Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

lint: do not warn about pointer cast between sockaddr variants

This commit is contained in:
rillig 2022-06-24 20:16:21 +00:00
parent 82c8f75d09
commit 0877aaac93
2 changed files with 45 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
tests/usr.bin/xlint/lint1/msg_247.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: msg_247.c,v 1.21 2022/06/24 20:02:58 rillig Exp $ */
/* $NetBSD: msg_247.c,v 1.22 2022/06/24 20:16:21 rillig Exp $ */
# 3 "msg_247.c"
// Test for message: pointer cast from '%s' to '%s' may be troublesome [247]
@ -14,13 +14,14 @@ struct Other {
int id;
};
void
PDisplay
example(struct Other *arg)
{
PDisplay display;
/*
* XXX: The target type is reported as 'struct <unnamed>'. In cases
* Before tree.c 1.461 from 2022-06-24, lint warned about the cast
* between the structs.
*
* XXX: The target type was reported as 'struct <unnamed>'. In cases
* like these, it would be helpful to print at least the type name
* of the pointer. This type name though is discarded immediately
* in the grammar rule 'typespec: T_TYPENAME'.
@ -28,8 +29,7 @@ example(struct Other *arg)
* with no hint at all that there is a typedef for a pointer to the
* struct.
*/
/* expect+1: warning: pointer cast from 'pointer to struct Other' to 'pointer to struct <unnamed>' may be troublesome [247] */
display = (PDisplay)arg;
return (PDisplay)arg;
}
/*
@ -249,21 +249,26 @@ struct sockaddr_in6 {
uint32_t sin6_scope_id;
};
/*
* Before tree.c 1.461 from 2022-06-24, lint warned about the cast between the
* sockaddr variants. Since then, lint allows casts between pointers to
* structs if the initial members have compatible types and either of the
* struct types continues with a byte array.
*/
void *
cast_between_sockaddr_variants(void *ptr)
{
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr' to 'pointer to struct sockaddr_in' may be troublesome [247] */
void *t1 = (struct sockaddr_in *)(struct sockaddr *)ptr;
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in' to 'pointer to struct sockaddr' may be troublesome [247] */
void *t2 = (struct sockaddr *)(struct sockaddr_in *)t1;
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr' to 'pointer to struct sockaddr_in6' may be troublesome [247] */
void *t3 = (struct sockaddr_in6 *)(struct sockaddr *)t2;
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in6' to 'pointer to struct sockaddr' may be troublesome [247] */
void *t4 = (struct sockaddr *)(struct sockaddr_in6 *)t3;
return t4;
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in6' to 'pointer to struct sockaddr_in' may be troublesome [247] */
void *t5 = (struct sockaddr_in *)(struct sockaddr_in6 *)t4;
/* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in' to 'pointer to struct sockaddr_in6' may be troublesome [247] */
void *t6 = (struct sockaddr_in6 *)(struct sockaddr_in *)t5;
return t6;
}

27
usr.bin/xlint/lint1/tree.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: tree.c,v 1.460 2022/06/24 19:27:43 rillig Exp $ */
/* $NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
__RCSID("$NetBSD: tree.c,v 1.460 2022/06/24 19:27:43 rillig Exp $");
__RCSID("$NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $");
#endif
#include <float.h>
@ -2490,6 +2490,14 @@ check_pointer_integer_conversion(op_t op, tspec_t nt, type_t *tp, tnode_t *tn)
}
}
static bool
is_byte_array(const type_t *tp)
{
return tp->t_tspec == ARRAY &&
(tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR);
}
static bool
should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst,
const type_t *ostp, tspec_t ost)
@ -2512,6 +2520,21 @@ should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst,
if (ost == CHAR || ost == UCHAR)
return false; /* for the sake of traditional C code */
/* Allow cast between pointers to sockaddr variants. */
if (nst == STRUCT && ost == STRUCT) {
const sym_t *nmem = nstp->t_str->sou_first_member;
const sym_t *omem = ostp->t_str->sou_first_member;
while (nmem != NULL && omem != NULL &&
eqtype(nmem->s_type, omem->s_type, true, false, NULL))
nmem = nmem->s_next, omem = omem->s_next;
if (nmem != NULL && is_byte_array(nmem->s_type))
return false;
if (omem != NULL && is_byte_array(omem->s_type))
return false;
if (nmem == NULL && omem == NULL)
return false;
}
if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str)
return true;