Re: [PATCH 1/1] fix system() behaviour when parameter is NULL

["Andy Shevchenko" <andy.shevchenko%gmail.com@localhost>]

On Fri, Aug 22, 2008 at 12:27 PM, Hubert Feyrer <hubert%feyrer.de@localhost> 
wrote:
>>>> +zero if none is available. Otherwise,
>>> s/shall/will/
>> Err.. sorry. There was copy'n'past from OpenGroup's manual.
Anyway in neighbour mail thread the other objection to resubmit the patch,
so, I put new one here

diff --git a/lib/libc/stdlib/system.3 b/lib/libc/stdlib/system.3
index 6c1c733..18b866e 100644
--- a/lib/libc/stdlib/system.3
+++ b/lib/libc/stdlib/system.3
@@ -67,7 +67,8 @@ is a
 .Dv NULL
 pointer,
 .Fn system
-will return non-zero.
+will return non-zero, if the command interpreter is available, or zero if none
+is available.
 Otherwise,
 .Fn system
 returns the termination status of the shell in the format specified by
diff --git a/lib/libc/stdlib/system.c b/lib/libc/stdlib/system.c
index 4cc3cbe..b156d67 100644
--- a/lib/libc/stdlib/system.c
+++ b/lib/libc/stdlib/system.c
@@ -64,8 +64,15 @@ system(command)
        const char *argp[] = {"sh", "-c", NULL, NULL};
        argp[2] = command;

-       if (command == NULL)            /* just checking... */
-               return(1);
+       /*
+        * ISO/IEC 9899:1999 in 7.20.4.6 describes this special case.
+        * We need to check availability of a command interpreter.
+        */
+       if (command == NULL) {
+               if (access(_PATH_BSHELL, X_OK) == 0)
+                       return 1;
+               return 0;
+       }

        sa.sa_handler = SIG_IGN;
        sigemptyset(&sa.sa_mask);

-- 
With Best Regards,
Andy Shevchenko