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lua5.2 support and fd leak fixed if pipe() or fork() fails #1

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lua5.2 support and fd leak fixed if pipe() or fork() fails #1

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14 changes: 9 additions & 5 deletions Makefile
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Original file line number Diff line number Diff line change
@@ -1,16 +1,20 @@
LUA_PREFIX = /usr/local/
PREFIX = /usr/local/
LUA_PKGCONF ?= lua

MODULE = lpc
VERSION = 1.0.0

INSTALL_PREFIX = $(PREFIX)/lib/lua/5.1/
ifneq ($(shell pkg-config $(LUA_PKGCONF) || echo not-installed),)
$(error $(LUA_PKGCONF).pc not found)
endif

INSTALL_PREFIX = $(DESTDIR)$(shell pkg-config $(LUA_PKGCONF) --variable=INSTALL_CMOD)

CC = gcc
TARGET = lpc.so
OBJS = lpc.o
LIBS =
CFLAGS = -I $(LUA_PREFIX)/include -fPIC
LDFLAGS = -shared -fPIC
CFLAGS = $(shell pkg-config $(LUA_PKGCONF) --cflags) -fPIC
LDFLAGS = $(shell pkg-config $(LUA_PKGCONF) --libs) -shared -fPIC

default: $(TARGET)

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178 changes: 112 additions & 66 deletions lpc.c
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
/*
** LuaProcessCall
** Copyright DarkGod 2007
**
** lua 5.1/5.2 compat (c) 2014 Timo Teräs
*/

#include <errno.h>
Expand All @@ -15,47 +15,98 @@
#include "lauxlib.h"
#include "lualib.h"

#define topfile(L) ((FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE))
#if LUA_VERSION_NUM < 502

static FILE *tofile (lua_State *L) {
FILE **f = topfile(L);
if (*f == NULL)
luaL_error(L, "attempt to use a closed file");
return *f;
static int lua_absindex(lua_State *L, int idx) {
return (idx > 0 || idx <= LUA_REGISTRYINDEX)? idx : lua_gettop(L) + idx + 1;
} /* lua_absindex() */

static void luaL_setfuncs(lua_State *L, const luaL_Reg *l, int nup) {
int i, t = lua_absindex(L, -1 - nup);

for (; l->name; l++) {
for (i = 0; i < nup; i++)
lua_pushvalue(L, -nup);
lua_pushcclosure(L, l->func, nup);
lua_setfield(L, t, l->name);
}

lua_pop(L, nup);
} /* luaL_setfuncs() */

#define luaL_newlibtable(L, l) \
lua_createtable(L, 0, (sizeof (l) / sizeof *(l)) - 1)

#define luaL_newlib(L, l) \
(luaL_newlibtable((L), (l)), luaL_setfuncs((L), (l), 0))

#ifndef LUA_FILEHANDLE /* Not defined by earlier LuaJIT releases */
#define LUA_FILEHANDLE "FILE*"
#endif

/*
* Lua 5.1 userdata is a simple FILE *, while LuaJIT is a struct with the
* first member a FILE *, similar to Lua 5.2.
*/
typedef struct luaL_Stream {
FILE *f;
} luaL_Stream;

static int luaL_fileresult(lua_State *L, int stat, const char *filename) {
int en = errno; /* calls to Lua API may change this value */
if (stat) {
lua_pushboolean(L, 1);
return 1;
}
else {
lua_pushnil(L);
if (filename)
lua_pushfstring(L, "%s: %s", filename, strerror(en));
else
lua_pushfstring(L, "%s", strerror(en));
lua_pushinteger(L, en);
return 3;
}
}

static int pushresult (lua_State *L, int i, const char *filename) {
int en = errno; /* calls to Lua API may change this value */
if (i) {
lua_pushboolean(L, 1);
return 1;
}
else {
lua_pushnil(L);
if (filename)
lua_pushfstring(L, "%s: %s", filename, strerror(en));
else
lua_pushfstring(L, "%s", strerror(en));
lua_pushinteger(L, en);
return 3;
}
#define isclosed(p) ((p)->f == NULL)
#define markclosed(p) ((p)->f = NULL)

#else

#define isclosed(p) ((p)->closef == NULL)
#define markclosed(p) ((p)->closef = NULL)

