feat(glx-runtime): GL 来自生态而非 /usr/lib,这次带上缺失的那个测试

Sunrisepeak · Sunrisepeak · commit f14f2bf3ca2e · 2026-08-08T12:02:26.000+08:00
重新应用 f44e896(#179),它在 #180 被整体 revert。改动本身是对的: compat.glx-runtime 之前从 /usr/lib* 符号链接**宿主的** libGL/libEGL,而 mcpp#352 正是这么来的 —— 宿主 Mesa 需要 GLIBC_2.43,mcpp 的 payload glibc 是 2.39,程序链接干净、退出 255、一行输出都没有。它也是 xlings hermetic 政策 禁止清单上的第一条。 被 revert 的原因不在这两个文件里。mesa 声明 `xim:glibc@>=2.38`,下限被任何 更高版本满足,于是 xim 在 2.39 旁边装了 2.44;而当时的 mcpp 用 readdir 的第一项 来解析「那个 glibc payload」,编译侧取了 2.44,产物的 interpreter 却仍是 2.39。 二进制开始引用 GLIBC_2.42 符号,而报错落在 asio-module 和 core 上 —— 两个不用 图形、不依赖 mesa、这次改动根本没碰的成员。 引擎侧已在 mcpp 2026.8.8.2 修好(runtime binding 从 subos 读,不再猜)。 真正缺的是**这里**的一个测试。这个仓库的每个测试都在测「它自己那个包」,所以 没有任何一个问出唯一重要的那个问题:装了这个,对**其他所有人**有没有影响? tests/check_graphics_install_side_effects.sh 就问这一个:装图形栈前后,各构建 一次与图形无关的成员,断言产物的 PT_INTERP 与 glibc 符号上界**逐字不变**。 它在任何早于 2026.8.8.2 的 mcpp 上都会失败,这是有意的 —— 图形栈不该落在一个 仍会犯这个错的工具链上。
diff --git a/pkgs/c/compat.glfw.lua b/pkgs/c/compat.glfw.lua
@@ -80,7 +80,7 @@ package = {
                 "src/posix_module.c",
             },
             deps = {
-                ["compat.glx-runtime"] = "2026.06.03",
+                ["compat.glx-runtime"] = "2026.08.08",
                 ["compat.x11"]       = "1.8.13",
                 ["compat.xcursor"]   = "1.2.3",
                 ["compat.xext"]      = "1.3.7",
diff --git a/pkgs/c/compat.glx-runtime.lua b/pkgs/c/compat.glx-runtime.lua
@@ -2,13 +2,59 @@ package = {
     spec        = "1",
     namespace   = "compat",
     name        = "glx-runtime",
-    description = "Host GLVND/GLX/OpenGL runtime adapter for mcpp Linux window applications",
+    description = "GLVND/GLX/OpenGL runtime for mcpp Linux window applications, from the xlings graphics stack",
     licenses    = {"MIT"},
     repo        = "https://github.com/KhronosGroup/OpenGL-Registry",
     type        = "package",
 
+    -- WHERE THE GL RUNTIME COMES FROM, AND WHY IT CHANGED
+    --
+    -- Until 2026.08.08 this package symlinked the HOST's libGL/libEGL out of
+    -- /usr/lib*. That is the thing mcpp#352 is: the host's Mesa needs
+    -- GLIBC_2.43 and mcpp's payload glibc is 2.39, so the program linked
+    -- cleanly and exited 255 with no output. It is also the boundary the
+    -- xlings hermetic policy names first -- any .so under /usr/lib* or /lib*.
+    --
+    -- The runtime now comes from `xim:graphics`, the ecosystem's own stack:
+    -- 22 packages plus two sentinels that probe for a host-side userspace half
+    -- they do not own (the proprietary NVIDIA driver, WSL2's D3D12) and
+    -- succeed having linked nothing when it is absent. One dependency, every
+    -- host shape, no conditional in this file.
+    --
+    -- Measured on an NVIDIA host after the change: libEGL resolves to
+    -- xim-x-libglvnd/1.7.0/lib/libEGL.so.1 and GL_RENDERER is the GPU, not
+    -- llvmpipe. Both halves of that matter -- "a window appeared" is a false
+    -- pass, because llvmpipe renders one too.
     xpm = {
         linux = {
+            -- The whole hermetic graphics stack. A RUNTIME dep, not a build
+            -- one: nothing here compiles against it, the produced consumer
+            -- loads it.
+            --
+            -- PLATFORM level, beside the version entries rather than inside
+            -- one. Every other recipe in both indexes places it here, and the
+            -- first attempt at this change put it inside the 2026.08.08 entry:
+            -- the descriptor parsed, the stack was never installed, and the
+            -- install failed on the required-library check -- an error naming
+            -- libGL.so.1 rather than the misplaced key. Whether a per-version
+            -- `deps` is rejected or merely unread was not determined; what is
+            -- established is that it does not take effect.
+            --
+            -- It therefore also applies to the legacy 2026.06.03 entry below,
+            -- which does not use it. That costs a consumer still pinned there
+            -- a download it will not read, and the alternative -- deleting the
+            -- published version -- would break them outright.
+            deps = { runtime = { "xim:graphics" } },
+            ["2026.08.08"] = {
+                url    = {
+                    GLOBAL = "https://raw.githubusercontent.com/KhronosGroup/OpenGL-Registry/a30033d3e812c9bf10094f1010374a6b15e192eb/README.adoc",
+                    CN     = "https://gitcode.com/mcpp-res/glx-runtime/releases/download/2026.08.08/glx-runtime-2026.08.08.adoc",
+                },
+                sha256 = "ea68efce197e68413ebb62c51ab4bccfb2309a2fca776d31b49d972f59f3640e",
+            },
+            -- Kept so already-published consumers pinned to it keep resolving.
+            -- It sources libGL from the HOST and is the configuration behind
+            -- mcpp#352; new consumers must not pin it.
             ["2026.06.03"] = {
                 url    = {
                     GLOBAL = "https://raw.githubusercontent.com/KhronosGroup/OpenGL-Registry/a30033d3e812c9bf10094f1010374a6b15e192eb/README.adoc",
@@ -41,6 +87,7 @@ package = {
 }
 
