Lua using wrong os.system ?

[s-ol]

$ lua5.1
Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
> os.execute('echo test')
test
> os.execute('echo test > /dev/null')
The system cannot find the path specified.
> os.execute('echo test > NUL')
>

this makes it very hard to run any lua based projects that build other things (like luarocks) because they must use windows cmd.exe syntax but somehow still work within the MSYS directory strucutre and use the mingw buildchain.

[s-ol]

I monkey-patched it very badly with this:

--- src/loslib.c.orig   2008-01-18 17:38:18.000000000 +0100
+++ src/loslib.c        2016-10-15 18:23:37.178565100 +0200
@@ -36,6 +36,10 @@

 static int os_execute (lua_State *L) {
+  lua_pushstring(L, "%WD%\\..\\..\\mingw32 bash -c \"");
+  lua_insert(L, -2);
+  lua_pushstring(L, "\"");
+  lua_concat(L, 3);
   lua_pushinteger(L, system(luaL_optstring(L, 1, NULL)));
   return 1;
 }

--- src/liolib.c.orig   2010-05-14 17:33:51.000000000 +0200
+++ src/liolib.c        2016-10-15 18:23:37.181581800 +0200
@@ -172,6 +172,10 @@
 ** correct __close for 'popen' files
 */
 static int io_popen (lua_State *L) {
+  lua_pushstring(L, "%WD%\\..\\..\\mingw32 bash -c \"");
+  lua_insert(L, -2);
+  lua_pushstring(L, "\"");
+  lua_concat(L, 3);
   const char *filename = luaL_checkstring(L, 1);
   const char *mode = luaL_optstring(L, 2, "r");
   FILE **pf = newfile(L);

but not only doesn't it escape the command string properly, it also opens a new shell window, takes ages and doesn't provide any output where it should. Is there a way not to open a new shell window?

well duh, and it's way easier:

--- src/loslib.c.orig   2008-01-18 17:38:18.000000000 +0100
+++ src/loslib.c        2016-10-15 18:23:37.178565100 +0200
@@ -36,6 +36,10 @@

 static int os_execute (lua_State *L) {
+  lua_pushstring(L, "%WD%\\bash -c \"");
+  lua_insert(L, -2);
+  lua_pushstring(L, "\"");
+  lua_concat(L, 3);
   lua_pushinteger(L, system(luaL_optstring(L, 1, NULL)));
   return 1;
 }

--- src/liolib.c.orig   2010-05-14 17:33:51.000000000 +0200
+++ src/liolib.c        2016-10-15 18:23:37.181581800 +0200
@@ -172,6 +172,10 @@
 ** correct __close for 'popen' files
 */
 static int io_popen (lua_State *L) {
+  lua_pushstring(L, "%WD%\\bash -c \"");
+  lua_insert(L, -2);
+  lua_pushstring(L, "\"");
+  lua_concat(L, 3);
   const char *filename = luaL_checkstring(L, 1);
   const char *mode = luaL_optstring(L, 2, "r");
   FILE **pf = newfile(L);

...buuuuut the whole io library still uses the wrong paths.

[Alexpux]

Well I'm not be able to fix it myself because of lack of time. Try do it yourself or ask someone

[SlySven]

Since you are spawning a bash instance to do the lifting can you not use the cygpath as well to tweak the paths to the wanted form?

$ cygpath --help
Usage: cygpath (-d|-m|-u|-w|-t TYPE) [-f FILE] [OPTION]... NAME...
       cygpath [-c HANDLE]
       cygpath [-ADHOPSW]
       cygpath [-F ID]

Convert Unix and Windows format paths, or output system path information

Output type options:

  -d, --dos             print DOS (short) form of NAMEs (C:\PROGRA~1\)
  -m, --mixed           like --windows, but with regular slashes (C:/WINNT)
  -M, --mode            report on mode of file (binmode or textmode)
  -u, --unix            (default) print Unix form of NAMEs (/cygdrive/c/winnt)
  -w, --windows         print Windows form of NAMEs (C:\WINNT)
  -t, --type TYPE       print TYPE form: 'dos', 'mixed', 'unix', or 'windows'

Path conversion options:

  -a, --absolute        output absolute path
  -l, --long-name       print Windows long form of NAMEs (with -w, -m only)
  -p, --path            NAME is a PATH list (i.e., '/bin:/usr/bin')
  -U, --proc-cygdrive   Emit /proc/cygdrive path instead of cygdrive prefix
                        when converting Windows path to UNIX path.
  -s, --short-name      print DOS (short) form of NAMEs (with -w, -m only)
  -C, --codepage CP     print DOS, Windows, or mixed pathname in Windows
                        codepage CP.  CP can be a numeric codepage identifier,
                        or one of the reserved words ANSI, OEM, or UTF8.
                        If this option is missing, cygpath defaults to the
                        character set defined by the current locale.

System information:

  -A, --allusers        use `All Users' instead of current user for -D, -O, -P
  -D, --desktop         output `Desktop' directory and exit
  -H, --homeroot        output `Profiles' directory (home root) and exit
  -O, --mydocs          output `My Documents' directory and exit
  -P, --smprograms      output Start Menu `Programs' directory and exit
  -S, --sysdir          output system directory and exit
  -W, --windir          output `Windows' directory and exit
  -F, --folder ID       output special folder with numeric ID and exit

Other options:

  -f, --file FILE       read FILE for input; use - to read from STDIN
  -o, --option          read options from FILE as well (for use with --file)
  -c, --close HANDLE    close HANDLE (for use in captured process)
  -i, --ignore          ignore missing argument
  -h, --help            output usage information and exit
  -V, --version         output version information and exit

[AgentRev]

Still a problem, os.execute is still incorrectly interpreted via Windows CMD instead of Bash.