#endif

#define tolstream(L) ((luaL_Stream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))

static FILE *tofile (lua_State *L) {
luaL_Stream *p = tolstream(L);
if (isclosed(p))
luaL_error(L, "attempt to use a closed file");
return p->f;
}

static int io_fclose (lua_State *L) {
FILE **p = topfile(L);
int ok = (fclose(*p) == 0);
*p = NULL;
return pushresult(L, ok, NULL);
static int io_fclose (lua_State *L)
{
luaL_Stream *p = tolstream(L);
int res = fclose(p->f);
markclosed(p);
return luaL_fileresult(L, (res == 0), NULL);
}

static FILE **newfile_fd(lua_State *L, int fd, const char *mode)
static luaL_Stream *newfile_fd(lua_State *L, int fd, const char *mode)
{
FILE **pf = (FILE **)lua_newuserdata(L, sizeof(FILE *));
*pf = NULL; /* file handle is currently `closed' */
luaL_Stream *p = (luaL_Stream *) lua_newuserdata(L, sizeof(luaL_Stream));
markclosed(p);
luaL_getmetatable(L, LUA_FILEHANDLE);
lua_setmetatable(L, -2);
*pf = fdopen(fd, mode);
return pf;
p->f = fdopen(fd, mode);
#if LUA_VERSION_NUM >= 502
p->closef = &io_fclose;
#endif
return p;
}

static int lpc_run(lua_State *L)
Expand All @@ -64,12 +115,12 @@ static int lpc_run(lua_State *L)
int p_in[2];
int pid;

if (pipe(p_out) == -1) { lua_pushnil(L); return 1; }
if (pipe(p_in) == -1) { lua_pushnil(L); return 1; }
if (pipe(p_out) == -1) goto err_noclose;
if (pipe(p_in) == -1) goto err_closeout;
if ((pid = fork()) == -1) goto err_closeinout;

if ((pid = fork()) == -1) { lua_pushnil(L); return 1; }
else if (pid == 0)
{
if (pid == 0) {
/* child */
char **args;
int n = lua_gettop(L); /* number of arguments */
int i;
Expand All @@ -93,20 +144,24 @@ static int lpc_run(lua_State *L)
_exit(1);
return 0;
}
else
{
FILE **in;
FILE **out;

/* Cleanup */
close(p_out[0]);
close(p_in[1]);

lua_pushnumber(L, pid);
out = newfile_fd(L, p_out[1], "w");
in = newfile_fd(L, p_in[0], "r");
return 3;
}
/* Cleanup */
close(p_out[0]);
close(p_in[1]);
lua_pushnumber(L, pid);
newfile_fd(L, p_out[1], "w");
newfile_fd(L, p_in[0], "r");
return 3;

err_closeinout:
close(p_in[0]);
close(p_in[1]);
err_closeout:
close(p_out[0]);
close(p_out[1]);
err_noclose:
lua_pushnil(L);
return 1;
}

static int lpc_wait(lua_State *L)
Expand All @@ -116,13 +171,9 @@ static int lpc_wait(lua_State *L)
int nonblock = luaL_optinteger(L, 2, 0);

if (waitpid(pid, &ret, (nonblock == 1) ? WNOHANG : 0) == pid)
{
lua_pushnumber(L, ret);
}
else
{
lua_pushnil(L);
}
return 1;
}

Expand All @@ -141,13 +192,9 @@ static int f_readable(lua_State *L)
FD_SET(fileno(f), &rfds);
retval = select(1 + fileno(f), &rfds, NULL, NULL, &tv);
if (retval == 1)
{
lua_pushboolean(L, 1);
}
else
{
lua_pushnil(L);
}
return 1;
}

Expand All @@ -166,13 +213,9 @@ static int f_writable(lua_State *L)
FD_SET(fileno(f), &wfds);
retval = select(1 + fileno(f), NULL, &wfds, NULL, &tv);
if (retval == 1)
{
lua_pushboolean(L, 1);
}
else
{
lua_pushboolean(L, 0);
}
return 1;
}

Expand All @@ -192,7 +235,7 @@ static void set_info (lua_State *L)
lua_settable (L, -3);
}

static const struct luaL_reg lpclib[] =
static const struct luaL_Reg lpclib[] =
{
{"run", lpc_run},
{"wait", lpc_wait},
Expand All @@ -207,15 +250,15 @@ static const luaL_Reg io_add_flib[] = {

static void createmeta(lua_State *L)
{
luaL_getmetatable(L, LUA_FILEHANDLE); /* get IO's metatable for file handles */
luaL_register(L, NULL, io_add_flib); /* file methods */
luaL_getmetatable(L, LUA_FILEHANDLE); /* get IO's metatable for file handles */
luaL_setfuncs(L, io_add_flib, 0); /* file methods */
}


int luaopen_lpc (lua_State *L)
{
createmeta(L);

#if LUA_VERSION_NUM < 502
luaL_openlib(L, "lpc", lpclib, 0);

/* create environment for 'run' */
Expand All @@ -225,6 +268,9 @@ int luaopen_lpc (lua_State *L)
lua_setfield(L, -2, "__close");
lua_setfenv(L, -2);
lua_pop(L, 1); /* pop 'run' */
#else
luaL_newlib(L, lpclib);
#endif

set_info(L);
return 1;
Expand Down