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linux-user: Rewrite do_getdents, do_getdents64
Always allocate host storage; this ensures that the struct is sufficiently aligned for the host. Merge the three host implementations of getdents via a few ifdefs. Utilize the same method for do_getdents64. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/704 Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20211114103539.298686-5-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson
Laurent Vivier
parent
1962cb0029
commit
aee14c77f4
@ -8140,172 +8140,155 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask,
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}
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#ifdef TARGET_NR_getdents
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static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3)
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static int do_getdents(abi_long dirfd, abi_long arg2, abi_long count)
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{
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int ret;
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g_autofree void *hdirp = NULL;
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void *tdirp;
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int hlen, hoff, toff;
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int hreclen, treclen;
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off64_t prev_diroff = 0;
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#ifdef EMULATE_GETDENTS_WITH_GETDENTS
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# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64
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struct target_dirent *target_dirp;
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struct linux_dirent *dirp;
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abi_long count = arg3;
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dirp = g_try_malloc(count);
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if (!dirp) {
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hdirp = g_try_malloc(count);
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if (!hdirp) {
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return -TARGET_ENOMEM;
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}
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ret = get_errno(sys_getdents(arg1, dirp, count));
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if (!is_error(ret)) {
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struct linux_dirent *de;
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struct target_dirent *tde;
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int len = ret;
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int reclen, treclen;
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int count1, tnamelen;
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#ifdef EMULATE_GETDENTS_WITH_GETDENTS
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hlen = sys_getdents(dirfd, hdirp, count);
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#else
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hlen = sys_getdents64(dirfd, hdirp, count);
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#endif
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count1 = 0;
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de = dirp;
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target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!target_dirp) {
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return -TARGET_EFAULT;
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}
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tde = target_dirp;
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while (len > 0) {
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reclen = de->d_reclen;
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tnamelen = reclen - offsetof(struct linux_dirent, d_name);
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assert(tnamelen >= 0);
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treclen = tnamelen + offsetof(struct target_dirent, d_name);
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assert(count1 + treclen <= count);
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tde->d_reclen = tswap16(treclen);
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tde->d_ino = tswapal(de->d_ino);
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tde->d_off = tswapal(de->d_off);
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memcpy(tde->d_name, de->d_name, tnamelen);
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de = (struct linux_dirent *)((char *)de + reclen);
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len -= reclen;
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tde = (struct target_dirent *)((char *)tde + treclen);
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count1 += treclen;
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}
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ret = count1;
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unlock_user(target_dirp, arg2, ret);
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hlen = get_errno(hlen);
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if (is_error(hlen)) {
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return hlen;
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}
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g_free(dirp);
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# else
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struct linux_dirent *dirp;
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abi_long count = arg3;
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dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!dirp) {
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tdirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!tdirp) {
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return -TARGET_EFAULT;
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}
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ret = get_errno(sys_getdents(arg1, dirp, count));
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if (!is_error(ret)) {
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struct linux_dirent *de;
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int len = ret;
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int reclen;
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de = dirp;
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while (len > 0) {
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reclen = de->d_reclen;
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if (reclen > len) {
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for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) {
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#ifdef EMULATE_GETDENTS_WITH_GETDENTS
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struct linux_dirent *hde = hdirp + hoff;
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#else
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struct linux_dirent64 *hde = hdirp + hoff;
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#endif
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struct target_dirent *tde = tdirp + toff;
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int namelen;
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uint8_t type;
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namelen = strlen(hde->d_name);
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hreclen = hde->d_reclen;
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treclen = offsetof(struct target_dirent, d_name) + namelen + 2;
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treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent));
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if (toff + treclen > count) {
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/*
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* If the host struct is smaller than the target struct, or
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* requires less alignment and thus packs into less space,
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* then the host can return more entries than we can pass
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* on to the guest.
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*/
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if (toff == 0) {
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toff = -TARGET_EINVAL; /* result buffer is too small */
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break;
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}
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de->d_reclen = tswap16(reclen);
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tswapls(&de->d_ino);
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tswapls(&de->d_off);
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de = (struct linux_dirent *)((char *)de + reclen);
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len -= reclen;
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}
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}
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unlock_user(dirp, arg2, ret);
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# endif
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#else
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/* Implement getdents in terms of getdents64 */
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struct linux_dirent64 *dirp;
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abi_long count = arg3;
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dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!dirp) {
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return -TARGET_EFAULT;
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}
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ret = get_errno(sys_getdents64(arg1, dirp, count));
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if (!is_error(ret)) {
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/*
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* Convert the dirent64 structs to target dirent. We do this
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* in-place, since we can guarantee that a target_dirent is no
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* larger than a dirent64; however this means we have to be
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* careful to read everything before writing in the new format.
