[Tarantool-patches] [PATCH v9 3/4] popen/lua: add popen module

Cyrill Gorcunov gorcunov at gmail.com
Fri Jan 10 11:25:55 MSK 2020


@TarantoolBot document
Title: popen module

Overview
========

Tarantool supports execution of external programs similarly
to well known Python's `subprocess` or Ruby's `Open3`. Note
though the `popen` module does not match one to one to the
helpers these languages provide and provides only basic
functions. The popen object creation is implemented via
`vfork()` system call which means the caller thread is
blocked until execution of a child process begins.

Functions
=========

The `popen` module provides two functions to create that named
popen object `popen.posix` which is the similar to libc `posix`
syscall and `popen.popen` to create popen object with more
specific options.

`handler, err = popen.posix(command, mode)`
-------------------------------------------

Creates a new child process and executes a command as the "sh -c command".

Parameters
```
command     is the command to run

mode        'r' - to grab child's stdout for read
            'w' - to write into child's stdin stream
            'rw' - combined mode to read and write
```

If `mode` has `r` then `stderr` output stream is always opened to be
able to redirect `stderr` to `stdout` by well known `2>&1` statement.
If `mode` is not specified at all then non of the std stram will be
opened inside a child process.

On success returns popen object handler setting `err` to nil,
otherwise error reported.

__Example 1__
```
ph = require('popen').posix("date", "r")
ph:read()
ph:close()
```

Executes "sh -c date" then reads the output and closes the popen object.

`handler, err = popen.popen(opts)`
----------------------------------

Creates a new child process and execute a program inside. The `opts` is
options table with the following keys

```
argv        an array containing the binary to execute together
            with command line arguments; this is the only mandatory
            key in the options table

env         an array of environment variables, if not set then they
            are inherited; if env=nil then environment will be empty

flags       a dictionary to describe communication pipes and other
            parameters of a process to run

            stdin=true
                to write into STDIN_FILENO of a child process
            stdin=false
                to close STDIN_FILENO inside a child process, default
            stdin="devnull"
                a child will get /dev/null as STDIN_FILENO

            stdout=true
                to read STDOUT_FILENO of a child process
            stdout=false
                to close STDOUT_FILENO inside a child process, default
            stdout="devnull"
                a child will get /dev/null as STDOUT_FILENO

            stderr=true
                to read STDERR_FILENO of a child process
            stderr=false
                to close STDERR_FILENO inside a child process, default
            stderr="devnull"
                a child will get /dev/null as STDERR_FILENO

            shell=true
                runs a child process via "sh -c", default
            shell=false
                invokes a child process executable directly

            close_fds=true
                close all inherited fds from a parent, default

            restore_signals=true
                all signals modified by a caller reset
                to default handler, default

            start_new_session=true
                start executable inside a new session, default
```

On success returns popen object handler setting `err` to nil,
otherwise error reported.

__Example 2__
```
ph, err = require('popen').popen({argv = {"/usr/bin/echo", "-n", "hello"},
                                 flags = {stdout=true, shell=false}})
```

`str, err = popen:read([stderr=true|false,timeout])`
----------------------------------------------------

Reads data from `stdout` or `stderr` streams with `timeout`. By default
it reads from `stdout` stream, to read from `stderr` stream set
`stderr=true`.

On success returns string `str` read and `err=nil`, otherwise `err ~= nil`.

__Example 3__
```
ph = require('popen').popen({argv = {"/usr/bin/echo", "-n", "hello"},
                            flags = {stdout=true, shell=false}})
ph:read()
---
- hello
```

`err = popen:write(str[,timeout])`
----------------------------------

Writes string `str` to `stdin` stream of a child process. Since the internal
buffer on the reader side is limited in size and depends on OS settings the `write`
may hang forever if buffer is full. For this wake `timeout` (float number) parameter
allows to specify number of seconds which once elapsed interrupt `write` attempts
and exit from this function. When not provided the `write` blocks until data is
written or error happened.

On success returns `err = nil`, otherwise `err ~= nil`.

__Example 4__
```
script = "prompt=''; read -n 5 prompt && echo -n $prompt;"
ph = require('popen').posix(script, "rw")
ph:write("12345")
ph:read()
---
- '12345'
```

`err = popen:write2(opts)`
--------------------------

Writes data from a buffer to a stream of a child process. `opts` is
a table of options with the following keys

```
buf     buffer with raw data to write
size    number of bytes to write
flags   dictionary to specify the input stream
        stdin=true
            to write into stdin stream
timeout write timeout in seconds, optional
```

Basically the `popen:write` is a wrapper over `popen:write2` call
with `opts` similar to `{timeout = -1, {flags = {stdin = true}}`.

On success `err = nil`, otherwise `err ~= nil`.

The reason for passing `{flags = {stdin = true}}` while we have only
one `stdin` is that we reserve the interface for future where we
might extend it without breaking backward compatibility.

`bytes, err = popen:read2(opts)`
--------------------------------

Reads data from a stream of a child process to a buffer. `opts` is
a table of options with the following keys

```
buf     destination buffer
size    number of bytes to read
flags   dictionary to specify the input stream
        stdout=true
            to read from stdout stream
        stderr=true
            to read from stderr stream
timeout read timeout in seconds, optional
```

Basically the `popen:read` is a wrapper over `popen:read2` call
with `opts` similar to `{timeout = -1, {flags = {stdout = true}}`.

On success returns number of `bytes` read and `err = nil`,
otherwise `err ~= nil`.

__Example 5__
```
buffer = require('buffer')
popen = require('popen')
ffi = require('ffi')

script = "echo -n 1 2 3 4 5 1>&2"
buf = buffer.ibuf()

ph = popen.posix(script, "rw")
ph:wait()
size = 128
dst = buf:reserve(size)
res, err = ph:read2({buf = dst, size = size, nil, flags = {stderr = true}})
res = buf:alloc(res)
ffi.string(buf.rpos, buf:size())
---
- 1 2 3 4 5
...
buf:recycle()
ph:close()
```

`res, err = popen:terminate()`
-----------------------------

Terminates a child process in a soft way sending `SIGTERM` signal.
On success returns `res = true, err = nil`, `err ~= nil` otherwise.

