nfs_lseek{,_async}: allow negative offsets and guard against file positions < 0

[deb_libnfs.git] / lib / libnfs.c

diff --git a/lib/libnfs.c b/lib/libnfs.c
index 9053ab1884992ff7b01287d8c5ac655c90e4fc6e..5ea3280fe6c1071cb3b0af0a6187214fa2d2f478 100644 (file)
--- a/lib/libnfs.c
+++ b/lib/libnfs.c
@@ -3034,7 +3034,7 @@ void nfs_getcwd(struct nfs_context *nfs, const char **cwd)
 struct lseek_cb_data {
        struct nfs_context *nfs;
        struct nfsfh *nfsfh;
-       uint64_t offset;
+       int64_t offset;
        nfs_cb cb;
        void *private_data;
 };
@@ -3044,6 +3044,7 @@ static void nfs_lseek_1_cb(struct rpc_context *rpc, int status, void *command_da
        GETATTR3res *res;
        struct lseek_cb_data *data = private_data;
        struct nfs_context *nfs = data->nfs;
+       uint64_t size = 0;
 
        assert(rpc->magic == RPC_CONTEXT_MAGIC);
 
@@ -3066,24 +3067,41 @@ static void nfs_lseek_1_cb(struct rpc_context *rpc, int status, void *command_da
                return;
        }
 
-       data->nfsfh->offset = data->offset + res->GETATTR3res_u.resok.obj_attributes.size;
-       data->cb(0, nfs, &data->nfsfh->offset, data->private_data);
+       size = res->GETATTR3res_u.resok.obj_attributes.size;
+
+       if (data->offset < 0 &&
+           (uint64_t)(-data->offset) > size) {
+               data->cb(-EINVAL, nfs, &data->nfsfh->offset, data->private_data);
+       } else {
+               data->nfsfh->offset = data->offset + size;
+               data->cb(0, nfs, &data->nfsfh->offset, data->private_data);
+       }
+
        free(data);
 }
 
-int nfs_lseek_async(struct nfs_context *nfs, struct nfsfh *nfsfh, uint64_t offset, int whence, nfs_cb cb, void *private_data)
+int nfs_lseek_async(struct nfs_context *nfs, struct nfsfh *nfsfh, int64_t offset, int whence, nfs_cb cb, void *private_data)
 {
        struct lseek_cb_data *data;
        struct GETATTR3args args;
 
        if (whence == SEEK_SET) {
-               nfsfh->offset = offset;
-               cb(0, nfs, &nfsfh->offset, private_data);
+               if (offset < 0) {
+                       cb(-EINVAL, nfs, &nfsfh->offset, private_data);
+               } else {
+                       nfsfh->offset = offset;
+                       cb(0, nfs, &nfsfh->offset, private_data);
+               }
                return 0;
        }
        if (whence == SEEK_CUR) {
-               nfsfh->offset += offset;
-               cb(0, nfs, &nfsfh->offset, private_data);
+               if (offset < 0 &&
+                   nfsfh->offset < (uint64_t)(-offset)) {
+                       cb(-EINVAL, nfs, &nfsfh->offset, private_data);
+               } else {
+                       nfsfh->offset += offset;
+                       cb(0, nfs, &nfsfh->offset, private_data);
+               }
                return 0;
        }