X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/dd3c57bc8cac59e0d657ee665ce462988d27d714..18c831dcd0ae4d660c70ccac69d27ed2a97851be:/sel/ident.c

diff --git a/sel/ident.c b/sel/ident.c
new file mode 100644
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--- /dev/null
+++ b/sel/ident.c
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+/* -*-c-*-
+ *
+ * Nonblocking RFC931 client
+ *
+ * (c) 1999 Mark Wooding
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#include "conn.h"
+#include "dstr.h"
+#include "exc.h"
+#include "ident.h"
+#include "selbuf.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @next@ --- *
+ *
+ * Arguments:	@char **pp@ = address of string pointer
+ *
+ * Returns:	Address of next token.
+ *
+ * Use:		Reads the next token from the result string.  Tokens are
+ *		terminated by whitespace, or `:' or `,' characters.  The
+ *		result string has had `\' escapes removed; it's stored in
+ *		the same memory as the input string.  The actual content
+ *		of the delimiter doesn't seem to be interesting, so it
+ *		gets thrown away.
+ */
+
+static char *next(char **pp)
+{
+  char *p, *q, *r;
+
+  /* --- Deal with reads past the end of the string --- */
+
+  if (!*pp)
+    return ("");
+
+  /* --- Initialize various pointers into the string --- */
+
+  p = q = r = *pp;
+
+  /* --- Skip past any leading whitespace --- */
+
+  while (isspace((unsigned char)*p))
+    p++;
+
+  /* --- Now start work on the string itself --- */
+
+  for (;;) {
+    if (*p == 0 || *p == ':' || *p == ',' || isspace((unsigned char)*p))
+      break;
+    else if (*p == '\\') {
+      p++;
+      if (!*p) {
+	*q++ = '\\';
+	break;
+      }
+    }
+    *q++ = *p++;
+  }
+
+  /* --- Tidy up afterwards --- */
+
+  while (isspace((unsigned char)*p))
+    p++;
+  if (*p == 0)
+    *pp = 0;
+  else if (*p == ':' || *p == ',')
+    *pp = p + 1;
+  else
+    *pp = p;
+  *q = 0;
+
+  return (r);
+}
+
+/* --- @parse@ --- *
+ *
+ * Arguments:	@char *p@ = pointer to input string from identd
+ *		@ident_reply *i@ = pointer to output block
+ *
+ * Returns:	---
+ *
+ * Use:		Parses a result string from an RFC931 (identd) server.
+ */
+
+static void parse(char *p, ident_reply *i)
+{
+  char *q;
+
+  /* --- Read the source and destination port numbers --- */
+
+  i->sport = atoi(next(&p));
+  i->dport = atoi(next(&p));
+
+  /* --- Find out what sort of a reply this is --- */
+
+  q = next(&p);
+  if (strcmp(q, "USERID") == 0) {
+    i->type = IDENT_USERID;
+    i->u.userid.os = next(&p);
+    i->u.userid.user = next(&p);
+  } else if (strcmp(q, "ERROR") == 0) {
+    i->type = IDENT_ERROR;
+    i->u.error = next(&p);
+  } else
+    i->type = IDENT_BAD;
+}
+
+/* --- @line@ --- *
+ *
+ * Arguments:	@char *s@ = pointer to string from ident server
+ *		@size_t len@ = length of the line
+ *		@void *p@ = pointer to my request block
+ *
+ * Returns:	---
+ *
+ * Use:		Handles a string from an ident server.
+ */
+
+static void line(char *s, size_t len, void *p)
+{
+  ident_request *rq = p;
+
+  rq->state = IDENT_DONE;
+  close(rq->b.reader.fd);
+  if (!s)
+    rq->func(0, rq->p);
+  else {
+    ident_reply i;
+    parse(s, &i);
+    rq->func(&i, rq->p);
+  }
+  selbuf_destroy(&rq->b);
+}
+
+/* --- @connected@ --- *
+ *
+ * Arguments:	@int fd@ = file descriptor
+ *		@void *p@ = pointer to request block
+ *
+ * Returns:	---
+ *
+ * Use:		Handles a connection to a remote ident server.