`res, err = popen:kill()`
-------------------------

Terminates a child process in a soft way sending `SIGKILL` signal.
On success returns `res = true, err = nil`, `err ~= nil` otherwise.

`res, err = popen:send_signal(signo)`
-------------------------------------

Sends signal with number `signo` to a child process.
On success returns `res = true, err = nil`, `err ~= nil`
otherwise.

`info, err = popen:info()`
--------------------------

Returns information about a child process in form of table
with the following keys

```
pid         PID of a child process, if already terminated
            the it set to -1

flags       flags been used to create the popen object; this
            is bitmap of popen.c.flag constants

stdout      file descriptor number associated with stdout
            stream on a parent side, -1 if not set

stderr      file descriptor number associated with stderr
            stream on a parent side, -1 if not set

stdint      file descriptor number associated with stdin
            stream on a parent side, -1 if not set

state       state of a child proces: "alive" if process
            is running, "exited" if finished execution,
            "signaled" is terminated by a signal

exit_code   if process is in "signaled" state then this
            number represent the signal number process
            been terminated with, if process is in "exited"
            state then it represent the exit code
```

__Example 6__
```
ph = require('popen').posix("echo -n 1 2 3 4 5 1>&2", "r")
ph:info()
---
- stdout: 12
  command: sh -c echo -n 1 2 3 4 5 1>&2
  stderr: 23
  flags: 61510
  state: exited
  stdin: -1
  exit_code: 0
  pid: -1
```

`err, state, exit_code = popen:state()`
--------------------------------------

Returns the current state of a chile process.

On success returns `err = nil`, `state` is one of the
constants `popen.c.state.ALIVE=1` when process is running,
`popen.c.state.EXITED=2` when it exited by self or
`popen.c.state.SIGNALED=3` when terminated via signal.
In case if the child process is terminated by a signal
the `exit_code` contains the signal number, otherwise
it is an error code the child set by self.

__Example 7__
```
ph = require('popen').posix("echo -n 1 2 3 4 5 1>&2", "r")
ph:state()
---
- null
- 2
- 0
```

`err, state, exit_code = popen:wait()`
--------------------------------------

Waits until a child process get exited or terminated.
Returns the same data as `popen:state()`. Basically
the `popen:wait()` is simply polling for the child state
with `popen:wait()` in a cycle.

`err = popen:close`
-------------------

Closes popen object releasing all resources occupied.

If a child process is running then it get killed first. Once
popen object is closed it no longed usable and any attempt
to call function over will cause an error.

On success `err = nil`.

Part-of #4031

Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
 src/CMakeLists.txt |   2 +
 src/lua/init.c     |   4 +
 src/lua/popen.c    | 590 +++++++++++++++++++++++++++++++++++++++++++++
 src/lua/popen.h    |  44 ++++
 src/lua/popen.lua  | 523 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 1163 insertions(+)
 create mode 100644 src/lua/popen.c
 create mode 100644 src/lua/popen.h
 create mode 100644 src/lua/popen.lua

