From 97a8f9f4dc1f94060b74943d9887cffed268b21b Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Fri, 14 Nov 2008 00:35:40 +0000
Subject: fixing resolver part 2: make _res structure members configurable. we
don't use most of it anyway.
---
include/resolv.h | 66 +++++++++++++++++++++++++++++++++-----------------------
1 file changed, 39 insertions(+), 27 deletions(-)
(limited to 'include')
diff --git a/include/resolv.h b/include/resolv.h
index 3434f5d8c..6651dded9 100644
--- a/include/resolv.h
+++ b/include/resolv.h
@@ -101,53 +101,64 @@ typedef res_sendhookact (*res_send_rhook) (const struct sockaddr_in *ns,
# define RES_DFLRETRY 2 /* Default #/tries. */
# define RES_MAXTIME 65535 /* Infinity, in milliseconds. */
+/* _res (an instance of this structure) uses 0.5kb in bss
+ * in "ordinary" libc's (glibc, xBSD). We want to be less wasteful.
+ * We (1) shuffle and shrink some integer fields,
+ * and (2) can switch off stuff we don't support.
+ * Everything inside __UCLIBC_HAS_COMPAT_RES_STATE__
+ * is not actually used by uclibc and can be configured off.
+ * However, this will prevent some programs from building.
+ * Really obscure stuff with no observed users in the wild is under
+ * __UCLIBC_HAS_EXTRA_COMPAT_RES_STATE__.
+ * I guess it's safe to set that to N.
+ */
struct __res_state {
- int retrans; /* retransmition time interval */
+#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
+ int retrans; /* retransmission time interval */
int retry; /* number of times to retransmit */
- u_long options; /* option flags - see below. */
- int nscount; /* number of name servers */
+#endif
+ u_int32_t options; /* (was: ulong) option flags - see below. */
struct sockaddr_in
nsaddr_list[MAXNS]; /* address of name server */
-# define nsaddr nsaddr_list[0] /* for backward compatibility */
- u_short id; /* current message id */
+#define nsaddr nsaddr_list[0] /* for backward compatibility */
char *dnsrch[MAXDNSRCH+1]; /* components of domain to search */
+#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
+ /* googling for "_res.defdname" says it's still sometimes used.
+ * Pity. It's huge, I want to move it to EXTRA_COMPAT... */
char defdname[256]; /* default domain (deprecated) */
- u_long pfcode; /* RES_PRF_ flags - see below. */
- unsigned ndots:4; /* threshold for initial abs. query */
- unsigned nsort:4; /* number of elements in sort_list[] */
- char unused[3];
+#endif
+ u_int8_t nscount; /* (was: int) number of name servers */
+ u_int8_t ndots; /* (was: unsigned:4) threshold for initial abs. query */
+#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
+ u_int8_t nsort; /* (was: unsigned:4) number of elements in sort_list[] */
+ u_int16_t pfcode; /* (was: ulong) RES_PRF_ flags. Used by dig. */
+ unsigned short id; /* current message id */
+ int res_h_errno; /* last one set for this context */
struct {
struct in_addr addr;
u_int32_t mask;
} sort_list[MAXRESOLVSORT];
- res_send_qhook qhook; /* query hook */
- res_send_rhook rhook; /* response hook */
- int res_h_errno; /* last one set for this context */
- int _vcsock; /* PRIVATE: for res_send VC i/o */
- u_int _flags; /* PRIVATE: see below */
union {
- char pad[52]; /* On an i386 this means 512b total. */
struct {
u_int16_t nscount;
-#if 0
- u_int16_t nsmap[MAXNS];
-#else
u_int16_t nstimes[MAXNS]; /* ms. */
-#endif
int nssocks[MAXNS];
+ /* below: not in xBSD. glibc only? */
u_int16_t nscount6;
u_int16_t nsinit;
struct sockaddr_in6 *nsaddrs[MAXNS];
-#if 0
-#ifdef _LIBC
- unsigned long long int initstamp
- __attribute__((packed));
-#else
- unsigned int _initstamp[2];
-#endif
-#endif
} _ext;
} _u;
+#endif
+#ifdef __UCLIBC_HAS_EXTRA_COMPAT_RES_STATE__
+ /* Truly obscure stuff.
+ * Googling for "_res.XXX" for these members
+ * turned up basically empty */
+ res_send_qhook qhook; /* query hook */
+ res_send_rhook rhook; /* response hook */
+ int _vcsock; /* PRIVATE: for res_send VC i/o */
+ unsigned _flags; /* PRIVATE: see below */
+#endif
};
typedef struct __res_state *res_state;
@@ -196,6 +207,7 @@ struct res_sym {
/*
* Resolver options (keep these in synch with res_debug.c, please)
+ * (which of these do we really implement??)
*/
#define RES_INIT 0x00000001 /* address initialized */
#define RES_DEBUG 0x00000002 /* print debug messages */
--
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