block: Refactor get_tmp_filename()

At present there are two callers of get_tmp_filename() and they are
inconsistent.

One does:

    /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
    char *tmp_filename = g_malloc0(PATH_MAX + 1);
    ...
    ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);

while the other does:

    s->qcow_filename = g_malloc(PATH_MAX);
    ret = get_tmp_filename(s->qcow_filename, PATH_MAX);

As we can see different 'size' arguments are passed. There are also
platform specific implementations inside the function, and the use
of snprintf is really undesirable.

The function name is also misleading. It creates a temporary file,
not just a filename.

Refactor this routine by changing its name and signature to:

    char *create_tmp_file(Error **errp)

and use g_get_tmp_dir() / g_mkstemp() for a consistent implementation.

While we are here, add some comments to mention that /var/tmp is
preferred over /tmp on non-win32 hosts.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Message-Id: <20221010040432.3380478-2-bin.meng@windriver.com>
[kwolf: Fixed incorrect errno negation and iotest 051]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Bin Meng 2022-10-10 12:04:31 +08:00 committed by Kevin Wolf
parent 6b6471eee1
commit 69fbfff95e
6 changed files with 38 additions and 34 deletions

View file

@ -375,7 +375,8 @@ if [ "${VALGRIND_QEMU_VM}" == "y" ]; then
_casenotrun "Valgrind needs a valid TMPDIR for itself"
fi
VALGRIND_QEMU_VM= \
TMPDIR=/nonexistent run_qemu -drive driver=null-co,snapshot=on
TMPDIR=/nonexistent run_qemu -drive driver=null-co,snapshot=on |
sed -e "s#'[^']*/vl\.[A-Za-z0-9]\{6\}'#SNAPSHOT_PATH#g"
# Using snapshot=on together with read-only=on
echo "info block" |

View file

@ -459,7 +459,7 @@ wrote 4096/4096 bytes at offset 0
read 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Testing: -drive driver=null-co,snapshot=on
QEMU_PROG: -drive driver=null-co,snapshot=on: Could not get temporary filename: No such file or directory
QEMU_PROG: -drive driver=null-co,snapshot=on: Could not open temporary file SNAPSHOT_PATH: No such file or directory
Testing: -drive file=TEST_DIR/t.qcow2,snapshot=on,read-only=on,if=none,id=drive0
QEMU X.Y.Z monitor - type 'help' for more information

View file

@ -539,7 +539,7 @@ wrote 4096/4096 bytes at offset 0
read 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Testing: -drive driver=null-co,snapshot=on
QEMU_PROG: -drive driver=null-co,snapshot=on: Could not get temporary filename: No such file or directory
QEMU_PROG: -drive driver=null-co,snapshot=on: Could not open temporary file SNAPSHOT_PATH: No such file or directory
Testing: -drive file=TEST_DIR/t.qcow2,snapshot=on,read-only=on,if=none,id=drive0
QEMU X.Y.Z monitor - type 'help' for more information