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e12de6005..e68030c5e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -38,6 +38,7 @@ lua_source(lua_sources lua/help.lua)
 lua_source(lua_sources lua/help_en_US.lua)
 lua_source(lua_sources lua/tap.lua)
 lua_source(lua_sources lua/fio.lua)
+lua_source(lua_sources lua/popen.lua)
 lua_source(lua_sources lua/csv.lua)
 lua_source(lua_sources lua/strict.lua)
 lua_source(lua_sources lua/clock.lua)
@@ -114,6 +115,7 @@ set (server_sources
      lua/socket.c
      lua/pickle.c
      lua/fio.c
+     lua/popen.c
      lua/httpc.c
      lua/utf8.c
      lua/info.c
diff --git a/src/lua/init.c b/src/lua/init.c
index 097dd8495..09f34d614 100644
--- a/src/lua/init.c
+++ b/src/lua/init.c
@@ -56,6 +56,7 @@
 #include "lua/msgpack.h"
 #include "lua/pickle.h"
 #include "lua/fio.h"
+#include "lua/popen.h"
 #include "lua/httpc.h"
 #include "lua/utf8.h"
 #include "lua/swim.h"
@@ -99,6 +100,7 @@ extern char strict_lua[],
 	help_en_US_lua[],
 	tap_lua[],
 	fio_lua[],
+	popen_lua[],
 	error_lua[],
 	argparse_lua[],
 	iconv_lua[],
@@ -141,6 +143,7 @@ static const char *lua_modules[] = {
 	"log", log_lua,
 	"uri", uri_lua,
 	"fio", fio_lua,
+	"popen", popen_lua,
 	"error", error_lua,
 	"csv", csv_lua,
 	"clock", clock_lua,
@@ -455,6 +458,7 @@ tarantool_lua_init(const char *tarantool_bin, int argc, char **argv)
 	tarantool_lua_errno_init(L);
 	tarantool_lua_error_init(L);
 	tarantool_lua_fio_init(L);
+	tarantool_lua_popen_init(L);
 	tarantool_lua_socket_init(L);
 	tarantool_lua_pickle_init(L);
 	tarantool_lua_digest_init(L);
diff --git a/src/lua/popen.c b/src/lua/popen.c
new file mode 100644
index 000000000..7be3c280a
--- /dev/null
+++ b/src/lua/popen.c
@@ -0,0 +1,590 @@
+/*
+ * Copyright 2010-2019, Tarantool AUTHORS, please see AUTHORS file.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above
+ *    copyright notice, this list of conditions and the
+ *    following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * <COPYRIGHT HOLDER> OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+#include <lualib.h>
+
+#include "diag.h"
+#include "core/popen.h"
+
+#include "lua/utils.h"
+#include "lua/popen.h"
+
+static inline int
+lbox_pushsyserror(struct lua_State *L)
+{
+	diag_set(SystemError, "popen: %s", strerror(errno));
+	return luaT_push_nil_and_error(L);
+}
+
+static inline int
+lbox_push_error(struct lua_State *L)
+{
+	diag_set(SystemError, "popen: %s", strerror(errno));
+	struct error *e = diag_last_error(diag_get());
+	assert(e != NULL);
+	luaT_pusherror(L, e);
+	return 1;
+}
+
+static inline int
+lbox_pushbool(struct lua_State *L, bool res)
+{
+	lua_pushboolean(L, res);
+	if (!res) {
+		lbox_push_error(L);
+		return 2;
+	}
+	return 1;
+}
+
+/**
+ * lbox_fio_popen_new - creates a new popen handle and runs a command inside
+ * @command:	a command to run
+ * @flags:	popen_flag_bits
+ *
+ * Returns pair @handle = data, @err = nil on success,
+ * @handle = nil, err ~= nil on error.
+ */
+static int
+lbox_popen_new(struct lua_State *L)
+{
+	struct popen_handle *handle;
+	struct popen_opts opts = { };
+	size_t i, argv_size;
+	ssize_t nr_env;
+
+	if (lua_gettop(L) < 1 || !lua_istable(L, 1))
+		luaL_error(L, "Usage: fio.run({opts}])");
+
+	lua_pushstring(L, "argv");
+	lua_gettable(L, -2);
+	if (!lua_istable(L, -1))
+		luaL_error(L, "fio.run: {argv=...} is not a table");
+	lua_pop(L, 1);
+
+	lua_pushstring(L, "flags");
+	lua_gettable(L, -2);
+	if (!lua_isnumber(L, -1))
+		luaL_error(L, "fio.run: {flags=...} is not a number");
+	opts.flags = lua_tonumber(L, -1);
+	lua_pop(L, 1);
+
+	lua_pushstring(L, "argc");
+	lua_gettable(L, -2);
+	if (!lua_isnumber(L, -1))
+		luaL_error(L, "fio.run: {argc=...} is not a number");
+	opts.nr_argv = lua_tonumber(L, -1);
+	lua_pop(L, 1);
+
+	if (opts.nr_argv < 1)
+		luaL_error(L, "fio.run: {argc} is too small");
+
+	/*
+	 * argv array should contain NULL element at the
+	 * end and probably "sh", "-c" at the start, so
+	 * reserve enough space for any flags.
+	 */
+	opts.nr_argv += 3;
+	argv_size = sizeof(char *) * opts.nr_argv;
+	opts.argv = malloc(argv_size);
+	if (!opts.argv)
+		luaL_error(L, "fio.run: can't allocate argv");
+
+	lua_pushstring(L, "argv");
+	lua_gettable(L, -2);
+	lua_pushnil(L);
+	for (i = 2; lua_next(L, -2) != 0; i++) {
+		assert(i < opts.nr_argv);
+		opts.argv[i] = (char *)lua_tostring(L, -1);
+		lua_pop(L, 1);
+	}
+	lua_pop(L, 1);
+
+	opts.argv[0] = NULL;
+	opts.argv[1] = NULL;
+	opts.argv[opts.nr_argv - 1] = NULL;
+
+	/*
+	 * Environment can be filled, empty
+	 * to inherit or contain one NULL to
+	 * be zapped.
+	 */
+	lua_pushstring(L, "envc");
+	lua_gettable(L, -2);
+	if (!lua_isnumber(L, -1)) {
+		free(opts.argv);
+		luaL_error(L, "fio.run: {envc=...} is not a number");
+	}
+	nr_env = lua_tonumber(L, -1);
+	lua_pop(L, 1);
+
+	if (nr_env >= 0) {
+		/* Should be NULL terminating */
+		opts.env = malloc((nr_env + 1) * sizeof(char *));
+		if (!opts.env) {
+			free(opts.argv);
+			luaL_error(L, "fio.run: can't allocate env");
+		}
+
+		lua_pushstring(L, "env");
+		lua_gettable(L, -2);
+		if (!lua_istable(L, -1)) {
+			free(opts.argv);
+			free(opts.env);
+			luaL_error(L, "fio.run: {env=...} is not a table");
+		}
+		lua_pushnil(L);
+		for (i = 0; lua_next(L, -2) != 0; i++) {
+			assert((ssize_t)i <= nr_env);
