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Re: [PATCH 5/5] linux-user: Add strace support for printing arguments of
From: |
Laurent Vivier |
Subject: |
Re: [PATCH 5/5] linux-user: Add strace support for printing arguments of fallocate() |
Date: |
Wed, 3 Jun 2020 16:54:18 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
Le 02/06/2020 à 13:53, Filip Bozuta a écrit :
> From: Filip Bozuta <Filip.Bozuta@syrmia.com>
>
> This patch implements strace argument printing functionality for following
> syscall:
>
> *fallocate - manipulate file space
>
> int fallocate(int fd, int mode, off_t offset, off_t len)
> man page: https://www.man7.org/linux/man-pages/man2/fallocate.2.html
>
> Implementation notes:
>
> This syscall's second argument "mode" is composed of predefined values
> which represent flags that determine the type of operation that is
> to be performed on the file space. For that reason, a printing
> function "print_fallocate" was stated in file "strace.list". This printing
> function uses an already existing function "print_flags()" to print flags
> of
> the "mode" argument. These flags are stated inside an array "falloc_flags"
> that contains values of type "struct flags". These values are instantiated
> using an existing macro "FLAG_GENERIC()". Most of these flags are defined
> after kernel version 3.0 which is why they are enwrapped in an #ifdef
> directive.
> The syscall's third ant fourth argument are of type "off_t" which can
> cause variations between 32/64-bit architectures. To handle this
> variation,
> function "target_offset64()" was copied from file "strace.c" and used in
> "print_fallocate" to print "off_t" arguments for 32-bit architectures.
>
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
> linux-user/strace.c | 56 ++++++++++++++++++++++++++++++++++++++++++
> linux-user/strace.list | 2 +-
> 2 files changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index 542bfdeb91..3998a00bb4 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -34,6 +34,22 @@ struct syscallname {
> #define UNUSED
> #endif
>
> +#if TARGET_ABI_BITS == 32
> +static inline uint64_t target_offset64(uint32_t word0, uint32_t word1)
> +{
> +#ifdef TARGET_WORDS_BIGENDIAN
> + return ((uint64_t)word0 << 32) | word1;
> +#else
> + return ((uint64_t)word1 << 32) | word0;
> +#endif
> +}
> +#else /* TARGET_ABI_BITS == 32 */
> +static inline uint64_t target_offset64(uint64_t word0, uint64_t word1)
> +{
> + return word0;
> +}
> +#endif /* TARGET_ABI_BITS != 32 */
> +
Rather than copying that from syscall.c perhaps you can move the
definition from linux-user/syscall.c to linux-user/qemu.h?
> /*
> * Structure used to translate flag values into strings. This is
> * similar that is in the actual strace tool.
> @@ -1097,6 +1113,26 @@ UNUSED static struct flags statx_mask[] = {
> FLAG_END,
> };
>
> +UNUSED static struct flags falloc_flags[] = {
> + FLAG_GENERIC(FALLOC_FL_KEEP_SIZE),
> + FLAG_GENERIC(FALLOC_FL_PUNCH_HOLE),
> +#ifdef FALLOC_FL_NO_HIDE_STALE
> + FLAG_GENERIC(FALLOC_FL_NO_HIDE_STALE),
> +#endif
> +#ifdef FALLOC_FL_COLLAPSE_RANGE
> + FLAG_GENERIC(FALLOC_FL_COLLAPSE_RANGE),
> +#endif
> +#ifdef FALLOC_FL_ZERO_RANGE
> + FLAG_GENERIC(FALLOC_FL_ZERO_RANGE),
> +#endif
> +#ifdef FALLOC_FL_INSERT_RANGE
> + FLAG_GENERIC(FALLOC_FL_INSERT_RANGE),
> +#endif
> +#ifdef FALLOC_FL_UNSHARE_RANGE
> + FLAG_GENERIC(FALLOC_FL_UNSHARE_RANGE),
> +#endif
> +};
> +
> /*
> * print_xxx utility functions. These are used to print syscall
> * parameters in certain format. All of these have parameter
> @@ -1514,6 +1550,26 @@ print_faccessat(const struct syscallname *name,
> }
> #endif
>
> +#ifdef TARGET_NR_fallocate
> +static void
> +print_fallocate(const struct syscallname *name,
> + abi_long arg0, abi_long arg1, abi_long arg2,
> + abi_long arg3, abi_long arg4, abi_long arg5)
> +{
> + print_syscall_prologue(name);
> + print_raw_param("%d", arg0, 0);
> + print_flags(falloc_flags, arg1, 0);
> +#if TARGET_ABI_BITS == 32
> + print_raw_param("%ld", target_offset64(arg2, arg3), 0);
> + print_raw_param("%ld", target_offset64(arg4, arg5), 1);
target_offset64 returns uint64_t so use PRIu64 rather than "%ld"
> +#else
> + print_raw_param("%ld", arg2, 0);
> + print_raw_param("%ld", arg3, 1);
TARGET_ABI_FMT_ld rather than "%ld"
> +#endif
> + print_syscall_epilogue(name);
> +}
> +#endif
> +
> #ifdef TARGET_NR_fchmodat
> static void
> print_fchmodat(const struct syscallname *name,
> diff --git a/linux-user/strace.list b/linux-user/strace.list
> index b72f757d3f..d7458ce884 100644
> --- a/linux-user/strace.list
> +++ b/linux-user/strace.list
> @@ -182,7 +182,7 @@
> { TARGET_NR_fadvise64_64, "fadvise64_64" , NULL, NULL, NULL },
> #endif
> #ifdef TARGET_NR_fallocate
> -{ TARGET_NR_fallocate, "fallocate" , NULL, NULL, NULL },
> +{ TARGET_NR_fallocate, "fallocate" , NULL, print_fallocate, NULL },
> #endif
> #ifdef TARGET_NR_fanotify_init
> { TARGET_NR_fanotify_init, "fanotify_init" , NULL, NULL, NULL },
>
Thanks,
Laurent
- [PATCH 0/5] Add strace support for printing arguments of selected syscalls, Filip Bozuta, 2020/06/02
- [PATCH 2/5] linux-user: Add strace support for printing argument of syscalls used for extend attributes, Filip Bozuta, 2020/06/02
- [PATCH 1/5] linux-user: Add strace support for a group of syscalls, Filip Bozuta, 2020/06/02
- [PATCH 4/5] linux-user: Add strace support for printing arguments of chown()/lchown(), Filip Bozuta, 2020/06/02
- [PATCH 5/5] linux-user: Add strace support for printing arguments of fallocate(), Filip Bozuta, 2020/06/02
- Re: [PATCH 5/5] linux-user: Add strace support for printing arguments of fallocate(),
Laurent Vivier <=
- [PATCH 3/5] linux-user: Add strace support for printing arguments of lseek(), Filip Bozuta, 2020/06/02
- Re: [PATCH 0/5] Add strace support for printing arguments of selected syscalls, no-reply, 2020/06/02
- Re: [PATCH 0/5] Add strace support for printing arguments of selected syscalls, Alex Bennée, 2020/06/03