Re: [Qemu-devel] [PATCH v2] slirp: Ensure smbd and shared directory exist when enable smb

[Jan Kiszka]

On 2012-07-06 08:04, Dunrong Huang wrote:
> Users may pass the following parameters to qemu:
>     $ qemu-kvm -net nic -net user,smb= ...
>     $ qemu-kvm -net nic -net user,smb ...
>     $ qemu-kvm -net nic -net user,smb=bad_directory ...
> 
> In these cases, qemu started successfully while samba server
> failed to start. Users will confuse since samba server
> failed silently without any indication of what it did wrong.
> 
> To avoid it, we check whether the shared directory exist and
> if users have permission to access this directory when QEMU's
> "built-in" SMB server is enabled.
> 
> Signed-off-by: Dunrong Huang <riegama...@gmail.com>
> ---
>  net/slirp.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/net/slirp.c b/net/slirp.c
> index 37b6ccf..ff36fa2 100644
> --- a/net/slirp.c
> +++ b/net/slirp.c
> @@ -489,6 +489,18 @@ static int slirp_smb(SlirpState* s, const char 
> *exported_dir,
>      char smb_cmdline[128];
>      FILE *f;
>  
> +    if (access(CONFIG_SMBD_COMMAND, F_OK)) {
> +        error_report("could not find '%s', please install it",
> +                     CONFIG_SMBD_COMMAND);
> +        return -1;
> +    }
> +
> +    if (access(exported_dir, R_OK | X_OK)) {
> +        error_report("no such directory '%s', or you do not have permission "
> +                     "to access it, please check it", exported_dir);
> +        return -1;
> +    }
> +
>      snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.%ld-%d",
>               (long)getpid(), instance++);
>      if (mkdir(s->smb_dir, 0700) < 0) {
> 

Thanks, applied to slirp queue.

I added a tiny patch on top that reports the exact error returned by
access():

diff --git a/net/slirp.c b/net/slirp.c
index eb80889..b82eab0 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -504,8 +504,8 @@ static int slirp_smb(SlirpState* s, const char 
*exported_dir,
     }
 
     if (access(exported_dir, R_OK | X_OK)) {
-        error_report("no such directory '%s', or you do not have permission "
-                     "to access it, please check it", exported_dir);
+        error_report("error accessing shared directory '%s': %s",
+                     exported_dir, strerror(errno));
         return -1;
     }
 

Jan

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