Handle JSON hooks that just close the file/exit and fix some other errors

JSON hooks might disappear and the common idiom to work around hooks
disappearing is to check for the hook in the shell snippet that is
in the apt.conf file and if it does not exist, do nothing. This caused
APT to fail however, expecting it to acknowledge the handshake.
Ignoring ECONNRESET on handshakes solves the problem.

The error case, and the other error cases also did not stop execution
of the hook, causing more errors to pile up. Fix this by directly going
to the closing part of the code.

LP: #1776218
(cherry picked from commit 1d53cffad22c92645090e0e6ddde31fe4f7c3b05)

2 files changed, 95 insertions, 2 deletions

diff --git a/apt-private/private-json-hooks.cc b/apt-private/private-json-hooks.cc
index 07c89ca23..0e4b4913b 100644
--- a/apt-private/private-json-hooks.cc
+++ b/apt-private/private-json-hooks.cc
@@ -387,21 +387,26 @@ bool RunJsonHook(std::string const &option, std::string const &method, const cha
 
       if (size < 0)
       {
-	 _error->Error("Could not read response to hello message from hook %s: %s", Opts->Value.c_str(), strerror(errno));
+	 if (errno != ECONNRESET)
+	    _error->Error("Could not read response to hello message from hook %s: %s", Opts->Value.c_str(), strerror(errno));
+	 goto out;
       }
       else if (strstr(line, "error") != nullptr)
       {
 	 _error->Error("Hook %s reported an error during hello: %s", Opts->Value.c_str(), line);
+	 goto out;
       }
 
       size = getline(&line, &linesize, F);
       if (size < 0)
       {
-	 _error->Error("Could not read message separator line after handshake from %s: %s", Opts->Value.c_str(), strerror(errno));
+	 _error->Error("Could not read message separator line after handshake from %s: %s", Opts->Value.c_str(), feof(F) ? "end of file" : strerror(errno));
+	 goto out;
       }
       else if (size == 0 || line[0] != '\n')
       {
 	 _error->Error("Expected empty line after handshake from %s, received %s", Opts->Value.c_str(), line);
+	 goto out;
       }
 
       fwrite(TheData.data(), TheData.size(), 1, F);
@@ -409,6 +414,7 @@ bool RunJsonHook(std::string const &option, std::string const &method, const cha
 
       fwrite(ByeData.data(), ByeData.size(), 1, F);
       fwrite("\n\n", 2, 1, F);
+   out:
       fclose(F);
       // Clean up the sub process
       if (ExecWait(Process, Opts->Value.c_str()) == false)
diff --git a/test/integration/test-apt-cli-json-hooks b/test/integration/test-apt-cli-json-hooks
index 0d2a55fb3..80922e01b 100755
--- a/test/integration/test-apt-cli-json-hooks
+++ b/test/integration/test-apt-cli-json-hooks
@@ -120,3 +120,90 @@ HOOK: empty
 HOOK: request {"jsonrpc":"2.0","method":"org.debian.apt.hooks.install.post","params":{"command":"install","search-terms":["foo"],"unknown-packages":[],"packages":[{"id":1,"name":"foo","architecture":"i386","mode":"install","automatic":false,"versions":{"candidate":{"id":1,"version":"1.0","architecture":"all","pin":500},"install":{"id":1,"version":"1.0","architecture":"all","pin":500}}}]}}
 HOOK: empty
 HOOK: BYE' apt install foo -s
+
+################## Error in hello response #########################
+
+cat > json-hook.sh << EOF
+#!/bin/bash
+exec 2>/dev/null
+trap '' SIGPIPE
+while true; do
+	read request <&\$APT_HOOK_SOCKET
+	read empty <&\$APT_HOOK_SOCKET
+
+	if echo "\$request" | grep -q ".hello"; then
+		printf '{"jsonrpc": "2.0", "error": {"version": "0.1"}, "id": 0}\n\n' >&\$APT_HOOK_SOCKET
+		break
+	fi
+done
+exit 0
+EOF
+
+
+testfailureequal 'Reading package lists...
+Building dependency tree...
+E: Hook '$HOOK' reported an error during hello: {"jsonrpc": "2.0", "error": {"version": "0.1"}, "id": 0}
+E: Hook '$HOOK' reported an error during hello: {"jsonrpc": "2.0", "error": {"version": "0.1"}, "id": 0}' apt install foo -s
+
+################## Missing separator line #########################
+cat > json-hook.sh << EOF
+#!/bin/bash
+exec 2>/dev/null
+trap '' SIGPIPE
+while true; do
+	read request <&\$APT_HOOK_SOCKET
+	read empty <&\$APT_HOOK_SOCKET
+
+	if echo "\$request" | grep -q ".hello"; then
+		printf '{"jsonrpc": "2.0", "result": {"version": "0.1"}, "id": 0}\n' >&\$APT_HOOK_SOCKET
+		break
+	fi
+done
+exit 0
+EOF
+
+
+testfailureequal 'Reading package lists...
+Building dependency tree...
+E: Could not read message separator line after handshake from '$HOOK': end of file
+E: Could not read message separator line after handshake from '$HOOK': end of file' apt install foo -s
+
+################## Wrong separator line #########################
+cat > json-hook.sh << EOF
+#!/bin/bash
+exec 2>/dev/null
+trap '' SIGPIPE
+while true; do
+	read request <&\$APT_HOOK_SOCKET
+	read empty <&\$APT_HOOK_SOCKET
+
+	if echo "\$request" | grep -q ".hello"; then
+		printf '{"jsonrpc": "2.0", "result": {"version": "0.1"}, "id": 0}\nXX' >&\$APT_HOOK_SOCKET
+		break
+	fi
+done
+exit 0
+EOF
+
+
+testfailureequal 'Reading package lists...
+Building dependency tree...
+E: Expected empty line after handshake from '$HOOK', received XX
+E: Expected empty line after handshake from '$HOOK', received XX' apt install foo -s
+
+##################### Removed hook || true ############################
+cat > rootdir/etc/apt/apt.conf.d/99-json-hooks << EOF
+	AptCli::Hooks::Install:: "true";
+	AptCli::Hooks::Search:: "true";
+EOF
+
+testsuccessequal 'Reading package lists...
+Building dependency tree...
+The following NEW packages will be installed:
+  foo
+0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
+Inst foo (1.0 unstable [all])
+Conf foo (1.0 unstable [all])' apt install foo -s
+
+
+