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Re: [PATCH 1/4] linux-user: Split out do_getdents, do_getdents64
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From: |
Warner Losh |
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Subject: |
Re: [PATCH 1/4] linux-user: Split out do_getdents, do_getdents64 |
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Date: |
Tue, 9 Nov 2021 09:45:34 -0700 |
> On Nov 7, 2021, at 5:48 AM, Richard Henderson <richard.henderson@linaro.org>
> wrote:
>
> Retain all 3 implementations of getdents for now.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> linux-user/syscall.c | 325 +++++++++++++++++++++++--------------------
> 1 file changed, 172 insertions(+), 153 deletions(-)
Reviewed by: Warner Losh <imp@bsdimp.com>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 544f5b662f..a2f605dec4 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -8137,6 +8137,176 @@ static int host_to_target_cpu_mask(const unsigned
> long *host_mask,
> return 0;
> }
>
> +#ifdef TARGET_NR_getdents
> +static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3)
> +{
> + int ret;
> +
> +#ifdef EMULATE_GETDENTS_WITH_GETDENTS
> +# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64
> + struct target_dirent *target_dirp;
> + struct linux_dirent *dirp;
> + abi_long count = arg3;
> +
> + dirp = g_try_malloc(count);
> + if (!dirp) {
> + return -TARGET_ENOMEM;
> + }
> +
> + ret = get_errno(sys_getdents(arg1, dirp, count));
> + if (!is_error(ret)) {
> + struct linux_dirent *de;
> + struct target_dirent *tde;
> + int len = ret;
> + int reclen, treclen;
> + int count1, tnamelen;
> +
> + count1 = 0;
> + de = dirp;
> + target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
> + if (!target_dirp) {
> + return -TARGET_EFAULT;
> + }
> + tde = target_dirp;
> + while (len > 0) {
> + reclen = de->d_reclen;
> + tnamelen = reclen - offsetof(struct linux_dirent, d_name);
> + assert(tnamelen >= 0);
> + treclen = tnamelen + offsetof(struct target_dirent, d_name);
> + assert(count1 + treclen <= count);
> + tde->d_reclen = tswap16(treclen);
> + tde->d_ino = tswapal(de->d_ino);
> + tde->d_off = tswapal(de->d_off);
> + memcpy(tde->d_name, de->d_name, tnamelen);
> + de = (struct linux_dirent *)((char *)de + reclen);
> + len -= reclen;
> + tde = (struct target_dirent *)((char *)tde + treclen);
> + count1 += treclen;
> + }
> + ret = count1;
> + unlock_user(target_dirp, arg2, ret);
> + }
> + g_free(dirp);
> +# else
> + struct linux_dirent *dirp;
> + abi_long count = arg3;
> +
> + dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
> + if (!dirp) {
> + return -TARGET_EFAULT;
> + }
> + ret = get_errno(sys_getdents(arg1, dirp, count));
> + if (!is_error(ret)) {
> + struct linux_dirent *de;
> + int len = ret;
> + int reclen;
> + de = dirp;
> + while (len > 0) {
> + reclen = de->d_reclen;
> + if (reclen > len) {
> + break;
> + }
> + de->d_reclen = tswap16(reclen);
> + tswapls(&de->d_ino);
> + tswapls(&de->d_off);
> + de = (struct linux_dirent *)((char *)de + reclen);
> + len -= reclen;
> + }
> + }
> + unlock_user(dirp, arg2, ret);
> +# endif
> +#else
> + /* Implement getdents in terms of getdents64 */
> + struct linux_dirent64 *dirp;
> + abi_long count = arg3;
> +
> + dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
> + if (!dirp) {
> + return -TARGET_EFAULT;
> + }
> + ret = get_errno(sys_getdents64(arg1, dirp, count));
> + if (!is_error(ret)) {
> + /*
> + * Convert the dirent64 structs to target dirent. We do this
> + * in-place, since we can guarantee that a target_dirent is no
> + * larger than a dirent64; however this means we have to be
> + * careful to read everything before writing in the new format.
