From b34aee04400d063ac6910fb1f287d64ef2828057 Mon Sep 17 00:00:00 2001
From: Mike Yuan <me@yhndnzj.com>
Date: Sat, 22 Nov 2025 18:56:41 +0100
Subject: [PATCH] core/exec-invoke: socket_fd must be set if any of stdio
 requests it

This is checked as one of the very first things in exec_invoke(),
hence remove the condition in fixup_input() and the whole
fixup_output().
---
 src/core/exec-invoke.c | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/src/core/exec-invoke.c b/src/core/exec-invoke.c
index 7d1a643b80c..4312fad505e 100644
--- a/src/core/exec-invoke.c
+++ b/src/core/exec-invoke.c
@@ -308,7 +308,6 @@ static int acquire_path(const char *path, int flags, mode_t mode) {
 
 static int fixup_input(
                 const ExecContext *context,
-                int socket_fd,
                 bool apply_tty_stdin) {
 
         ExecInput std_input;
@@ -320,23 +319,12 @@ static int fixup_input(
         if (exec_input_is_terminal(std_input) && !apply_tty_stdin)
                 return EXEC_INPUT_NULL;
 
-        if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0)
-                return EXEC_INPUT_NULL;
-
         if (std_input == EXEC_INPUT_DATA && context->stdin_data_size == 0)
                 return EXEC_INPUT_NULL;
 
         return std_input;
 }
 
-static int fixup_output(ExecOutput output, int socket_fd) {
-
-        if (output == EXEC_OUTPUT_SOCKET && socket_fd < 0)
-                return EXEC_OUTPUT_INHERIT;
-
-        return output;
-}
-
 static int setup_input(
                 const ExecContext *context,
                 const ExecParameters *params,
@@ -361,7 +349,7 @@ static int setup_input(
                 return STDIN_FILENO;
         }
 
-        i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
+        i = fixup_input(context, params->flags & EXEC_APPLY_TTY_STDIN);
 
         switch (i) {
 
@@ -445,16 +433,17 @@ static int setup_input(
         }
 }
 
-static bool can_inherit_stderr_from_stdout(
-                const ExecContext *context,
-                ExecOutput o,
-                ExecOutput e) {
+static bool can_inherit_stderr_from_stdout(const ExecContext *context) {
+        ExecOutput o, e;
 
         assert(context);
 
         /* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the
          * stderr fd */
 
+        o = context->std_output;
+        e = context->std_error;
+
         if (e == EXEC_OUTPUT_INHERIT)
                 return true;
         if (e != o)
@@ -508,12 +497,11 @@ static int setup_output(
                 return STDERR_FILENO;
         }
 
-        i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
-        o = fixup_output(context->std_output, socket_fd);
+        i = fixup_input(context, params->flags & EXEC_APPLY_TTY_STDIN);
+        o = context->std_output;
 
         if (fileno == STDERR_FILENO) {
-                ExecOutput e;
-                e = fixup_output(context->std_error, socket_fd);
+                ExecOutput e = context->std_error;
 
                 /* This expects the input and output are already set up */
 
@@ -527,7 +515,7 @@ static int setup_output(
                         return fileno;
 
                 /* Duplicate from stdout if possible */
-                if (can_inherit_stderr_from_stdout(context, o, e)) {
+                if (can_inherit_stderr_from_stdout(context)) {
                         r = fd_is_writable(STDOUT_FILENO);
                         if (r <= 0) {
                                 if (r < 0)
-- 
2.47.3