Date: Sat, 5 Jan 2019 16:37:59 -0800 From: Mark Millard <marklmi@yahoo.com> To: Kyle Evans <kevans@FreeBSD.org>, freebsd-emulation@freebsd.org, ports-list freebsd <freebsd-ports@freebsd.org> Cc: Sean Bruno <sbruno@freebsd.org>, freebsd-arm <freebsd-arm@freebsd.org> Subject: qemu-arm-static has target_msqid_ds too small vs. arm natives msqid_ds Message-ID: <C10A9B6F-3FC6-4B10-B883-593895985683@yahoo.com>
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[The context here is FreeBSD head -r341836 based and ports head -r488859 =
based.]
Note: I assume that "struct target_msqid_ds" is meant to match the =
memory layout
of the target's native "struct msqid_ds". Otherwise the reported =
differences
below could be irrelevant.
For armv7 (and likely armv6) the following code:
printf("sizeof(struct msqid_ds) =3D %lu\n", (unsigned long) =
sizeof(struct msqid_ds));
printf("msg_perm %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_perm));
printf("__msg_first %lu\n", (unsigned long) offsetof(struct =
msqid_ds, __msg_first));
printf("__msg_last %lu\n", (unsigned long) offsetof(struct =
msqid_ds, __msg_last));
printf("msg_cbytes %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_cbytes));
printf("msg_qnum %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_qnum));
printf("msg_qbytes %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_qbytes));
printf("msg_lspid %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_lspid));
printf("msg_lrpid %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_lrpid));
printf("msg_stime %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_stime));
printf("msg_rtime %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_rtime));
printf("msg_ctime %lu\n", (unsigned long) offsetof(struct =
msqid_ds, msg_ctime));
produces:
sizeof(struct msqid_ds) =3D 80
msg_perm 0
__msg_first 24
__msg_last 28
msg_cbytes 32
msg_qnum 36
msg_qbytes 40
msg_lspid 44
msg_lrpid 48
msg_stime 56
msg_rtime 64
msg_ctime 72
However gdb reports for qemu-arm-static (on amd64):
(gdb) p/d sizeof(struct target_msqid_ds)
$14 =3D 64
(gdb) p/d &((struct target_msqid_ds *)0)->msg_first
$15 =3D 24
(gdb) p/d &((struct target_msqid_ds *)0)->msg_last=20
$16 =3D 28
(gdb) p/d &((struct target_msqid_ds *)0)->msg_cbytes
$17 =3D 32
(gdb) p/d &((struct target_msqid_ds *)0)->msg_qnum =20
$18 =3D 36
(gdb) p/d &((struct target_msqid_ds *)0)->msg_qbytes
$19 =3D 40
(gdb) p/d &((struct target_msqid_ds *)0)->msg_lspid=20
$20 =3D 44
(gdb) p/d &((struct target_msqid_ds *)0)->msg_lrpid
$21 =3D 48
(gdb) p/d &((struct target_msqid_ds *)0)->msg_stime
$22 =3D 52
(gdb) p/d &((struct target_msqid_ds *)0)->msg_rtime
$23 =3D 56
(gdb) p/d &((struct target_msqid_ds *)0)->msg_ctime
$24 =3D 60
so after msg_lrpid the offsets are different.
/usr/include/sys/msg.h has:
struct msqid_ds {
struct ipc_perm msg_perm; /* msg queue permission bits */
struct msg *__msg_first; /* first message in the queue */
struct msg *__msg_last; /* last message in the queue */
msglen_t msg_cbytes; /* number of bytes in use on the queue =
*/
msgqnum_t msg_qnum; /* number of msgs in the queue */
msglen_t msg_qbytes; /* max # of bytes on the queue */
pid_t msg_lspid; /* pid of last msgsnd() */
pid_t msg_lrpid; /* pid of last msgrcv() */
time_t msg_stime; /* time of last msgsnd() */
time_t msg_rtime; /* time of last msgrcv() */
time_t msg_ctime; /* time of last msgctl() */
};
=
/wrkdirs/usr/ports/emulators/qemu-user-static/work/qemu-bsd-user-4ef7d07/b=
sd-user/syscall_defs.h
has:
struct target_msqid_ds {
struct target_ipc_perm msg_perm; /* msg queue permission bits */
abi_ulong msg_first; /* first message in the queue */
abi_ulong msg_last; /* last message in the queue */
abi_ulong msg_cbytes; /* # of bytes in use on the queue */
abi_ulong msg_qnum; /* number of msgs in the queue */
abi_ulong msg_qbytes; /* max # of bytes on the queue */
int32_t msg_lspid; /* pid of last msgsnd() */
int32_t msg_lrpid; /* pid of last msgrcv() */
abi_ulong msg_stime; /* time of last msgsnd() */
abi_ulong msg_rtime; /* time of last msgrcv() */
abi_ulong msg_ctime; /* time of last msgctl() */
};
abi_ulong's for msg_stime, msg_rtime, and msg_ctime are the wrong
size for armv7: arm uses 64-bit time_t. As of 12+ only i386
uses 32-bit time_t if I understand right. In 11.x 32-bit powerpc
also uses 32-bit time_t.
=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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