\r\n", j->h->from);
+  out[sizeof(out)-1] = 0;
+
+  if (really_string(sock, out) < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending From");
+    return;
+  }
+
+  if (j->h->subject) {
+    snprintf(out, sizeof(out), "Subject: %s\r\n", j->h->subject);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending Subject");
+      return;
+    }
+  }
+
+  if (j->h->to) {
+    snprintf(out, sizeof(out), "To: %s\r\n", j->h->to);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending To");
+      return;
+    }
+  }
+
+  if (j->h->cc) {
+    snprintf(out, sizeof(out), "Cc: %s\r\n", j->h->cc);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending Cc");
+      return;
+    }
+  }
+
+  if (j->h->bcc) {
+    snprintf(out, sizeof(out), "Bcc: %s\r\n", j->h->bcc);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending Bcc");
+      return;
+    }
+  }
+
+  if ((s = uw_get_global(j->ctx, "extra_mail_headers"))) {
+    if (really_string(sock, s) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending extra headers");
+      return;
+    }
+  }
+
+  if (j->xbody) {
+    char separator[11];
+    separator[sizeof(separator)-1] = 0;
+
+    do {
+      int i;
+
+      for (i = 0; i < sizeof(separator)-1; ++i)
+        separator[i] = 'A' + (rand() % 26);
+    } while (strstr(j->body, separator) || strstr(j->xbody, separator));
+
+    snprintf(out, sizeof(out), "MIME-Version: 1.0\r\n"
+             "Content-Type: multipart/alternative; boundary=\"%s\"\r\n"
+             "\r\n"
+             "--%s\r\n"
+             "Content-Type: text/plain\r\n"
+             "\r\n",
+             separator, separator);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending multipart beginning");
+      return;
+    }
+
+    if (really_string(sock, j->body) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending message text body");
+      return;
+    }
+
+    snprintf(out, sizeof(out), "\r\n"
+             "--%s\r\n"
+             "Content-Type: text/html\r\n"
+             "\r\n",
+             separator);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending multipart middle");
+      return;
+    }
+
+    if (really_string(sock, j->xbody) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending message HTML body");
+      return;
+    }
+
+    snprintf(out, sizeof(out), "\r\n"
+             "--%s--",
+             separator);
+    out[sizeof(out)-1] = 0;
+
+    if (really_string(sock, out) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending multipart end");
+      return;
+    }
+  } else {
+    if (really_string(sock, "Content-Type: text/plain\r\n\r\n") < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending text Content-Type");
+      return;
+    }
+
+    if (really_string(sock, j->body) < 0) {
+      close(sock);
+      uw_set_error_message(j->ctx, "Error sending message body");
+      return;
+    }
+  }
+
+  if (really_string(sock, "\r\n.\r\n") < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending message terminator");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 250) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't respond to end of message with code 250.");
+    return;
+  }
+
+  if (really_string(sock, "QUIT\n") < 0) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Error sending QUIT");
+    return;
+  }
+
+  if (smtp_read(j->ctx, sock, buf, &pos) != 221) {
+    close(sock);
+    uw_set_error_message(j->ctx, "Mail server doesn't respond to QUIT with code 221.");
+    return;
+  }
+
+  close(sock);
+}
+
+uw_unit uw_Mail_send(uw_context ctx, uw_Mail_headers h, uw_Basis_string body, uw_Basis_string xbody) {
+  job *j;
+  char *s;
+
+  if (!h || !h->from)
+    uw_error(ctx, FATAL, "No From address set for e-mail message");
+
+  if (!h->to && !h->cc && !h->bcc)
+    uw_error(ctx, FATAL, "No recipients specified for e-mail message");
+
+  for (s = strchr(body, '.'); s; s = strchr(s+1, '.'))
+    if ((s[1] == '\n' || s[1] == '\r')
+        && (s <= body || s[-1] == '\n' || s[-1] == '\r'))
+      uw_error(ctx, FATAL, "Message body contains a line with just a period");
+
+  if (xbody) {
+    for (s = strchr(xbody, '.'); s; s = strchr(s+1, '.'))
+      if ((s[1] == '\n' || s[1] == '\r')
+          && (s <= xbody || s[-1] == '\n' || s[-1] == '\r'))
+        uw_error(ctx, FATAL, "HTML message body contains a line with just a period");
+  }
+
+  j = uw_malloc(ctx, sizeof(job));
+
+  j->ctx = ctx;
+  j->h = h;
+  j->body = body;
+  j->xbody = xbody;
+
+  uw_register_transactional(ctx, j, commit, NULL, NULL);
+
+  return uw_unit_v;
+}