[lit] Make builtin cat work with stdin
cat with no files passed to it is supposed to read from STDIN according
to POSIX. The builtin cat lacking this behavior led to the clang test in
dev-fd-fs.c to fail because it expected this behavior. This is a simple
modification and I do not think it is possible to rewrite the test
without this easily while preserving the semantics around named pipes.
Reviewers: petrhosek, arichardson, ilovepi, cmtice, jh7370
Reviewed By: jh7370, arichardson, ilovepi, cmtice
Pull Request: https://github.com/llvm/llvm-project/pull/158447
diff --git a/clang/test/Misc/dev-fd-fs.c b/clang/test/Misc/dev-fd-fs.c
index ea94d95..b989ab8 100644
--- a/clang/test/Misc/dev-fd-fs.c
+++ b/clang/test/Misc/dev-fd-fs.c
@@ -1,6 +1,5 @@
// Check that we can operate on files from /dev/fd.
// REQUIRES: dev-fd-fs
-// REQUIRES: shell
// Check reading from named pipes. We cat the input here instead of redirecting
// it to ensure that /dev/fd/0 is a named pipe, not just a redirected file.
diff --git a/llvm/utils/lit/lit/builtin_commands/cat.py b/llvm/utils/lit/lit/builtin_commands/cat.py
index ddab5556..2797e0c 100644
--- a/llvm/utils/lit/lit/builtin_commands/cat.py
+++ b/llvm/utils/lit/lit/builtin_commands/cat.py
@@ -49,6 +49,9 @@
import os, msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+ if len(filenames) == 0:
+ sys.stdout.write(sys.stdin.read())
+ sys.exit(0)
for filename in filenames:
try:
contents = None
diff --git a/llvm/utils/lit/tests/Inputs/shtest-cat/cat.txt b/llvm/utils/lit/tests/Inputs/shtest-cat/cat.txt
index 4014b0f..c5b5d24 100644
--- a/llvm/utils/lit/tests/Inputs/shtest-cat/cat.txt
+++ b/llvm/utils/lit/tests/Inputs/shtest-cat/cat.txt
@@ -70,3 +70,7 @@
# NP-CAT-OUTPUT-NEXT:M-HM-IM-JM-KM-LM-MM-NM-OM-PM-QM-RM-SM-TM-UM-VM-WM-XM-YM-ZM-[
# NP-CAT-OUTPUT-NEXT:M-\M-]M-^M-_M-`M-aM-bM-cM-dM-eM-fM-gM-hM-iM-jM-kM-lM-mM-nM-o
# NP-CAT-OUTPUT-NEXT:M-pM-qM-rM-sM-tM-uM-vM-wM-xM-yM-zM-{M-|M-}M-~M-^?
+
+## Test that cat will pipe stdin to stdout if no other files are specified.
+# RUN: echo test | cat | FileCheck --check-prefix=CAT-STDIN %s
+# CAT-STDIN: test
