[PATCH 4/4] builtins: add import builtin

[Matheus Afonso Martins Moreira]

The new import builtin works just like the source builtin
but it searches only the directories in BASH_IMPORT_PATH,
allowing programmers to create reusable libraries without
their scripts needing to be placed in the same locations
as normal executable commands or other sourceable scripts.

Signed-off-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>
---
 AUTHORS              |  1 +
 MANIFEST             |  1 +
 Makefile.in          |  4 +-
 builtins/Makefile.in |  6 ++-
 builtins/import.def  | 99 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 108 insertions(+), 3 deletions(-)
 create mode 100644 builtins/import.def

diff --git a/AUTHORS b/AUTHORS
index 9ad0ba28..ec4098c4 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -121,6 +121,7 @@ builtins/getopts.def        Brian Fox, Chet Ramey
 builtins/hash.def      Brian Fox, Chet Ramey
 builtins/hashcom.h     Brian Fox, Chet Ramey
 builtins/help.def      Brian Fox, Chet Ramey
+builtins/import.def    Matheus Afonso Martins Moreira
 builtins/let.def       Chet Ramey, Brian Fox
 builtins/history.def   Brian Fox, Chet Ramey
 builtins/jobs.def      Brian Fox, Chet Ramey
diff --git a/MANIFEST b/MANIFEST
index a45b3cfc..75754375 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -180,6 +180,7 @@ builtins/getopt.h   f
 builtins/getopts.def   f
 builtins/hash.def      f
 builtins/help.def      f
+builtins/import.def    f
 builtins/let.def       f
 builtins/history.def   f
 builtins/jobs.def      f
diff --git a/Makefile.in b/Makefile.in
index 0b4df73a..83da6d32 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -510,7 +510,8 @@ BUILTIN_DEFS = $(DEFSRC)/alias.def $(DEFSRC)/bind.def 
$(DEFSRC)/break.def \
               $(DEFSRC)/echo.def $(DEFSRC)/enable.def $(DEFSRC)/eval.def \
               $(DEFSRC)/exec.def $(DEFSRC)/exit.def $(DEFSRC)/fc.def \
               $(DEFSRC)/fg_bg.def $(DEFSRC)/hash.def $(DEFSRC)/help.def \
-              $(DEFSRC)/history.def $(DEFSRC)/jobs.def $(DEFSRC)/kill.def \
+              $(DEFSRC)/history.def $(DEFSRC)/import.def \
+              $(DEFSRC)/jobs.def $(DEFSRC)/kill.def \
               $(DEFSRC)/let.def $(DEFSRC)/read.def $(DEFSRC)/return.def \
               $(DEFSRC)/set.def $(DEFSRC)/setattr.def $(DEFSRC)/shift.def \
               $(DEFSRC)/source.def $(DEFSRC)/suspend.def $(DEFSRC)/test.def \
@@ -1757,6 +1758,7 @@ builtins/getopts.o: $(DEFSRC)/getopts.def
 builtins/hash.o: $(DEFSRC)/hash.def
 builtins/help.o: $(DEFSRC)/help.def
 builtins/history.o: $(DEFSRC)/history.def
+builtins/import.o: $(DEFSRC)/import.def
 builtins/inlib.o: $(DEFSRC)/inlib.def
 builtins/jobs.o: $(DEFSRC)/jobs.def
 builtins/kill.o: $(DEFSRC)/kill.def
diff --git a/builtins/Makefile.in b/builtins/Makefile.in
index 642878c6..e19105e1 100644
--- a/builtins/Makefile.in
+++ b/builtins/Makefile.in
@@ -137,7 +137,8 @@ DEFSRC =  $(srcdir)/alias.def $(srcdir)/bind.def 
$(srcdir)/break.def \
          $(srcdir)/enable.def $(srcdir)/eval.def $(srcdir)/getopts.def \
          $(srcdir)/exec.def $(srcdir)/exit.def $(srcdir)/fc.def \
          $(srcdir)/fg_bg.def $(srcdir)/hash.def $(srcdir)/help.def \
-         $(srcdir)/history.def $(srcdir)/jobs.def $(srcdir)/kill.def \
+         $(srcdir)/history.def $(srcdir)/import.def \
