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authorDenis Vlasenko <vda.linux@googlemail.com>2008-11-14 00:35:40 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2008-11-14 00:35:40 +0000
commit97a8f9f4dc1f94060b74943d9887cffed268b21b (patch)
treeccadfe75a8f4332e1ff7e38fb7bb4d7400acb59b
parent676ddd7a30ee8cef3796c51bc922fd76166cbfc9 (diff)
fixing resolver part 2: make _res structure members
configurable. we don't use most of it anyway.
-rw-r--r--extra/Configs/Config.in19
-rw-r--r--include/resolv.h66
-rw-r--r--libc/inet/resolv.c28
3 files changed, 74 insertions, 39 deletions
diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
index 9e2112c84..4979d5822 100644
--- a/extra/Configs/Config.in
+++ b/extra/Configs/Config.in
@@ -772,7 +772,7 @@ config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
bool "BSD obsolete signal functions"
default n
help
- These functions are provided as a compatibility interface for
+ These functions are provided as a compatibility interface for
programs that make use of the historical System V signal API.
This API is obsolete:
new applications should use the POSIX signal API (sigaction(2),
@@ -1066,6 +1066,23 @@ config UCLIBC_HAS_BSD_RES_CLOSE
Most people will say N.
+config UCLIBC_HAS_COMPAT_RES_STATE
+ bool "Use compatible but bloated _res"
+ default y
+ help
+ Answer Y if you build network utilities and they muck with resolver
+ internals a lot (_res global structure). uclibc does not use most
+ of _res.XXX fields, and with this option OFF they won't even exist.
+ Which will make e.g. dig build fail.
+ Answering N saves around 400 bytes in bss.
+
+config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
+ bool "Use extra compatible but extra bloated _res"
+ default n
+ help
+ Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
+ As far as I can say, this should never be needed.
+
endif
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 */
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index 7ef2fba45..b7ab27690 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -1255,20 +1255,26 @@ int res_init(void)
__UCLIBC_MUTEX_LOCK(__resolv_lock); /* must be a recursive lock! */
__close_nameservers();
__open_nameservers();
+ memset(rp, 0, sizeof(*rp));
+ rp->options = RES_INIT;
+#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
rp->retrans = RES_TIMEOUT;
rp->retry = 4;
- rp->options = RES_INIT;
- rp->id = (u_int) random();
- rp->nsaddr.sin_addr.s_addr = INADDR_ANY;
- rp->nsaddr.sin_family = AF_INET;
- rp->nsaddr.sin_port = htons(NAMESERVER_PORT);
+ rp->id = random();
+#endif
+ /* man resolv.conf says:
+ * "On a normally configured system this file should not be necessary.
+ * The only name server to be queried will be on the local machine;
+ * the domain name is determined from the host name
+ * and the domain search path is constructed from the domain name" */
+ rp->nscount = 1;
+ rp->nsaddr_list[0].sin_addr.s_addr = INADDR_ANY;
+ rp->nsaddr_list[0].sin_family = AF_INET;
+ rp->nsaddr_list[0].sin_port = htons(NAMESERVER_PORT);
rp->ndots = 1;
- /** rp->pfcode = 0; **/
+#ifdef __UCLIBC_HAS_EXTRA_COMPAT_RES_STATE__
rp->_vcsock = -1;
- /** rp->_flags = 0; **/
- /** rp->qhook = NULL; **/
- /** rp->rhook = NULL; **/
- /** rp->_u._ext.nsinit = 0; **/
+#endif
if (__searchdomains) {
int i;
@@ -1286,8 +1292,8 @@ int res_init(void)
rp->nsaddr_list[i].sin_port = htons(NAMESERVER_PORT);
}
}
+ rp->nscount = __nameservers;
}
- rp->nscount = __nameservers;
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
return 0;