[PATCH] gdb/debuginfod: Whitespace-only URL should disable debuginfod

[Aaron Merey <amerey@redhat.com>]

On Fri, Apr 29, 2022 at 10:22 AM Pedro Alves <pedro@palves.net> wrote:
> Does the rest of the function need to see "urls" with the leading space?  It seems like the 
> code further below will also skip leading spaces anyhow.  IOW, we can't make this be: 
>
>     urls = skip_spaces (urls);
>
> or both lines replaced with:
>
>     const char *urls = skip_spaces (getenv (DEBUGINFOD_URLS_ENV_VAR));
>
> ?

I kept the "urls" with the leading whitespace so that we parse each URL 
consistent with debuginfod's use of ' ' as the sole URL delimiter 
(skip_space also skips tabs, newlines, etc).  However debuginfod severs
should not have URLs containing unescaped whitespace so it's really a 
moot point.

I've fixed this by combining skip_spaces and getenv on one line.

Aaron

From 4cd3582892440d2092c65df8472427566dbceaa9 Mon Sep 17 00:00:00 2001
From: Aaron Merey <amerey@redhat.com>
Date: Wed, 27 Apr 2022 16:41:24 -0400

Currently debuginfod is disabled when the string of server URLs
is unset or set to be the empty string (via the $DEBUGINFOD_URLS
environment variable or the 'set debuginfod urls' gdb command).

Extend this functionality so that a whitespace-only URL also disables
debuginfod.

Modify a testcase to verify that a whitespace-only URL disables
debuginfod.
---
 gdb/debuginfod-support.c                        |  7 ++++---
 .../gdb.debuginfod/fetch_src_and_symbols.exp    | 17 +++++++++++++----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
index 4ce2e786b6a..dffcd782e7d 100644
--- a/gdb/debuginfod-support.c
+++ b/gdb/debuginfod-support.c
@@ -173,10 +173,11 @@ get_debuginfod_client ()
 static bool
 debuginfod_is_enabled ()
 {
-  const char *urls = getenv (DEBUGINFOD_URLS_ENV_VAR);
+  const char *urls = skip_spaces (getenv (DEBUGINFOD_URLS_ENV_VAR));
 
-  if (urls == nullptr || urls[0] == '\0'
-      || debuginfod_enabled == debuginfod_off)
+  if (debuginfod_enabled == debuginfod_off
+      || urls == nullptr
+      || *urls == '\0')
     return false;
 
   if (debuginfod_enabled == debuginfod_ask)
diff --git a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
index bd90bcd0cfe..74d026464b9 100644
--- a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
+++ b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
@@ -309,7 +309,8 @@ proc local_url { } {
     clean_restart
     # Disable confirmation to avoid having to deal with a query.  See
     # test_urls.
-    gdb_test_multiple "with confirm off -- file $binfile" "notice empty URL" {
+    set file_cmd "with confirm off -- file $binfile"
+    gdb_test_multiple $file_cmd "notice empty URL" {
 	-re -wrap "This GDB supports auto-downloading.*" {
 	    fail $gdb_test_name
 	}
@@ -318,9 +319,17 @@ proc local_url { } {
 	}
     }
 
-    test_urls "   " \
-        "" \
-        "notice whitespace URL"
+    # Whitespace-only URLS disables Debuginfod.
+    setenv DEBUGINFOD_URLS "    "
+    clean_restart
+    gdb_test_multiple $file_cmd "notice whitespace URL" {
+	-re -wrap "This GDB supports auto-downloading.*" {
+	    fail $gdb_test_name
+	}
+	-re -wrap "" {
+	    pass $gdb_test_name
+	}
+    }
 
     set url "http://127.0.0.1:$port"
 
-- 
2.35.1