From 63f510ebf2378820aced3ad58a4eeeb8a46caa05 Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Thu, 11 Jul 2024 09:22:12 +0200
Subject: [PATCH] (submit/cleanup-xi) Xi: use stack allocation for temporary
 buffers

Small buffers easily fit on stack, which is much faster (just moving SP),
and alloca()'ed buffers are cleaned up automatically on function leave,
no extra free() needed.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
---
 Xi/getdctl.c    | 3 +--
 Xi/getfctl.c    | 4 +---
 Xi/xiselectev.c | 8 ++------
 3 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/Xi/getdctl.c b/Xi/getdctl.c
index 88462b767..e4f4a855b 100644
--- a/Xi/getdctl.c
+++ b/Xi/getdctl.c
@@ -153,7 +153,6 @@ int
 ProcXGetDeviceControl(ClientPtr client)
 {
     int rc, total_length = 0;
-    char *savbuf;
     DeviceIntPtr dev;
 
     REQUEST(xGetDeviceControlReq);
@@ -186,7 +185,7 @@ ProcXGetDeviceControl(ClientPtr client)
     char *buf = calloc(1, total_length);
     if (!buf)
         return BadAlloc;
-    savbuf = buf;
+    char *savbuf = buf;
 
     switch (stuff->control) {
     case DEVICE_RESOLUTION:
diff --git a/Xi/getfctl.c b/Xi/getfctl.c
index 64dab777a..bf3db9864 100644
--- a/Xi/getfctl.c
+++ b/Xi/getfctl.c
@@ -244,7 +244,6 @@ int
 ProcXGetFeedbackControl(ClientPtr client)
 {
     int rc, total_length = 0;
-    char *savbuf;
     DeviceIntPtr dev;
     KbdFeedbackPtr k;
     PtrFeedbackPtr p;
@@ -298,7 +297,7 @@ ProcXGetFeedbackControl(ClientPtr client)
     char *buf = (char *) calloc(1, total_length);
     if (!buf)
         return BadAlloc;
-    savbuf = buf;
+    char *savbuf = buf;
 
     for (k = dev->kbdfeed; k; k = k->next)
         CopySwapKbdFeedback(client, k, &buf);
@@ -322,6 +321,5 @@ ProcXGetFeedbackControl(ClientPtr client)
     }
     WriteToClient(client, sizeof(xGetFeedbackControlReply), &rep);
     WriteToClient(client, total_length, savbuf);
-    free(savbuf);
     return Success;
 }
diff --git a/Xi/xiselectev.c b/Xi/xiselectev.c
index 3e3ccdc58..6bd117414 100644
--- a/Xi/xiselectev.c
+++ b/Xi/xiselectev.c
@@ -342,7 +342,6 @@ ProcXIGetSelectedEvents(ClientPtr client)
 {
     int rc, i;
     WindowPtr win;
-    char *buffer = NULL;
     OtherInputMasks *masks;
     InputClientsPtr others = NULL;
     xXIEventMask *evmask = NULL;
@@ -374,10 +373,8 @@ ProcXIGetSelectedEvents(ClientPtr client)
     if (!others)
         goto finish;
 
-    buffer =
-        calloc(MAXDEVICES, sizeof(xXIEventMask) + pad_to_int32(XI2MASKSIZE));
-    if (!buffer)
-        return BadAlloc;
+    char buffer[MAXDEVICES * (sizeof(xXIEventMask) + pad_to_int32(XI2MASKSIZE))];
+    memset(buffer, 0, sizeof(buffer));
 
     evmask = (xXIEventMask *) buffer;
     for (i = 0; i < MAXDEVICES; i++) {
@@ -423,6 +420,5 @@ finish: ;
     WriteToClient(client, sizeof(xXIGetSelectedEventsReply), &rep);
     WriteToClient(client, length * 4, buffer);
 
-    free(buffer);
     return Success;
 }