Add a ckpt_read_string() function to allow reading of a variable-length (but length-capped) string from the checkpoint stream.
Changes in v3: - Return immediately on allocation failure instead of falling through to the inevitable crash Changes in v2: - Avoid memcpy() by reading into the allocated buffer directly Signed-off-by: Dan Smith <[email protected]> --- checkpoint/restart.c | 36 ++++++++++++++++++++++++++++++++++++ include/linux/checkpoint.h | 1 + 2 files changed, 37 insertions(+), 0 deletions(-) diff --git a/checkpoint/restart.c b/checkpoint/restart.c index 65cafd9..b1ffc54 100644 --- a/checkpoint/restart.c +++ b/checkpoint/restart.c @@ -285,6 +285,42 @@ int ckpt_read_consume(struct ckpt_ctx *ctx, int len, int type) return ret; } +/** + * ckpt_read_string - read a string (variable length) + * @ctx: checkpoint context + * @str: pointer to buffer to store allocated string (caller must kfree()) + * @max: maximum acceptable length + * + * This can be used to read a variable-length string from the checkpoint + * stream. @max limits the size of the resulting buffer. Returns zero on + * success, negative on failure. + */ +int ckpt_read_string(struct ckpt_ctx *ctx, char **str, int max) +{ + int len; + int ret = 0; + + *str = NULL; + + len = _ckpt_read_obj_type(ctx, NULL, 0, CKPT_HDR_STRING); + if (len < 0) + return len; + else if (len > max) + return -EINVAL; + + *str = kzalloc(len + 1, GFP_KERNEL); + if (!*str) + return -ENOMEM; + + ret = ckpt_kread(ctx, *str, len); + if (ret < 0) { + kfree(*str); + *str = NULL; + } + + return ret; +} + /*********************************************************************** * Restart */ diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h index 87b683b..a6935b3 100644 --- a/include/linux/checkpoint.h +++ b/include/linux/checkpoint.h @@ -68,6 +68,7 @@ extern int _ckpt_read_obj_type(struct ckpt_ctx *ctx, extern int _ckpt_read_nbuffer(struct ckpt_ctx *ctx, void *ptr, int len); extern int _ckpt_read_buffer(struct ckpt_ctx *ctx, void *ptr, int len); extern int _ckpt_read_string(struct ckpt_ctx *ctx, void *ptr, int len); +extern int ckpt_read_string(struct ckpt_ctx *ctx, char **str, int max); extern void *ckpt_read_obj_type(struct ckpt_ctx *ctx, int len, int type); extern void *ckpt_read_buf_type(struct ckpt_ctx *ctx, int len, int type); extern int ckpt_read_consume(struct ckpt_ctx *ctx, int len, int type); -- 1.6.0.4 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
