Re: use of program_name

[James Youngman]

On Thu, Jan 05, 2006 at 03:06:59PM -0800, Paul Eggert wrote:

> address@hidden (James Youngman) writes:
> 
> > I would prefer an arrangement which results in a compilation or link
> > failure if the user (i.e. software maintainer) fails to initialise
> > things properly.
> 
> Perhaps we could change progname.h so that 'program_name' is a
> function that returns the program name, instead of being a global
> variable.  That should catch mishaps at link-time, if not before.

The enclosed patch makes this change.

2006-01-06  James Youngman <address@hidden>

        * lib/progname.h, lib/error.h (program_name): Change program_name
        from a global variable to a global function.
        
        * lib/error.c (error): Use it.
        
        * lib/progname.c (program_name): define program_name().

        * lib/argmatch.c, lib/c-stack.c, lib/chdir-long.c, lib/dirname.c,
          lib/euidaccess.c, lib/group-member.c, lib/xstrtol.c (main): use
          program_name() as a global function not a global variable.
        
        * doc/standards.texi: Modify examples to show the new usage pattern
          for program_name.
        
Index: doc/standards.texi
===================================================================
RCS file: /sources/gnulib/gnulib/doc/standards.texi,v
retrieving revision 1.10
diff -u -r1.10 standards.texi
--- doc/standards.texi  25 Dec 2005 23:59:50 -0000      1.10
+++ doc/standards.texi  6 Jan 2006 11:35:14 -0000
@@ -3,7 +3,7 @@
 @setfilename standards.info
 @settitle GNU Coding Standards
 @c This date is automagically updated when you save this file:
address@hidden lastupdate December 25, 2005
address@hidden lastupdate January 6, 2006
 @c %**end of header
 
 @dircategory GNU organization
@@ -2726,7 +2726,10 @@
 #include <errno.h>
 #include <stdio.h>
 
-char *program_name = "myprogram";
+const char *program_name(void)
address@hidden
+  return "myprogram";
address@hidden
 
 FILE *
 xfopen (char const *name)
Index: lib/argmatch.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/argmatch.c,v
retrieving revision 1.39
diff -u -r1.39 argmatch.c
--- lib/argmatch.c      19 Sep 2005 17:28:14 -0000      1.39
+++ lib/argmatch.c      6 Jan 2006 11:35:14 -0000
@@ -213,7 +213,12 @@
 /*
  * Based on "getversion.c" by David MacKenzie <address@hidden>
  */
-char *program_name;
+static const char *myname;
+
+const char *program_name(void)
+{
+  return myname;
+}
 
 /* When to make backup files.  */
 enum backup_type
@@ -257,11 +262,11 @@
   const char *cp;
   enum backup_type backup_type = no_backups;
 
-  program_name = (char *) argv[0];
+  myname = (char *) argv[0];
 
   if (argc > 2)
     {
-      fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name);
+      fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name());
       exit (1);
     }
 
@@ -270,7 +275,7 @@
                             backup_args, backup_vals);
 
   if (argc == 2)
-    backup_type = XARGMATCH (program_name, argv[1],
+    backup_type = XARGMATCH (program_name(), argv[1],
                             backup_args, backup_vals);
 
   printf ("The version control is `%s'\n",
Index: lib/c-stack.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/c-stack.c,v
retrieving revision 1.7
diff -u -r1.7 c-stack.c
--- lib/c-stack.c       19 Sep 2005 17:28:14 -0000      1.7
+++ lib/c-stack.c       6 Jan 2006 11:35:14 -0000
@@ -1,6 +1,6 @@
 /* Stack overflow handling.
 
-   Copyright (C) 2002, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -98,8 +98,6 @@
 # define SIGACTION_WORKS 0
 #endif
 
-extern char *program_name;
-
 /* The user-specified action to take when a SEGV-related program error
    or stack overflow occurs.  */
 static void (* volatile segv_action) (int);
@@ -121,7 +119,7 @@
   char const *message;
   segv_action (signo);
   message = signo ? program_error_message : stack_overflow_message;
-  write (STDERR_FILENO, program_name, strlen (program_name));
+  write (STDERR_FILENO, program_name(), strlen (program_name()));
   write (STDERR_FILENO, ": ", 2);
   write (STDERR_FILENO, message, strlen (message));
   write (STDERR_FILENO, "\n", 1);
@@ -288,12 +286,18 @@
   return *p + recurse (array);
 }
 
