[RFC PATCH glibc 1/12] hurd: Refactor readlinkat()
Sergey Bugaev
bugaevc@gmail.com
Sun Feb 12 11:10:32 GMT 2023
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
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