> + */
> + struct linux_dirent64 *de;
> + struct target_dirent *tde;
> + int len = ret;
> + int tlen = 0;
> +
> + de = dirp;
> + tde = (struct target_dirent *)dirp;
> + while (len > 0) {
> + int namelen, treclen;
> + int reclen = de->d_reclen;
> + uint64_t ino = de->d_ino;
> + int64_t off = de->d_off;
> + uint8_t type = de->d_type;
> +
> + namelen = strlen(de->d_name);
> + treclen = offsetof(struct target_dirent, d_name) + namelen + 2;
> + treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long));
> +
> + memmove(tde->d_name, de->d_name, namelen + 1);
> + tde->d_ino = tswapal(ino);
> + tde->d_off = tswapal(off);
> + tde->d_reclen = tswap16(treclen);
> + /*
> + * The target_dirent type is in what was formerly a padding
> + * byte at the end of the structure:
> + */
> + *(((char *)tde) + treclen - 1) = type;
> +
> + de = (struct linux_dirent64 *)((char *)de + reclen);
> + tde = (struct target_dirent *)((char *)tde + treclen);
> + len -= reclen;
> + tlen += treclen;
> + }
> + ret = tlen;
> + }
> + unlock_user(dirp, arg2, ret);
> +#endif
> + return ret;
> +}
> +#endif /* TARGET_NR_getdents */
> +
> +#if defined(TARGET_NR_getdents64) && defined(__NR_getdents64)
> +static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3)
> +{
> + struct linux_dirent64 *dirp;
> + abi_long count = arg3;
> + int ret;
> +
> + dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
> + if (!dirp) {
> + return -TARGET_EFAULT;
> + }
> + ret = get_errno(sys_getdents64(arg1, dirp, count));
> + if (!is_error(ret)) {
> + struct linux_dirent64 *de;
> + int len = ret;
> + int reclen;
> + de = dirp;
> + while (len > 0) {
> + reclen = de->d_reclen;
> + if (reclen > len) {
> + break;
> + }
> + de->d_reclen = tswap16(reclen);
> + tswap64s((uint64_t *)&de->d_ino);
> + tswap64s((uint64_t *)&de->d_off);
> + de = (struct linux_dirent64 *)((char *)de + reclen);
> + len -= reclen;
> + }
> + }
> + unlock_user(dirp, arg2, ret);
> + return ret;
> +}
> +#endif /* TARGET_NR_getdents64 */
> +
> #if defined(TARGET_NR_pivot_root) && defined(__NR_pivot_root)
> _syscall2(int, pivot_root, const char *, new_root, const char *, put_old)
> #endif
> @@ -10227,162 +10397,11 @@ static abi_long do_syscall1(void *cpu_env, int
> num, abi_long arg1,
> #endif
> #ifdef TARGET_NR_getdents
> case TARGET_NR_getdents:
> -#ifdef EMULATE_GETDENTS_WITH_GETDENTS
> -#if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64
> - {
> - struct target_dirent *target_dirp;
> - struct linux_dirent *dirp;
> - abi_long count = arg3;
> -
> - dirp = g_try_malloc(count);
> - if (!dirp) {
> - return -TARGET_ENOMEM;
> - }
> -
> - ret = get_errno(sys_getdents(arg1, dirp, count));
> - if (!is_error(ret)) {
> - struct linux_dirent *de;
> - struct target_dirent *tde;
> - int len = ret;
> - int reclen, treclen;
> - int count1, tnamelen;
> -
> - count1 = 0;
> - de = dirp;
> - if (!(target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0)))
> - return -TARGET_EFAULT;
> - tde = target_dirp;
> - while (len > 0) {
> - reclen = de->d_reclen;
> - tnamelen = reclen - offsetof(struct linux_dirent,
> d_name);
> - assert(tnamelen >= 0);
> - treclen = tnamelen + offsetof(struct target_dirent,
> d_name);
> - assert(count1 + treclen <= count);
> - tde->d_reclen = tswap16(treclen);
> - tde->d_ino = tswapal(de->d_ino);
> - tde->d_off = tswapal(de->d_off);
> - memcpy(tde->d_name, de->d_name, tnamelen);
> - de = (struct linux_dirent *)((char *)de + reclen);
> - len -= reclen;
> - tde = (struct target_dirent *)((char *)tde + treclen);
> - count1 += treclen;
> - }
> - ret = count1;
> - unlock_user(target_dirp, arg2, ret);
> - }
> - g_free(dirp);
> - }
> -#else
> - {
> - struct linux_dirent *dirp;
> - abi_long count = arg3;
> -
> - if (!(dirp = lock_user(VERIFY_WRITE, arg2, count, 0)))
> - return -TARGET_EFAULT;
> - ret = get_errno(sys_getdents(arg1, dirp, count));
> - if (!is_error(ret)) {
> - struct linux_dirent *de;
> - int len = ret;
> - int reclen;
> - de = dirp;
> - while (len > 0) {
> - reclen = de->d_reclen;
> - if (reclen > len)
> - break;
> - de->d_reclen = tswap16(reclen);
> - tswapls(&de->d_ino);
> - tswapls(&de->d_off);
> - de = (struct linux_dirent *)((char *)de + reclen);
> - len -= reclen;
> - }
> - }
> - unlock_user(dirp, arg2, ret);
> - }
> -#endif
> -#else
> - /* Implement getdents in terms of getdents64 */
> - {
> - struct linux_dirent64 *dirp;
> - abi_long count = arg3;
> -
> - dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
> - if (!dirp) {
> - return -TARGET_EFAULT;
> - }
> - ret = get_errno(sys_getdents64(arg1, dirp, count));
> - if (!is_error(ret)) {
> - /* Convert the dirent64 structs to target dirent. We do this
> - * in-place, since we can guarantee that a target_dirent is
> no
> - * larger than a dirent64; however this means we have to be
> - * careful to read everything before writing in the new
> format.