+			opts.env[i] = (char *)lua_tostring(L, -1);
+			lua_pop(L, 1);
+		}
+		lua_pop(L, 1);
+
+		opts.env[nr_env] = NULL;
+	} else {
+		/*
+		 * Just zap it to nil, the popen will
+		 * process inheriting by self.
+		 */
+		opts.env = NULL;
+	}
+
+	handle = popen_new(&opts);
+
+	free(opts.argv);
+	free(opts.env);
+
+	if (!handle)
+		return lbox_pushsyserror(L);
+
+	lua_pushlightuserdata(L, handle);
+	return 1;
+}
+
+/**
+ * lbox_fio_popen_kill - kill popen's child process
+ * @handle:	a handle carries child process to kill
+ *
+ * Returns true if process is killed and false
+ * otherwise. Note the process is simply signaled
+ * and it doesn't mean it is killed immediately,
+ * Poll lbox_fio_pstatus if need to find out when
+ * exactly the child is reaped out.
+ */
+static int
+lbox_popen_kill(struct lua_State *L)
+{
+	struct popen_handle *p = lua_touserdata(L, 1);
+	return lbox_pushbool(L, popen_send_signal(p, SIGKILL) == 0);
+}
+
+/**
+ * lbox_fio_popen_term - terminate popen's child process
+ * @handle:	a handle carries child process to terminate
+ *
+ * Returns true if process is terminated and false
+ * otherwise.
+ */
+static int
+lbox_popen_term(struct lua_State *L)
+{
+	struct popen_handle *p = lua_touserdata(L, 1);
+	return lbox_pushbool(L, popen_send_signal(p, SIGTERM) == 0);
+}
+
+/**
+ * lbox_fio_popen_signal - send signal to a child process
+ * @handle:	a handle carries child process to terminate
+ * @signo:	signal number to send
+ *
+ * Returns true if signal is sent.
+ */
+static int
+lbox_popen_signal(struct lua_State *L)
+{
+	struct popen_handle *p = lua_touserdata(L, 1);
+	int signo = lua_tonumber(L, 2);
+	return lbox_pushbool(L, popen_send_signal(p, signo) == 0);
+}
+
+/**
+ * lbox_popen_state - fetch popen child process status
+ * @handle:	a handle to fetch status from
+ *
+ * Returns @err = nil, @reason = POPEN_STATE_x,
+ * @exit_code = 'number' on success, @err ~= nil on error.
+ */
+static int
+lbox_popen_state(struct lua_State *L)
+{
+	struct popen_handle *p = lua_touserdata(L, 1);
+	int state, exit_code, ret;
+
+	ret = popen_state(p, &state, &exit_code);
+	if (ret < 0)
+		return lbox_push_error(L);
+
+	lua_pushnil(L);
+	lua_pushinteger(L, state);
+	lua_pushinteger(L, exit_code);
+	return 3;
+}
+
+/**
+ * lbox_popen_read - read data from a child peer
+ * @handle:	handle of a child process
+ * @buf:	destination buffer
+ * @count:	number of bytes to read
+ * @flags:	which peer to read (stdout,stderr)
+ * @timeout:	timeout in seconds; ignored if negative
+ *
+ * Returns @size = 'read bytes', @err = nil on success,
+ * @size = nil, @err ~= nil on error.
+ */
+static int
+lbox_popen_read(struct lua_State *L)
+{
+	struct popen_handle *handle = lua_touserdata(L, 1);
+	uint32_t ctypeid;
+	void *buf =  *(char **)luaL_checkcdata(L, 2, &ctypeid);
+	size_t count = lua_tonumber(L, 3);
+	unsigned int flags = lua_tonumber(L, 4);
+	ev_tstamp timeout = lua_tonumber(L, 5);
+	ssize_t ret;
+
+	ret = popen_read_timeout(handle, buf, count,
+				 flags, timeout);
+	if (ret < 0)
+		return lbox_pushsyserror(L);
+
+	lua_pushinteger(L, ret);
+	return 1;
+}
+
+/**
+ * lbox_popen_write - write data to a child peer
+ * @handle:	a handle of a child process
+ * @buf:	source buffer
+ * @count:	number of bytes to write
+ * @flags:	which peer to write (stdin)
+ * @timeout:	timeout in seconds; ignored if negative
+ *
+ * Returns @err = nil on succes, @err ~= nil on error.
+ */
+static int
+lbox_popen_write(struct lua_State *L)
+{
+	struct popen_handle *handle = lua_touserdata(L, 1);
+	void *buf = (void *)lua_tostring(L, 2);
+	uint32_t ctypeid = 0;
+	if (buf == NULL)
+		buf =  *(char **)luaL_checkcdata(L, 2, &ctypeid);
+	size_t count = lua_tonumber(L, 3);
+	unsigned int flags = lua_tonumber(L, 4);
+	ev_tstamp timeout = lua_tonumber(L, 5);
+	ssize_t ret;
+
+	ret = popen_write_timeout(handle, buf, count, flags, timeout);
+	if (ret < 0)
+		return lbox_pushsyserror(L);
+	return lbox_pushbool(L, ret == 0);
+}
+
+/**
+ * lbox_popen_info - return information about popen handle
+ * @handle:	a handle of a child process
+ *
+ * Returns a @table ~= nil, @err = nil on success,
+ * @table = nil, @err ~= nil on error.
+ */
+static int
+lbox_popen_info(struct lua_State *L)
+{
+	struct popen_handle *handle = lua_touserdata(L, 1);
+	int state, exit_code, ret;
+	struct popen_stat st = { };
+
+	if (popen_stat(handle, &st))
+		return lbox_pushsyserror(L);
+
+	ret = popen_state(handle, &state, &exit_code);
+	if (ret < 0)
+		return lbox_pushsyserror(L);
+
+	assert(state < POPEN_STATE_MAX);
+
+	lua_newtable(L);
+
+	lua_pushliteral(L, "pid");
+	lua_pushinteger(L, st.pid);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "command");
+	lua_pushstring(L, popen_command(handle));
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "flags");
+	lua_pushinteger(L, st.flags);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "state");
+	lua_pushstring(L, popen_state_str(state));
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "exit_code");
+	lua_pushinteger(L, exit_code);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "stdin");
+	lua_pushinteger(L, st.fds[STDIN_FILENO]);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "stdout");
+	lua_pushinteger(L, st.fds[STDOUT_FILENO]);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "stderr");