 import("xim.libxpkg.pkginfo")
+import("xim.libxpkg.system")
 import("xim.libxpkg.log")
 
 local function sh_quote(value)
@@ -60,6 +107,26 @@ local function split_paths(value)
     return out
 end
 
+-- Where to take the GL libraries from.
+--
+-- The SUBOS VIEW (`<subos>/lib`), not a payload directory. A payload path pins
+-- a version, so a consumer's recorded RUNPATH would name mesa 25.0.7.1 forever
+-- and stop resolving the day it is upgraded; the view is the stable
+-- indirection -- the role /run/opengl-driver plays on NixOS. xlings repoints
+-- it as the active version changes and this package needs no new release.
+--
+-- The view also carries libc.so.6, crt1.o and the rest of the C runtime, and
+-- those must NEVER reach a consumer's RUNPATH: the consumer runs under mcpp's
+-- payload loader, and pairing one loader with another glibc's libc.so.6 faults
+-- inside the dynamic linker before main, with empty output. What keeps them
+-- out is the pattern list below -- so that list is a safety boundary, not a
+-- convenience, and nothing resembling `libc*` may ever be added to it.
+--
+-- MCPP_HOST_GL_LIBRARY_PATH still works and is now the ONLY door back to the
+-- host. Using it leaves the hermetic guarantee: the libraries it names were
+-- built against the host's glibc, and loading them under mcpp's payload glibc
+-- is exactly the configuration mcpp#352 reports. It exists for a machine whose
+-- GPU vendor the ecosystem does not cover yet.
 local function candidate_dirs()
     local out = {}
     local seen = {}
@@ -71,13 +138,12 @@ local function candidate_dirs()
     end
 
     for _, dir in ipairs(split_paths(os.getenv("MCPP_HOST_GL_LIBRARY_PATH"))) do
+        log.warn("MCPP_HOST_GL_LIBRARY_PATH names %s: GL will come from the "
+                 .. "host, which is the configuration behind mcpp#352", dir)
         add(dir)
     end
-    add("/lib/x86_64-linux-gnu")
-    add("/usr/lib/x86_64-linux-gnu")
-    add("/lib64")
-    add("/usr/lib64")
-    add("/usr/lib")
+
+    add(path.join(system.subos_sysrootdir(), "lib"))
     return out
 end
 
@@ -90,7 +156,11 @@ local host_gl_patterns = {
     "libEGL.so*",
     "libEGL_*.so*",
     "libGLES*.so*",
-    "libnvidia*.so*",
+    -- No libnvidia* here. The proprietary driver reaches the subos through
+    -- xim:nvidia-gl-host-link, which links it under the glvnd vendor names
+    -- already matched above; taking it by its own name would be a second
+    -- route to the same libraries, and the two would disagree the day the
+    -- driver is upgraded under us.
     "libglapi.so*",
     "libdrm*.so*",
     "libexpat.so*",
@@ -104,90 +174,43 @@ local required = {
     ["libGL.so.1"] = false,
 }
 
