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-rw-r--r--src/network/lookup.h11
-rw-r--r--src/network/res_msend.c82
-rw-r--r--src/network/resolvconf.c93
3 files changed, 126 insertions, 60 deletions
diff --git a/src/network/lookup.h b/src/network/lookup.h
index 69419115..0468edbc 100644
--- a/src/network/lookup.h
+++ b/src/network/lookup.h
@@ -2,6 +2,7 @@
 #define LOOKUP_H
 
 #include <stdint.h>
+#include <stddef.h>
 
 struct address {
 	int family;
@@ -15,6 +16,14 @@ struct service {
 	unsigned char proto, socktype;
 };
 
+#define MAXNS 3
+
+struct resolvconf {
+	struct address ns[MAXNS];
+	unsigned nns, attempts, ndots;
+	unsigned timeout;
+};
+
 /* The limit of 48 results is a non-sharp bound on the number of addresses
  * that can fit in one 512-byte DNS packet full of v4 results and a second
  * packet full of v6 results. Due to headers, the actual limit is lower. */
@@ -25,4 +34,6 @@ int __lookup_serv(struct service buf[static MAXSERVS], const char *name, int pro
 int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags);
 int __lookup_ipliteral(struct address buf[static 1], const char *name, int family);
 
+int __get_resolv_conf(struct resolvconf *, char *, size_t);
+
 #endif
diff --git a/src/network/res_msend.c b/src/network/res_msend.c
index d0e8e481..0ee914d4 100644
--- a/src/network/res_msend.c
+++ b/src/network/res_msend.c
@@ -31,14 +31,11 @@ int __res_msend(int nqueries, const unsigned char *const *queries,
 	const int *qlens, unsigned char *const *answers, int *alens, int asize)
 {
 	int fd;
-	FILE *f, _f;
-	unsigned char _buf[256];
-	char line[64], *s, *z;
-	int timeout = 5000, attempts = 2, retry_interval, servfail_retry;
+	int timeout, attempts, retry_interval, servfail_retry;
 	union {
 		struct sockaddr_in sin;
 		struct sockaddr_in6 sin6;
-	} sa = {0}, ns[3] = {{0}};
+	} sa = {0}, ns[MAXNS] = {{0}};
 	socklen_t sl = sizeof sa.sin;
 	int nns = 0;
 	int family = AF_INET;
@@ -48,65 +45,30 @@ int __res_msend(int nqueries, const unsigned char *const *queries,
 	int cs;
 	struct pollfd pfd;
 	unsigned long t0, t1, t2;
-	struct address iplit;
+	struct resolvconf conf;
 
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 
-	/* Get nameservers from resolv.conf, fallback to localhost */
-	f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
-	if (!f) switch (errno) {
-	case ENOENT:
-	case ENOTDIR:
-	case EACCES:
-		goto no_resolv_conf;
-	default:
-		return -1;
-	}
-	for (nns=0; nns<3 && fgets(line, sizeof line, f); ) {
-		if (!strncmp(line, "options", 7) && isspace(line[7])) {
-			unsigned long x;
-			char *p, *z;
-			p = strstr(line, "timeout:");
-			if (p && isdigit(p[8])) {
-				p += 8;
-				x = strtoul(p, &z, 10);
-				if (z != p) timeout = x < 30 ? x*1000 : 30000;
-			}
-			p = strstr(line, "attempts:");
-			if (p && isdigit(p[9])) {
-				p += 9;
-				x = strtoul(p, &z, 10);
-				if (z != p) attempts = x < 10 ? x : 10;
-				if (!attempts) attempts = 1;
-			}
+	/* Get nameservers & timeout/retry settings from resolv.conf */
+	if (__get_resolv_conf(&conf, 0, 0) < 0) return -1;
+
+	timeout = 1000*conf.timeout;
+	attempts = conf.attempts;
+
+	nns = conf.nns;
+	for (nns=0; nns<conf.nns; nns++) {
+		struct address *iplit = &conf.ns[nns];
+		if (iplit->family == AF_INET) {
+			memcpy(&ns[nns].sin.sin_addr, iplit->addr, 4);
+			ns[nns].sin.sin_port = htons(53);
+			ns[nns].sin.sin_family = AF_INET;
+		} else {
+			sl = sizeof sa.sin6;
+			memcpy(&ns[nns].sin6.sin6_addr, iplit->addr, 16);
+			ns[nns].sin6.sin6_port = htons(53);
+			ns[nns].sin6.sin6_scope_id = iplit->scopeid;
+			ns[nns].sin6.sin6_family = family = AF_INET6;
 		}
-		if (strncmp(line, "nameserver", 10) || !isspace(line[10]))
-			continue;
-		for (s=line+11; isspace(*s); s++);
-		for (z=s; *z && !isspace(*z); z++);
-		*z=0;
-
-		if (__lookup_ipliteral(&iplit, s, AF_UNSPEC)>0) {
-			if (iplit.family == AF_INET) {
-				memcpy(&ns[nns].sin.sin_addr, iplit.addr, 4);
-				ns[nns].sin.sin_port = htons(53);
-				ns[nns++].sin.sin_family = AF_INET;
-			} else {
-				sl = sizeof sa.sin6;
-				memcpy(&ns[nns].sin6.sin6_addr, iplit.addr, 16);
-				ns[nns].sin6.sin6_port = htons(53);
-				ns[nns].sin6.sin6_scope_id = iplit.scopeid;
-				ns[nns++].sin6.sin6_family = family = AF_INET6;
-			}
-		}
-	}
-	__fclose_ca(f);
-no_resolv_conf:
-	if (!nns) {
-		ns[0].sin.sin_family = AF_INET;
-		ns[0].sin.sin_port = htons(53);
-		ns[0].sin.sin_addr.s_addr = htonl(0x7f000001);
-		nns=1;
 	}
 
