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make dns lookups (and thus getaddrinfo) cancellable

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This commit is contained in:
Rich Felker 2011-09-21 23:27:17 -04:00
commit 12d547b262
1 changed files with 11 additions and 4 deletions
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15
src/network/__dns.c
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@ -19,6 +19,11 @@
#define PACKET_MAX 512 #define PACKET_MAX 512
#define PTR_MAX (64 + sizeof ".in-addr.arpa") #define PTR_MAX (64 + sizeof ".in-addr.arpa")
static void cleanup(void *p)
{
close((intptr_t)p);
}
int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt) int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
{ {
time_t t0 = time(0); time_t t0 = time(0);
@ -44,6 +49,8 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
int id; int id;
int cs; int cs;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
/* Construct query template - RR and ID will be filled later */ /* Construct query template - RR and ID will be filled later */
if (strlen(name)-1 >= 254U) return EAI_NONAME; if (strlen(name)-1 >= 254U) return EAI_NONAME;
q[2] = q[5] = 1; q[2] = q[5] = 1;
@ -81,8 +88,6 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
sl = sizeof sa.sin; sl = sizeof sa.sin;
} }
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
/* Get local address and open/bind a socket */ /* Get local address and open/bind a socket */
sa.sin.sin_family = family; sa.sin.sin_family = family;
fd = socket(family, SOCK_DGRAM, 0); fd = socket(family, SOCK_DGRAM, 0);
@ -96,6 +101,9 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
pfd.fd = fd; pfd.fd = fd;
pfd.events = POLLIN; pfd.events = POLLIN;
pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
pthread_setcancelstate(cs, 0);
/* Loop until we timeout; break early on success */ /* Loop until we timeout; break early on success */
for (; time(0)-t0 < TIMEOUT; ) { for (; time(0)-t0 < TIMEOUT; ) {
@ -143,8 +151,7 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
if (got+failed == rrcnt) break; if (got+failed == rrcnt) break;
} }
out: out:
close(fd); pthread_cleanup_pop(1);
pthread_setcancelstate(cs, 0);
/* Return the number of results, or an error code if none */ /* Return the number of results, or an error code if none */
if (got) return got; if (got) return got;