Re: os.exit()/os.execute() behaviour (Lua 5.1)

[Harley Laue <losinggeneration@...>]

On 05/17/13 08:39, Luiz Henrique de Figueiredo wrote:
> > I ran into some issues testing for os.execute() results.
> Lua 5.2 does a better job there.
Here's a patch to make loslib.c in Lua 5.1.5 match how it works in Lua 
5.2 (this was a quick code import from Lua 5.2.1, so it may not be correct.)

Basically when LUA_USE_POSIX is defined, it uses WIFEXITED with 
WEXITSTATUS to normalize the exit code a bit (the inspectstat macro.)
--- loslib.orig.c	2013-05-17 08:53:19.651764788 -0500
+++ loslib.c	2013-05-17 08:53:28.699764584 -0500
@@ -19,6 +19,60 @@
 #include "lauxlib.h"
 #include "lualib.h"
 
+/* From lua 5.2 */
+#if !defined(inspectstat)	/* { */
+
+#if defined(LUA_USE_POSIX)
+
+#include <sys/wait.h>
+
+/*
+** use appropriate macros to interpret 'pclose' return status
+*/
+#define inspectstat(stat,what)  \
+   if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
+   else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }
+
+#else
+
+#define inspectstat(stat,what)  /* no op */
+
+#endif
+
+#endif				/* } */
+
+static int luaL_fileresult (lua_State *L, int stat, const char *fname) {
+  int en = errno;  /* calls to Lua API may change this value */
+  if (stat) {
+    lua_pushboolean(L, 1);
+    return 1;
+  }
+  else {
+    lua_pushnil(L);
+    if (fname)
+      lua_pushfstring(L, "%s: %s", fname, strerror(en));
+    else
+      lua_pushfstring(L, "%s", strerror(en));
+    lua_pushinteger(L, en);
+    return 3;
+  }
+}
+
+static int luaL_execresult (lua_State *L, int stat) {
+  const char *what = "exit";  /* type of termination */
+  if (stat == -1)  /* error? */
+    return luaL_fileresult(L, 0, NULL);
+  else {
+    inspectstat(stat, what);  /* interpret result */
+    if (*what == 'e' && stat == 0)  /* successful termination? */
+      lua_pushboolean(L, 1);
+    else
+      lua_pushnil(L);
+    lua_pushstring(L, what);
+    lua_pushinteger(L, stat);
+    return 3;  /* return true/nil,what,code */
+  }
+}
 
 static int os_pushresult (lua_State *L, int i, const char *filename) {
   int en = errno;  /* calls to Lua API may change this value */
@@ -34,11 +88,26 @@
   }
 }
 
+static int os_execute (lua_State *L) {
+  const char *cmd = luaL_optstring(L, 1, NULL);
+  int stat = system(cmd);
+  if (cmd != NULL)
+    return luaL_execresult(L, stat);
+  else {
+    lua_pushboolean(L, stat);  /* true if there is a shell */
+    return 1;
+  }
+}
+
+/*  End from lua 5.2 */
 
+/* Original os_execute from lua 5.1.5 */
+/*
 static int os_execute (lua_State *L) {
   lua_pushinteger(L, system(luaL_optstring(L, 1, NULL)));
   return 1;
 }
+*/
 
 
 static int os_remove (lua_State *L) {