-char *program_name;
+char *myname;
+
+const char *progam_name(void)
+{
+  return myname;
+}
+
 
 int
 main (int argc __attribute__ ((unused)), char **argv)
 {
-  program_name = argv[0];
+  myname = argv[0];
   fprintf (stderr,
           "The last output line should contain \"stack overflow\".\n");
   if (c_stack_action (0) == 0)
Index: lib/chdir-long.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/chdir-long.c,v
retrieving revision 1.6
diff -u -r1.6 chdir-long.c
--- lib/chdir-long.c    19 Sep 2005 17:28:14 -0000      1.6
+++ lib/chdir-long.c    6 Jan 2006 11:35:14 -0000
@@ -221,7 +221,13 @@
 # include "closeout.h"
 # include "error.h"
 
-char *program_name;
+char *myname;
+
+const char *program_name(void)
+{
+  return myname;
+}
+
 
 int
 main (int argc, char *argv[])
@@ -230,7 +236,7 @@
   size_t n = 0;
   int len;
 
-  program_name = argv[0];
+  myname = argv[0];
   atexit (close_stdout);
 
   len = getline (&line, &n, stdin);
Index: lib/dirname.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/dirname.c,v
retrieving revision 1.35
diff -u -r1.35 dirname.c
--- lib/dirname.c       19 Sep 2005 17:28:14 -0000      1.35
+++ lib/dirname.c       6 Jan 2006 11:35:14 -0000
@@ -96,14 +96,20 @@
 # define MAX_BUFF_LEN 1024
 # include <stdio.h>
 
-char *program_name;
+char *myname;
+
+const char *program_name(void)
+{
+  return myname;
+}
+
 
 int
 main (int argc, char *argv[])
 {
   char buff[MAX_BUFF_LEN + 1];
 
-  program_name = argv[0];
+  myname = argv[0];
 
   buff[MAX_BUFF_LEN] = 0;
   while (fgets (buff, MAX_BUFF_LEN, stdin) && buff[0])
Index: lib/error.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/error.c,v
retrieving revision 1.43
diff -u -r1.43 error.c
--- lib/error.c 14 May 2005 06:03:58 -0000      1.43
+++ lib/error.c 6 Jan 2006 11:35:14 -0000
@@ -1,5 +1,5 @@
 /* Error handler for noninteractive utilities
-   Copyright (C) 1990-1998, 2000-2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1990-1998, 2000-2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    This program is free software; you can redistribute it and/or modify
@@ -57,7 +57,6 @@
 #ifdef _LIBC
 /* In the GNU C library, there is a predefined variable for this.  */
 
-# define program_name program_invocation_name
 # include <errno.h>
 # include <libio/libioP.h>
 
@@ -92,10 +91,6 @@
 #  define SIZE_MAX ((size_t) -1)
 # endif
 
-/* The calling program should define program_name and set it to the
-   name of the executing program.  */
-extern char *program_name;
-
 # if HAVE_STRERROR_R || defined strerror_r
 #  define __strerror_r strerror_r
 # endif
@@ -208,10 +203,10 @@
     {
 #if _LIBC
       if (_IO_fwide (stderr, 0) > 0)
-       __fwprintf (stderr, L"%s: ", program_name);
+       __fwprintf (stderr, L"%s: ", program_name());
       else
 #endif
-       fprintf (stderr, "%s: ", program_name);
+       fprintf (stderr, "%s: ", program_name());
     }
 
   va_start (args, message);
@@ -268,10 +263,10 @@
     {
 #if _LIBC
       if (_IO_fwide (stderr, 0) > 0)
-       __fwprintf (stderr, L"%s: ", program_name);
+       __fwprintf (stderr, L"%s: ", program_name());
       else
 #endif
-       fprintf (stderr, "%s:", program_name);
+       fprintf (stderr, "%s:", program_name());
     }
 
   if (file_name != NULL)
Index: lib/error.h
===================================================================
RCS file: /sources/gnulib/gnulib/lib/error.h,v
retrieving revision 1.20
diff -u -r1.20 error.h
--- lib/error.h 14 May 2005 06:03:58 -0000      1.20
+++ lib/error.h 6 Jan 2006 11:35:14 -0000
@@ -1,5 +1,5 @@
 /* Declaration for error-reporting function
-   Copyright (C) 1995, 1996, 1997, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 2003, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    This program is free software; you can redistribute it and/or modify
@@ -52,6 +52,12 @@
    function without parameters instead.  */
 extern void (*error_print_progname) (void);
 
