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 <ebl...@redhat.com>
---
v2: rebase on top of qapi work
---
v3: rebase to latest
v2 was here: https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg03565.html
v1 was here: https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg05730.html
qga/guest-agent-core.h | 9 ++-------
qga/commands-posix.c | 19 ++++++-------------
qga/commands-win32.c | 19 ++++++-------------
qga/commands.c | 21 +++++++++++++++++++++
tests/test-qga.c | 9 ++++-----
qga/qapi-schema.json | 33 +++++++++++++++++++++++++++++++--
6 files changed, 70 insertions(+), 40 deletions(-)
diff --git a/qga/guest-agent-core.h b/qga/guest-agent-core.h
index 238dc6b..0a49516 100644
--- a/qga/guest-agent-core.h
+++ b/qga/guest-agent-core.h
@@ -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);
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 9589b2d..9f51fae 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -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;
}
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index cf0757c..2799f5f 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -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;
}
diff --git a/qga/commands.c b/qga/commands.c
index 5b56786..e091ee1 100644
--- a/qga/commands.c
+++ b/qga/commands.c
@@ -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;
+}
diff --git a/tests/test-qga.c b/tests/test-qga.c
index 993b007..4d7542e 100644
--- a/tests/test-qga.c
+++ b/tests/test-qga.c
@@ -7,7 +7,6 @@
#include "libqtest.h"
#include "config-host.h"
-#include "qga/guest-agent-core.h"
typedef struct {
char *test_dir;
@@ -451,8 +450,8 @@ 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");
@@ -544,8 +543,8 @@ 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");
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 01c9ee4..c21f308 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -314,6 +314,34 @@
'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:
#
# Seek to a position in the file, as with fseek(), and return the
@@ -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' }
##
--
2.5.0