--- Is FILE a 64-bit ELF? e_ident[EI_CLASS] == ELFCLASS64.
---
--- Five bytes read directly. `file`/`readelf`/`patchelf` would each answer this
--- and each may be absent when a hook runs, and a probe that answers "cannot
--- tell" by assuming "fine" is the bug below.
-local function is_elf64(file)
-    local f = io.open(file, "rb")
-    if not f then return false end
-    local head = f:read(5)
-    f:close()
-    return head ~= nil and #head == 5
-       and head:sub(1, 4) == "\127ELF" and head:byte(5) == 2
-end
-
--- Link the host's GL runtime into one directory, FIRST HIT WINS, 64-bit only.
---
--- openxlings/xlings' mcpp#352: on Fedora 44 this produced
---     libGLX.so.0 -> /usr/lib/libGLX.so.0
--- a 32-bit library, and the application died with
---     libGLX.so.0: wrong ELF class: ELFCLASS32
---
--- TWO BUGS, and the obvious diagnosis ("the candidate order assumes Debian") is
--- not either of them -- `/usr/lib64` is already ahead of `/usr/lib` in the list:
---
---   1. `ln -sf` OVERWRITES. The loop reached /usr/lib64 first and linked the
---      correct file, then reached /usr/lib and replaced it. Last-wins, not
---      first-wins. `libOpenGL.so.0` survived as 64-bit purely because that host's
---      32-bit glvnd does not ship it -- which is why exactly one link in the bug
---      report was right.
---   2. NO ABI CHECK ANYWHERE, including in `required` below, which asserted that
---      libGLX.so.0 and libGL.so.1 EXIST. Both existed. Both were 32-bit.
---
--- There is no directory layout to assume: the FHS biarch clause makes /usr/lib
--- 32-bit (Fedora/RHEL/SUSE), Debian explicitly declined that clause and uses
--- /usr/lib/<triplet> so its /usr/lib is 64-bit, and Arch is a third answer
--- again. So the fix cannot be a better ordering -- it has to be an ABI check,
--- which makes the order stop mattering.
 local function link_runtime_libs(outdir)
     os.mkdir(outdir)
-    local claimed = {}
     for _, dir in ipairs(candidate_dirs()) do
         for _, pattern in ipairs(host_gl_patterns) do
-            -- Enumerate, then decide per file, instead of letting the shell
-            -- link them: the decision needs the ELF class and "have I already
-            -- taken this name", neither of which a `ln -sf` loop can express.
-            local pipe = io.popen("ls -1 " .. sh_quote(dir) .. "/" .. pattern
-                                  .. " 2>/dev/null")
-            if pipe then
-                for line in pipe:lines() do
-                    local lib = line:gsub("[\r\n]+$", "")
-                    local name = lib:match("[^/]+$")
-                    if lib ~= "" and name and not claimed[name]
-                       and is_elf64(lib) then
-                        claimed[name] = lib
-                        os.exec("ln -sf " .. sh_quote(lib) .. " "
-                                .. sh_quote(path.join(outdir, name)))
-                    end
-                end
-                pipe:close()
-            end
+            os.exec(
+                "for lib in " .. sh_quote(dir) .. "/" .. pattern ..
+                "; do [ -e \"$lib\" ] || continue; " ..
+                "ln -sf \"$lib\" " .. sh_quote(outdir) .. "/\"$(basename \"$lib\")\"; " ..
+                "done"
+            )
         end
     end
 
     for name, _ in pairs(required) do
-        local link = path.join(outdir, name)
-        -- Existence AND ABI. Existence alone passed on the Fedora host with
-        -- both links 32-bit, which is how a broken package reported success and
-        -- the failure surfaced as a silent exit code 255 from the application.
-        if not os.isfile(link) then
-            log.error("required host GL runtime library not found: %s", name)
-            log.error("  searched: %s", table.concat(candidate_dirs(), " "))
-            log.error("  install your distro's GL runtime (mesa / libglvnd)")
+        if not os.isfile(path.join(outdir, name)) then
+            log.error("%s is not in this subos. The GL runtime comes from "
+                      .. "`xim:graphics`; if it is declared and this still "
+                      .. "fires, the stack did not finish installing", name)
             return false
         end
-        if not is_elf64(link) then
-            log.error("host %s is not 64-bit (%s)", name, claimed[name] or link)
-            log.error("  a 32-bit library here fails at dlopen with")
-            log.error("  `wrong ELF class: ELFCLASS32` and the application")
-            log.error("  exits without output. Install the 64-bit GL runtime.")
+    end
+
+    -- Nothing resembling a C runtime may have come along. Asserted rather
+    -- than trusted: the pattern list is what keeps it out, and a pattern is
+    -- one careless edit away from matching more than it meant to. The failure
+    -- it prevents has no diagnostic of its own -- the consumer dies inside
+    -- the dynamic linker before main, printing nothing.
+    for _, bad in ipairs({"libc.so.6", "libc.so", "ld-linux-x86-64.so.2",
+                          "libpthread.so.0", "libdl.so.2", "libm.so.6"}) do
+        if os.isfile(path.join(outdir, bad)) then
+            log.error("%s was linked into the GL runtime directory. It would "
+                      .. "land on every consumer's RUNPATH and pair a second "
+                      .. "libc with mcpp's loader, which faults before main "
+                      .. "with no output at all", bad)
             return false
         end
     end
-    log.info("glx-runtime: linked %d host GL libraries (64-bit)",
-             (function() local n = 0 for _ in pairs(claimed) do n = n + 1 end return n end)())
     return true
 end
 
diff --git a/tests/check_graphics_install_side_effects.sh b/tests/check_graphics_install_side_effects.sh
