Re: env: add -S option (split string for shebang lines in scripts)

[Eric Blake]

On 04/27/2018 08:13 AM, Eric Blake wrote:

>> Well, env doesn't know at that point that -S is coming later ... still
>> the error message is really confusing.  Any idea?
> 
> We could include ' ' (and maybe '\t') as part of the short-option
> optstring accepted in getopt_long(), as an undocumented silent no-op.
> That would make '-v ' behave the same as '-v'.  But I'm not sure if it
> is ever possible to coax getopt_long() into parsing '-v-' as accepting a
> short option named '-' (since usually, the string '--' is treated as
> end-of-options).  Worth a try, to see if it works?

I tested it, and it DOES seem to work:

Pre-patch:

$ env "$(printf -- '-0\t -0')" | grep nosuch
env: invalid option -- '        '
Try 'env --help' for more information.
$

Post-patch:
$ ./src/env "$(printf -- '-0\t -0')" | grep nosuch
$

(Admittedly, my experiment was done without the -S patch in place, but
you can figure out how to incorporate it)

diff --git i/src/env.c w/src/env.c
index bacef9b02..db2085034 100644
--- i/src/env.c
+++ w/src/env.c
@@ -96,10 +96,15 @@ main (int argc, char **argv)
   initialize_exit_failure (EXIT_CANCELED);
   atexit (close_stdout);

-  while ((optc = getopt_long (argc, argv, "+C:iu:0", longopts, NULL))
!= -1)
+  while ((optc = getopt_long (argc, argv, "+C:iu:0 \t-", longopts,
NULL)) != -1)
     {
       switch (optc)
         {
+        case ' ':
+        case '\t':
+        case '-':
+          /* Undocumented no-ops, to allow '-v -S' to behave like '-vS' */
+          break;
         case 'i':
           ignore_environment = true;
           break;
@@ -128,7 +133,7 @@ main (int argc, char **argv)
     }

   optind = 0;                  /* Force GNU getopt to re-initialize. */
-  while ((optc = getopt_long (argc, argv, "+C:iu:0", longopts, NULL))
!= -1)
+  while ((optc = getopt_long (argc, argv, "+C:iu:0 \t-", longopts,
NULL)) != -1)
     if (optc == 'u' && unsetenv (optarg))
       die (EXIT_CANCELED, errno, _("cannot unset %s"), quote (optarg));


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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