[PATCH v2 2/4] Parse resolv.conf with new lineread implementation

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 2283 bytes --]

Switch the resolv.conf parsing in conf.c to use the new lineread
implementation.  This means that it can now handle a resolv.conf file which
contains blank lines.

There are quite a few other fragilities with the resolv.conf parsing, but
that's out of scope for this patch.

Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
 conf.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/conf.c b/conf.c
index 3a5d650..22949fd 100644
--- a/conf.c
+++ b/conf.c
@@ -38,6 +38,7 @@
 #include "udp.h"
 #include "tcp.h"
 #include "pasta.h"
+#include "lineread.h"
 
 /**
  * get_bound_ports() - Get maps of ports with bound sockets
@@ -320,7 +321,9 @@ static void get_dns(struct ctx *c)
 	struct in6_addr *dns6 = &c->dns6[0];
 	struct fqdn *s = c->dns_search;
 	uint32_t *dns4 = &c->dns4[0];
-	char buf[BUFSIZ], *p, *end;
+	struct lineread resolvconf;
+	int line_len;
+	char *line, *p, *end;
 
 	dns4_set = !c->v4  || !!*dns4;
 	dns6_set = !c->v6  || !IN6_IS_ADDR_UNSPECIFIED(dns6);
@@ -333,13 +336,14 @@ static void get_dns(struct ctx *c)
 	if ((fd = open("/etc/resolv.conf", O_RDONLY | O_CLOEXEC)) < 0)
 		goto out;
 
-	for (*buf = 0; line_read(buf, BUFSIZ, fd); *buf = 0) {
-		if (!dns_set && strstr(buf, "nameserver ") == buf) {
-			p = strrchr(buf, ' ');
+	lineread_init(&resolvconf, fd);
+	while ((line_len = lineread_get(&resolvconf, &line)) > 0) {
+		if (!dns_set && strstr(line, "nameserver ") == line) {
+			p = strrchr(line, ' ');
 			if (!p)
 				continue;
 
-			end = strpbrk(buf, "%\n");
+			end = strpbrk(line, "%\n");
 			if (end)
 				*end = 0;
 
@@ -356,13 +360,13 @@ static void get_dns(struct ctx *c)
 				dns6++;
 				memset(dns6, 0, sizeof(*dns6));
 			}
-		} else if (!dnss_set && strstr(buf, "search ") == buf &&
+		} else if (!dnss_set && strstr(line, "search ") == line &&
 			   s == c->dns_search) {
-			end = strpbrk(buf, "\n");
+			end = strpbrk(line, "\n");
 			if (end)
 				*end = 0;
 
-			if (!strtok(buf, " \t"))
+			if (!strtok(line, " \t"))
 				continue;
 
 			while (s - c->dns_search < ARRAY_SIZE(c->dns_search) - 1
@@ -374,6 +378,8 @@ static void get_dns(struct ctx *c)
 		}
 	}
 
+	if (line_len < 0)
+		warn("Error reading /etc/resolv.conf: %s", strerror(errno));
 	close(fd);
 
 out:
-- 
@@ -38,6 +38,7 @@
 #include "udp.h"
 #include "tcp.h"
 #include "pasta.h"
+#include "lineread.h"
 
 /**
  * get_bound_ports() - Get maps of ports with bound sockets
@@ -320,7 +321,9 @@ static void get_dns(struct ctx *c)
 	struct in6_addr *dns6 = &c->dns6[0];
 	struct fqdn *s = c->dns_search;
 	uint32_t *dns4 = &c->dns4[0];
-	char buf[BUFSIZ], *p, *end;
+	struct lineread resolvconf;
+	int line_len;
+	char *line, *p, *end;
 
 	dns4_set = !c->v4  || !!*dns4;
 	dns6_set = !c->v6  || !IN6_IS_ADDR_UNSPECIFIED(dns6);
@@ -333,13 +336,14 @@ static void get_dns(struct ctx *c)
 	if ((fd = open("/etc/resolv.conf", O_RDONLY | O_CLOEXEC)) < 0)
 		goto out;
 
-	for (*buf = 0; line_read(buf, BUFSIZ, fd); *buf = 0) {
-		if (!dns_set && strstr(buf, "nameserver ") == buf) {
-			p = strrchr(buf, ' ');
+	lineread_init(&resolvconf, fd);
+	while ((line_len = lineread_get(&resolvconf, &line)) > 0) {
+		if (!dns_set && strstr(line, "nameserver ") == line) {
+			p = strrchr(line, ' ');
 			if (!p)
 				continue;
 
-			end = strpbrk(buf, "%\n");
+			end = strpbrk(line, "%\n");
 			if (end)
 				*end = 0;
 
@@ -356,13 +360,13 @@ static void get_dns(struct ctx *c)
 				dns6++;
 				memset(dns6, 0, sizeof(*dns6));
 			}
-		} else if (!dnss_set && strstr(buf, "search ") == buf &&
+		} else if (!dnss_set && strstr(line, "search ") == line &&
 			   s == c->dns_search) {
-			end = strpbrk(buf, "\n");
+			end = strpbrk(line, "\n");
 			if (end)
 				*end = 0;
 
-			if (!strtok(buf, " \t"))
+			if (!strtok(line, " \t"))
 				continue;
 
 			while (s - c->dns_search < ARRAY_SIZE(c->dns_search) - 1
@@ -374,6 +378,8 @@ static void get_dns(struct ctx *c)
 		}
 	}
 
+	if (line_len < 0)
+		warn("Error reading /etc/resolv.conf: %s", strerror(errno));
 	close(fd);
 
 out:
-- 
2.36.1