+	lua_pushinteger(L, st.fds[STDERR_FILENO]);
+	lua_settable(L, -3);
+
+	return 1;
+}
+
+/**
+ * lbox_popen_delete - close a popen handle
+ * @handle:	a handle to close
+ *
+ * If there is a running child it get killed first.
+ *
+ * Returns true if a handle is closeed, false otherwise.
+ */
+static int
+lbox_popen_delete(struct lua_State *L)
+{
+	void *handle = lua_touserdata(L, 1);
+	return lbox_pushbool(L, popen_delete(handle) == 0);
+}
+
+/**
+ * tarantool_lua_popen_init - Create popen methods
+ */
+void
+tarantool_lua_popen_init(struct lua_State *L)
+{
+	static const struct luaL_Reg popen_methods[] = {
+		{ },
+	};
+
+	/* public methods */
+	luaL_register_module(L, "popen", popen_methods);
+
+	static const struct luaL_Reg builtin_methods[] = {
+		{ "new",		lbox_popen_new,		},
+		{ "delete",		lbox_popen_delete,	},
+		{ "kill",		lbox_popen_kill,	},
+		{ "term",		lbox_popen_term,	},
+		{ "signal",		lbox_popen_signal,	},
+		{ "state",		lbox_popen_state,	},
+		{ "read",		lbox_popen_read,	},
+		{ "write",		lbox_popen_write,	},
+		{ "info",		lbox_popen_info,	},
+		{ },
+	};
+
+	/* builtin methods */
+	lua_pushliteral(L, "builtin");
+	lua_newtable(L);
+
+	luaL_register(L, NULL, builtin_methods);
+	lua_settable(L, -3);
+
+	/*
+	 * Popen constants.
+	 */
+#define lua_gen_const(_n, _v)		\
+	lua_pushliteral(L, _n);		\
+	lua_pushinteger(L, _v);		\
+	lua_settable(L, -3)
+
+	lua_pushliteral(L, "c");
+	lua_newtable(L);
+
+	/*
+	 * Flag masks.
+	 */
+	lua_pushliteral(L, "flag");
+	lua_newtable(L);
+
+	lua_gen_const("NONE",			POPEN_FLAG_NONE);
+
+	lua_gen_const("STDIN",			POPEN_FLAG_FD_STDIN);
+	lua_gen_const("STDOUT",			POPEN_FLAG_FD_STDOUT);
+	lua_gen_const("STDERR",			POPEN_FLAG_FD_STDERR);
+
+	lua_gen_const("STDIN_DEVNULL",		POPEN_FLAG_FD_STDIN_DEVNULL);
+	lua_gen_const("STDOUT_DEVNULL",		POPEN_FLAG_FD_STDOUT_DEVNULL);
+	lua_gen_const("STDERR_DEVNULL",		POPEN_FLAG_FD_STDERR_DEVNULL);
+
+	lua_gen_const("STDIN_CLOSE",		POPEN_FLAG_FD_STDIN_CLOSE);
+	lua_gen_const("STDOUT_CLOSE",		POPEN_FLAG_FD_STDOUT_CLOSE);
+	lua_gen_const("STDERR_CLOSE",		POPEN_FLAG_FD_STDERR_CLOSE);
+
+	lua_gen_const("SHELL",			POPEN_FLAG_SHELL);
+	lua_gen_const("SETSID",			POPEN_FLAGS_SETSID);
+	lua_gen_const("CLOSE_FDS",		POPEN_FLAG_CLOSE_FDS);
+	lua_gen_const("RESTORE_SIGNALS",	POPEN_FLAGS_RESTORE_SIGNALS);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "state");
+	lua_newtable(L);
+
+	lua_gen_const("ALIVE",			POPEN_STATE_ALIVE);
+	lua_gen_const("EXITED",			POPEN_STATE_EXITED);
+	lua_gen_const("SIGNALED",		POPEN_STATE_SIGNALED);
+	lua_settable(L, -3);
+
+	lua_pushliteral(L, "signal");
+	lua_newtable(L);
+#define lua_gen_signal(_signo)		\
+	lua_gen_const(#_signo, _signo)
+
+#ifdef SIGHUP
+	lua_gen_signal(SIGHUP);
+#endif
+#ifdef SIGINT
+	lua_gen_signal(SIGINT);
+#endif
+#ifdef SIGQUIT
+	lua_gen_signal(SIGQUIT);
+#endif
+#ifdef SIGILL
+	lua_gen_signal(SIGILL);
+#endif
+#ifdef SIGTRAP
+	lua_gen_signal(SIGTRAP);
+#endif
+#ifdef SIGABRT
+	lua_gen_signal(SIGABRT);
+#endif
+#ifdef SIGIOT
+	lua_gen_signal(SIGIOT);
+#endif
+#ifdef SIGBUS
+	lua_gen_signal(SIGBUS);
+#endif
+#ifdef SIGFPE
+	lua_gen_signal(SIGFPE);
+#endif
+#ifdef SIGKILL
+	lua_gen_signal(SIGKILL);
+#endif
+#ifdef SIGUSR1
+	lua_gen_signal(SIGUSR1);
+#endif
+#ifdef SIGSEGV
+	lua_gen_signal(SIGSEGV);
+#endif
+#ifdef SIGUSR2
+	lua_gen_signal(SIGUSR2);
+#endif
+#ifdef SIGPIPE
+	lua_gen_signal(SIGPIPE);
+#endif
+#ifdef SIGALRM
+	lua_gen_signal(SIGALRM);
+#endif
+#ifdef SIGTERM
+	lua_gen_signal(SIGTERM);
+#endif
+#ifdef SIGSTKFLT
+	lua_gen_signal(SIGSTKFLT);
+#endif
+#ifdef SIGCHLD
+	lua_gen_signal(SIGCHLD);
+#endif
+#ifdef SIGCONT
+	lua_gen_signal(SIGCONT);
+#endif
+#ifdef SIGSTOP
+	lua_gen_signal(SIGSTOP);
+#endif
+#ifdef SIGTSTP
+	lua_gen_signal(SIGTSTP);
+#endif
+#ifdef SIGTTIN
+	lua_gen_signal(SIGTTIN);
+#endif
+#ifdef SIGTTOU
+	lua_gen_signal(SIGTTOU);
+#endif
+#ifdef SIGURG
+	lua_gen_signal(SIGURG);
+#endif
+#ifdef SIGXCPU
+	lua_gen_signal(SIGXCPU);
+#endif
+#ifdef SIGXFSZ
+	lua_gen_signal(SIGXFSZ);
+#endif
+#ifdef SIGVTALRM
+	lua_gen_signal(SIGVTALRM);
+#endif
+#ifdef SIGPROF
+	lua_gen_signal(SIGPROF);
+#endif
+#ifdef SIGWINCH
+	lua_gen_signal(SIGWINCH);
+#endif
+#ifdef SIGIO
+	lua_gen_signal(SIGIO);
+#endif
+#ifdef SIGPOLL
+	lua_gen_signal(SIGPOLL);
+#endif
+#ifdef SIGPWR
+	lua_gen_signal(SIGPWR);
+#endif
+#ifdef SIGSYS
+	lua_gen_signal(SIGSYS);
+#endif
+#undef lua_gen_signal
+	lua_settable(L, -3);
+
+#undef lua_gen_const
+
+	lua_settable(L, -3);
+	lua_pop(L, 1);
+}
diff --git a/src/lua/popen.h b/src/lua/popen.h
new file mode 100644
index 000000000..4e3f137c5
--- /dev/null
+++ b/src/lua/popen.h
@@ -0,0 +1,44 @@
+#ifndef INCLUDES_TARANTOOL_LUA_POPEN_H
+#define INCLUDES_TARANTOOL_LUA_POPEN_H
+/*
+ * Copyright 2010-2019, Tarantool AUTHORS, please see AUTHORS file.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above
+ *    copyright notice, this list of conditions and the
+ *    following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * <COPYRIGHT HOLDER> OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#if defined(__cplusplus)
+extern "C" {
+#endif /* defined(__cplusplus) */
+
+struct lua_State;
+void tarantool_lua_popen_init(struct lua_State *L);
+
+#if defined(__cplusplus)
+} /* extern "C" */
