[patch] "exec" to enable a binary string in pipe

[kosh]

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syntax: (exec str-process)
syntax: (exec str-process [str-stdin])

Current exec function second syntax (p_exec:nl-filesys.c) is unable use a binary string.

There is caused by strlen function which treat as a NULL terminator character.



newLISP's cell string has own length. I think this problem can be avoided, if use it.



For instance, patch is here:

Code Select Expand


--- nl-filesys.orig.c. Mon Apr 19 07:29:16 2010
+++ nl-filesys.c Sun May 30 23:07:09 2010
@@ -958,10 +957,11 @@
 
 CELL * p_exec(CELL * params)
 {
-CELL * lineList;
+  CELL * cell;
 char * line;
-char * command, * data;
+  char * command;
 FILE * handle;
+  size_t nwrite;
 
 params = getString(params, &command);
 if(params == nilCell)
@@ -969,21 +969,26 @@
  if((handle = popen(command , "r")) == NULL)
  return(nilCell);
 
- lineList = getCell(CELL_EXPRESSION);
+      cell = getCell(CELL_EXPRESSION);
  while((line = readStreamLine(&readLineStream, handle)) != NULL)
- addList(lineList, stuffString(line));
+        addList(cell, stuffString(line));
 
  pclose(handle);
- return(lineList);
+      return(cell);
  }
     
-getString(params, &data);
+  /* getString(params, &data); */
+  cell = evaluateExpression(params);
+  if (cell->type != CELL_STRING)
+    return(errorProcExt(ERR_STRING_EXPECTED, params));
 
 if((handle = popen(command, "w")) == NULL)
  return(nilCell);
 
-if(fwrite(data, sizeof(char), strlen(data), handle) < strlen(data))
- return(nilCell);
+  /* if(fwrite(data, sizeof(char), strlen(data), handle) < strlen(data)) */
+  nwrite = fwrite((char *)cell->contents, sizeof(char), cell->aux -1, handle);
+  if (nwrite < (cell->aux -1))
+    return nilCell;
 
 pclose(handle);
 return(trueCell);


Now, exec function enable binary string.

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[~/src/newlisp-10.2.4]$ ./newlisp -C
newLISP v.10.2.4 on Win32 IPv4, execute 'newlisp -h' for more info.

> (exec "sha1sum -" (get-url "http://www.newlisp.org/downloads/UTF-8_win32/newlisp.exe"))
db2c8f9161993bd965dd8efd75d3aa6f22f71c6f *-
true
> !curl http://www.newlisp.org/downloads/UTF-8_win32/SHA1.txt
SHA1(newlisp.dll)= 145bb1a411dd12c9e43ea052014038fd383f95ed
SHA1(newlisp.exe)= db2c8f9161993bd965dd8efd75d3aa6f22f71c6f

[TedWalther]

I like your idea and hope Lutz includes it.



However, I don't think this will fix your problem.  Exec passes that string to the shell, which in turns parses the command line.  But all shells I know of are written in C and take C style strings, so at the first byte, it will stop processing anyway.



I support your fix, because it is conceivable that one day someone will compile newlisp to use some other shell than the standard one for exec, possibly even one that has proper strings, not just C style strings.  Then it would work.

[TedWalther]

Actually, I can see how this would be helpful with "here" documents.  So it would be a useful patch right now.