From 9ef5fc9a29c9d831035d4fb727c30817ffc19946 Mon Sep 17 00:00:00 2001 From: "Enrico Weigelt, metux IT consult" Date: Wed, 24 Jul 2024 15:38:15 +0200 Subject: [PATCH] Xext: vidmode: untwist ProcVidModeGetAllModeLines() and use stack buffer The ProcVidModeGetAllModeLines() is a bit complicated, because reply structs differ depending the active protocol version. In order to make it easier to understand and allow further simplification of the request/reply marshalling (see ticket #1701), splitting the two protocol versions into separate functions. Also collecting the whole payload in a stack buffer (size is already known anyways), in order to save arbirary number of individual WriteToClient() calls, but send out the whole reply in one pass, which in turn allows further simplifications in the sending path. Signed-off-by: Enrico Weigelt, metux IT consult --- Xext/vidmode.c | 127 ++++++++++++++++++++++++++++++------------------- 1 file changed, 78 insertions(+), 49 deletions(-) diff --git a/Xext/vidmode.c b/Xext/vidmode.c index aca854008..c93b26077 100644 --- a/Xext/vidmode.c +++ b/Xext/vidmode.c @@ -310,6 +310,72 @@ ProcVidModeGetModeLine(ClientPtr client) return Success; } +static char *fillModeInfoV1(ClientPtr client, char *buf, int dotClock, DisplayModePtr mode) +{ + xXF86OldVidModeModeInfo info = { + .dotclock = dotClock, + .hdisplay = VidModeGetModeValue(mode, VIDMODE_H_DISPLAY), + .hsyncstart = VidModeGetModeValue(mode, VIDMODE_H_SYNCSTART), + .hsyncend = VidModeGetModeValue(mode, VIDMODE_H_SYNCEND), + .htotal = VidModeGetModeValue(mode, VIDMODE_H_TOTAL), + .vdisplay = VidModeGetModeValue(mode, VIDMODE_V_DISPLAY), + .vsyncstart = VidModeGetModeValue(mode, VIDMODE_V_SYNCSTART), + .vsyncend = VidModeGetModeValue(mode, VIDMODE_V_SYNCEND), + .vtotal = VidModeGetModeValue(mode, VIDMODE_V_TOTAL), + .flags = VidModeGetModeValue(mode, VIDMODE_FLAGS), + }; + + if (client->swapped) { + swapl(&info.dotclock); + swaps(&info.hdisplay); + swaps(&info.hsyncstart); + swaps(&info.hsyncend); + swaps(&info.htotal); + swaps(&info.vdisplay); + swaps(&info.vsyncstart); + swaps(&info.vsyncend); + swaps(&info.vtotal); + swapl(&info.flags); + } + + memcpy(buf, &info, sizeof(info)); + return buf + sizeof(info); +} + +static char *fillModeInfoV2(ClientPtr client, char *buf, int dotClock, DisplayModePtr mode) +{ + xXF86VidModeModeInfo info = { + .dotclock = dotClock, + .hdisplay = VidModeGetModeValue(mode, VIDMODE_H_DISPLAY), + .hsyncstart = VidModeGetModeValue(mode, VIDMODE_H_SYNCSTART), + .hsyncend = VidModeGetModeValue(mode, VIDMODE_H_SYNCEND), + .htotal = VidModeGetModeValue(mode, VIDMODE_H_TOTAL), + .hskew = VidModeGetModeValue(mode, VIDMODE_H_SKEW), + .vdisplay = VidModeGetModeValue(mode, VIDMODE_V_DISPLAY), + .vsyncstart = VidModeGetModeValue(mode, VIDMODE_V_SYNCSTART), + .vsyncend = VidModeGetModeValue(mode, VIDMODE_V_SYNCEND), + .vtotal = VidModeGetModeValue(mode, VIDMODE_V_TOTAL), + .flags = VidModeGetModeValue(mode, VIDMODE_FLAGS), + }; + + if (client->swapped) { + swapl(&info.dotclock); + swaps(&info.hdisplay); + swaps(&info.hsyncstart); + swaps(&info.hsyncend); + swaps(&info.htotal); + swapl(&info.hskew); + swaps(&info.vdisplay); + swaps(&info.vsyncstart); + swaps(&info.vsyncend); + swaps(&info.vtotal); + swapl(&info.flags); + } + + memcpy(buf, &info, sizeof(info)); + return buf + sizeof(info); +} + static int ProcVidModeGetAllModeLines(ClientPtr client) { @@ -355,59 +421,22 @@ ProcVidModeGetAllModeLines(ClientPtr client) swapl(&rep.length); swapl(&rep.modecount); } - WriteToClient(client, sizeof(xXF86VidModeGetAllModeLinesReply), &rep); + + char *payload = calloc(1, payload_len); + if (!payload) + return BadAlloc; + + char *walk = payload; do { - xXF86VidModeModeInfo mdinf = { - .dotclock = dotClock, - .hdisplay = VidModeGetModeValue(mode, VIDMODE_H_DISPLAY), - .hsyncstart = VidModeGetModeValue(mode, VIDMODE_H_SYNCSTART), - .hsyncend = VidModeGetModeValue(mode, VIDMODE_H_SYNCEND), - .htotal = VidModeGetModeValue(mode, VIDMODE_H_TOTAL), - .hskew = VidModeGetModeValue(mode, VIDMODE_H_SKEW), - .vdisplay = VidModeGetModeValue(mode, VIDMODE_V_DISPLAY), - .vsyncstart = VidModeGetModeValue(mode, VIDMODE_V_SYNCSTART), - .vsyncend = VidModeGetModeValue(mode, VIDMODE_V_SYNCEND), - .vtotal = VidModeGetModeValue(mode, VIDMODE_V_TOTAL), - .flags = VidModeGetModeValue(mode, VIDMODE_FLAGS), - .privsize = 0 - }; - if (client->swapped) { - swapl(&mdinf.dotclock); - swaps(&mdinf.hdisplay); - swaps(&mdinf.hsyncstart); - swaps(&mdinf.hsyncend); - swaps(&mdinf.htotal); - swapl(&mdinf.hskew); - swaps(&mdinf.vdisplay); - swaps(&mdinf.vsyncstart); - swaps(&mdinf.vsyncend); - swaps(&mdinf.vtotal); - swapl(&mdinf.flags); - swapl(&mdinf.privsize); - } - if (ver < 2) { - xXF86OldVidModeModeInfo oldmdinf = { - .dotclock = mdinf.dotclock, - .hdisplay = mdinf.hdisplay, - .hsyncstart = mdinf.hsyncstart, - .hsyncend = mdinf.hsyncend, - .htotal = mdinf.htotal, - .vdisplay = mdinf.vdisplay, - .vsyncstart = mdinf.vsyncstart, - .vsyncend = mdinf.vsyncend, - .vtotal = mdinf.vtotal, - .flags = mdinf.flags, - .privsize = mdinf.privsize - }; - WriteToClient(client, sizeof(xXF86OldVidModeModeInfo), &oldmdinf); - } - else { - WriteToClient(client, sizeof(xXF86VidModeModeInfo), &mdinf); - } - + walk = (ver < 2) ? fillModeInfoV1(client, walk, dotClock, mode) + : fillModeInfoV2(client, walk, dotClock, mode); } while (pVidMode->GetNextModeline(pScreen, &mode, &dotClock)); + WriteToClient(client, sizeof(xXF86VidModeGetAllModeLinesReply), &rep); + WriteToClient(client, payload_len, payload); + free(payload); + return Success; }