+/* program_name() should be defined by the application and should 
+ * return the program's name.  This is normally the same string as was
+ * passed to main() as argv[0].
+ */
+extern const char *program_name(void);
+  
 /* This variable is incremented each time `error' is called.  */
 extern unsigned int error_message_count;
 
Index: lib/euidaccess.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/euidaccess.c,v
retrieving revision 1.21
diff -u -r1.21 euidaccess.c
--- lib/euidaccess.c    23 Sep 2005 04:15:13 -0000      1.21
+++ lib/euidaccess.c    6 Jan 2006 11:35:14 -0000
@@ -201,8 +201,13 @@
 # include <stdio.h>
 # include <stdlib.h>
 
-char *program_name;
-
+char *myname;
+
+const char *program_name() 
+{
+  return myname;
+}
+
 int
 main (int argc, char **argv)
 {
@@ -210,7 +215,7 @@
   int mode;
   int err;
 
-  program_name = argv[0];
+  myname = argv[0];
   if (argc < 3)
     abort ();
   file = argv[1];
Index: lib/group-member.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/group-member.c,v
retrieving revision 1.17
diff -u -r1.17 group-member.c
--- lib/group-member.c  23 Sep 2005 04:15:13 -0000      1.17
+++ lib/group-member.c  6 Jan 2006 11:35:14 -0000
@@ -111,14 +111,19 @@
 
 #ifdef TEST
 
-char *program_name;
-
+char *myname;
+
+const char *program_name(void)
+{
+  return myname;
+}
+
 int
 main (int argc, char **argv)
 {
   int i;
 
-  program_name = argv[0];
+  myname = argv[0];
 
   for (i=1; i<argc; i++)
     {
Index: lib/progname.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/progname.c,v
retrieving revision 1.5
diff -u -r1.5 progname.c
--- lib/progname.c      19 Sep 2005 17:28:14 -0000      1.5
+++ lib/progname.c      6 Jan 2006 11:35:14 -0000
@@ -31,7 +31,13 @@
 
 /* String containing name the program is called with.
    To be initialized by main().  */
-const char *program_name = NULL;
+static const char *the_program_name = NULL;
+
+
+const char *program_name(void)
+{
+  return the_program_name;
+}
 
 /* Set program_name, based on argv[0].  */
 void
@@ -49,5 +55,5 @@
     argv0 = base;
   if (strncmp (base, "lt-", 3) == 0)
     argv0 = base + 3;
-  program_name = argv0;
+  the_program_name = argv0;
 }
Index: lib/progname.h
===================================================================
RCS file: /sources/gnulib/gnulib/lib/progname.h,v
retrieving revision 1.5
diff -u -r1.5 progname.h
--- lib/progname.h      14 May 2005 06:03:58 -0000      1.5
+++ lib/progname.h      6 Jan 2006 11:35:14 -0000
@@ -1,5 +1,5 @@
 /* Program name management.
-   Copyright (C) 2001-2004 Free Software Foundation, Inc.
+   Copyright (C) 2001-2004, 2005 Free Software Foundation, Inc.
    Written by Bruno Haible <address@hidden>, 2001.
 
    This program is free software; you can redistribute it and/or modify
@@ -29,8 +29,8 @@
 #endif
 
 
-/* String containing name the program is called with.  */
-extern const char *program_name;
+/* Returns a string containing the name the program was called with. */
+extern const char *program_name(void);
 
 /* Set program_name, based on argv[0].  */
 extern void set_program_name (const char *argv0);
Index: lib/xstrtol.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/xstrtol.c,v
retrieving revision 1.38
diff -u -r1.38 xstrtol.c
--- lib/xstrtol.c       19 Sep 2005 17:28:15 -0000      1.38
+++ lib/xstrtol.c       6 Jan 2006 11:35:14 -0000
@@ -256,15 +256,20 @@
 # include <stdio.h>
 # include "error.h"
 
-char *program_name;
-
+char *myname;
+
+static const char *program_name(void)
+{
+  return myname;
+}
+
 int
 main (int argc, char **argv)
 {
   strtol_error s_err;
   int i;
 
-  program_name = argv[0];
+  myname = argv[0];
   for (i=1; i<argc; i++)
     {
       char *p;