From 57f85a153ebb9c741c91fc7447877164a32c8efd Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Thu, 15 Jun 2023 21:56:27 -0500
Subject: [PATCH] Add cpio -L

---
 tests/cpio.test   | 7 ++++++-
 toys/posix/cpio.c | 5 +++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/tests/cpio.test b/tests/cpio.test
index 6f5eddef..45d528d8 100755
--- a/tests/cpio.test
+++ b/tests/cpio.test
@@ -68,7 +68,8 @@ testing "-i keeps existing files" "echo new >a/b && $CPIO -i <a.cpio 2>/dev/null
 testing "-id keeps existing files" "echo new >a/b && $CPIO -id <a.cpio 2>/dev/null; cat a/b" "new\n" "" ""
 testing "-iu replaces existing files; no error" "echo new >a/b && $CPIO -iu <a.cpio && cat a/b" "old\n" "" ""
 testing "-idu replaces existing files; no error" "echo new >a/b && $CPIO -idu <a.cpio && cat a/b" "old\n" "" ""
-testing "skip NUL" "for i in a b; do dd if=/dev/zero bs=512 count=1 2>/dev/null; cat a.cpio; done | $CPIO -t -H newc" \
+# The kernel's initramfs extractor does this
+toyonly testing "skip NUL" "for i in a b; do dd if=/dev/zero bs=512 count=1 2>/dev/null; cat a.cpio; done | $CPIO -t -H newc" \
   "a\na/b\na\na/b\n" "" ""
 rm -rf a a.cpio
 
@@ -92,3 +93,7 @@ fi
 skipnot [ $(id -u) -eq 0 ]
 testing "-t preserve ownership" "$CPIO -t <a.cpio >/dev/null && stat -c '%U:%G' a/file a/symlink a/dir" "${USR}:${GRP}\n${USR}:${GRP}\n${USR}:${GRP}\n" "" ""
 rm -rf a a.cpio
+
+echo payload > one
+ln -s one two
+testing '-L' "$CPI_O -L | grep -ao payload" 'payload\n' '' 'two\n'
diff --git a/toys/posix/cpio.c b/toys/posix/cpio.c
index bbcde4b5..48b9b889 100644
--- a/toys/posix/cpio.c
+++ b/toys/posix/cpio.c
@@ -19,7 +19,7 @@
  * TODO: hardlink support, -A, -0, -a, -L, --sparse
  * TODO: --renumber-archives (probably always?) --ignore-devno --reproducible
 
-USE_CPIO(NEWTOY(cpio, "(ignore-devno)(renumber-inodes)(quiet)(no-preserve-owner)R(owner):md(make-directories)uH:p|i|t|F:v(verbose)o|[!pio][!pot][!pF]", TOYFLAG_BIN))
+USE_CPIO(NEWTOY(cpio, "(ignore-devno)(renumber-inodes)(quiet)(no-preserve-owner)R(owner):md(make-directories)uLH:p|i|t|F:v(verbose)o|[!pio][!pot][!pF]", TOYFLAG_BIN))
 
 config CPIO
   bool "cpio"
@@ -32,6 +32,7 @@ config CPIO
     -d	Create directories if needed
     -F FILE	Use archive FILE instead of stdin/stdout
     -i	Extract from archive into file system (stdin=archive)
+    -L	Follow symlinks
     -o	Create archive (stdin=list of files, stdout=archive)
     -p DEST	Copy-pass mode, copy stdin file list to directory DEST
     -R USER	Replace owner with USER[:GROUP]
@@ -265,7 +266,7 @@ void cpio_main(void)
       if (len<1) break;
       if (name[len-1] == '\n') name[--len] = 0;
       nlen = len+1;
-      if (lstat(name, &st) || (S_ISREG(st.st_mode)
+      if ((FLAG(L)?stat:lstat)(name, &st) || (S_ISREG(st.st_mode)
           && st.st_size && (fd = open(name, O_RDONLY))<0)
           || (S_ISLNK(st.st_mode) && !(link = xreadlink(name))))
       {
-- 
2.39.2