Re: [Qemu-devel] [PATCH 2/8] qga: implement file commands for Windows guest

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Denis V. Lunev (2014-12-31 07:06:48)
> From: Olga Krishtal <okrishtal@parallels.com>
> 
> The following commands are implemented:
> - guest_file_open
> - guest_file_close
> - guest_file_write
> - guest_file_read
> - guest_file_seek
> - guest_file_flush
> 
> Motivation is quite simple: Windows guests should be supported with the
> same set of features as Linux one. Also this patch is a prerequisite for
> Windows guest-exec command support.
> 
> Signed-off-by: Olga Krishtal <okrishtal@parallels.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
>  qga/commands-win32.c | 271 +++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 250 insertions(+), 21 deletions(-)
> 
> diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> index 3bcbeae..5db96ef 100644
> --- a/qga/commands-win32.c
> +++ b/qga/commands-win32.c
> @@ -14,10 +14,13 @@
>  #include <glib.h>
>  #include <wtypes.h>
>  #include <powrprof.h>
> +#include <stdio.h>
> +#include <string.h>
>  #include "qga/guest-agent-core.h"
>  #include "qga/vss-win32.h"
>  #include "qga-qmp-commands.h"
>  #include "qapi/qmp/qerror.h"
> +#include "qemu/queue.h"
> 
>  #ifndef SHTDN_REASON_FLAG_PLANNED
>  #define SHTDN_REASON_FLAG_PLANNED 0x80000000
> @@ -29,6 +32,146 @@
>                         (365 * (1970 - 1601) +       \
>                          (1970 - 1601) / 4 - 3))
> 
> +#define INVALID_SET_FILE_POINTER ((DWORD)-1)
> +
> +typedef struct GuestFileHandle {
> +    int64_t id;
> +    HANDLE fh;
> +    QTAILQ_ENTRY(GuestFileHandle) next;
> +} GuestFileHandle;
> +
> +static struct {
> +    QTAILQ_HEAD(, GuestFileHandle) filehandles;
> +} guest_file_state;
> +
> +
> +typedef struct OpenFlags {
> +    const char *forms;
> +    DWORD desired_access;
> +    DWORD creation_disposition;
> +} OpenFlags;
> +static OpenFlags guest_file_open_modes[] = {
> +    {"r",   GENERIC_READ,               OPEN_EXISTING},
> +    {"rb",  GENERIC_READ,               OPEN_EXISTING},
> +    {"w",   GENERIC_WRITE,              CREATE_ALWAYS},
> +    {"wb",  GENERIC_WRITE,              CREATE_ALWAYS},
> +    {"a",   GENERIC_WRITE,              OPEN_ALWAYS  },
> +    {"r+",  GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
> +    {"rb+", GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
> +    {"r+b", GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
> +    {"w+",  GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
> +    {"wb+", GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
> +    {"w+b", GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
> +    {"a+",  GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  },
> +    {"ab+", GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  },
> +    {"a+b", GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  }
> +};
> +
> +static OpenFlags *find_open_flag(const char *mode_str)
> +{
> +    int mode;
> +    Error **errp = NULL;
> +
> +    for (mode = 0; mode < ARRAY_SIZE(guest_file_open_modes); ++mode) {
> +        OpenFlags *flags = guest_file_open_modes + mode;
> +
> +        if (strcmp(flags->forms, mode_str) == 0) {
> +            return flags;
> +        }
> +    }
> +
> +    error_setg(errp, "invalid file open mode '%s'", mode_str);
> +    return NULL;
> +}
> +
> +static int64_t guest_file_handle_add(HANDLE fh, Error **errp)
> +{
> +    GuestFileHandle *gfh;
> +    int64_t handle;
> +
> +    handle = ga_get_fd_handle(ga_state, errp);
> +    if (handle < 0) {
> +        return -1;
> +    }
> +    gfh = g_malloc0(sizeof(GuestFileHandle));
> +    gfh->id = handle;
> +    gfh->fh = fh;
> +    QTAILQ_INSERT_TAIL(&guest_file_state.filehandles, gfh, next);
> +
> +    return handle;
> +}
> +
> +static GuestFileHandle *guest_file_handle_find(int64_t id, Error **errp)
> +{
> +    GuestFileHandle *gfh;
> +    QTAILQ_FOREACH(gfh, &guest_file_state.filehandles, next) {
> +        if (gfh->id == id) {
> +            return gfh;
> +        }
> +    }
> +    error_setg(errp, "handle '%" PRId64 "' has not been found", id);
> +    return NULL;
> +}
> +
> +int64_t qmp_guest_file_open(const char *path, bool has_mode,
> +                            const char *mode, Error **errp)
> +{
> +    int64_t fd;
> +    HANDLE fh;
> +    HANDLE templ_file = NULL;
> +    DWORD share_mode = FILE_SHARE_READ;
> +    DWORD flags_and_attr = FILE_ATTRIBUTE_NORMAL;
> +    LPSECURITY_ATTRIBUTES sa_attr = NULL;
> +    OpenFlags *guest_flags;
> +
> +    if (!has_mode) {
> +        mode = "r";
> +    }
> +    slog("guest-file-open called, filepath: %s, mode: %s", path, mode);
> +    guest_flags = find_open_flag(mode);
> +    if (guest_flags == NULL) {
> +        error_setg(errp, "invalid file open mode");
> +        return -1;
> +    }
> +
> +    fh = CreateFile(path, guest_flags->desired_access, share_mode, sa_attr,
> +                    guest_flags->creation_disposition, flags_and_attr,
> +                    templ_file);
> +    if (fh == INVALID_HANDLE_VALUE) {
> +        error_setg_errno(errp, GetLastError(), "failed to open file '%s'",
> +                         path);

For working with GetLastError() I think error_setg_win32() is what you
want. Same for all the other occurrences.