udebug: add more checks for uninitialized buffers

Simplifies and fixes error handling

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/udebug.c b/udebug.c
index 16beefda3d2942ee5481331f26715148ec4f82e7..0d8d0d42474ac5acad8d560d8578a2fc87a43617 100644 (file)
--- a/udebug.c
+++ b/udebug.c
@@ -460,11 +460,11 @@ int udebug_buf_init(struct udebug_buf *buf, size_t entries, size_t size)
        buf->head_size = head_size;
        buf->data_size = size;
        buf->ring_size = entries;
-       buf->fd = fd;
 
        if (__udebug_buf_map(buf))
                goto err_close;
 
+       buf->fd = fd;
        buf->hdr->ring_size = entries;
        buf->hdr->data_size = size;
 
@@ -545,8 +545,12 @@ void *udebug_entry_append(struct udebug_buf *buf, const void *data, uint32_t len
 uint16_t udebug_entry_trim(struct udebug_buf *buf, uint16_t len)
 {
        struct udebug_hdr *hdr = buf->hdr;
-       struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
+       struct udebug_ptr *ptr;
+
+       if (!hdr)
+               return 0;
 
+       ptr = udebug_ring_ptr(hdr, hdr->head);
        if (len)
                ptr->len -= len;
 
@@ -556,8 +560,12 @@ uint16_t udebug_entry_trim(struct udebug_buf *buf, uint16_t len)
 void udebug_entry_set_length(struct udebug_buf *buf, uint16_t len)
 {
        struct udebug_hdr *hdr = buf->hdr;
-       struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
+       struct udebug_ptr *ptr;
+
+       if (!hdr)
+               return;
 
+       ptr = udebug_ring_ptr(hdr, hdr->head);
        ptr->len = len;
 }
 
@@ -608,10 +616,15 @@ out:
 void udebug_entry_add(struct udebug_buf *buf)
 {
        struct udebug_hdr *hdr = buf->hdr;
-       struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
+       struct udebug_ptr *ptr;
        uint32_t notify;
        uint8_t *data;
 
+       if (!hdr)
+               return;
+
+       ptr = udebug_ring_ptr(hdr, hdr->head);
+
        /* ensure strings are always 0-terminated */
        data = udebug_buf_ptr(buf, ptr->start + ptr->len);
        *data = 0;
@@ -685,6 +698,9 @@ __udebug_buf_add(struct udebug *ctx, struct udebug_buf *buf)
 int udebug_buf_add(struct udebug *ctx, struct udebug_buf *buf,
                   const struct udebug_buf_meta *meta)
 {
+       if (!buf->hdr)
+               return -1;
+
        list_add_tail(&buf->list, &ctx->local_rings);
        buf->ctx = ctx;
        buf->meta = meta;