1 files changed, 93 insertions, 0 deletions
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;
+}