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Diffstat (limited to 'libc')
-rw-r--r--libc/inet/resolv.c63
1 files changed, 42 insertions, 21 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index d806a9dc9..828ca1359 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -474,6 +474,7 @@ int attribute_hidden __decode_dotted(const unsigned char * const data, int offse
#endif
#ifdef L_lengthd
+/* Returns -1 only if data == NULL */
int attribute_hidden __length_dotted(const unsigned char * const data, int offset)
{
int orig_offset = offset;
@@ -533,8 +534,8 @@ int attribute_hidden __decode_question(const unsigned char * const message, int
offset += i;
+//TODO: what if strdup fails?
q->dotted = strdup(temp);
-//TODO: what if this fails?
q->qtype = (message[offset + 0] << 8) | message[offset + 1];
q->qclass = (message[offset + 2] << 8) | message[offset + 3];
@@ -543,10 +544,12 @@ int attribute_hidden __decode_question(const unsigned char * const message, int
#endif
#ifdef L_lengthq
+/* Returns -1 only if message == NULL */
int attribute_hidden __length_question(const unsigned char * const message, int offset)
{
int i;
+ /* returns -1 only if message == NULL */
i = __length_dotted(message, offset);
if (i < 0)
return i;
@@ -807,11 +810,15 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
/* nsip is really __nameserver[] which is a global that
needs to hold __resolv_lock before access!! */
dns = nsip[local_ns];
-/* TODO: all future accesses to 'dns' are guarded by __resolv_lock too.
+/* TODO: all future accesses to 'dns' were guarded by __resolv_lock too.
* Why? We already fetched nsip[local_ns] here,
* future changes to nsip[] by other threads cannot affect us.
* We can use 'dns' without locking. If I'm wrong,
- * please explain in comments why locking is needed. */
+ * please explain in comments why locking is needed.
+ * One thing that worries me is - what if __close_nameservers() free()s
+ * dns under us? __resolv_lock'ing around accesses to dns won't help either,
+ * as free() might occur between accesses!
+ */
if (variant >= 0) {
if (variant < __searchdomains) {
strncat(lookup, ".", MAXDNAME);
@@ -821,7 +828,7 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
DPRINTF("lookup name: %s\n", lookup);
- q.dotted = (char *)lookup;
+ q.dotted = lookup;
q.qtype = type;
q.qclass = C_IN; /* CLASS_IN */
@@ -835,11 +842,11 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
retries+1, NAMESERVER_PORT, dns);
#ifdef __UCLIBC_HAS_IPV6__
- __UCLIBC_MUTEX_LOCK(__resolv_lock);
- /* 'dns' is really __nameserver[] which is a global that
- needs to hold __resolv_lock before access!! */
+ //__UCLIBC_MUTEX_LOCK(__resolv_lock);
+ ///* 'dns' is really __nameserver[] which is a global that
+ // needs to hold __resolv_lock before access!! */
v6 = inet_pton(AF_INET6, dns, &sa6.sin6_addr) > 0;
- __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
+ //__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
fd = socket(v6 ? AF_INET6 : AF_INET, SOCK_DGRAM, IPPROTO_UDP);
#else
fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
@@ -861,11 +868,11 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
#ifdef __UCLIBC_HAS_IPV4__
sa.sin_family = AF_INET;
sa.sin_port = htons(NAMESERVER_PORT);
- __UCLIBC_MUTEX_LOCK(__resolv_lock);
- /* 'dns' is really __nameserver[] which is a global that
- needs to hold __resolv_lock before access!! */
+ //__UCLIBC_MUTEX_LOCK(__resolv_lock);
+ ///* 'dns' is really __nameserver[] which is a global that
+ // needs to hold __resolv_lock before access!! */
sa.sin_addr.s_addr = inet_addr(dns);
- __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
+ //__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
rc = connect(fd, (struct sockaddr *) &sa, sizeof(sa));
#endif
#ifdef __UCLIBC_HAS_IPV6__
@@ -912,7 +919,7 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
len = recv(fd, packet, PACKETSZ, 0);
if (len < HFIXEDSZ) {
- /* too short ! */
+ /* too short! */
goto again;
}
@@ -925,25 +932,36 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
goto again;
}
- DPRINTF("Got response %s\n", "(i think)!");
+ DPRINTF("Got response (i think)!\n");
DPRINTF("qrcount=%d,ancount=%d,nscount=%d,arcount=%d\n",
h.qdcount, h.ancount, h.nscount, h.arcount);
DPRINTF("opcode=%d,aa=%d,tc=%d,rd=%d,ra=%d,rcode=%d\n",
h.opcode, h.aa, h.tc, h.rd, h.ra, h.rcode);
- if ((h.rcode) || (h.ancount < 1)) {
- /* negative result, not present */
+ if (h.rcode == NXDOMAIN) {
+// bug 660 says we treat negative response as an error and retry
+// which is, eh, an error. :) We were incurring long delays because of this.
+ /* this is not an error - don't goto again! */
+ h_errno = HOST_NOT_FOUND;
+ goto fail1;
+ }
+ if (h.rcode != 0) /* error */
goto again;
+ /* code below won't work correctly with h.ancount == 0, so... */
+ if (h.ancount < 1) {
+ h_errno = NO_DATA; /* is this correct code? */
+ goto fail1;
}
pos = HFIXEDSZ;
for (j = 0; j < h.qdcount; j++) {
DPRINTF("Skipping question %d at %d\n", j, pos);
+ /* returns -1 only if packet == NULL (can't happen) */
i = __length_question(packet, pos);
+ //if (i < 0)
+ // goto again;
DPRINTF("Length of question %d is %d\n", j, i);
- if (i < 0)
- goto again;
pos += i;
}
DPRINTF("Decoding answer at pos %d\n", pos);
@@ -1044,11 +1062,12 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
}
fail:
+ h_errno = NETDB_INTERNAL;
+ fail1:
if (fd != -1)
close(fd);
free(lookup);
free(packet);
- h_errno = NETDB_INTERNAL;
/* Mess with globals while under lock */
if (local_ns != -1) {
__UCLIBC_MUTEX_LOCK(mylock);
@@ -1107,7 +1126,8 @@ void attribute_hidden __open_nameservers(void)
if (strcmp(argv[0], "nameserver") == 0) {
for (i = 1; i < argc && __nameservers < MAX_SERVERS; i++) {
- __nameserver[__nameservers++] = strdup(argv[i]); /* TODO: what if this fails? */
+// TODO: what if strdup fails?
+ __nameserver[__nameservers++] = strdup(argv[i]);
DPRINTF("adding nameserver %s\n", argv[i]);
}
}
@@ -1119,7 +1139,8 @@ void attribute_hidden __open_nameservers(void)
__searchdomain[__searchdomains] = NULL;
}
for (i = 1; i < argc && __searchdomains < MAX_SEARCH; i++) {
- __searchdomain[__searchdomains++] = strdup(argv[i]); /* TODO: what if this fails? */
+// TODO: what if strdup fails?
+ __searchdomain[__searchdomains++] = strdup(argv[i]);
DPRINTF("adding search %s\n", argv[i]);
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 15:45:00 +0000