cgmanager get/set: clean up child (v2)

(Thanks, Dwight, this one look right?)

Make sure we reap our child at cgm_{s,g}et.

Changelog: Fix change in behavior on empty read from the do_cgm_get()
           helper that was spotted by Dwight.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dwight Engen <dwight.engen@oracle.com>

diff --git a/src/lxc/cgmanager.c b/src/lxc/cgmanager.c
index c4f48e9ac7b5f11be565b54a58ddd675c3f7ef0c..4db61c1c5db47f24b0423f4b6409108dd2272760 100644 (file)
--- a/src/lxc/cgmanager.c
+++ b/src/lxc/cgmanager.c
@@ -794,32 +794,38 @@ static int cgm_get(const char *filename, char *value, size_t len, const char *na
                close(p[1]);
                return -1;
        }
-       if (!pid)
+       if (!pid) // do_cgm_get exits
                do_cgm_get(name, lxcpath, filename, p[1], len && value);
        close(p[1]);
        ret = read(p[0], &newlen, sizeof(newlen));
        if (ret != sizeof(newlen)) {
                close(p[0]);
-               return -1;
+               ret = -1;
+               goto out;
        }
        if (!len || !value) {
                close(p[0]);
-               return newlen;
+               ret = newlen;
+               goto out;
        }
        memset(value, 0, len);
        if (newlen < 0) { // child is reporting an error
                close(p[0]);
-               return -1;
+               ret = -1;
+               goto out;
        }
        if (newlen == 0) { // empty read
                close(p[0]);
-               return 0;
+               ret = 0;
+               goto out;
        }
        readlen = newlen > len ? len : newlen;
        ret = read(p[0], value, readlen);
        close(p[0]);
-       if (ret != readlen)
-               return -1;
+       if (ret != readlen) {
+               ret = -1;
+               goto out;
+       }
        if (newlen >= len) {
                value[len-1] = '\0';
                newlen = len-1;
@@ -828,7 +834,11 @@ static int cgm_get(const char *filename, char *value, size_t len, const char *na
                value[newlen++] = '\n';
                value[newlen] = '\0';
        }
-       return newlen;
+       ret = newlen;
+out:
+       if (wait_for_pid(pid))
+               WARN("do_cgm_get exited with error");
+       return ret;
 }
 
 static void do_cgm_set(const char *name, const char *lxcpath, const char *filename, const char *value, int outp)
@@ -920,11 +930,13 @@ static int cgm_set(const char *filename, const char *value, const char *name, co
                close(p[0]);
                return -1;
        }
-       if (!pid)
+       if (!pid) // do_cgm_set exits
                do_cgm_set(name, lxcpath, filename, value, p[1]);
        close(p[1]);
        ret = read(p[0], &v, sizeof(v));
        close(p[0]);
+       if (wait_for_pid(pid))
+               WARN("do_cgm_set exited with error");
        if (ret != sizeof(v) || !v)
                return -1;
        return 0;