+#endif /* defined(__cplusplus) */
+
+#endif /* INCLUDES_TARANTOOL_LUA_POPEN_H */
diff --git a/src/lua/popen.lua b/src/lua/popen.lua
new file mode 100644
index 000000000..2186e252a
--- /dev/null
+++ b/src/lua/popen.lua
@@ -0,0 +1,523 @@
+-- popen.lua (builtin file)
+--
+-- vim: ts=4 sw=4 et
+
+local buffer = require('buffer')
+local popen = require('popen')
+local fiber = require('fiber')
+local ffi = require('ffi')
+local bit = require('bit')
+
+local const_char_ptr_t = ffi.typeof('const char *')
+
+local builtin = popen.builtin
+popen.builtin = nil
+
+local popen_methods = { }
+
+local function default_flags()
+    local flags = popen.c.flag.NONE
+
+    -- default flags: close everything and use shell
+    flags = bit.bor(flags, popen.c.flag.STDIN_CLOSE)
+    flags = bit.bor(flags, popen.c.flag.STDOUT_CLOSE)
+    flags = bit.bor(flags, popen.c.flag.STDERR_CLOSE)
+    flags = bit.bor(flags, popen.c.flag.SHELL)
+    flags = bit.bor(flags, popen.c.flag.SETSID)
+    flags = bit.bor(flags, popen.c.flag.CLOSE_FDS)
+    flags = bit.bor(flags, popen.c.flag.RESTORE_SIGNALS)
+
+    return flags
+end
+
+--
+-- A map for popen option keys into tfn ('true|false|nil') values
+-- where bits are just set without additional manipulations.
+--
+-- For example stdin=true means to open stdin end for write,
+-- stdin=false to close the end, finally stdin[=nil] means to
+-- provide /dev/null into a child peer.
+local flags_map_tfn = {
+    stdin = {
+        popen.c.flag.STDIN,
+        popen.c.flag.STDIN_CLOSE,
+        popen.c.flag.STDIN_DEVNULL,
+    },
+    stdout = {
+        popen.c.flag.STDOUT,
+        popen.c.flag.STDOUT_CLOSE,
+        popen.c.flag.STDOUT_DEVNULL,
+    },
+    stderr = {
+        popen.c.flag.STDERR,
+        popen.c.flag.STDERR_CLOSE,
+        popen.c.flag.STDERR_DEVNULL,
+    },
+}
+
+--
+-- A map for popen option keys into tf ('true|false') values
+-- where bits are set on 'true' and clear on 'false'.
+local flags_map_tf = {
+    shell = {
+        popen.c.flag.SHELL,
+    },
+    close_fds = {
+        popen.c.flag.CLOSE_FDS
+    },
+    restore_signals = {
+        popen.c.flag.RESTORE_SIGNALS
+    },
+    start_new_session = {
+        popen.c.flag.SETSID
+    },
+}
+
+--
+-- Parses flags options from flags_map_tfn and
+-- flags_map_tf tables.
+local function parse_flags(epfx, flags, opts)
+    if opts == nil then
+        return flags
+    end
+    for k,v in pairs(opts) do
+        if flags_map_tfn[k] == nil then
+            if flags_map_tf[k] == nil then
+                error(string.format("%s: Unknown key %s", epfx, k))
+            end
+            if v == true then
+                flags = bit.bor(flags, flags_map_tf[k][1])
+            elseif v == false then
+                flags = bit.band(flags, bit.bnot(flags_map_tf[k][1]))
+            else
+                error(string.format("%s: Unknown value %s", epfx, v))
+            end
+        else
+            if v == true then
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][2]))
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][3]))
+                flags = bit.bor(flags, flags_map_tfn[k][1])
+            elseif v == false then
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][1]))
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][3]))
+                flags = bit.bor(flags, flags_map_tfn[k][2])
+            elseif v == "devnull" then
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][1]))
+                flags = bit.band(flags, bit.bnot(flags_map_tfn[k][2]))
+                flags = bit.bor(flags, flags_map_tfn[k][3])
+            else
+                error(string.format("%s: Unknown value %s", epfx, v))
+            end
+        end
+    end
+    return flags
+end
+
+--
+-- Parse "mode" string to flags
+local function parse_mode(epfx, flags, mode)
+    if mode == nil then
+        return flags
+    end
+    for i = 1, #mode do
+        local c = mode:sub(i, i)
+        if c == 'r' then
+            flags = bit.band(flags, bit.bnot(popen.c.flag.STDOUT_CLOSE))
+            flags = bit.bor(flags, popen.c.flag.STDOUT)
+            flags = bit.band(flags, bit.bnot(popen.c.flag.STDERR_CLOSE))
+            flags = bit.bor(flags, popen.c.flag.STDERR)
+        elseif c == 'w' then
+            flags = bit.band(flags, bit.bnot(popen.c.flag.STDIN_CLOSE))
+            flags = bit.bor(flags, popen.c.flag.STDIN)
+        else
+            error(string.format("%s: Unknown mode %s", epfx, c))
+        end
+    end
+    return flags
+end
+
+--
+-- Close a popen object and release all resources.
+-- In case if there is a running child process
+-- it will be killed.
+--
+-- Returns @ret = true if popen object is closed, and
+-- @ret = false, @err ~= nil on error.
+popen_methods.close = function(self)
+    local ret, err = builtin.delete(self.cdata)
+    if err ~= nil then
+        return false, err
+    end
+    self.cdata = nil
+    return true
+end
+
+--
+-- Kill a child process
+--
+-- Returns @ret = true on success,
+-- @ret = false, @err ~= nil on error.
+popen_methods.kill = function(self)
+    return builtin.kill(self.cdata)
+end
+
+--
+-- Terminate a child process
+--
+-- Returns @ret = true on success,
+-- @ret = false, @err ~= nil on error.
+popen_methods.terminate = function(self)
