LU-11566 utils: fix lctl llog_print for large configs

[fs/lustre-release.git] / lustre / obdclass / obd_config.c

diff --git a/lustre/obdclass/obd_config.c b/lustre/obdclass/obd_config.c
index 869e64c..61625ff 100644 (file)
--- a/lustre/obdclass/obd_config.c
+++ b/lustre/obdclass/obd_config.c
@@ -1944,11 +1944,11 @@ static struct lcfg_type_data *lcfg_cmd2data(__u32 cmd)
  */
 int class_config_yaml_output(struct llog_rec_hdr *rec, char *buf, int size)
 {
-       struct lustre_cfg       *lcfg = (struct lustre_cfg *)(rec + 1);
-       char                    *ptr = buf;
-       char                    *end = buf + size;
-       int                      rc = 0, i;
-       struct lcfg_type_data   *ldata;
+       struct lustre_cfg *lcfg = (struct lustre_cfg *)(rec + 1);
+       char *ptr = buf;
+       char *end = buf + size;
+       int rc = 0, i;
+       struct lcfg_type_data *ldata;
 
        LASSERT(rec->lrh_type == OBD_CFG_REC);
        rc = lustre_cfg_sanity_check(lcfg, rec->lrh_len);
@@ -1965,24 +1965,37 @@ int class_config_yaml_output(struct llog_rec_hdr *rec, char *buf, int size)
        /* form YAML entity */
        ptr += snprintf(ptr, end - ptr, "- { index: %u, event: %s",
                        rec->lrh_index, ldata->ltd_name);
+       if (end - ptr <= 0)
+               goto out_overflow;
 
-       if (lcfg->lcfg_flags)
+       if (lcfg->lcfg_flags) {
                ptr += snprintf(ptr, end - ptr, ", flags: %#08x",
                                lcfg->lcfg_flags);
-       if (lcfg->lcfg_num)
+               if (end - ptr <= 0)
+                       goto out_overflow;
+       }
+       if (lcfg->lcfg_num) {
                ptr += snprintf(ptr, end - ptr, ", num: %#08x",
                                lcfg->lcfg_num);
+               if (end - ptr <= 0)
+                       goto out_overflow;
+       }
        if (lcfg->lcfg_nid) {
                char nidstr[LNET_NIDSTR_SIZE];
 
                libcfs_nid2str_r(lcfg->lcfg_nid, nidstr, sizeof(nidstr));
                ptr += snprintf(ptr, end - ptr, ", nid: %s(%#llx)",
                                nidstr, lcfg->lcfg_nid);
+               if (end - ptr <= 0)
+                       goto out_overflow;
        }
 
-       if (LUSTRE_CFG_BUFLEN(lcfg, 0) > 0)
+       if (LUSTRE_CFG_BUFLEN(lcfg, 0) > 0) {
                ptr += snprintf(ptr, end - ptr, ", device: %s",
                                lustre_cfg_string(lcfg, 0));
+               if (end - ptr <= 0)
+                       goto out_overflow;
+       }
 
        if (lcfg->lcfg_command == LCFG_SET_PARAM) {
                /*
@@ -1995,7 +2008,7 @@ int class_config_yaml_output(struct llog_rec_hdr *rec, char *buf, int size)
                size_t len;
 
                if (tmp == NULL)
-                       return -ENOTTY;
+                       goto out_done;
 
                ptr += snprintf(ptr, end - ptr, ", %s: ", ldata->ltd_bufs[0]);
                len = tmp - cfg_str + 1;
@@ -2009,16 +2022,25 @@ int class_config_yaml_output(struct llog_rec_hdr *rec, char *buf, int size)
        }
 
        for (i = 1; i < lcfg->lcfg_bufcount; i++) {
-               if (LUSTRE_CFG_BUFLEN(lcfg, i) > 0)
+               if (LUSTRE_CFG_BUFLEN(lcfg, i) > 0) {
                        ptr += snprintf(ptr, end - ptr, ", %s: %s",
                                        ldata->ltd_bufs[i - 1],
                                        lustre_cfg_string(lcfg, i));
+                       if (end - ptr <= 0)
+                               goto out_overflow;
+               }
        }
 
 out_done:
        ptr += snprintf(ptr, end - ptr, " }\n");
-       /* return consumed bytes */
+out_overflow:
+       /* Return consumed bytes.  If the buffer overflowed, zero last byte */
        rc = ptr - buf;
+       if (rc > size) {
+               rc = -EOVERFLOW;
+               *(end - 1) = '\0';
+       }
+
        return rc;
 }