[PATCH v1] xstrtol: Remove dead code

[Alejandro Colomar]

strtol(3) has a limited set of possible states:

-  The base was invalid.
   -  return 0
   -  errno = EINVAL
   -  endp is not set
   We cover this case with the assure() call, before strtol(3).

-  No conversion was performed.
   -  return 0
   -  errno may be EINVAL, or may be unset.
   -  *endp == s
   We cover this case with the 'if (*p == s)' check.

-  Conversion performed with extra trailing characters.
   -  return any number
   -  errno is not set
   -  *endp != s
   -  **endp != '\0'
   We let this fall through.

-  String fully converted.
   -  return any number
   -  errno is not set
   -  *endp != s
   -  **endp == '\0'
   We let this fall through.

-  Overflow
   -  return LONG_MAX or LONG_MIN
   -  errno = ERANGE
   -  *endp != s
   We cover this with 'else if (errno != 0)'

The condition '*endp != s && errno != 0 && errno != ERANGE' is
unreachable.  The only errno possible if '*endp != s' is ERANGE.

Fixes: 790855e18a1d (2003-10-14, "Handle invalid suffixes and overflow 
independently, so that ...")
Cc: Paul Eggert <eggert@cs.ucla.edu>
Cc: Bruno Haible <bruno@clisp.org>
Cc: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Cc: Eli Schwartz <eschwartz93@gmail.com>
Cc: Sam James <sam@gentoo.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Cc: "Andrew J. Hesford" <ajh@sideband.org>
Cc: Michael Vetter <jubalh@iodoru.org>
Cc: <liba2i@lists.linux.dev>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---
Range-diff against v0:
-:  ---------- > 1:  1af702673f xstrtol: Remove dead code

 lib/xstrtol.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/xstrtol.c b/lib/xstrtol.c
index 575c16d45f..5d10ce041e 100644
--- a/lib/xstrtol.c
+++ b/lib/xstrtol.c
@@ -110,10 +110,8 @@ __xstrtol (const char *s, char **ptr, int strtol_base,
       else
         return LONGINT_INVALID;
     }
-  else if (errno != 0)
+  else if (errno == ERANGE)
     {
-      if (errno != ERANGE)
-        return LONGINT_INVALID;
       err = LONGINT_OVERFLOW;
     }
 
-- 
2.45.2

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