diff mbox series

[RFC,1/12] hurd: Refactor readlinkat()

Message ID 20230212111044.610942-2-bugaevc@gmail.com
State Committed, archived
Headers
Series Towards glibc on x86_64-gnu |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Sergey Bugaev Feb. 12, 2023, 11:10 a.m. UTC 
  Make the code flow more linear using early returns where possible. This
makes it so much easier to reason about what runs on error / successful
code paths.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/readlinkat.c | 55 ++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 23 deletions(-)

Comments

Samuel Thibault Feb. 12, 2023, 2:49 p.m. UTC | #1 
Applied, thanks!

Sergey Bugaev via Libc-alpha, le dim. 12 févr. 2023 14:10:32 +0300, a ecrit:
> Make the code flow more linear using early returns where possible. This
> makes it so much easier to reason about what runs on error / successful
> code paths.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/readlinkat.c | 55 ++++++++++++++++++++--------------
>  1 file changed, 32 insertions(+), 23 deletions(-)
> 
> diff --git a/sysdeps/mach/hurd/readlinkat.c b/sysdeps/mach/hurd/readlinkat.c
> index 1efb09ca..dabdbb37 100644
> --- a/sysdeps/mach/hurd/readlinkat.c
> +++ b/sysdeps/mach/hurd/readlinkat.c
> @@ -31,38 +31,47 @@ __readlinkat (int fd, const char *file_name, char *buf, size_t len)
>    error_t err;
>    file_t file_stat;
>    struct stat64 st;
> +  enum retry_type doretry;
> +  char retryname[1024];
> +  file_t file;
> +  char *rbuf = buf;
>  
>    file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0);
>    if (file_stat == MACH_PORT_NULL)
>      return -1;
>  
>    err = __io_stat (file_stat, &st);
> -  if (! err)
> -    if (S_ISLNK (st.st_mode))
> -      {
> -	enum retry_type doretry;
> -	char retryname[1024];
> -	file_t file;
> -	char *rbuf = buf;
> +  if (err)
> +    goto out;
> +  if (!S_ISLNK (st.st_mode))
> +    {
> +      err = EINVAL;
> +      goto out;
> +    }
>  
> -	err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, 0, &doretry, retryname, &file);
> -	if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0'))
> -	  err = EGRATUITOUS;
> -	if (! err)
> -	  {
> -	    err = __io_read (file, &rbuf, &len, 0, len);
> -	    if (!err && rbuf != buf)
> -	      {
> -		memcpy (buf, rbuf, len);
> -		__vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
> -	      }
> +  err = __dir_lookup (file_stat, "", O_READ | O_NOLINK,
> +                      0, &doretry, retryname, &file);
> +  if (err)
> +    goto out;
> +  if (doretry != FS_RETRY_NORMAL || retryname[0] != '\0')
> +    {
> +      err = EGRATUITOUS;
> +      goto out;
> +    }
> +
> +  err = __io_read (file, &rbuf, &len, 0, len);
> +  __mach_port_deallocate (__mach_task_self (), file);
> +  if (err)
> +    goto out;
> +
> +  if (rbuf != buf)
> +    {
> +      memcpy (buf, rbuf, len);
> +      __vm_deallocate (__mach_task_self (), (vm_address_t) rbuf, len);
> +    }
>  
> -	    __mach_port_deallocate (__mach_task_self (), file);
> -	  }
> -      }
> -    else
> -      err = EINVAL;
>  
> + out:
>    __mach_port_deallocate (__mach_task_self (), file_stat);
>  
>    return err ? __hurd_fail (err) : len;
> -- 
> 2.39.1
>
diff mbox series

Patch

diff --git a/sysdeps/mach/hurd/readlinkat.c b/sysdeps/mach/hurd/readlinkat.c
index 1efb09ca..dabdbb37 100644
--- a/sysdeps/mach/hurd/readlinkat.c
+++ b/sysdeps/mach/hurd/readlinkat.c
@@ -31,38 +31,47 @@  __readlinkat (int fd, const char *file_name, char *buf, size_t len)
   error_t err;
   file_t file_stat;
   struct stat64 st;
+  enum retry_type doretry;
+  char retryname[1024];
+  file_t file;
+  char *rbuf = buf;
 
   file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0);
   if (file_stat == MACH_PORT_NULL)
     return -1;
 
   err = __io_stat (file_stat, &st);
-  if (! err)
-    if (S_ISLNK (st.st_mode))
-      {
-	enum retry_type doretry;
-	char retryname[1024];
-	file_t file;
-	char *rbuf = buf;
+  if (err)
+    goto out;
+  if (!S_ISLNK (st.st_mode))
+    {
+      err = EINVAL;
+      goto out;
+    }
 
-	err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, 0, &doretry, retryname, &file);
-	if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0'))
-	  err = EGRATUITOUS;
-	if (! err)
-	  {
-	    err = __io_read (file, &rbuf, &len, 0, len);
-	    if (!err && rbuf != buf)
-	      {
-		memcpy (buf, rbuf, len);
-		__vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
-	      }
+  err = __dir_lookup (file_stat, "", O_READ | O_NOLINK,
+                      0, &doretry, retryname, &file);
+  if (err)
+    goto out;
+  if (doretry != FS_RETRY_NORMAL || retryname[0] != '\0')
+    {
+      err = EGRATUITOUS;
+      goto out;
+    }
+
+  err = __io_read (file, &rbuf, &len, 0, len);
+  __mach_port_deallocate (__mach_task_self (), file);
+  if (err)
+    goto out;
+
+  if (rbuf != buf)
+    {
+      memcpy (buf, rbuf, len);
+      __vm_deallocate (__mach_task_self (), (vm_address_t) rbuf, len);
+    }
 
-	    __mach_port_deallocate (__mach_task_self (), file);
-	  }
-      }
-    else
-      err = EINVAL;
 
+ out:
   __mach_port_deallocate (__mach_task_self (), file_stat);
 
   return err ? __hurd_fail (err) : len;