pop3

commit 57d78289bb609835e7da65d1b001ea80603949ef
parent 1aa4eae25df8f50e7fff71c0801c1ae17eacb84e
Author: Jacob R. Edwards <jacob@jacobedwards.org>
Date:   Sun,  3 Apr 2022 17:37:27 +0000

Add mailer option

This option pipes each message through the given program instead
of printing them to the standard output.

Diffstat:
M
pop3.1
 | 
6
+++++-
M
pop3.c
 | 
69
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------

2 files changed, 66 insertions(+), 9 deletions(-)
diff --git a/pop3.1 b/pop3.1
@@ -1,4 +1,4 @@
-.\"	$Id: pop3.1,v 1.2 2022/03/25 22:54:19 jacob Exp $
+.\"	$Id: pop3.1,v 1.3 2022/04/03 17:37:27 jacob Exp $
 .\"
 .\" Copyright (c) 2022 Jacob R. Edwards
 .\"
@@ -23,6 +23,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl kqst
+.Op Fl m Ar mailer
 .Op Fl p Ar port
 .Op Fl u Ar user
 .Ar host
@@ -53,6 +54,9 @@ by default
 is used.
 .It Fl t
 Trace POP3 communication.
+.It Fl m Ar mailer
+Pipe each message through
+.Ar mailer .
 .It Fl p Ar port
 Connect to
 .Ar host
diff --git a/pop3.c b/pop3.c
@@ -1,4 +1,4 @@
-/*	$Id: pop3.c,v 1.1 2022/03/07 07:42:39 jacob Exp $	*/
+/*	$Id: pop3.c,v 1.2 2022/04/03 17:37:27 jacob Exp $	*/
 
 /*
  * Copyright (c) 2022 Jacob R. Edwards
@@ -21,6 +21,7 @@
 
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 
 #include <netdb.h>
 
@@ -29,6 +30,7 @@
 #include <libgen.h>
 #include <limits.h>
 #include <readpassphrase.h>
+#include <signal.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -56,6 +58,7 @@ static int trace;
 static char *port = "110";
 static char *user;
 static char *host;
+static char *mailer;
 
 struct scanlisting {
 	char msg[4 + 1]; /* See LISTMAX */
@@ -88,7 +91,7 @@ usage(char *why)
 {
 	if (why)
 		fprintf(stderr, "%s\n", why);
-	fprintf(stderr, "usage: %s [-kqst] [-u user] [-p port] host\n",
+	fprintf(stderr, "usage: %s [-kqst] [-m mailer] [-p port] [-u user] host\n",
 	    getprogname());
 	exit(1);
 }
@@ -387,17 +390,64 @@ pop_dele(FILE *fp, char *msg)
 }
 
 int
-mbox(FILE *fp, int delete)
+mail(FILE *fp, char *msg, char *mailer)
+{
+	int fds[2];
+	int status;
+	pid_t pid;
+
+	if (pipe(fds))
+		return -1;
+
+	switch ((pid = fork())) {
+	case -1:
+		close(fds[0]);
+		close(fds[1]);
+		return -1;
+	case 0:
+		if (close(fds[1]) < 0 || dup2(fds[0], 0) < 0)
+			_exit(127);
+		execlp(mailer, mailer, NULL);
+		_exit(127);
+	}
+
+	if (close(fds[0]) < 0 || dup2(fds[1], 1) < 0 ||
+	    pop_retr(fp, msg) || fflush(stdout)) {
+		close(fds[1]);
+		kill(pid, SIGTERM);
+		return -1;
+	}
+
+	if (close(fds[1]) < 0 || close(1) < 0) {
+		kill(pid, SIGTERM);
+		return -1;
+	}
+
+	if (waitpid(pid, &status, 0) < 0)
+		return -1;
+	return WEXITSTATUS(status);
+}
+
+int
+mbox(FILE *fp, char *msg, char *unused)
+{
+	return pop_retr(fp, msg);
+}
+
+int
+getmail(FILE *fp, int delete, char *mailer)
 {
 	int len, i;
 	struct scanlisting *listings;
+	int (*sendmail)(FILE *, char *, char *);
 
 	listings = pop_list(fp, &len);
 	if (listings == NULL)
 		return 1;
 
+	sendmail = mailer ? mail : mbox;
 	for (i = 0; i < len; ++i) {
-		if (pop_retr(fp, listings[i].msg) ||
+		if (sendmail(fp, listings[i].msg, mailer) ||
 		    (delete && pop_dele(fp, listings[i].msg))) {
 			free(listings);
 			return 1;
@@ -440,15 +490,18 @@ main(int argc, char *argv[])
 	FILE *fp;
 	int c;
 
-	if (pledge("stdio tty inet dns", NULL))
+	if (pledge("stdio tty inet dns proc exec", NULL))
 		die("pledge");
 
 	user = getlogin();
-	while ((c = getopt(argc, argv, "kp:qstu:")) >= 0) {
+	while ((c = getopt(argc, argv, "km:p:qstu:")) >= 0) {
 		switch (c) {
 		case 'k':
 			keep = 1;
 			break;
+		case 'm':
+			mailer = optarg;
+			break;
 		case 'p':
 			port = optarg;
 			break;
@@ -484,10 +537,10 @@ main(int argc, char *argv[])
 	if (auth(fp, user, usestdin))
 		die("unable to authenticate for '%s'", user);
 
-	if (pledge("stdio", NULL))
+	if (pledge(mailer ? "stdio proc exec" : "stdio", NULL))
 		die("pledge");
 
-	if (query ?  stat(fp) : mbox(fp, !keep))
+	if (query ? stat(fp) : getmail(fp, !keep, mailer))
 		die("unable to complete transaction");
 	return !pop_quit(fp);
 }