 	/* Get local address and open/bind a socket */
diff --git a/src/network/resolvconf.c b/src/network/resolvconf.c
new file mode 100644
index 00000000..0743a88f
--- /dev/null
+++ b/src/network/resolvconf.c
@@ -0,0 +1,93 @@
+#include "lookup.h"
+#include "stdio_impl.h"
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+#include <netinet/in.h>
+
+int __get_resolv_conf(struct resolvconf *conf, char *search, size_t search_sz)
+{
+	char line[256];
+	unsigned char _buf[256];
+	FILE *f, _f;
+	int nns;
+
+	conf->ndots = 1;
+	conf->timeout = 5;
+	conf->attempts = 2;
+	if (search) *search = 0;
+
+	f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
+	if (!f) switch (errno) {
+	case ENOENT:
+	case ENOTDIR:
+	case EACCES:
+		goto no_resolv_conf;
+	default:
+		return -1;
+	}
+
+	while (fgets(line, sizeof line, f)) {
+		char *p, *z;
+		if (!strchr(line, '\n') && !feof(f)) {
+			/* Ignore lines that get truncated rather than
+			 * potentially misinterpreting them. */
+			int c;
+			do c = getc(f);
+			while (c != '\n' && c != EOF);
+			continue;
+		}
+		if (!strncmp(line, "options", 7) && isspace(line[7])) {
+			p = strstr(line, "ndots:");
+			if (p && isdigit(p[6])) {
+				p += 6;
+				unsigned long x = strtoul(p, &z, 10);
+				if (z != p) conf->ndots = x > 15 ? 15 : x;
+			}
+			p = strstr(line, "attempts:");
+			if (p && isdigit(p[6])) {
+				p += 6;
+				unsigned long x = strtoul(p, &z, 10);
+				if (z != p) conf->attempts = x > 10 ? 10 : x;
+			}
+			p = strstr(line, "timeout:");
+			if (p && (isdigit(p[8]) || p[8]=='.')) {
+				p += 8;
+				unsigned long x = strtoul(p, &z, 10);
+				if (z != p) conf->timeout = x > 60 ? 60 : x;
+			}
+			continue;
+		}
+		if (!strncmp(line, "nameserver", 10) && isspace(line[10])) {
+			if (nns >= MAXNS) continue;
+			for (p=line+11; isspace(*p); p++);
+			for (z=p; *z && !isspace(*z); z++);
+			*z=0;
+			if (__lookup_ipliteral(conf->ns+nns, p, AF_UNSPEC) > 0)
+				nns++;
+			continue;
+		}
+
+		if (!search) continue;
+		if (strncmp(line, "domain", 6) || strncmp(line, "search", 6)
+		    || !isspace(line[6]))
+			continue;
+		for (p=line+7; isspace(*p); p++);
+		size_t l = strlen(p);
+		/* This can never happen anyway with chosen buffer sizes. */
+		if (l >= search_sz) continue;
+		memcpy(search, p, l+1);
+	}
+
+	__fclose_ca(f);
+
+no_resolv_conf:
+	if (!nns) {
+		__lookup_ipliteral(conf->ns, "127.0.0.1", AF_UNSPEC);
+		nns = 1;
+	}
+
+	conf->nns = nns;
+
+	return 0;
+}
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-05 16:49:44 +0000