+    return builtin.term(self.cdata)
+end
+
+--
+-- Send signal with number @signo to a child process
+--
+-- Returns @ret = true on success,
+-- @ret = false, @err ~= nil on error.
+popen_methods.send_signal = function(self, signo)
+    return builtin.signal(self.cdata, signo)
+end
+
+--
+-- Fetch a child process state
+--
+-- Returns @err = nil, @state = popen.c.state, @exit_code = num,
+-- otherwise @err ~= nil.
+popen_methods.state = function(self)
+    return builtin.state(self.cdata)
+end
+
+--
+-- Wait until a child process get exited.
+--
+-- Returns the same as popen_methods.status.
+popen_methods.wait = function(self)
+    local err, state, code
+    while true do
+        err, state, code = builtin.state(self.cdata)
+        if err or state ~= popen.c.state.ALIVE then
+            break
+        end
+        fiber.sleep(self.wait_secs)
+    end
+    return err, state, code
+end
+
+--
+-- popen:read2 - read a stream of a child process
+-- @opts:       options table
+--
+-- The options should have the following keys
+--
+-- @buf:        const_char_ptr_t buffer
+-- @size:       size of the buffer
+-- @flags:      stdout=true or stderr=true
+-- @timeout:    read timeout in seconds, < 0 to ignore
+--
+-- Returns @res = bytes, err = nil in case if read processed
+-- without errors, @res = nil, @err ~= nil otherwise.
+popen_methods.read2 = function(self, opts)
+    local flags = parse_flags("popen:read2",
+                              popen.c.flag.NONE,
+                              opts['flags'])
+    local timeout = -1
+
+    if opts['buf'] == nil then
+        error("popen:read2 {'buf'} key is missed")
+    elseif opts['size'] == nil then
+        error("popen:read2 {'size'} key is missed")
+    elseif opts['timeout'] ~= nil then
+        timeout = tonumber(opts['timeout'])
+    end
+
+    return builtin.read(self.cdata, opts['buf'],
+                        tonumber(opts['size']),
+                        flags, timeout)
+end
+
+--
+-- popen:write2 - write to a child's streem
+-- @opts:       options table
+--
+-- The options should have the following keys
+--
+-- @buf:        const_char_ptr_t buffer
+-- @size:       size of the buffer
+-- @flags:      stdin=true
+-- @timeout:    write timeout in seconds, < 0 to ignore
+--
+-- Returns @err = nil on success, @err ~= nil otherwise.
+popen_methods.write2 = function(self, opts)
+    local flags = parse_flags("popen:write2",
+                              popen.c.flag.NONE,
+                              opts['flags'])
+    local timeout = -1
+
+    if opts['buf'] == nil then
+        error("popen:write2 {'buf'} key is missed")
+    elseif opts['size'] == nil then
+        error("popen:write2 {'size'} key is missed")
+    elseif opts['timeout'] ~= nil then
+        timeout = tonumber(opts['timeout'])
+    end
+
+    return builtin.write(self.cdata, opts['buf'],
+                         tonumber(opts['size']),
+                         flags, timeout)
+end
+
+--
+-- popen:read - read string from a stream
+-- @stderr:     set to true to read from stderr, optional
+-- @timeout:    timeout in seconds, optional
+--
+-- Returns a result string, or res = nil, @err ~= nil on error.
+popen_methods.read = function(self, stderr, timeout)
+    local ibuf = buffer.ibuf()
+    local buf = ibuf:reserve(self.read_size)
+    local flags
+
+    if stderr ~= nil then
+        flags = { stderr = true }
+    else
+        flags = { stdout = true }
+    end
+
+    if timeout == nil then
+        timeout = -1
+    end
+
+    local res, err = self:read2({
+        buf     = buf,
+        size    = self.read_size,
+        flags   = flags,
+        timeout = timeout,
+    })
+
+    if err ~= nil then
+        ibuf:recycle()
+        return nil, err
+    end
+
+    ibuf:alloc(res)
+    res = ffi.string(ibuf.rpos, ibuf:size())
+    ibuf:recycle()
+
+    return res
+end
+
+--
+-- popen:write - write string @str to stdin stream
+-- @str:        string to write
+-- @timeout:    timeout in seconds, optional
+--
+-- Returns @err = nil on success, @err ~= nil on error.
+popen_methods.write = function(self, str, timeout)
+    if timeout == nil then
+        timeout = -1
+    end
+    return self:write2({
+        buf     = str,
+        size    = #str,
+        flags   = { stdin = true },
+        timeout = timeout,
+    })
+end
+
+--
+-- popen:info -- obtain information about a popen object
+--
+-- Returns @info table, err == nil on success,
+-- @info = nil, @err ~= nil otherwise.
+--
+-- The @info table contains the following keys:
+--
+-- @pid:        pid of a child process
+-- @flags:      flags associated (popen.c.flag bitmap)
+-- @stdout:     parent peer for stdout, -1 if closed
+-- @stderr:     parent peer for stderr, -1 if closed
+-- @stdin:      parent peer for stdin, -1 if closed
+-- @state:      alive | exited | signaled
+-- @exit_code:  exit code of a child process if been
+--              exited or killed by a signal
+--
+-- The child should never be in "unknown" state, reserved
+-- for unexpected errors.
+--
+popen_methods.info = function(self)
+    return builtin.info(self.cdata)
+end
+
+--
+-- Create a new popen object from options
+--
+-- Returns ret ~= nil, err = nil on success,
+-- ret = nil, err ~= nil on failure.
+local function popen_reify(opts)
