[PATCH iproute2] nstat: fix load_ugly_table() limits

[PATCH iproute2] nstat: fix load_ugly_table() limits

[Eric Dumazet]

A recent change reduced max line length from 4096 to 2048 bytes,
but we already have lines above the 2048 threshold, and we keep
adding more SNMP counters in linux.

Switch to getline() and do not worry about future kernel changes.

Fixes: da8034a01904 ("misc: avoid snprintf warnings in ss and nstat")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 misc/nstat.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/misc/nstat.c b/misc/nstat.c
index 88f1c7698243235b12f58cd067afce488af1be4c..653580eae0603327ea654510ae1f23a79578c1fe 100644
--- a/misc/nstat.c
+++ b/misc/nstat.c
@@ -177,11 +177,13 @@ static int count_spaces(const char *line)
 
 static void load_ugly_table(FILE *fp)
 {
-	char buf[2048];
+	char *buf = NULL;
+	size_t buflen = 0;
+	ssize_t nread;
 	struct nstat_ent *db = NULL;
 	struct nstat_ent *n;
 
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while ((nread = getline(&buf, &buflen, fp)) != -1) {
 		char idbuf[4096];
 		int  off;
 		char *p;
@@ -218,7 +220,8 @@ static void load_ugly_table(FILE *fp)
 			p = next;
 		}
 		n = db;
-		if (fgets(buf, sizeof(buf), fp) == NULL)
+		nread = getline(&buf, &buflen, fp);
+		if (nread == -1)
 			abort();
 		count2 = count_spaces(buf);
 		if (count2 > count1)
@@ -237,6 +240,7 @@ static void load_ugly_table(FILE *fp)
 				n = n->next;
 		} while (p > buf + off + 2);
 	}
+	free(buf);
 
 	while (db) {
 		n = db;
-- 
2.20.1.415.g653613c723-goog

Re: [PATCH iproute2] nstat: fix load_ugly_table() limits

[Stephen Hemminger]

On Fri, 21 Dec 2018 22:53:35 -0800
Eric Dumazet <edumazet@google.com> wrote:

> A recent change reduced max line length from 4096 to 2048 bytes,
> but we already have lines above the 2048 threshold, and we keep
> adding more SNMP counters in linux.
> 
> Switch to getline() and do not worry about future kernel changes.
> 
> Fixes: da8034a01904 ("misc: avoid snprintf warnings in ss and nstat")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Sure, applied.