[Bug libfortran/42996] New: Incorrect length returned from get_command_argument intrinsic

[Bug libfortran/42996] New: Incorrect length returned from get_command_argument intrinsic

[ian_harvey at bigpond dot com]

According to the F2003 standard, the LENGTH argument does "not consider any
possible truncation or padding in assigning the command argument value to the
VALUE argument" (13.7.42).  However, gfortran appears to use the minimum of the
length of the VALUE argument (if present) and the length of the command
argument.

(svn revision 156557)


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           Summary: Incorrect length returned from get_command_argument
                    intrinsic
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ian_harvey at bigpond dot com
 GCC build triplet: i686-pc-mingw32
  GCC host triplet: i686-pc-mingw32
GCC target triplet: i686-pc-mingw32


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42996

[Bug libfortran/42996] Incorrect length returned from get_command_argument intrinsic

[ian_harvey at bigpond dot com]

------- Comment #1 from ian_harvey at bigpond dot com  2010-02-08 10:48 -------
Created an attachment (id=19819)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19819&action=view)
Simple test case

Call the resulting program with an argument longer than one character.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42996

[Bug libfortran/42996] Incorrect length returned from get_command_argument intrinsic

[burnus at gcc dot gnu dot org]

------- Comment #2 from burnus at gcc dot gnu dot org  2010-02-08 13:19 -------
Confirm - I get for "./a.out test" the following result.

Current (gfortran):
   With no value, length was:4 and status:0
   With LEN=1 value, length was:1 and status:-1 <<<<< Bad: len = 1
   With LEN=10 value, length was:4 and status:0

Expected (NAG f95, ifort):
   With no value, length was:4 and status:0
   With LEN=1 value, length was:4 and status:-1 <<<<< OK: len = 4
   With LEN=10 value, length was:4 and status:0

By the way, the manual is correct:
http://gcc.gnu.org/onlinedocs/gfortran/GET_005fCOMMAND_005fARGUMENT.html


Draft patch:

diff --git a/libgfortran/intrinsics/args.c b/libgfortran/intrinsics/args.c
index 7187bec..83a0502 100644
--- a/libgfortran/intrinsics/args.c
+++ b/libgfortran/intrinsics/args.c
@@ -147,11 +147,9 @@ get_command_argument_i4 (GFC_INTEGER_4 *number, char
*value,
   if (value != NULL && stat_flag != GFC_GC_FAILURE)
     {
       if (arglen > value_len)
-       {
-        arglen = value_len;
         stat_flag = GFC_GC_VALUE_TOO_SHORT;
-       }
-      memcpy (value, argv[*number], arglen);
+
+      memcpy (value, argv[*number], arglen > value_len ? value_len : arglen);
     }

   if (length != NULL)


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burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-02-08 13:19:24
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42996

[Bug libfortran/42996] Incorrect length returned from get_command_argument intrinsic

[burnus at gcc dot gnu dot org]

------- Comment #3 from burnus at gcc dot gnu dot org  2010-02-09 17:05 -------
Subject: Bug 42996

Author: burnus
Date: Tue Feb  9 17:04:57 2010
New Revision: 156630

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=156630
Log:
2010-02-09  Tobias Burnus  <burnus@net-b.de>

        PR fortran/42996
        * intrinsics/args.c (get_command_argument_i4): Always return
        commandline-argument length for length parameter.


Modified:
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/intrinsics/args.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42996

[Bug libfortran/42996] Incorrect length returned from get_command_argument intrinsic

[burnus at gcc dot gnu dot org]

------- Comment #4 from burnus at gcc dot gnu dot org  2010-02-09 17:07 -------
FIXED on the trunk (4.5).

Thanks for the bug report!


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burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42996