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[Qemu-devel] [PATCH v2] file-posix: specify expected filetypes
From: |
John Snow |
Subject: |
[Qemu-devel] [PATCH v2] file-posix: specify expected filetypes |
Date: |
Mon, 15 Jan 2018 17:50:47 -0500 |
I don't think there's a legitimate reason to open directories as if
they were files. This prevents QEMU from opening and attempting to probe
a directory inode, which can break in exciting ways. One of those ways
is lseek on ext4/xfs, which will return 0x7fffffffffffffff as the file
size instead of EISDIR. This can coax QEMU into responding with a
confusing "file too big" instead of "Hey, that's not a file".
See: https://bugs.launchpad.net/qemu/+bug/1739304/
Signed-off-by: John Snow <address@hidden>
---
v2: Is something like this what you had in mind, Kevin?
I couldn't make the hdev/cdrom checks more specific
as I'm not sure which environments expect which, but
if you know I can tighten it.
block/file-posix.c | 38 +++++++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 9 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index 36ee89e940..fe06cdb8f8 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -417,7 +417,8 @@ static QemuOptsList raw_runtime_opts = {
};
static int raw_open_common(BlockDriverState *bs, QDict *options,
- int bdrv_flags, int open_flags, Error **errp)
+ int bdrv_flags, int open_flags,
+ bool device, Error **errp)
{
BDRVRawState *s = bs->opaque;
QemuOpts *opts;
@@ -556,10 +557,30 @@ static int raw_open_common(BlockDriverState *bs, QDict
*options,
error_setg_errno(errp, errno, "Could not stat file");
goto fail;
}
- if (S_ISREG(st.st_mode)) {
- s->discard_zeroes = true;
- s->has_fallocate = true;
+
+ if (!device) {
+ if (S_ISBLK(st.st_mode)) {
+ warn_report("Opening a block device as file using 'file'"
+ "driver is deprecated");
+ } else if (S_ISCHR(st.st_mode)) {
+ warn_report("Opening a character device as file using the 'file'"
+ "driver is deprecated");
+ } else if (!S_ISREG(st.st_mode)) {
+ error_setg(errp, "A regular file was expected by the 'file'
driver,"
+ "but something else was given");
+ goto fail;
+ } else {
+ s->discard_zeroes = true;
+ s->has_fallocate = true;
+ }
+ } else {
+ if (!(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
+ error_setg(errp, "host_device/host_cdrom driver expects either"
+ "a character or block device");
+ goto fail;
+ }
}
+
if (S_ISBLK(st.st_mode)) {
#ifdef BLKDISCARDZEROES
unsigned int arg;
@@ -589,7 +610,6 @@ static int raw_open_common(BlockDriverState *bs, QDict
*options,
s->needs_alignment = true;
}
#endif
-
#ifdef CONFIG_XFS
if (platform_test_xfs_fd(s->fd)) {
s->is_xfs = true;
@@ -611,7 +631,7 @@ static int raw_open(BlockDriverState *bs, QDict *options,
int flags,
BDRVRawState *s = bs->opaque;
s->type = FTYPE_FILE;
- return raw_open_common(bs, options, flags, 0, errp);
+ return raw_open_common(bs, options, flags, 0, false, errp);
}
typedef enum {
@@ -2575,7 +2595,7 @@ hdev_open_Mac_error:
s->type = FTYPE_FILE;
- ret = raw_open_common(bs, options, flags, 0, &local_err);
+ ret = raw_open_common(bs, options, flags, 0, true, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
#if defined(__APPLE__) && defined(__MACH__)
@@ -2802,7 +2822,7 @@ static int cdrom_open(BlockDriverState *bs, QDict
*options, int flags,
s->type = FTYPE_CD;
/* open will not fail even if no CD is inserted, so add O_NONBLOCK */
- return raw_open_common(bs, options, flags, O_NONBLOCK, errp);
+ return raw_open_common(bs, options, flags, O_NONBLOCK, true, errp);
}
static int cdrom_probe_device(const char *filename)
@@ -2915,7 +2935,7 @@ static int cdrom_open(BlockDriverState *bs, QDict
*options, int flags,
s->type = FTYPE_CD;
- ret = raw_open_common(bs, options, flags, 0, &local_err);
+ ret = raw_open_common(bs, options, flags, 0, true, &local_err);
if (ret) {
error_propagate(errp, local_err);
return ret;
--
2.14.3
- [Qemu-devel] [PATCH v2] file-posix: specify expected filetypes,
John Snow <=