+         $(srcdir)/jobs.def $(srcdir)/kill.def \
          $(srcdir)/let.def $(srcdir)/read.def $(srcdir)/return.def \
          $(srcdir)/set.def $(srcdir)/setattr.def $(srcdir)/shift.def \
          $(srcdir)/source.def $(srcdir)/suspend.def $(srcdir)/test.def \
@@ -153,7 +154,7 @@ OFILES = builtins.o \
        alias.o bind.o break.o builtin.o caller.o cd.o colon.o command.o \
        common.o declare.o echo.o enable.o eval.o evalfile.o \
        evalstring.o exec.o exit.o fc.o fg_bg.o hash.o help.o history.o \
-       jobs.o kill.o let.o mapfile.o \
+       import.o jobs.o kill.o let.o mapfile.o \
        pushd.o read.o return.o set.o setattr.o shift.o source.o \
        suspend.o test.o times.o trap.o type.o ulimit.o umask.o \
        wait.o getopts.o shopt.o printf.o getopt.o bashgetopt.o complete.o
@@ -298,6 +299,7 @@ fg_bg.o: fg_bg.def
 hash.o: hash.def
 help.o: help.def
 history.o: history.def
+import.o: import.def
 jobs.o: jobs.def
 kill.o: kill.def
 let.o: let.def
diff --git a/builtins/import.def b/builtins/import.def
new file mode 100644
index 00000000..4c1bb66a
--- /dev/null
+++ b/builtins/import.def
@@ -0,0 +1,99 @@
+This file is import.def, from which is created import.c.
+It implements the builtin "import" in Bash.
+
+Copyright (C) 1987-2024 Free Software Foundation, Inc.
+
+This file is part of GNU Bash, the Bourne Again SHell.
+
+Bash is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Bash is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+
+$PRODUCES import.c
+
+$BUILTIN import
+$FUNCTION import_builtin
+$SHORT_DOC import FILENAME [arguments]
+Execute commands from a file in the current shell.
+
+Read and execute commands from FILENAME in the current shell.
+The entries in $BASH_IMPORT_PATH are used to find the directory
+containing FILENAME. If any ARGUMENTS are supplied, they become
+the positional parameters when FILENAME is executed.
+
+Exit Status:
+Returns the status of the last command executed in FILENAME;
+fails if FILENAME cannot be read.
+$END
+
+#include <config.h>
+
+#include "../bashtypes.h"
+#include "posixstat.h"
+#include "filecntl.h"
+#if ! defined(_MINIX) && defined (HAVE_SYS_FILE_H)
+#  include <sys/file.h>
+#endif
+#include <errno.h>
+
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif
+
+#include "../bashansi.h"
+#include "../bashintl.h"
+
+#include "../shell.h"
+#include "../execute_cmd.h"
+#include "../flags.h"
+#include "../findcmd.h"
+#include "common.h"
+#include "bashgetopt.h"
+#include "../trap.h"
+
+#if !defined (errno)
+extern int errno;
+#endif /* !errno */
+
+/* Find, read and execute commands from the file passed as argument. */
+int
+import_builtin (list)
+     WORD_LIST *list;
+{
+  char *filename;
+
+  if (no_options (list))
+    return (EX_USAGE);
+  list = loptend;
+
+  if (list == 0)
+    {
+      builtin_error (_("filename argument required"));
+      builtin_usage ();
+      return (EX_USAGE);
+    }
+
+#if defined (RESTRICTED_SHELL)
+  if (restricted && strchr (list->word->word, '/'))
+    {
+      sh_restricted (list->word->word);
+      return (EXECUTION_FAILURE);
+    }
+#endif
+
+  if (absolute_pathname (list->word->word))
+    filename = savestring (list->word->word);
+  else
+    filename = find_user_import (list->word->word);
+
+  return execute_file_contents (list, filename, "import");
+}
-- 
2.44.0