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*/
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struct linux_dirent64 *de;
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struct target_dirent *tde;
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int len = ret;
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int tlen = 0;
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de = dirp;
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tde = (struct target_dirent *)dirp;
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while (len > 0) {
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int namelen, treclen;
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int reclen = de->d_reclen;
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uint64_t ino = de->d_ino;
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int64_t off = de->d_off;
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uint8_t type = de->d_type;
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namelen = strlen(de->d_name);
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treclen = offsetof(struct target_dirent, d_name) + namelen + 2;
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treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long));
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memmove(tde->d_name, de->d_name, namelen + 1);
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tde->d_ino = tswapal(ino);
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tde->d_off = tswapal(off);
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tde->d_reclen = tswap16(treclen);
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/*
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* The target_dirent type is in what was formerly a padding
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* byte at the end of the structure:
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* Return what we have, resetting the file pointer to the
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* location of the first record not returned.
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*/
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*(((char *)tde) + treclen - 1) = type;
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de = (struct linux_dirent64 *)((char *)de + reclen);
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tde = (struct target_dirent *)((char *)tde + treclen);
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len -= reclen;
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tlen += treclen;
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lseek64(dirfd, prev_diroff, SEEK_SET);
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break;
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}
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ret = tlen;
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}
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unlock_user(dirp, arg2, ret);
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prev_diroff = hde->d_off;
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tde->d_ino = tswapal(hde->d_ino);
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tde->d_off = tswapal(hde->d_off);
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tde->d_reclen = tswap16(treclen);
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memcpy(tde->d_name, hde->d_name, namelen + 1);
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/*
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* The getdents type is in what was formerly a padding byte at the
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* end of the structure.
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*/
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#ifdef EMULATE_GETDENTS_WITH_GETDENTS
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type = *((uint8_t *)hde + hreclen - 1);
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#else
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type = hde->d_type;
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#endif
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return ret;
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*((uint8_t *)tde + treclen - 1) = type;
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}
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unlock_user(tdirp, arg2, toff);
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return toff;
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}
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#endif /* TARGET_NR_getdents */
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#if defined(TARGET_NR_getdents64) && defined(__NR_getdents64)
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static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3)
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static int do_getdents64(abi_long dirfd, abi_long arg2, abi_long count)
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{
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struct linux_dirent64 *dirp;
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abi_long count = arg3;
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int ret;
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g_autofree void *hdirp = NULL;
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void *tdirp;
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int hlen, hoff, toff;
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int hreclen, treclen;
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off64_t prev_diroff = 0;
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dirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!dirp) {
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hdirp = g_try_malloc(count);
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if (!hdirp) {
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return -TARGET_ENOMEM;
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}
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hlen = get_errno(sys_getdents64(dirfd, hdirp, count));
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if (is_error(hlen)) {
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return hlen;
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}
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tdirp = lock_user(VERIFY_WRITE, arg2, count, 0);
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if (!tdirp) {
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return -TARGET_EFAULT;
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}
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ret = get_errno(sys_getdents64(arg1, dirp, count));
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if (!is_error(ret)) {
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struct linux_dirent64 *de;
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int len = ret;
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int reclen;
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de = dirp;
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while (len > 0) {
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reclen = de->d_reclen;
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if (reclen > len) {
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for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) {
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struct linux_dirent64 *hde = hdirp + hoff;
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struct target_dirent64 *tde = tdirp + toff;
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int namelen;
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namelen = strlen(hde->d_name) + 1;
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hreclen = hde->d_reclen;
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treclen = offsetof(struct target_dirent64, d_name) + namelen;
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treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent64));
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if (toff + treclen > count) {
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/*
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* If the host struct is smaller than the target struct, or
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* requires less alignment and thus packs into less space,
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* then the host can return more entries than we can pass
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* on to the guest.
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*/
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if (toff == 0) {
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toff = -TARGET_EINVAL; /* result buffer is too small */
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break;
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}
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de->d_reclen = tswap16(reclen);
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tswap64s((uint64_t *)&de->d_ino);
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tswap64s((uint64_t *)&de->d_off);
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de = (struct linux_dirent64 *)((char *)de + reclen);
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len -= reclen;
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/*
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* Return what we have, resetting the file pointer to the
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* location of the first record not returned.
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*/
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lseek64(dirfd, prev_diroff, SEEK_SET);
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break;
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}
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prev_diroff = hde->d_off;
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tde->d_ino = tswap64(hde->d_ino);
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tde->d_off = tswap64(hde->d_off);
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tde->d_reclen = tswap16(treclen);
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tde->d_type = hde->d_type;
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memcpy(tde->d_name, hde->d_name, namelen);
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}
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unlock_user(dirp, arg2, ret);
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return ret;
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unlock_user(tdirp, arg2, toff);
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return toff;
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}
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#endif /* TARGET_NR_getdents64 */
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