dns lookups: protect against cancellation and fix incorrect error codes

diff --git a/src/network/__dns.c b/src/network/__dns.c
index b53ad4a..b3c876f 100644 (file)
--- a/src/network/__dns.c
+++ b/src/network/__dns.c
@@ -11,6 +11,7 @@
 #include <time.h>
 #include <ctype.h>
 #include <unistd.h>
+#include <pthread.h>
 #include "__dns.h"
 #include "stdio_impl.h"
 
@@ -42,14 +43,15 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
        struct timeval tv;
        fd_set fds;
        int id;
+       int cs;
 
        /* Construct query template - RR and ID will be filled later */
-       if (strlen(name)-1 >= 254U) return -1;
+       if (strlen(name)-1 >= 254U) return EAI_NONAME;
        q[2] = q[5] = 1;
        strcpy((char *)q+13, name);
        for (i=13; q[i]; i=j+1) {
                for (j=i; q[j] && q[j] != '.'; j++);
-               if (j-i-1u > 62u) return -1;
+               if (j-i-1u > 62u) return EAI_NONAME;
                q[i-1] = j-i;
        }
        q[i+3] = 1;
@@ -80,12 +82,14 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
                sl = sizeof sa.sin;
        }
 
+       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
        /* Get local address and open/bind a socket */
        sa.sin.sin_family = family;
        fd = socket(family, SOCK_DGRAM, 0);
        if (bind(fd, (void *)&sa, sl) < 0) {
-               close(fd);
-               return -1;
+               errcode = EAI_SYSTEM;
+               goto out;
        }
        /* Nonblocking to work around Linux UDP select bug */
        fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
@@ -140,7 +144,9 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
                /* Check to see if we have answers to all queries */
                if (got+failed == rrcnt) break;
        }
+out:
        close(fd);
+       pthread_setcancelstate(cs, 0);
 
        /* Return the number of results, or an error code if none */
        if (got) return got;