Re: [PATCH v4 06/15] qga: use qga_open_cloexec() for safe_open_or_create()

[Markus Armbruster]

marcandre.lureau@redhat.com writes:

> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> The function takes care of setting CLOEXEC, and reporting error.
>
> The reported error message will differ, from:
>   "failed to open file 'foo' (mode: 'r')"
> to:
>   "Failed to open file 'foo'"
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> ---
>  qga/commands-posix.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 8ee149e550..28fe19d932 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -27,6 +27,7 @@
>  #include "qemu/cutils.h"
>  #include "commands-common.h"
>  #include "block/nvme.h"
> +#include "cutils.h"
>  
>  #ifdef HAVE_UTMPX
>  #include <utmpx.h>
> @@ -339,6 +340,7 @@ find_open_flag(const char *mode_str, Error **errp)
>  static FILE *
>  safe_open_or_create(const char *path, const char *mode, Error **errp)
>  {
> +    ERRP_GUARD();
>      int oflag;
>      int fd = -1;
>      FILE *f = NULL;
> @@ -370,20 +372,17 @@ safe_open_or_create(const char *path, const char *mode, 
> Error **errp)
>       * open() is decisive and its third argument is ignored, and the second
>       * open() and the fchmod() are never called.
>       */
> -    fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0);
> +    fd = qga_open_cloexec(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0, 
> errp);

Long line.

>      if (fd == -1 && errno == EEXIST) {
> +        error_free(*errp);
> +        *errp = NULL;
>          oflag &= ~(unsigned)O_CREAT;
> -        fd = open(path, oflag);
> +        fd = qga_open_cloexec(path, oflag, 0, errp);
>      }
>      if (fd == -1) {
> -        error_setg_errno(errp, errno,
> -                         "failed to open file '%s' (mode: '%s')",
> -                         path, mode);
>          goto end;
>      }
>  
> -    qemu_set_cloexec(fd);
> -
>      if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) {
>          error_setg_errno(errp, errno, "failed to set permission "
>                           "0%03o on new file '%s' (mode: '%s')",

Simpler:

  diff --git a/qga/commands-posix.c b/qga/commands-posix.c
  index 8ee149e550..516658a7f6 100644
  --- a/qga/commands-posix.c
  +++ b/qga/commands-posix.c
  @@ -27,6 +27,7 @@
   #include "qemu/cutils.h"
   #include "commands-common.h"
   #include "block/nvme.h"
  +#include "cutils.h"

   #ifdef HAVE_UTMPX
   #include <utmpx.h>
  @@ -370,10 +371,10 @@ safe_open_or_create(const char *path, const char *mode, 
Error **errp)
        * open() is decisive and its third argument is ignored, and the second
        * open() and the fchmod() are never called.
        */
  -    fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0);
  +    fd = qga_open_cloexec(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0, 
NULL);
       if (fd == -1 && errno == EEXIST) {
           oflag &= ~(unsigned)O_CREAT;
  -        fd = open(path, oflag);
  +        fd = qga_open_cloexec(path, oflag, 0, NULL);
       }
       if (fd == -1) {
           error_setg_errno(errp, errno,
  @@ -382,8 +383,6 @@ safe_open_or_create(const char *path, const char *mode, 
Error **errp)
           goto end;
       }

  -    qemu_set_cloexec(fd);
  -
       if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) {
           error_setg_errno(errp, errno, "failed to set permission "
                            "0%03o on new file '%s' (mode: '%s')",

qga_open_cloexec()'s parameter @errp then has no user, and can be
dropped.

Recommendation, not demand.