Re: [PATCH v4] linux-user: Add close_range() syscall
On 10/25/22 11:39, Helge Deller wrote:
On 10/25/22 00:39, Richard Henderson wrote:
On 10/25/22 06:43, Helge Deller wrote:
+ abi_long maxfd = arg2;
+
+ if ((sizeof(abi_long) == 4 && arg2 == (abi_long)0x7FFFUL) ||
+ (sizeof(abi_long) == 8 && arg2 ==
(abi_long)0x7FFFULL)) {
+ maxfd = target_fd_max;
+ }
+
+ for (fd = arg1; fd < maxfd; fd++) {
Why do we need explicit checks for INT32/64_MAX?
If the guest passes 0x7FFEULL,
A 32-bit guest (on a 64bit host) will pass 0x7FFFUL...
do we really need to iterate over all of those impossible values?
The compiler will optimize one of those checks away, so it's effectively
just one expression.
By impossible values, I mean all descriptors above target_fd_max.
The compiler will most certainly not optimize the number of loop iterations.
r~
Re: [PATCH v4] linux-user: Add close_range() syscall
On 10/25/22 03:39, Helge Deller wrote:
On 10/25/22 00:39, Richard Henderson wrote:
On 10/25/22 06:43, Helge Deller wrote:
+ abi_long maxfd = arg2;
+
+ if ((sizeof(abi_long) == 4 && arg2 == (abi_long)0x7FFFUL) ||
+ (sizeof(abi_long) == 8 && arg2 ==
(abi_long)0x7FFFULL)) {
+ maxfd = target_fd_max;
+ }
+
+ for (fd = arg1; fd < maxfd; fd++) {
Why do we need explicit checks for INT32/64_MAX?
If the guest passes 0x7FFEULL,
A 32-bit guest (on a 64bit host) will pass 0x7FFFUL...
do we really need to iterate over all of those impossible values?
The compiler will optimize one of those checks away, so it's effectively
just one expression.
My above comments are correct, but
I should think some expression involving MIN() is in order.
that's even better.
Will resend v5 patch.
Helge
Re: [PATCH v4] linux-user: Add close_range() syscall
On 10/25/22 00:39, Richard Henderson wrote:
On 10/25/22 06:43, Helge Deller wrote:
+ abi_long maxfd = arg2;
+
+ if ((sizeof(abi_long) == 4 && arg2 == (abi_long)0x7FFFUL) ||
+ (sizeof(abi_long) == 8 && arg2 ==
(abi_long)0x7FFFULL)) {
+ maxfd = target_fd_max;
+ }
+
+ for (fd = arg1; fd < maxfd; fd++) {
Why do we need explicit checks for INT32/64_MAX?
If the guest passes 0x7FFEULL,
A 32-bit guest (on a 64bit host) will pass 0x7FFFUL...
do we really need to iterate over all of those impossible values?
The compiler will optimize one of those checks away, so it's effectively
just one expression.
I should think some expression involving MIN() is in order.
Helge
Re: [PATCH v4] linux-user: Add close_range() syscall
On 10/25/22 06:43, Helge Deller wrote:
+abi_long maxfd = arg2;
+
+if ((sizeof(abi_long) == 4 && arg2 == (abi_long)0x7FFFUL) ||
+(sizeof(abi_long) == 8 && arg2 ==
(abi_long)0x7FFFULL)) {
+maxfd = target_fd_max;
+}
+
+for (fd = arg1; fd < maxfd; fd++) {
Why do we need explicit checks for INT32/64_MAX? If the guest passes
0x7FFEULL, do we really need to iterate over all of those impossible values?
I should think some expression involving MIN() is in order.
r~
[PATCH v4] linux-user: Add close_range() syscall
Signed-off-by: Helge Deller
---
Changes:
v4: Fix check for arg2
v3: fd_trans_unregister() only called if close_range() doesn't fail
v2: consider CLOSE_RANGE_CLOEXEC flag
diff --git a/linux-user/strace.list b/linux-user/strace.list
index 3df2184580..cd995e5d56 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -103,6 +103,9 @@
#ifdef TARGET_NR_close
{ TARGET_NR_close, "close" , "%s(%d)", NULL, NULL },
#endif
+#ifdef TARGET_NR_close_range
+{ TARGET_NR_close_range, "close_range" , "%s(%u,%u,%u)", NULL, NULL },
+#endif
#ifdef TARGET_NR_connect
{ TARGET_NR_connect, "connect" , "%s(%d,%#x,%d)", NULL, NULL },
#endif
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 12195d4e99..984039f928 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -339,6 +339,13 @@ _syscall3(int,sys_syslog,int,type,char*,bufp,int,len)
#ifdef __NR_exit_group
_syscall1(int,exit_group,int,error_code)
#endif
+#if defined(__NR_close_range) && defined(TARGET_NR_close_range)
+#define __NR_sys_close_range __NR_close_range
+_syscall3(int,sys_close_range,int,first,int,last,int,flags)
+#ifndef CLOSE_RANGE_CLOEXEC
+#define CLOSE_RANGE_CLOEXEC (1U << 2)
+#endif
+#endif
#if defined(__NR_futex)
_syscall6(int,sys_futex,int *,uaddr,int,op,int,val,
const struct timespec *,timeout,int *,uaddr2,int,val3)
@@ -8735,6 +8742,24 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int
num, abi_long arg1,
case TARGET_NR_close:
fd_trans_unregister(arg1);
return get_errno(close(arg1));
+#if defined(__NR_close_range) && defined(TARGET_NR_close_range)
+case TARGET_NR_close_range:
+ret = get_errno(sys_close_range(arg1, arg2, arg3));
+if (ret == 0 && !(arg3 & CLOSE_RANGE_CLOEXEC)) {
+abi_long fd;
+abi_long maxfd = arg2;
+
+if ((sizeof(abi_long) == 4 && arg2 == (abi_long)0x7FFFUL) ||
+(sizeof(abi_long) == 8 && arg2 ==
(abi_long)0x7FFFULL)) {
+maxfd = target_fd_max;
+}
+
+for (fd = arg1; fd < maxfd; fd++) {
+fd_trans_unregister(fd);
+}
+}
+return ret;
+#endif
case TARGET_NR_brk:
return do_brk(arg1);
