commit de3549a23456a4bfd2584e3566a2a97a0c0f82c1
author Vadim Yanitskiy <vyanitskiy@sysmocom.de> Wed Nov 17 06:34:48 2021 +0300
committer fixeria <vyanitskiy@sysmocom.de> Thu Nov 18 13:11:20 2021 +0000
tree 78b432ace71ae54e3c2d6d1b411292a11bad2269
parent 2768246e7a368b7b74f16fe9db8c8a5ce02c6c88

bitvec_read_field(): indicate errors using errno

This function returns an *unsigned* integer (uint64_t), so returning
a negative value on error is a bad idea.  A negative value turns into
a huge positive value, what was demonstrated in the bitvec_test:

  bitvec_read_field(idx=512, len=16) => ffffffffffffffea
  bitvec_read_field(idx=0, len=65) => ffffffffffffffea
  bitvec_read_field(idx=64, len=16) => ffffffffffffffea

The 0xffffffffffffffea above is basically:

  (uint64_t) -EINVAL, or
  (uint64_t) -22 + 1, or
  0xffffffffffffffff - 0x16 + 1.

Let's make use of the errno in order to indicate an error to the caller.

Change-Id: I2cc734caa3365d03c2ae2b3f2cd9544933c25e9e
Related: OS#4388

tests/bitvec/bitvec_test.ok

diff --git a/tests/bitvec/bitvec_test.ok b/tests/bitvec/bitvec_test.ok
index b118502..a0e31d3 100644
--- a/tests/bitvec/bitvec_test.ok
+++ b/tests/bitvec/bitvec_test.ok
@@ -171,21 +171,21 @@
 bitvec bytes used.
 
 test bitvec_read_field():
-bitvec_read_field(idx=0, len=64) => deadbeeffeebdaed
-bitvec_read_field(idx=0, len=32) => deadbeef
-bitvec_read_field(idx=0, len=16) => dead
-bitvec_read_field(idx=0, len=8) => de
-bitvec_read_field(idx=0, len=0) => 0
-bitvec_read_field(idx=8, len=8) => ad
-bitvec_read_field(idx=8, len=4) => a
-bitvec_read_field(idx=8, len=0) => 0
-bitvec_read_field(idx=10, len=9) => 16d
-bitvec_read_field(idx=10, len=7) => 5b
-bitvec_read_field(idx=10, len=5) => 16
-bitvec_read_field(idx=10, len=3) => 5
-bitvec_read_field(idx=10, len=1) => 1
-bitvec_read_field(idx=512, len=16) => ffffffffffffffea
-bitvec_read_field(idx=0, len=65) => ffffffffffffffea
-bitvec_read_field(idx=64, len=16) => ffffffffffffffea
+bitvec_read_field(idx=0, len=64) => deadbeeffeebdaed (success)
+bitvec_read_field(idx=0, len=32) => deadbeef (success)
+bitvec_read_field(idx=0, len=16) => dead (success)
+bitvec_read_field(idx=0, len=8) => de (success)
+bitvec_read_field(idx=0, len=0) => 0 (success)
+bitvec_read_field(idx=8, len=8) => ad (success)
+bitvec_read_field(idx=8, len=4) => a (success)
+bitvec_read_field(idx=8, len=0) => 0 (success)
+bitvec_read_field(idx=10, len=9) => 16d (success)
+bitvec_read_field(idx=10, len=7) => 5b (success)
+bitvec_read_field(idx=10, len=5) => 16 (success)
+bitvec_read_field(idx=10, len=3) => 5 (success)
+bitvec_read_field(idx=10, len=1) => 1 (success)
+bitvec_read_field(idx=512, len=16) => 0 (error)
+bitvec_read_field(idx=0, len=65) => bd5b7ddffdd7b5db (error)
+bitvec_read_field(idx=64, len=16) => 0 (error)
 
 bitvec ok.