+ */
+
+static void connected(int fd, void *p)
+{
+  ident_request *rq = p;
+  dstr d = DSTR_INIT;
+
+  /* --- Handle an error during the connect --- */
+
+  if (fd < 0)
+    goto fail_0;
+
+  /* --- Initialize the string to send to the remote host --- */
+
+  TRY {
+    dstr_putf(&d, "%u, %u\r\n",
+	      ntohs(rq->remote.sin_port), ntohs(rq->local.sin_port));
+  } CATCH switch (exc_type) {
+    case EXC_NOMEM:
+      EXIT_TRY;
+      goto fail_1;
+    default:
+      RETHROW;
+  } END_TRY;
+
+  /* --- Do the rest of the work --- */
+
+  if (write(fd, d.buf, d.len) < d.len)
+    goto fail_1;
+  dstr_destroy(&d);
+  rq->state = IDENT_READ;
+  selbuf_init(&rq->b, rq->s, fd, line, rq);
+  return;
+
+  /* --- Tidy up after misfortunes --- */
+
+fail_1:
+  dstr_destroy(&d);
+  close(fd);
+fail_0:
+  rq->state = IDENT_DONE;
+  rq->func(0, rq->p);
+}
+
+/* --- @ident_abort@ --- *
+ *
+ * Arguments:	@ident_request *rq@ = pointer to request block
+ *
+ * Returns:	---
+ *
+ * Use:		Cancels an ident request in progress.
+ */
+
+void ident_abort(ident_request *rq)
+{
+  switch (rq->state) {
+    case IDENT_CONN:
+      conn_kill(&rq->c);
+      break;
+    case IDENT_READ:
+      close(rq->b.reader.fd);
+      selbuf_destroy(&rq->b);
+      break;
+  }
+}
+
+/* --- @go@ --- *
+ *
+ * Arguments:	@ident_request *rq@ = pointer to request block
+ *
+ * Returns:	---
+ *
+ * Use:		Starts a connection to the remote ident server.
+ */
+
+static void go(ident_request *rq)
+{
+  int fd;
+  struct sockaddr_in sin;
+  int opt;
+
+  /* --- Create the socket I'll use --- */
+
+  if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
+    goto fail_0;
+  memset(&sin, 0, sizeof(sin));
+  sin.sin_family = AF_INET;
+  sin.sin_port = 0;
+  sin.sin_addr = rq->local.sin_addr;
+  if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
+    goto fail_1;
+
+  /* --- Out-of-band data would confuse us --- */
+
+  opt = 1;
+  setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
+
+  /* --- Start a connection to the remote server --- */
+
+  sin.sin_family = AF_INET;
+  sin.sin_port = htons(113);
+  sin.sin_addr = rq->remote.sin_addr;
+  if (conn_init(&rq->c, rq->s, fd, (struct sockaddr *)&sin, sizeof(sin),
+		connected, rq))
+    goto fail_1;
+
+  /* --- Finish off initializing the block --- */
+
+  rq->state = IDENT_CONN;
+  return;
+
+  /* --- Tidy up after lossage --- */
+
+fail_1:
+  close(fd);
+fail_0:
+  rq->state = IDENT_DONE;
+  rq->func(0, rq->p);
+}
+
+/* --- @ident@ --- *
+ *
+ * Arguments:	@ident_request *rq@ = pointer to request block
+ *		@sel_state *s@ = I/O multiplexor
+ *		@const struct sockaddr_in *local, *remote@ = addresses
+ *		@void (*func)(ident_reply *i, void *p)@ = handler function
+ *		@void *p@ = argument for handler
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes an ident request.
+ */
+
+void ident(ident_request *rq, sel_state *s,
+	   const struct sockaddr_in *local,
+	   const struct sockaddr_in *remote,
+	   void (*func)(ident_reply */*i*/, void */*p*/),
+	   void *p)
+{
+  memcpy(&rq->local, local, sizeof(rq->local));
+  memcpy(&rq->remote, remote, sizeof(rq->remote));
+  rq->func = func;
+  rq->p = p;
+  rq->s = s;
+  go(rq);
+}
+
+/* --- @ident_socket@ --- *
+ *
+ * Arguments:	@ident_request *rq@ = pointer to request block
+ *		@sel_state *s@ = I/O multiplexor
+ *		@int sk@ = connected socket file descriptor
+ *		@void (*func)(ident_reply *i, void *p)@ = handler function
+ *		@void *p@ = argument for handler
+ *
+ * Returns:	---
+ *
+ * Use:		An alternative interface to @ident@.  Initializes an ident
+ *		request from a connected socket, rather than from an explicit
+ *		address.  This will call @getsockname@ and @getpeername@ to
+ *		find out what the socket is actually connected to, which adds
+ *		convenience but wastes time.
+ */
+
+void ident_socket(ident_request *rq, sel_state *s, int sk,
+		  void (*func)(ident_reply */*i*/, void */*p*/),
+		  void *p)
+{
+  size_t sinsz;
+  if ((sinsz = sizeof(struct sockaddr_in),
+       getsockname(sk, (struct sockaddr *)&rq->local, &sinsz)) ||
+      (sinsz = sizeof(struct sockaddr_in),
+       getpeername(sk, (struct sockaddr *)&rq->remote, &sinsz))) {
+    rq->state = IDENT_DONE;
+    func(0, p);
+    return;
+  }
+
+  rq->func = func;
+  rq->p = p;
+  rq->s = s;
+  go(rq);
+}
+
+/*----- That's all, folks -------------------------------------------------*/