add optional support for program_invocation_name/program_invocation_short_name

extra/Configs/Config.in

@@ -446,6 +446,20 @@ config HAS_SHADOW
 	  Answer N if you do not need shadow password support.
 	  Most people will answer Y.
 
+config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
+	bool "Support for program_invocation_name"
+	default n
+	help
+	  Support for the GNU-specific program_invocation_name and
+	  program_invocation_short_name strings.  Some GNU packages
+	  (like tar and coreutils) utilize these for extra useful
+	  output, but in general are not required.
+
+	  At startup, these external strings are automatically set
+	  up based on the value of ARGV[0].
+
+	  If unsure, just answer N.
+
 config UNIX98PTY_ONLY
 	bool "Support only Unix 98 PTYs"
 	default y

include/errno.h

@@ -49,7 +49,7 @@ extern int errno;
 # endif
 #endif
 
-#if 0 /*def __USE_GNU      uClibc note: not supported */
+#ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
 
 /* The full and simple forms of the name with which the program was
    invoked.  These variables are set up automatically at startup based on

include/libc-internal.h

@@ -238,6 +238,7 @@ extern char *__strcat (char *__restrict __dest, __const char *__restrict __src)
 extern char *__strncpy (char *__restrict __dest,
 		      __const char *__restrict __src, size_t __n) attribute_hidden;
 extern char *__strchr (__const char *__s, int __c) attribute_hidden;
+extern char *__strrchr (__const char *__s, int __c) attribute_hidden;
 extern int __strncmp (__const char *__s1, __const char *__s2, size_t __n) attribute_hidden;
 extern char *__strdup (__const char *__s) attribute_hidden;
 extern int __strcasecmp (__const char *__s1, __const char *__s2) attribute_hidden;

libc/misc/internals/__uClibc_main.c

@@ -63,6 +63,14 @@ extern void weak_function _locale_init(void) attribute_hidden;
 #ifdef __UCLIBC_HAS_THREADS__
 extern void weak_function __pthread_initialize_minimal(void);
 #endif
+#ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
+char *program_invocation_name = (char *) "";
+char *program_invocation_short_name = (char *) "";
+hidden_strong_alias (program_invocation_name, __progname_full)
+hidden_strong_alias (program_invocation_short_name, __progname)
+#else
+attribute_hidden const char *__progname = NULL;
+#endif
 
 /*
  * Declare the __environ global variable and create a weak alias environ.
@@ -73,7 +81,6 @@ char **__environ = 0;
 weak_alias(__environ, environ)
 
 size_t __pagesize = 0;
-const char *__progname = 0;
 
 #ifndef O_NOFOLLOW
 # define O_NOFOLLOW	0
@@ -253,7 +260,18 @@ __uClibc_main(int (*main)(int, char **, char **), int argc,
     }
 #endif
 
+#ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
+    if (argv && argv[0]) {
+	__progname_full = *argv;
+	__progname = __strrchr(*argv, '/');
+	if (likely(__progname != NULL))
+		++__progname;
+	else
+		__progname = __progname_full;
+    }
+#else
     __progname = *argv;
+#endif
 
 #ifdef __UCLIBC_CTOR_DTOR__
     /* Arrange for the application's dtors to run before we exit.  */