Re: [PATCH] osdep: Introduce qemu_get_fd() to wrap the common codes

[Christian Schoenebeck]

On Mittwoch, 31. August 2022 10:25:27 CEST Guoyi Tu wrote:
> On 8/18/22 20:58, Christian Schoenebeck wrote:
> > On Donnerstag, 18. August 2022 14:06:04 CEST Guoyi Tu wrote:
> >> Ping...
> >> 
> >> Any comments are welcome
> >> 
> >> On 8/12/22 19:01, Guoyi Tu wrote:
> >>> socket_get_fd() have much the same codes as monitor_fd_param(),
> >>> so qemu_get_fd() is introduced to implement the common logic.
> >>> now socket_get_fd() and monitor_fd_param() directly call this
> >>> function.
> > 
> > s/have/has/, s/now/Now/, some proper rephrasing wouldn't hurt either.
> 
> will fix it.
> 
> >>> Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn>
> >>> ---
> >>> 
> >>>    include/qemu/osdep.h |  1 +
> >>>    monitor/misc.c       | 21 +--------------------
> >>>    util/osdep.c         | 25 +++++++++++++++++++++++++
> >>>    util/qemu-sockets.c  | 17 +++++------------
> >>>    4 files changed, 32 insertions(+), 32 deletions(-)
> >>> 
> >>> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> >>> index b1c161c035..b920f128a7 100644
> >>> --- a/include/qemu/osdep.h
> >>> +++ b/include/qemu/osdep.h
> >>> @@ -491,6 +491,7 @@ int qemu_open_old(const char *name, int flags, ...);
> >>> 
> >>>    int qemu_open(const char *name, int flags, Error **errp);
> >>>    int qemu_create(const char *name, int flags, mode_t mode, Error
> >>>    **errp);
> >>>    int qemu_close(int fd);
> >>> 
> >>> +int qemu_get_fd(Monitor *mon, const char *fdname, Error **errp);
> >>> 
> >>>    int qemu_unlink(const char *name);
> >>>    #ifndef _WIN32
> >>>    int qemu_dup_flags(int fd, int flags);
> >>> 
> >>> diff --git a/monitor/misc.c b/monitor/misc.c
> >>> index 3d2312ba8d..0d3372cf2b 100644
> >>> --- a/monitor/misc.c
> >>> +++ b/monitor/misc.c
> >>> @@ -1395,26 +1395,7 @@ void monitor_fdset_dup_fd_remove(int dup_fd)
> >>> 
> >>>    int monitor_fd_param(Monitor *mon, const char *fdname, Error **errp)
> >>>    {
> >>> 
> >>> -    int fd;
> >>> -    Error *local_err = NULL;
> >>> -
> >>> -    if (!qemu_isdigit(fdname[0]) && mon) {
> >>> -        fd = monitor_get_fd(mon, fdname, &local_err);
> >>> -    } else {
> >>> -        fd = qemu_parse_fd(fdname);
> >>> -        if (fd == -1) {
> >>> -            error_setg(&local_err, "Invalid file descriptor number
> >>> '%s'",
> >>> -                       fdname);
> >>> -        }
> >>> -    }
> >>> -    if (local_err) {
> >>> -        error_propagate(errp, local_err);
> >>> -        assert(fd == -1);
> >>> -    } else {
> >>> -        assert(fd != -1);
> >>> -    }
> >>> -
> >>> -    return fd;
> >>> +    return qemu_get_fd(mon, fdname, errp);
> >>> 
> >>>    }
> >>>    
> >>>    /* Please update hmp-commands.hx when adding or changing commands */
> >>> 
> >>> diff --git a/util/osdep.c b/util/osdep.c
> >>> index 60fcbbaebe..c57551ca78 100644
> >>> --- a/util/osdep.c
> >>> +++ b/util/osdep.c
> >>> @@ -23,6 +23,7 @@
> >>> 
> >>>     */
> >>>    
> >>>    #include "qemu/osdep.h"
> >>>    #include "qapi/error.h"
> >>> 
> >>> +#include "qemu/ctype.h"
> >>> 
> >>>    #include "qemu/cutils.h"
> >>>    #include "qemu/sockets.h"
> >>>    #include "qemu/error-report.h"
> >>> 
> >>> @@ -413,6 +414,30 @@ int qemu_close(int fd)
> >>> 
> >>>        return close(fd);
> >>>    
> >>>    }
> >>> 
> >>> +int qemu_get_fd(Monitor *mon, const char *fdname, Error **errp)
> >>> +{
> >>> +    int fd;
> >>> +    Error *local_err = NULL;
> >>> +
> >>> +    if (!qemu_isdigit(fdname[0]) && mon) {
> >>> +        fd = monitor_get_fd(mon, fdname, &local_err);
> >>> +    } else {
> >>> +        fd = qemu_parse_fd(fdname);
> >>> +        if (fd == -1) {
> >>> +            error_setg(&local_err, "Invalid file descriptor number
> >>> '%s'",
> >>> +                       fdname);
> >>> +        }
> >>> +    }
> >>> +    if (local_err) {
> >>> +        error_propagate(errp, local_err);
> >>> +        assert(fd == -1);
> >>> +    } else {
> >>> +        assert(fd != -1);
> >>> +    }
> >>> +
> >>> +    return fd;
> >>> +}
> >>> +
> > 
> > Up to here you are basically just moving the code of monitor_fd_param() to
> > a project wide shared new function qemu_get_fd(), but why? I mean you
> > could simply call monitor_fd_param() in socket_get_fd() below, no?
> 
> monitor_fd_param() is implemented in misc.c which is not linkded when
> build the test codes that test the socket_connect() api, such as
> test-unit-sockets.c and test-char.c. If call monitor_fd_param() directly

