From 9729930344687c7077531ab07cb9dc275795b413 Mon Sep 17 00:00:00 2001 From: Michael Vogt Date: Tue, 1 Oct 2024 17:14:54 +0200 Subject: linux-user: add strace support for openat2 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 Reviewed-by: Laurent Vivier Message-ID: [rth: Add braces around the expanded how structure, like strace(3)] Signed-off-by: Richard Henderson --- linux-user/qemu.h | 9 +++++++++ linux-user/strace.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ linux-user/strace.list | 3 +++ linux-user/syscall.c | 8 +------- linux-user/syscall_defs.h | 5 +++++ 5 files changed, 65 insertions(+), 7 deletions(-) (limited to 'linux-user') 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..d3cdd09dc1 100644 --- a/linux-user/strace.c +++ b/linux-user/strace.c @@ -13,6 +13,9 @@ #include #include #include +#ifdef HAVE_OPENAT2_H +#include +#endif #include #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 +3498,38 @@ 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; + + print_syscall_prologue(name); + print_at_dirfd(arg0, 0); + print_string(arg1, 0); + + if ((abi_ulong)arg3 >= sizeof(struct target_open_how_ver0) && + copy_struct_from_user(&how, sizeof(how), arg2, arg3) == 0) { + how.flags = tswap64(how.flags); + how.mode = tswap64(how.mode); + how.resolve = tswap64(how.resolve); + qemu_log("{"); + 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, 1); + qemu_log("},"); + } else { + print_pointer(arg2, 0); + } + print_raw_param(TARGET_ABI_FMT_lu, arg3, 1); + print_syscall_epilogue(name); +} +#endif + #ifdef TARGET_NR_pidfd_send_signal static void print_pidfd_send_signal(CPUArchState *cpu_env, const struct syscallname *name, diff --git a/linux-user/strace.list b/linux-user/strace.list index dfd4237d14..ef658224fc 100644 --- a/linux-user/strace.list +++ b/linux-user/strace.list @@ -715,6 +715,9 @@ #ifdef TARGET_NR_openat { TARGET_NR_openat, "openat" , NULL, print_openat, NULL }, #endif +#ifdef TARGET_NR_openat2 +{ TARGET_NR_openat2, "openat2" , NULL, print_openat2, NULL }, +#endif #ifdef TARGET_NR_osf_adjtime { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL }, #endif diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 2febc3bc3f..1354e75694 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -608,8 +608,7 @@ static int check_zeroed_user(abi_long addr, size_t ksize, size_t usize) * * Similar to kernels uaccess.h:copy_struct_from_user() */ -static int -copy_struct_from_user(void *dst, size_t ksize, abi_ptr src, size_t usize) +int copy_struct_from_user(void *dst, size_t ksize, abi_ptr src, size_t usize) { size_t size = MIN(ksize, usize); size_t rest = MAX(ksize, usize) - size; @@ -682,11 +681,6 @@ safe_syscall3(ssize_t, write, int, fd, const void *, buff, size_t, count) safe_syscall4(int, openat, int, dirfd, const char *, pathname, \ int, flags, mode_t, mode) -struct open_how_ver0 { - __u64 flags; - __u64 mode; - __u64 resolve; -}; safe_syscall4(int, openat2, int, dirfd, const char *, pathname, \ const struct open_how_ver0 *, how, size_t, size) diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index de5091c977..0ade83745e 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -2749,6 +2749,11 @@ struct target_sched_param { }; /* from kernel's include/uapi/linux/openat2.h */ +struct open_how_ver0 { + __u64 flags; + __u64 mode; + __u64 resolve; +}; struct target_open_how_ver0 { abi_ullong flags; abi_ullong mode; -- cgit v1.2.3