Fix 'zpool history' sometimes fails without reporting any error

The corresponding function 'zpool_get_history' in libzfs would printing
an error messages only when the ioctl call failed.

Add missing error reporting, specifically memory allocation failures
and error from 'zpool_history_unpack'.

Also avoid possibly reading of uninitialized 'err' variable in case
the requested offset pasts EOF.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Damian Szuberski <szuberskidamian@gmail.com>
Signed-off-by: WHR <msl0000023508@gmail.com>
Issue #13322
Closes #13320

diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index a923995f2722e3477221b0b449187d0abd796610..cd7062a88c86d057fb20baadd5b0d391c98c3114 100644 (file)
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -4439,17 +4439,17 @@ int
 zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp, uint64_t *off,
     boolean_t *eof)
 {
+       libzfs_handle_t *hdl = zhp->zpool_hdl;
        char *buf;
        int buflen = 128 * 1024;
        nvlist_t **records = NULL;
        uint_t numrecords = 0;
-       int err, i;
+       int err = 0, i;
        uint64_t start = *off;
 
-       buf = malloc(buflen);
-       if (buf == NULL)
-               return (ENOMEM);
-       /* process about 1MB a time */
+       buf = zfs_alloc(hdl, buflen);
+
+       /* process about 1MiB a time */
        while (*off - start < 1024 * 1024) {
                uint64_t bytes_read = buflen;
                uint64_t leftover;
@@ -4464,8 +4464,12 @@ zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp, uint64_t *off,
                }
 
                if ((err = zpool_history_unpack(buf, bytes_read,
-                   &leftover, &records, &numrecords)) != 0)
+                   &leftover, &records, &numrecords)) != 0) {
+                       zpool_standard_error_fmt(hdl, err,
+                           dgettext(TEXT_DOMAIN,
+                           "cannot get history for '%s'"), zhp->zpool_name);
                        break;
+               }
                *off -= leftover;
                if (leftover == bytes_read) {
                        /*
@@ -4474,9 +4478,7 @@ zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp, uint64_t *off,
                         */
                        buflen *= 2;
                        free(buf);
-                       buf = malloc(buflen);
-                       if (buf == NULL)
-                               return (ENOMEM);
+                       buf = zfs_alloc(hdl, buflen);
                }
        }