From e50240012b56272abfd1ce2c873dc99e7a89631b Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Thu, 6 Jun 2024 21:52:55 +0000
Subject: driver: implemented and integrated the -L (follow symlink items)
 cmdline option.

---
 src/driver/tpax_driver_ctx.c     |  5 ++++
 src/internal/tpax_driver_impl.h  |  1 +
 src/logic/tpax_archive_enqueue.c | 49 ++++++++++++++++++++++++++++++++++++++++
 src/skin/tpax_skin_default.c     |  9 ++++++++
 4 files changed, 64 insertions(+)

(limited to 'src')

diff --git a/src/driver/tpax_driver_ctx.c b/src/driver/tpax_driver_ctx.c
index 71b4656..97eb776 100644
--- a/src/driver/tpax_driver_ctx.c
+++ b/src/driver/tpax_driver_ctx.c
@@ -534,6 +534,11 @@ int tpax_lib_get_driver_ctx(
 					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ARGS;
 					break;
 
+				case TAG_PAX_SYMLINK_ITEMS:
+					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ARGS;
+					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ITEMS;
+					break;
+
 				case TAG_STRICT_PATH:
 					cctx.drvflags |= TPAX_DRIVER_STRICT_PATH_INPUT;
 					break;
diff --git a/src/internal/tpax_driver_impl.h b/src/internal/tpax_driver_impl.h
index a074535..aa65eed 100644
--- a/src/internal/tpax_driver_impl.h
+++ b/src/internal/tpax_driver_impl.h
@@ -49,6 +49,7 @@ enum app_tags {
 	TAG_PURE_PATH,
 	TAG_PRESERVE_ATIME,
 	TAG_PAX_SYMLINK_ARGS,
+	TAG_PAX_SYMLINK_ITEMS,
 };
 
 struct tpax_dirent {
diff --git a/src/logic/tpax_archive_enqueue.c b/src/logic/tpax_archive_enqueue.c
index ab07ab5..1b45a2f 100644
--- a/src/logic/tpax_archive_enqueue.c
+++ b/src/logic/tpax_archive_enqueue.c
@@ -19,6 +19,7 @@
 #include <tpax/tpax_specs.h>
 #include "tpax_driver_impl.h"
 #include "tpax_getdents_impl.h"
+#include "tpax_readlink_impl.h"
 #include "tpax_tmpfile_impl.h"
 #include "tpax_errinfo_impl.h"
 
@@ -267,14 +268,21 @@ static int tpax_archive_enqueue_dir_entries(
 {
 	int                             fd;
 	int                             fdat;
+	int                             fdlnk;
 	int                             depth;
 	bool                            fkeep;
+	bool                            flinks;
 	long                            nbytes;
+	struct dirent *                 lnkent;
 	struct dirent *                 dirent;
 	struct dirent *                 dirents;
+	struct tpax_dirent *            cdent;
 	struct tpax_unit_ctx *          uctx;
 	struct stat                     st;
+	struct stat                     lnkst;
 	uintptr_t                       addr;
+	char                            lnktgt[PATH_MAX];
+	char                            lnkbuf[PATH_MAX + sizeof(struct dirent)];
 
 	/* init */
 	fdat  = dent->fdat;
@@ -306,6 +314,8 @@ static int tpax_archive_enqueue_dir_entries(
 			TPAX_SYSTEM_ERROR(dctx),
 			uctx);
 
+	lnkent = (struct dirent *)lnkbuf;
+	flinks = (dctx->cctx->drvflags & TPAX_DRIVER_PAX_SYMLINK_ITEMS);
 	nbytes = tpax_getdents(fd,dirents,TPAX_DIRENT_BUFLEN);
 
 	while ((nbytes == -EINTR) || ((nbytes < 0) && (errno == EINTR)))
@@ -344,6 +354,45 @@ static int tpax_archive_enqueue_dir_entries(
 				return tpax_archive_enqueue_ret(
 					TPAX_NESTED_ERROR(dctx),
 					uctx);
+
+			/* follow encountered symlink arguments as needed */
+			fdlnk = (flinks && (dirent->d_type == DT_LNK))
+				? openat(fd,dirent->d_name,O_RDONLY|O_CLOEXEC)
+				: (-1);
+
+			if (fdlnk >= 0) {
+				if (fstat(fdlnk,&lnkst) <0) {
+					close(fdlnk);
+					return tpax_archive_enqueue_ret(
+						TPAX_SYSTEM_ERROR(dctx),
+						uctx);
+				}
+
+				if (tpax_readlinkat(fd,dirent->d_name,lnktgt,PATH_MAX) < 0)
+					return tpax_archive_enqueue_ret(
+						TPAX_SYSTEM_ERROR(dctx),
+						uctx);
+
+				close(fdlnk);
+
+				if (tpax_dirent_init_from_uctx(&lnkst,lnktgt,lnkent) < 0)
+					return tpax_archive_enqueue_ret(
+						TPAX_CUSTOM_ERROR(
+							dctx,
+							TPAX_ERR_FLOW_ERROR),
+						0);
+
+				cdent = tpax_get_driver_dirmark(dctx);
+				cdent->flags |= TPAX_ITEM_NAMEREF;
+
+				if (tpax_archive_add_queue_item(
+						dctx,lnkent,cdent,0,depth+1,
+						TPAX_ITEM_IMPLICIT|TPAX_ITEM_SYMLINK,
+						fd,&fkeep) < 0)
+					return tpax_archive_enqueue_ret(
+						TPAX_NESTED_ERROR(dctx),
+						0);
+			}
 		}
 
 		addr    = (uintptr_t)dirent;
diff --git a/src/skin/tpax_skin_default.c b/src/skin/tpax_skin_default.c
index 5bddb70..bfb4551 100644
--- a/src/skin/tpax_skin_default.c
+++ b/src/skin/tpax_skin_default.c
@@ -74,6 +74,15 @@ const tpax_hidden struct argv_option tpax_default_options[] = {
 			"or directory to the archive using the name of the "
 			"symbolic link."},
 
+	{"Wpax-symlink-items",
+			'L',TAG_PAX_SYMLINK_ITEMS,ARGV_OPTARG_NONE,
+			ARGV_OPTION_HYBRID_ONLY,0,0,
+			"when a command-line argument is a symbolic link, or when "
+			"an item added by way of recursion is a symbolic link, "
+			"add the underlying (referenced) file-system object "
+			"or directory to the archive using the name of the "
+			"symbolic link."},
+
 	{"Wstrict-path-input",
 			0,TAG_STRICT_PATH,ARGV_OPTARG_NONE,
 			ARGV_OPTION_HYBRID_ONLY,0,0,
-- 
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