[lxc-devel] [lxcfs/master] bugfixes

[brauner on Github]

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From 352980a760536c0b59ae225991739cfb5cf83e64 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at mailbox.org>
Date: Mon, 25 Apr 2016 13:42:45 +0200
Subject: [PATCH] bugfixes

- fix do_mount_cgroups(): it previously returned ret uninitialized on failure
- snprintf() returns -1 on error so let's use ssize_t whenever possible
- use additional ssize_t variable to catch snprintf() error for swap
  calculation

Signed-off-by: Christian Brauner <christian.brauner at mailbox.org>
---
 bindings.c | 26 ++++++++++++++------------
 lxcfs.c    |  2 +-
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/bindings.c b/bindings.c
index 5393cdc..a90d808 100644
--- a/bindings.c
+++ b/bindings.c
@@ -2865,7 +2865,7 @@ static int read_file(const char *path, char *buf, size_t size,
 		return 0;
 
 	while (getline(&line, &linelen, f) != -1) {
-		size_t l = snprintf(cache, cache_size, "%s", line);
+		ssize_t l = snprintf(cache, cache_size, "%s", line);
 		if (l < 0) {
 			perror("Error writing to cache");
 			rv = 0;
@@ -3003,7 +3003,7 @@ static int proc_meminfo_read(char *buf, size_t size, off_t offset,
 		goto err;
 
 	while (getline(&line, &linelen, f) != -1) {
-		size_t l;
+		ssize_t l;
 		char *printme, lbuf[100];
 
 		memset(lbuf, 0, 100);
@@ -3158,7 +3158,7 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
 		goto err;
 
 	while (getline(&line, &linelen, f) != -1) {
-		size_t l;
+		ssize_t l;
 		if (firstline) {
 			firstline = false;
 			if (strstr(line, "IBM/S390") != NULL) {
@@ -3235,7 +3235,7 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
 
 	if (is_s390x) {
 		char *origcache = d->buf;
-		size_t l;
+		ssize_t l;
 		do {
 			d->buf = malloc(d->buflen);
 		} while (!d->buf);
@@ -3335,7 +3335,7 @@ static int proc_stat_read(char *buf, size_t size, off_t offset,
 	}
 
 	while (getline(&line, &linelen, f) != -1) {
-		size_t l;
+		ssize_t l;
 		int cpu;
 		char cpu_char[10]; /* That's a lot of cores */
 		char *c;
@@ -3507,7 +3507,7 @@ static int proc_uptime_read(char *buf, size_t size, off_t offset,
 	long int reaperage = getreaperage(fc->pid);
 	unsigned long int busytime = get_reaper_busy(fc->pid), idletime;
 	char *cache = d->buf;
-	size_t total_len = 0;
+	ssize_t total_len = 0;
 
 #if RELOADTEST
 	iwashere();
@@ -3602,7 +3602,7 @@ static int proc_diskstats_read(char *buf, size_t size, off_t offset,
 		goto err;
 
 	while (getline(&line, &linelen, f) != -1) {
-		size_t l;
+		ssize_t l;
 		char lbuf[256];
 
 		i = sscanf(line, "%u %u %71s", &major, &minor, dev_name);
@@ -3685,7 +3685,8 @@ static int proc_swaps_read(char *buf, size_t size, off_t offset,
 	char *memswlimit_str = NULL, *memlimit_str = NULL, *memusage_str = NULL, *memswusage_str = NULL,
              *memswlimit_default_str = NULL, *memswusage_default_str = NULL;
 	unsigned long memswlimit = 0, memlimit = 0, memusage = 0, memswusage = 0, swap_total = 0, swap_free = 0;
-	size_t total_len = 0, rv = 0;
+	ssize_t total_len = 0, rv = 0;
+	ssize_t l = 0;
 	char *cache = d->buf;
 
 	if (offset) {
@@ -3761,12 +3762,13 @@ static int proc_swaps_read(char *buf, size_t size, off_t offset,
 	}
 
 	if (swap_total > 0) {
-		total_len += snprintf(d->buf + total_len, d->size - total_len,
-				 "none%*svirtual\t\t%lu\t%lu\t0\n", 36, " ",
-				 swap_total, swap_free);
+		l = snprintf(d->buf + total_len, d->size - total_len,
+				"none%*svirtual\t\t%lu\t%lu\t0\n", 36, " ",
+				swap_total, swap_free);
+		total_len += l;
 	}
 
-	if (total_len < 0) {
+	if (total_len < 0 || l < 0) {
 		perror("Error writing to cache");
 		rv = 0;
 		goto err;
diff --git a/lxcfs.c b/lxcfs.c
index 6f37052..7455267 100644
--- a/lxcfs.c
+++ b/lxcfs.c
@@ -836,7 +836,7 @@ static bool do_mount_cgroup(char *controller)
 
 static bool do_mount_cgroups(void)
 {
-	bool ret;
+	bool ret = false;
 	FILE *f;
 	char *line = NULL;
 	size_t len = 0;