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[Stable-8.0.4,04/63] linux-user: Fix fcntl() and fcntl64() to return O_LARGEFILE for 32-bit targets

Message ID 20230804191647.1875608-1-mjt@tls.msk.ru
State New
Headers show
Series Patch Round-up for stable 8.0.4, freeze on 2023-08-05 | expand

Commit Message

Michael Tokarev Aug. 4, 2023, 7:16 p.m. UTC 
From: Helge Deller <deller@gmx.de>

When running a 32-bit guest on a 64-bit host, fcntl[64](F_GETFL) should
return with the TARGET_O_LARGEFILE flag set, because all 64-bit hosts
support large files unconditionally.

But on 64-bit hosts, O_LARGEFILE has the value 0, so the flag
translation can't be done with the fcntl_flags_tbl[]. Instead add the
TARGET_O_LARGEFILE flag afterwards.

Note that for 64-bit guests the compiler will optimize away this code,
since TARGET_O_LARGEFILE is zero.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit e0ddf8eac9f83c0bc5a3d39605d873ee0fe53421)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 333e6b7026..011cadb281 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7132,6 +7132,10 @@  static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
         ret = get_errno(safe_fcntl(fd, host_cmd, arg));
         if (ret >= 0) {
             ret = host_to_target_bitmask(ret, fcntl_flags_tbl);
+            /* tell 32-bit guests it uses largefile on 64-bit hosts: */
+            if (O_LARGEFILE == 0 && HOST_LONG_BITS == 64) {
+                ret |= TARGET_O_LARGEFILE;
+            }
         }
         break;