> - */
> - struct linux_dirent64 *de;
> - struct target_dirent *tde;
> - int len = ret;
> - int tlen = 0;
> -
> - de = dirp;
> - tde = (struct target_dirent *)dirp;
> - while (len > 0) {
> - int namelen, treclen;
> - int reclen = de->d_reclen;
> - uint64_t ino = de->d_ino;
> - int64_t off = de->d_off;
> - uint8_t type = de->d_type;
> -
> - namelen = strlen(de->d_name);
> - treclen = offsetof(struct target_dirent, d_name)
> - + namelen + 2;
> - treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long));
> -
> - memmove(tde->d_name, de->d_name, namelen + 1);
> - tde->d_ino = tswapal(ino);
> - tde->d_off = tswapal(off);
> - tde->d_reclen = tswap16(treclen);
> - /* The target_dirent type is in what was formerly a
> padding
> - * byte at the end of the structure:
> - */
> - *(((char *)tde) + treclen - 1) = type;
> -
> - de = (struct linux_dirent64 *)((char *)de + reclen);
> - tde = (struct target_dirent *)((char *)tde + treclen);
> - len -= reclen;
> - tlen += treclen;
> - }
> - ret = tlen;
> - }
> - unlock_user(dirp, arg2, ret);
> - }
> -#endif
> - return ret;
> + return do_getdents(arg1, arg2, arg3);
> #endif /* TARGET_NR_getdents */
> #if defined(TARGET_NR_getdents64) && defined(__NR_getdents64)
> case TARGET_NR_getdents64:
> - {
> - struct linux_dirent64 *dirp;
> - abi_long count = arg3;
> - if (!(dirp = lock_user(VERIFY_WRITE, arg2, count, 0)))
> - return -TARGET_EFAULT;
> - ret = get_errno(sys_getdents64(arg1, dirp, count));
> - if (!is_error(ret)) {
> - struct linux_dirent64 *de;
> - int len = ret;
> - int reclen;
> - de = dirp;
> - while (len > 0) {
> - reclen = de->d_reclen;
> - if (reclen > len)
> - break;
> - de->d_reclen = tswap16(reclen);
> - tswap64s((uint64_t *)&de->d_ino);
> - tswap64s((uint64_t *)&de->d_off);
> - de = (struct linux_dirent64 *)((char *)de + reclen);
> - len -= reclen;
> - }
> - }
> - unlock_user(dirp, arg2, ret);
> - }
> - return ret;
> + return do_getdents64(arg1, arg2, arg3);
> #endif /* TARGET_NR_getdents64 */
> #if defined(TARGET_NR__newselect)
> case TARGET_NR__newselect:
> --
> 2.25.1
>
>
signature.asc
Description: Message signed with OpenPGP
- [PATCH 0/4] linux-user: Fix getdents alignment issues (#704), Richard Henderson, 2021/11/07
- [PATCH 1/4] linux-user: Split out do_getdents, do_getdents64, Richard Henderson, 2021/11/07
- [PATCH 3/4] linux-user: Fix member types of target_dirent64, Richard Henderson, 2021/11/07
- [PATCH 4/4] linux-user: Rewrite do_getdents, do_getdents64, Richard Henderson, 2021/11/07
- [PATCH 2/4] linux-user: Always use flexible arrays for dirent d_name, Richard Henderson, 2021/11/07
- Re: [PATCH 0/4] linux-user: Fix getdents alignment issues (#704), Warner Losh, 2021/11/09
- Re: [PATCH 0/4] linux-user: Fix getdents alignment issues (#704), Laurent Vivier, 2021/11/10