Le 23/09/2024 à 21:37, Michael Vogt a écrit :
This commit adds support for the `openat2()` to `QEMU_STRACE`. It
will use the `openat2.h` header if available to create user
readable flags for the `resolve` argument but does not require
the header otherwise.
It also makes `copy_struct_from_user()` available via `qemu.h`
and `open_how_ver0` via `syscall_defs.h` so that strace.c can use
them.
Signed-off-by: Michael Vogt <mv...@redhat.com>
---
linux-user/qemu.h | 9 +++++++++
linux-user/strace.c | 40 +++++++++++++++++++++++++++++++++++++++
linux-user/strace.list | 3 +++
linux-user/syscall.c | 8 +-------
linux-user/syscall_defs.h | 5 +++++
meson.build | 1 +
6 files changed, 59 insertions(+), 7 deletions(-)
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 2e90a97175..98ad848ab2 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -313,6 +313,15 @@ static inline bool access_ok(CPUState *cpu, int type,
int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
+/*
+ * copy_struct_from_user() copies a target struct to a host struct, in
+ * a way that guarantees backwards-compatibility for struct syscall
+ * arguments.
+ *
+ * Similar to kernels uaccess.h:copy_struct_from_user()
+ */
+int copy_struct_from_user(void *dst, size_t ksize, abi_ptr src, size_t usize);
+
/* Functions for accessing guest memory. The tget and tput functions
read/write single values, byteswapping as necessary. The lock_user
function
gets a pointer to a contiguous area of guest memory, but does not perform
diff --git a/linux-user/strace.c b/linux-user/strace.c
index b4d1098170..77d5108e5d 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -13,6 +13,9 @@
#include <linux/if_packet.h>
#include <linux/in6.h>
#include <linux/netlink.h>
+#ifdef HAVE_OPENAT2_H
+#include <linux/openat2.h>
+#endif
#include <sched.h>
#include "qemu.h"
#include "user-internals.h"
@@ -1063,6 +1066,18 @@ UNUSED static const struct flags open_flags[] = {
FLAG_END,
};
+UNUSED static const struct flags openat2_resolve_flags[] = {
+#ifdef HAVE_OPENAT2_H
+ FLAG_GENERIC(RESOLVE_NO_XDEV),
+ FLAG_GENERIC(RESOLVE_NO_MAGICLINKS),
+ FLAG_GENERIC(RESOLVE_NO_SYMLINKS),
+ FLAG_GENERIC(RESOLVE_BENEATH),
+ FLAG_GENERIC(RESOLVE_IN_ROOT),
+ FLAG_GENERIC(RESOLVE_CACHED),
+#endif
+ FLAG_END,
+};
+
UNUSED static const struct flags mount_flags[] = {
#ifdef MS_BIND
FLAG_GENERIC(MS_BIND),
@@ -3483,6 +3498,31 @@ print_openat(CPUArchState *cpu_env, const struct
syscallname *name,
}
#endif
+#ifdef TARGET_NR_openat2
+static void
+print_openat2(CPUArchState *cpu_env, const struct syscallname *name,
+ abi_long arg0, abi_long arg1, abi_long arg2,
+ abi_long arg3, abi_long arg4, abi_long arg5)
+{
+ struct open_how_ver0 how = {0};
+
+ print_syscall_prologue(name);
+ print_at_dirfd(arg0, 0);
+ print_string(arg1, 0);
+ if (copy_struct_from_user(&how, sizeof(how), arg2, arg3) == 0) {
I think you need also to tswap64() all the fields of how.
+ print_open_flags(how.flags, 0);
+ if (how.flags & TARGET_O_CREAT) {
+ print_file_mode(how.mode, 0);
+ }
+ print_flags(openat2_resolve_flags, how.resolve, 0);
+ } else {
+ print_pointer(arg2, 0);
+ }
+ print_raw_param("size=" TARGET_ABI_FMT_lu, arg3, 1);
Why the "size="?
You can write: print_raw_param(TARGET_ABI_FMT_lu, arg3, 1);
Thanks,
Laurent
