Re: [Qemu-devel] [PATCH v4] linux-user: fix emulation of getdents

[Dmitry V. Levin]

In case when TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64, the last
byte of the target dirent structure (aka d_type byte) was never copied
from the host dirent structure, thus breaking everything that relies
on valid d_type value, e.g. glob(3).

Signed-off-by: Dmitry V. Levin <address@hidden>
---
 linux-user/syscall.c      | 11 +++++------
 linux-user/syscall_defs.h |  8 ++++----
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 41c869b..8a8aaca 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7025,15 +7025,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
arg1,
                tde = target_dirp;
                 while (len > 0) {
                     reclen = de->d_reclen;
-                   treclen = reclen - (2 * (sizeof(long) - sizeof(abi_long)));
+                    tnamelen = reclen - offsetof(struct linux_dirent, d_name);
+                    assert(tnamelen >= 0);
+                    treclen = tnamelen + offsetof(struct target_dirent, 
d_name);
+                    assert(count1 + treclen <= count);
                     tde->d_reclen = tswap16(treclen);
                     tde->d_ino = tswapal(de->d_ino);
                     tde->d_off = tswapal(de->d_off);
-                   tnamelen = treclen - (2 * sizeof(abi_long) + 2);
-                   if (tnamelen > 256)
-                        tnamelen = 256;
-                    /* XXX: may not be correct */
-                    pstrcpy(tde->d_name, tnamelen, de->d_name);
+                    memcpy(tde->d_name, de->d_name, tnamelen);
                     de = (struct linux_dirent *)((char *)de + reclen);
                     len -= reclen;
                     tde = (struct target_dirent *)((char *)tde + treclen);
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 2cfda5a..a98cbf7 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -255,10 +255,10 @@ struct kernel_statfs {
 };
 
 struct target_dirent {
-       abi_long        d_ino;
-       abi_long        d_off;
-       unsigned short  d_reclen;
-       char            d_name[256]; /* We must not include limits.h! */
+        abi_long        d_ino;
+        abi_long        d_off;
+        unsigned short  d_reclen;
+        char            d_name[];
 };
 
 struct target_dirent64 {

-- 
ldv