From 3264774571cc1ae5fbb4dee29d4216e041cdd73d Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sat, 27 Aug 2022 00:48:08 -0500
Subject: [PATCH] Tar compression autodetect wasn't falling back to gzip -d
 without zcat because fallback compressor name selection happened before
 autodetect.

---
 tests/tar.test   |  6 ++++++
 toys/posix/tar.c | 12 ++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/tests/tar.test b/tests/tar.test
index 84f99083..24a43a81 100755
--- a/tests/tar.test
+++ b/tests/tar.test
@@ -218,6 +218,12 @@ toyonly testing "cat tbz | extract dir/file (autodetect)" \
   "dir/\ndir/file\ndrwxr-x--- 1494637555 dd/dir\n-rw-r----- 1494637555 dd/dir/file\n" \
   "" ""
 
+mkdir path && ln -s "$(which gzip)" "$(which tar)" path/
+toyonly [ -x path/gzip ]
+testing "autodetect falls back to gzip -d when no zcat" \
+  "PATH=path; tar tf $FILES/tar/tar.tgz" "dir/\ndir/file\n" "" ""
+rm -rf path
+
 yes | head -n $((1<<18)) > bang
 { dd bs=$((1<<16)) count=1 status=none; dd bs=8192 seek=14 count=1 status=none; dd bs=4096 seek=64 count=5 status=none; } < bang > fweep
 testing "sparse without overflow" "$TAR --sparse fweep | SUM 3" \
diff --git a/toys/posix/tar.c b/toys/posix/tar.c
index 4ac10e75..9d57f30e 100644
--- a/toys/posix/tar.c
+++ b/toys/posix/tar.c
@@ -878,10 +878,14 @@ static void do_XT(char **pline, long len)
   if (pline) trim2list(TT.X ? &TT.excl : &TT.incl, *pline);
 }
 
+static  char *get_archiver()
+{
+  return FLAG(I) ? TT.I : FLAG(z) ? "gzip" : FLAG(J) ? "xz" : "bzip2";
+}
+
 void tar_main(void)
 {
-  char *s, **args = toys.optargs,
-    *archiver = FLAG(I) ? TT.I : (FLAG(z) ? "gzip" : (FLAG(J) ? "xz":"bzip2"));
+  char *s, **args = toys.optargs;
   int len = 0, ii;
 
   // Needed when extracting to command
@@ -980,7 +984,7 @@ void tar_main(void)
 
       // Toybox provides more decompressors than compressors, so try them first
       TT.pid = xpopen_both(zcat ? (char *[]){zcat->str, 0} :
-        (char *[]){archiver, "-d", 0}, pipefd);
+        (char *[]){get_archiver(), "-d", 0}, pipefd);
       if (CFG_TOYBOX_FREE) llist_traverse(zcat, free);
 
       if (!hdr) {
@@ -1052,7 +1056,7 @@ void tar_main(void)
     if (FLAG(j)||FLAG(z)||FLAG(I)||FLAG(J)) {
       int pipefd[2] = {-1, TT.fd};
 
-      xpopen_both((char *[]){archiver, 0}, pipefd);
+      xpopen_both((char *[]){get_archiver(), 0}, pipefd);
       close(TT.fd);
       TT.fd = pipefd[0];
     }
-- 
2.39.2