diff options
author | Richard Henderson <richard.henderson@linaro.org> | 2021-11-14 11:35:39 +0100 |
---|---|---|
committer | Laurent Vivier <laurent@vivier.eu> | 2021-11-21 16:19:17 +0100 |
commit | aee14c77f42533f2480dfa8552f531efde6c19ee (patch) | |
tree | 3e9551fec316da1b1ff381eeef52be3c29fc6aad /linux-user | |
parent | 1962cb0029197bc0cd4bb0461171cda677e64966 (diff) |
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>
Diffstat (limited to 'linux-user')
-rw-r--r-- | linux-user/syscall.c | 261 |
1 files changed, 122 insertions, 139 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 499415ad81..f1cfcc8104 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8140,172 +8140,155 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, } #ifdef TARGET_NR_getdents -static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents(abi_long dirfd, abi_long arg2, abi_long count) { - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + off64_t prev_diroff = 0; + + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } #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; + hlen = sys_getdents(dirfd, hdirp, count); +#else + hlen = sys_getdents64(dirfd, hdirp, count); +#endif - dirp = g_try_malloc(count); - if (!dirp) { - return -TARGET_ENOMEM; + hlen = get_errno(hlen); + if (is_error(hlen)) { + return hlen; } - 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) { + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { 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 + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + struct linux_dirent *hde = hdirp + hoff; #else - /* Implement getdents in terms of getdents64 */ - struct linux_dirent64 *dirp; - abi_long count = arg3; + struct linux_dirent64 *hde = hdirp + hoff; +#endif + struct target_dirent *tde = tdirp + toff; + int namelen; + uint8_t type; - 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; + namelen = strlen(hde->d_name); + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent, d_name) + namelen + 2; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent)); - 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); + if (toff + treclen > count) { /* - * The target_dirent type is in what was formerly a padding - * byte at the end of the structure: + * If the host struct is smaller than the target struct, or + * requires less alignment and thus packs into less space, + * then the host can return more entries than we can pass + * on to the guest. */ - *(((char *)tde) + treclen - 1) = type; - - de = (struct linux_dirent64 *)((char *)de + reclen); - tde = (struct target_dirent *)((char *)tde + treclen); - len -= reclen; - tlen += treclen; + if (toff == 0) { + toff = -TARGET_EINVAL; /* result buffer is too small */ + break; + } + /* + * Return what we have, resetting the file pointer to the + * location of the first record not returned. + */ + lseek64(dirfd, prev_diroff, SEEK_SET); + break; } - ret = tlen; - } - unlock_user(dirp, arg2, ret); + + prev_diroff = hde->d_off; + tde->d_ino = tswapal(hde->d_ino); + tde->d_off = tswapal(hde->d_off); + tde->d_reclen = tswap16(treclen); + memcpy(tde->d_name, hde->d_name, namelen + 1); + + /* + * The getdents type is in what was formerly a padding byte at the + * end of the structure. + */ +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + type = *((uint8_t *)hde + hreclen - 1); +#else + type = hde->d_type; #endif - return ret; + *((uint8_t *)tde + treclen - 1) = type; + } + + unlock_user(tdirp, arg2, toff); + return toff; } #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) +static int do_getdents64(abi_long dirfd, abi_long arg2, abi_long count) { - struct linux_dirent64 *dirp; - abi_long count = arg3; - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + off64_t prev_diroff = 0; + + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + hlen = get_errno(sys_getdents64(dirfd, hdirp, count)); + if (is_error(hlen)) { + return hlen; + } + + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { 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) { + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { + struct linux_dirent64 *hde = hdirp + hoff; + struct target_dirent64 *tde = tdirp + toff; + int namelen; + + namelen = strlen(hde->d_name) + 1; + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent64, d_name) + namelen; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent64)); + + if (toff + treclen > count) { + /* + * If the host struct is smaller than the target struct, or + * requires less alignment and thus packs into less space, + * then the host can return more entries than we can pass + * on to the guest. + */ + if (toff == 0) { + toff = -TARGET_EINVAL; /* result buffer is too small */ 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; + /* + * Return what we have, resetting the file pointer to the + * location of the first record not returned. + */ + lseek64(dirfd, prev_diroff, SEEK_SET); + break; } + + prev_diroff = hde->d_off; + tde->d_ino = tswap64(hde->d_ino); + tde->d_off = tswap64(hde->d_off); + tde->d_reclen = tswap16(treclen); + tde->d_type = hde->d_type; + memcpy(tde->d_name, hde->d_name, namelen); } - unlock_user(dirp, arg2, ret); - return ret; + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents64 */ |