I guess you mean tests/unit/test-util-sockets.c, but I understand.

The thing is though, as you can see from the header of osdep.h, only things 
should be added to osdep.h which are really needed project wide:

  (1) things which everybody needs
  (2) things without which code would work on most platforms but
      fail to compile or misbehave on a minority of host OSes

I don't have the impression that this function would fall into this 
definition, so it would be better to find another location for it.

> in socket_get_fd(), we need to implement a stub version of
> monitor_fd_param() which actually has the same codes according to the
> codes in test-unit-socket.c which overwrite the monitor_get_fd().
> 
> what about moving monitor_fd_param() to the osdep.c and calling
> monitor_fd_param() in socket_get_fd() ?
> 
> >>>    /*
> >>>    
> >>>     * Delete a file from the filesystem, unless the filename is
> >>> 
> >>> /dev/fdset/...
> >>> 
> >>>     *
> >>> 
> >>> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
> >>> index 13b5b197f9..92960ee6eb 100644
> >>> --- a/util/qemu-sockets.c
> >>> +++ b/util/qemu-sockets.c
> >>> @@ -1142,19 +1142,12 @@ static int socket_get_fd(const char *fdstr,
> >>> Error **errp)
> >>> 
> >>>    {
> >>>    
> >>>        Monitor *cur_mon = monitor_cur();
> >>>        int fd;
> >>> 
> >>> -    if (cur_mon) {
> >>> -        fd = monitor_get_fd(cur_mon, fdstr, errp);
> >>> -        if (fd < 0) {
> >>> -            return -1;
> >>> -        }
> >>> -    } else {
> >>> -        if (qemu_strtoi(fdstr, NULL, 10, &fd) < 0) {
> >>> -            error_setg_errno(errp, errno,
> >>> -                             "Unable to parse FD number %s",
> >>> -                             fdstr);
> >>> -            return -1;
> >>> -        }
> >>> +
> >>> +    fd = qemu_get_fd(cur_mon, fdstr, errp);
> >>> +    if (fd < 0) {
> >>> +        return -1;
> >>> 
> >>>        }
> > 
> > This part looks like behaviour change to me. Haven't looked into the
> > details though whether it would be OK. Just saying.
> 
> In my opinion the logic is almost the same.
> 
> >>> +
> > 
> > Unintentional white line added?
> 
> will delete it.
> 
> Thanks for your coomments
> 
> >>>        if (!fd_is_socket(fd)) {
> >>>        
> >>>            error_setg(errp, "File descriptor '%s' is not a socket",
> >>>            fdstr);
> >>>            close(fd);