commit 25268a18550323f6babbcc260838fa09941e5c85
author Vivian Wang <uwu@dram.page> Tue Jul 23 18:05:45 2024 +0800
committer Richard Henderson <richard.henderson@linaro.org> Tue Jul 30 07:59:23 2024 +1000
tree 157eec75ba42209af3d7613e3247909576747649
parent 22531d8cc58f390986e7070eca5d1628aa7b2fe0

linux-user/main: Check errno when getting AT_EXECFD

It's possible for AT_EXECFD to end up with a valid value of 0. Check
errno when using qemu_getauxval instead of return value to handle this
case.

Not handling this case leads to a confusing condition where the
executable ends up as fd 0, i.e. stdin.

Signed-off-by: Vivian Wang <uwu@dram.page>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: 0b959cf5e4cc ("linux-user: Use qemu_getauxval for AT_EXECFD")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2448
Message-ID: <20240723100545.405476-3-uwu@dram.page>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/main.c

diff --git a/linux-user/main.c b/linux-user/main.c
index 7d3cf45..8143a0d 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -755,8 +755,9 @@
     /*
      * Manage binfmt-misc open-binary flag
      */
+    errno = 0;
     execfd = qemu_getauxval(AT_EXECFD);
-    if (execfd == 0) {
+    if (errno != 0) {
         execfd = open(exec_path, O_RDONLY);
         if (execfd < 0) {
             printf("Error while loading %s: %s\n", exec_path, strerror(errno));