io: rework io.popen to use posix_spawn()

..and accept 'rw' flag to make reading _and_
writing to the process' stdin and stdout possible.

3 files changed, 110 insertions, 61 deletions

diff --git a/lem/io/core.c b/lem/io/core.c
index c56463c..b5fe4d6 100644
--- a/lem/io/core.c
+++ b/lem/io/core.c
@@ -30,11 +30,13 @@
 #include <arpa/inet.h>
 #include <netinet/tcp.h>
 #include <netdb.h>
+#include <spawn.h>
 
 #if defined(__FreeBSD__) || defined(__APPLE__)
 #include <sys/un.h>
 #include <sys/ucred.h>
 #include <netinet/in.h>
+extern char **environ;
 #ifndef UNIX_PATH_MAX
 #define UNIX_PATH_MAX 104
 #endif
@@ -107,6 +109,9 @@ error:
 #include "tcp.c"
 #include "unix.c"
 
+/*
+ * io.open()
+ */
 struct open {
 	struct lem_async a;
 	const char *path;
@@ -249,6 +254,70 @@ io_open(lua_State *T)
 	return lua_yield(T, 3);
 }
 
+/*
+ * io.popen()
+ */
+static const char *const io_popen_modes[] = { "r", "w", "rw", NULL };
+
+static int
+io_popen(lua_State *T)
+{
+	const char *cmd = luaL_checkstring(T, 1);
+	int mode = luaL_checkoption(T, 2, "r", io_popen_modes);
+	char *const argv[4] = { "/bin/sh", "-c", (char *)cmd, NULL };
+	posix_spawn_file_actions_t fa;
+	int fd[2];
+	int err;
+
+	posix_spawn_file_actions_init(&fa);
+	switch (mode) {
+	case 0: /* "r" */
+		if (pipe(fd))
+			return io_strerror(T, errno);
+		posix_spawn_file_actions_adddup2(&fa, fd[1], 1);
+		posix_spawn_file_actions_addclose(&fa, fd[1]);
+		break;
+	case 1: /* "w" */
+		if (pipe(fd))
+			return io_strerror(T, errno);
+		err = fd[0];
+		fd[0] = fd[1];
+		fd[1] = err;
+		posix_spawn_file_actions_adddup2(&fa, fd[1], 0);
+		posix_spawn_file_actions_addclose(&fa, fd[1]);
+		break;
+	case 2: /* "rw" */
+		if (socketpair(AF_UNIX, SOCK_STREAM, 0, fd))
+			return io_strerror(T, errno);
+		posix_spawn_file_actions_adddup2(&fa, fd[1], 0);
+		posix_spawn_file_actions_adddup2(&fa, fd[1], 1);
+		posix_spawn_file_actions_addclose(&fa, fd[1]);
+		break;
+	}
+
+	/* set our socket flags */
+	if (fcntl(fd[0], F_SETFD, FD_CLOEXEC) == -1 ||
+			fcntl(fd[0], F_SETFL, O_NONBLOCK) == -1) {
+		err = errno;
+		goto error;
+	}
+
+	err = posix_spawn(NULL, argv[0], &fa, NULL, argv, environ);
+	lem_debug("err = %d, %s", err, strerror(err));
+	if (err)
+		goto error;
+
+	posix_spawn_file_actions_destroy(&fa);
+	close(fd[1]);
+	stream_new(T, fd[0], lua_upvalueindex(1));
+	return 1;
+error:
+	posix_spawn_file_actions_destroy(&fa);
+	close(fd[0]);
+	close(fd[1]);
+	return io_strerror(T, err);
+}
+
 static void
 push_stdstream(lua_State *L, int fd)
 {
@@ -384,7 +453,7 @@ luaopen_lem_io_core(lua_State *L)
 	lua_setfield(L, -2, "open");
 	/* insert popen function */
 	lua_getfield(L, -1, "Stream"); /* upvalue 1 = Stream */
-	lua_pushcclosure(L, stream_popen, 1);
+	lua_pushcclosure(L, io_popen, 1);
 	lua_setfield(L, -2, "popen");
 
 	/* create tcp table */
diff --git a/lem/io/stream.c b/lem/io/stream.c
index 204df81..0056233 100644
--- a/lem/io/stream.c
+++ b/lem/io/stream.c
@@ -530,63 +530,3 @@ stream_sendfile(lua_State *T)
 	lua_settop(T, 2);
 	return lua_yield(T, 2);
 }
-
-static int
-stream_popen(lua_State *T)
-{
-	const char *cmd = luaL_checkstring(T, 1);
-	const char *mode = luaL_optstring(T, 2, "r");
-	int fd[2];
-	int err;
-
-	if (mode[0] != 'r' && mode[0] != 'w')
-		return luaL_error(T, "invalid mode string");
-
-	if (pipe(fd))
-		return io_strerror(T, errno);
-
-	switch (fork()) {
-	case -1: /* error */
-		err = errno;
-		close(fd[0]);
-		close(fd[1]);
-		return io_strerror(T, err);
-
-	case 0: /* child */
-		if (mode[0] == 'r') {
-			close(fd[0]);
-			dup2(fd[1], 1);
-		} else {
-			close(fd[1]);
-			dup2(fd[0], 0);
-		}
-
-		execl("/bin/sh", "/bin/sh", "-c", cmd, NULL);
-		exit(EXIT_FAILURE);
-	}
-
-	if (mode[0] == 'r') {
-		if (close(fd[1])) {
-			err = errno;
-			close(fd[0]);
-			return io_strerror(T, err);
-		}
-	} else {
-		if (close(fd[0])) {
-			err = errno;
-			close(fd[1]);
-			return io_strerror(T, err);
-		}
-		fd[0] = fd[1];
-	}
-
-	/* make the pipe non-blocking */
-	if (fcntl(fd[0], F_SETFL, O_NONBLOCK) == -1) {
-		err = errno;
-		close(fd[0]);
-		return io_strerror(T, err);
-	}
-
-	stream_new(T, fd[0], lua_upvalueindex(1));
-	return 1;
-}
diff --git a/test/popen.lua b/test/popen.lua
new file mode 100755
index 0000000..d13cbd0
--- /dev/null
+++ b/test/popen.lua
@@ -0,0 +1,40 @@
+#!bin/lem
+--
+-- This file is part of LEM, a Lua Event Machine.
+-- Copyright 2013 Emil Renner Berthing
+--
+-- LEM is free software: you can redistribute it and/or modify it
+-- under the terms of the GNU Lesser General Public License as
+-- published by the Free Software Foundation, either version 3 of
+-- the License, or (at your option) any later version.
+--
+-- LEM 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 Lesser General Public License for more details.
+--
+-- You should have received a copy of the GNU Lesser General Public
+-- License along with LEM.  If not, see <http://www.gnu.org/licenses/>.
+--
+
+package.path = '?.lua'
+package.cpath = '?.so'
+
+local utils = require 'lem.utils'
+local io    = require 'lem.io'
+
+local write, format = io.write, string.format
+
+local p = assert(io.popen('telnet localhost 8080', 'rw'))
+
+assert(p:write('GET / HTTP/1.0'))
+assert(p:write('\n'))
+assert(p:write('\n'))
+
+local n = 0
+for line in p:lines() do
+	n = n+1
+	write(format('%4d: %s\n', n, line))
+end
+
+-- vim: syntax=lua ts=2 sw=2 noet: