libiberty: add ldirname function

This patch adds a function ldirname to libiberty.  It is implemented
in terms of lbasename.  Basically, given a given pathname, the dirname
part is what is not the basename minus the last directory separator
separating the dirname with the basename.

include/ChangeLog

	* libiberty.h (ldirname): New function declaration.
	(dos_ldirname): Likewise.
	(unix_ldirname): Likewise.

libiberty/ChangeLog

	* ldirname.c: New file.
	* Makefile.in (CFILES): Add ldirname.c.
	(REQUIRED_OFILES): Add ldirname.$(objext).
	(./ldirname.$(objext)): New rule.
	* makefile.vms (OBJS): Add ldirname.obj.
	* configure.com (FILES): Add ldirname.

5 files changed, 121 insertions, 3 deletions

diff --git a/include/libiberty.h b/include/libiberty.h
index 9cd1de4..f2e763a 100644
--- a/include/libiberty.h
+++ b/include/libiberty.h
@@ -133,6 +133,18 @@ extern const char *dos_lbasename (const char *) ATTRIBUTE_RETURNS_NONNULL ATTRIB
 
 extern const char *unix_lbasename (const char *) ATTRIBUTE_RETURNS_NONNULL ATTRIBUTE_NONNULL(1);
 
+/* A dirname () that is always compiled in.  */
+
+extern char *ldirname (const char *) ATTRIBUTE_NONNULL(1);
+
+/* Same, but assumes DOS semantics regardless of host.  */
+
+extern char *dos_ldirname (const char *) ATTRIBUTE_NONNULL(1);
+
+/* Same, but assumes Unix semantics regardless of host.  */
+
+extern char *unix_ldirname (const char *) ATTRIBUTE_NONNULL(1);
+
 /* A well-defined realpath () that is always compiled in.  */
 
 extern char *lrealpath (const char *);
diff --git a/libiberty/Makefile.in b/libiberty/Makefile.in
index 0db1243..4870fa9 100644
--- a/libiberty/Makefile.in
+++ b/libiberty/Makefile.in
@@ -136,6 +136,7 @@ CFILES = alloca.c argv.c asprintf.c atexit.c				\
 	hashtab.c hex.c							\
 	index.c insque.c						\
 	lbasename.c							\
+	ldirname.c							\
 	lrealpath.c							\
 	make-relative-prefix.c						\
 	make-temp-file.c md5.c memchr.c memcmp.c memcpy.c memmem.c	\
@@ -179,7 +180,7 @@ REQUIRED_OFILES =							\
 	./fnmatch.$(objext) ./fopen_unlocked.$(objext)			\
 	./getopt.$(objext) ./getopt1.$(objext) ./getpwd.$(objext)	\
 	./getruntime.$(objext) ./hashtab.$(objext) ./hex.$(objext)	\
-	./lbasename.$(objext) ./lrealpath.$(objext)			\
+	./lbasename.$(objext) ./ldirname.$(objext) ./lrealpath.$(objext)\
 	./make-relative-prefix.$(objext) ./make-temp-file.$(objext)	\
 	./objalloc.$(objext)						\
 	./obstack.$(objext)						\
@@ -965,6 +966,17 @@ $(CONFIGURED_OFILES): stamp-picdir stamp-noasandir
 	else true; fi
 	$(COMPILE.c) $(srcdir)/lbasename.c $(OUTPUT_OPTION)
 
+./ldirname.$(objext): $(srcdir)/ldirname.c config.h $(INCDIR)/ansidecl.h \
+	$(INCDIR)/filenames.h $(INCDIR)/hashtab.h $(INCDIR)/libiberty.h \
+	$(INCDIR)/safe-ctype.h
+	if [ x"$(PICFLAG)" != x ]; then \
+	  $(COMPILE.c) $(PICFLAG) $(srcdir)/ldirname.c -o pic/$@; \
+	else true; fi
+	if [ x"$(NOASANFLAG)" != x ]; then \
+	  $(COMPILE.c) $(PICFLAG) $(NOASANFLAG) $(srcdir)/ldirname.c -o noasan/$@; \
+	else true; fi
+	$(COMPILE.c) $(srcdir)/ldirname.c $(OUTPUT_OPTION)
+
 ./lrealpath.$(objext): $(srcdir)/lrealpath.c config.h $(INCDIR)/ansidecl.h \
 	$(INCDIR)/libiberty.h
 	if [ x"$(PICFLAG)" != x ]; then \
diff --git a/libiberty/configure.com b/libiberty/configure.com
index 0301829..55aee2f 100644
--- a/libiberty/configure.com
+++ b/libiberty/configure.com
@@ -17,7 +17,7 @@ $DECK
 $ FILES="getopt,obstack,xexit,xmalloc,hex,getopt1,cplus-dem,cp-demangle,"+-
     "cp-demint,asprintf,vasprintf,mkstemps,concat,getruntime,getpagesize,"+-
     "getpwd,xstrerror,xmemdup,xstrdup,xatexit,choose-temp,fnmatch,objalloc,"+-
-    "safe-ctype,hashtab,lbasename,argv,lrealpath,make-temp-file,"+-
+    "safe-ctype,hashtab,lbasename,ldirname,argv,lrealpath,make-temp-file,"+-
     "stpcpy,unlink-if-ordinary"
 $ OPT="/noopt/debug/warnings=disable=(missingreturn)"
 $ CFLAGS=OPT + "/include=([],[-.include])/name=(as_is,shortened)" +-
diff --git a/libiberty/ldirname.c b/libiberty/ldirname.c
new file mode 100644
index 0000000..e3cd5c8
--- /dev/null
+++ b/libiberty/ldirname.c
@@ -0,0 +1,94 @@
+/* Libiberty dirname.  Like dirname, but is not overridden by the
+   system C library.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+This file is part of the libiberty library.
+Libiberty is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+Libiberty is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with libiberty; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+/*
+
+@deftypefn Replacement {char*} ldirname (const char *@var{name})
+
+Given a pointer to a string containing a typical pathname
+(@samp{/usr/src/cmd/ls/ls.c} for example), returns a string containing the
+passed string up to, but not including, the final directory separator.
+
+If the given pathname doesn't contain a directory separator then this funtion
+returns the empty string; this includes an empty given pathname.  @code{NULL}
+is returned on memory allocation error.
+
+@end deftypefn
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "ansidecl.h"
+#include "libiberty.h"
+#include "safe-ctype.h"
+#include "filenames.h"
+
+/* For malloc.  */
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+/* For memcpy.  */
+# if HAVE_STRING_H
+#  include <string.h>
+# else
+#  if HAVE_STRINGS_H
+#   include <strings.h>
+#  endif
+# endif
+
+#define LDIRNAME(FPREFIX,DIRSEP)					\
+  char *FPREFIX##_ldirname (const char *name)				\
+  {									\
+    /* Note that lbasename guarantees that the returned */		\
+    /* pointer lies within the passed string.  */			\
+    const char *basename = FPREFIX##_lbasename (name);			\
+    size_t size = basename - name;					\
+    char *res = NULL;							\
+    									\
+    res = (char*) malloc (size + 1);					\
+    if (res != NULL)							\
+      {									\
+	if (size > 0)							\
+	  {								\
+	    if (IS_DIR_SEPARATOR_1 ((DIRSEP),name[size - 1]))		\
+	      size -= 1;						\
+	    memcpy (res, name, size);					\
+	  }								\
+	res[size] = '\0';						\
+      }									\
+    									\
+    return res;								\
+  }
+
+LDIRNAME(dos,1)
+LDIRNAME(unix,0)
+
+char *
+ldirname (const char *name)
+{
+#if defined (HAVE_DOS_BASED_FILE_SYSTEM)
+  return dos_ldirname (name);
+#else
+  return unix_ldirname (name);
+#endif
+}
diff --git a/libiberty/makefile.vms b/libiberty/makefile.vms
index 15a7d0a..4cfcc98 100644
--- a/libiberty/makefile.vms
+++ b/libiberty/makefile.vms
@@ -12,7 +12,7 @@ OBJS=getopt.obj,obstack.obj,xexit.obj,xmalloc.obj,hex.obj,\
     asprintf.obj vasprintf.obj,mkstemps.obj,filename_cmp.obj,\
     concat.obj,getruntime.obj,getpagesize.obj,getpwd.obj,xstrerror.obj,\
     xmemdup.obj,xstrdup.obj,xatexit.obj,choose-temp.obj,fnmatch.obj,\
-    objalloc.obj,safe-ctype.obj,hashtab.obj,lbasename.obj,argv.obj,\
+    objalloc.obj,safe-ctype.obj,hashtab.obj,lbasename.obj,ldirname.obj,argv.obj,\
     lrealpath.obj,make-temp-file.obj,stpcpy.obj,unlink-if-ordinary.obj,\
     dwarfnames.obj