qga: Support enum names in guest-file-seek

Magic constants are a pain to use, especially when we run the
risk that our choice of '1' for QGA_SEEK_CUR might differ from
the host or guest's choice of SEEK_CUR.  Better is to use an
enum value, via a qapi alternate type for back-compatibility.

With this,
 {"command":"guest-file-seek", "arguments":{"handle":1,
  "offset":0, "whence":"cur"}}
becomes a synonym for the older
 {"command":"guest-file-seek", "arguments":{"handle":1,
  "offset":0, "whence":1}}

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
Eric Blake 2016-02-09 14:27:16 -07:00 committed by Michael Roth
parent 774ae4254d
commit 0b4b49387c
6 changed files with 70 additions and 40 deletions

View File

@ -550,31 +550,24 @@ GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
}
struct GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
int64_t whence_code, Error **errp)
GuestFileWhence *whence_code,
Error **errp)
{
GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
GuestFileSeek *seek_data = NULL;
FILE *fh;
int ret;
int whence;
Error *err = NULL;
if (!gfh) {
return NULL;
}
/* We stupidly exposed 'whence':'int' in our qapi */
switch (whence_code) {
case QGA_SEEK_SET:
whence = SEEK_SET;
break;
case QGA_SEEK_CUR:
whence = SEEK_CUR;
break;
case QGA_SEEK_END:
whence = SEEK_END;
break;
default:
error_setg(errp, "invalid whence code %"PRId64, whence_code);
whence = ga_parse_whence(whence_code, &err);
if (err) {
error_propagate(errp, err);
return NULL;
}

View File

@ -385,7 +385,8 @@ done:
}
GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
int64_t whence_code, Error **errp)
GuestFileWhence *whence_code,
Error **errp)
{
GuestFileHandle *gfh;
GuestFileSeek *seek_data;
@ -394,6 +395,7 @@ GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
off_pos.QuadPart = offset;
BOOL res;
int whence;
Error *err = NULL;
gfh = guest_file_handle_find(handle, errp);
if (!gfh) {
@ -401,18 +403,9 @@ GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
}
/* We stupidly exposed 'whence':'int' in our qapi */
switch (whence_code) {
case QGA_SEEK_SET:
whence = SEEK_SET;
break;
case QGA_SEEK_CUR:
whence = SEEK_CUR;
break;
case QGA_SEEK_END:
whence = SEEK_END;
break;
default:
error_setg(errp, "invalid whence code %"PRId64, whence_code);
whence = ga_parse_whence(whence_code, &err);
if (err) {
error_propagate(errp, err);
return NULL;
}

View File

@ -473,3 +473,24 @@ done:
return ge;
}
/* Convert GuestFileWhence (either a raw integer or an enum value) into
* the guest's SEEK_ constants. */
int ga_parse_whence(GuestFileWhence *whence, Error **errp)
{
/* Exploit the fact that we picked values to match QGA_SEEK_*. */
if (whence->type == QTYPE_QSTRING) {
whence->type = QTYPE_QINT;
whence->u.value = whence->u.name;
}
switch (whence->u.value) {
case QGA_SEEK_SET:
return SEEK_SET;
case QGA_SEEK_CUR:
return SEEK_CUR;
case QGA_SEEK_END:
return SEEK_END;
}
error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
return -1;
}

View File

@ -12,16 +12,10 @@
*/
#include "qapi/qmp/dispatch.h"
#include "qemu-common.h"
#include "qga-qmp-commands.h"
#define QGA_READ_COUNT_DEFAULT 4096
/* Mapping of whence codes used by guest-file-seek. */
enum {
QGA_SEEK_SET = 0,
QGA_SEEK_CUR = 1,
QGA_SEEK_END = 2,
};
typedef struct GAState GAState;
typedef struct GACommandState GACommandState;
extern GAState *ga_state;
@ -44,6 +38,7 @@ void ga_set_frozen(GAState *s);
void ga_unset_frozen(GAState *s);
const char *ga_fsfreeze_hook(GAState *s);
int64_t ga_get_fd_handle(GAState *s, Error **errp);
int ga_parse_whence(GuestFileWhence *whence, Error **errp);
#ifndef _WIN32
void reopen_fd_to_null(int fd);

View File

@ -313,6 +313,34 @@
{ 'struct': 'GuestFileSeek',
'data': { 'position': 'int', 'eof': 'bool' } }
##
# @QGASeek:
#
# Symbolic names for use in @guest-file-seek
#
# @set: Set to the specified offset (same effect as 'whence':0)
# @cur: Add offset to the current location (same effect as 'whence':1)
# @end: Add offset to the end of the file (same effect as 'whence':2)
#
# Since: 2.6
##
{ 'enum': 'QGASeek', 'data': [ 'set', 'cur', 'end' ] }
##
# @GuestFileWhence:
#
# Controls the meaning of offset to @guest-file-seek.
#
# @value: Integral value (0 for set, 1 for cur, 2 for end), available
# for historical reasons, and might differ from the host's or
# guest's SEEK_* values (since: 0.15)
# @name: Symbolic name, and preferred interface
#
# Since: 2.6
##
{ 'alternate': 'GuestFileWhence',
'data': { 'value': 'int', 'name': 'QGASeek' } }
##
# @guest-file-seek:
#
@ -324,14 +352,15 @@
#
# @offset: bytes to skip over in the file stream
#
# @whence: 0 for SEEK_SET, 1 for SEEK_CUR, or 2 for SEEK_END
# @whence: Symbolic or numeric code for interpreting offset
#
# Returns: @GuestFileSeek on success.
#
# Since: 0.15.0
##
{ 'command': 'guest-file-seek',
'data': { 'handle': 'int', 'offset': 'int', 'whence': 'int' },
'data': { 'handle': 'int', 'offset': 'int',
'whence': 'GuestFileWhence' },
'returns': 'GuestFileSeek' }
##

View File

@ -6,7 +6,6 @@
#include <sys/un.h>
#include "libqtest.h"
#include "qga/guest-agent-core.h"
typedef struct {
char *test_dir;
@ -450,8 +449,8 @@ static void test_qga_file_ops(gconstpointer fix)
/* seek */
cmd = g_strdup_printf("{'execute': 'guest-file-seek',"
" 'arguments': { 'handle': %" PRId64 ", "
" 'offset': %d, 'whence': %d } }",
id, 6, QGA_SEEK_SET);
" 'offset': %d, 'whence': '%s' } }",
id, 6, "set");
ret = qmp_fd(fixture->fd, cmd);
qmp_assert_no_error(ret);
val = qdict_get_qdict(ret, "return");
@ -543,8 +542,8 @@ static void test_qga_file_write_read(gconstpointer fix)
/* seek to 0 */
cmd = g_strdup_printf("{'execute': 'guest-file-seek',"
" 'arguments': { 'handle': %" PRId64 ", "
" 'offset': %d, 'whence': %d } }",
id, 0, QGA_SEEK_SET);
" 'offset': %d, 'whence': '%s' } }",
id, 0, "set");
ret = qmp_fd(fixture->fd, cmd);
qmp_assert_no_error(ret);
val = qdict_get_qdict(ret, "return");