+    local cdata, err = builtin.new(opts)
+    if err ~= nil then
+        return nil, err
+    end
+
+    local handle = {
+        -- a handle itself for future use
+        cdata           = cdata,
+
+        -- sleeping period for the @wait method
+        wait_secs       = 0.3,
+
+        -- size of a read buffer to allocate
+        -- in case of implicit read, this number
+        -- is taken from luatest repo to fit the
+        -- value people are familiar with
+        read_size       = 4096,
+    }
+
+    setmetatable(handle, {
+        __index     = popen_methods,
+    })
+
+    return handle
+end
+
+--
+-- popen.posix - create a new child process and execute a command inside
+-- @command:    a command to run
+-- @mode:       r - to grab child's stdout for read
+--              (stderr kept opened as well for 2>&1 redirection)
+--              w - to obtain stdin for write
+--
+-- Returns handle ~= nil, err = nil on success, err ~= nil otherwise.
+--
+-- Note: Since there are two options only the following parameters
+-- are implied (see default_flags): all fds except stdin/out/err
+-- are closed, signals are restored to default handlers, the command
+-- is executed in a new session.
+--
+-- Examples:
+--
+--  ph = require('popen').posix("date", "r")
+--      runs date as "sh -c date" to read the output,
+--      closing all file descriptors except stdout/err
+--      inside a child process
+--
+popen.posix = function(command, mode)
+    local flags = default_flags()
+
+    if type(command) ~= 'string' then
+        error("Usage: popen.posix(command[, rw])")
+    end
+
+    -- Mode gives simplified flags
+    flags = parse_mode("popen.posix", flags, mode)
+
+    local opts = {
+        argv    = { command },
+        argc    = 1,
+        flags   = flags,
+        envc    = -1,
+    }
+
+    return popen_reify(opts)
+end
+
+-- popen.popen - execute a child program in a new process
+-- @opt:    options table
+--
+-- @opts carries of the following options:
+--
+--  @argv:  an array of a program to run with
+--          command line options, mandatory
+--
+--  @env:   an array of environment variables to
+--          be used inside a process, if not
+--          set then the current environment is
+--          inherited, if set to an empty array
+--          then the environment will be dropped
+--
+--  @flags: a dictionary to describe communication pipes
+--          and other parameters of a process to run
+--
+--      stdin=true      to write into STDIN_FILENO of a child process
+--      stdin=false     to close STDIN_FILENO inside a child process [*]
+--      stdin="devnull" a child will get /dev/null as STDIN_FILENO
+--
+--      stdout=true     to read STDOUT_FILENO of a child process
+--      stdout=false    to close STDOUT_FILENO inside a child process [*]
+--      stdout="devnull" a child will get /dev/null as STDOUT_FILENO
+--
+--      stderr=true     to read STDERR_FILENO from a child process
+--      stderr=false    to close STDERR_FILENO inside a child process [*]
+--      stderr="devnull" a child will get /dev/null as STDERR_FILENO
+--
+--      shell=true      runs a child process via "sh -c" [*]
+--      shell=false     invokes a child process executable directly
+--
+--      close_fds=true  close all inherited fds from a parent [*]
+--
+--      restore_signals=true
+--                      all signals modified by a caller reset
+--                      to default handler [*]
+--
+--      start_new_session=true
+--                      start executable inside a new session [*]
+--
+-- [*] are default values
+--
+-- Returns handle ~= nil, err = nil on success, err ~= nil otherwise.
+--
+-- Examples:
+--
+--  ph = require('popen').popen({argv = {"date"}, flags = {stdout=true}})
+--  ph:read()
+--  ph:close()
+--
+--      Execute 'date' command inside a shell, read the result
+--      and close the popen object
+--
+--  ph = require('popen').popen({argv = {"/usr/bin/echo", "-n", "hello"},
+--                               flags = {stdout=true, shell=false}})
+--  ph:read()
+--  ph:close()
+--
+--      Execute /usr/bin/echo with arguments '-n','hello' directly
+--      without using a shell, read the result from stdout and close
+--      the popen object
+--
+popen.popen = function(opts)
+    local flags = default_flags()
+
+    if opts == nil or type(opts) ~= 'table' then
+        error("Usage: popen({argv={}[, envp={}, flags={}]")
+    end
+
+    -- Test for required arguments
+    if opts["argv"] == nil then
+        error("popen: argv key is missing")
+    end
+
+    -- Process flags and save updated mask
+    -- to pass into engine (in case of missing
+    -- flags we just use defaults).
+    if opts["flags"] ~= nil then
+        flags = parse_flags("popen", flags, opts["flags"])
+    end
+    opts["flags"] = flags
+
+    -- We will need a number of args for speed sake
+    opts["argc"] = #opts["argv"]
+
+    -- Same applies to the environment (note though
+    -- that env={} is pretty valid and env=nil
+    -- as well.
+    if opts["env"] ~= nil then
+        opts["envc"] = #opts["env"]
+    else
+        opts["envc"] = -1
+    end
+
+    return popen_reify(opts)
+end
+
+return popen
-- 
2.20.1



More information about the Tarantool-patches mailing list