[PATCH v2] Decode paths associated with file descriptors returned by syscalls

[Dmitry V. Levin]

On Tue, Jun 03, 2014 at 09:02:39AM +0530, zubin.mithra at gmail.com wrote:
> From: Zubin Mithra <zubin.mithra at gmail.com>
> 
> * defs.h (RVAL_FD): New macro.
> * defs.h (RVAL_MASK, RVAL_STR, RVAL_NONE): Macro values modified.
> * desc.c (sys_dup): New function.
> * desc.c (sys_delete_module): New function.
> * desc.c (sys_open, sys_dup2, sys_dup3, sys_creat): Modified to return
>   RVAL_FD
> * linux/dummy.h (sys_delete_module, sys_dup): Macros removed
> * linux/syscall.h (sys_close, sys_delete_module, sys_dup): New prototype
> * syscall.c (trace_syscall_exiting): Modified to handle RVAL_FD return
>   value
> 
> Signed-off-by: Zubin Mithra <zubin.mithra at gmail.com>
> ---
>  defs.h          |  7 ++++---
>  desc.c          | 15 +++++++++++++--
>  file.c          |  8 +++++++-
>  linux/dummy.h   |  2 --
>  linux/syscall.h |  2 ++
>  syscall.c       |  8 ++++++++
>  6 files changed, 34 insertions(+), 8 deletions(-)
> 
> diff --git a/defs.h b/defs.h
> index c862de5..99493b3 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -533,10 +533,11 @@ extern const struct xlat whence_codes[];
>  # endif
>  # define RVAL_LUDECIMAL	007	/* long unsigned decimal format */
>  #endif
> -#define RVAL_MASK	007	/* mask for these values */
> +#define RVAL_FD 	010 	/* file descriptors */
> +#define RVAL_MASK	017	/* mask for these values */
>  
> -#define RVAL_STR	010	/* Print `auxstr' field after return val */
> -#define RVAL_NONE	020	/* Print nothing */
> +#define RVAL_STR	020	/* Print `auxstr' field after return val */
> +#define RVAL_NONE	040	/* Print nothing */
>  
>  #define TRACE_FILE	001	/* Trace file-related syscalls. */
>  #define TRACE_IPC	002	/* Trace IPC-related syscalls. */
> diff --git a/desc.c b/desc.c
> index 0c9a817..5bb1b21 100644
> --- a/desc.c
> +++ b/desc.c
> @@ -265,6 +265,15 @@ sys_close(struct tcb *tcp)
>  	return 0;
>  }
>  
> +int
> +sys_dup(struct tcb *tcp)
> +{
> +	if (entering(tcp)) {
> +		printfd(tcp, tcp->u_arg[0]);
> +	}
> +	return RVAL_FD;
> +}
> +
>  static int
>  do_dup2(struct tcb *tcp, int flags_arg)
>  {
> @@ -283,13 +292,15 @@ do_dup2(struct tcb *tcp, int flags_arg)
>  int
>  sys_dup2(struct tcb *tcp)
>  {
> -	return do_dup2(tcp, -1);
> +	do_dup2(tcp, -1);
> +	return RVAL_FD;
>  }
>  
>  int
>  sys_dup3(struct tcb *tcp)
>  {
> -	return do_dup2(tcp, 2);
> +	do_dup2(tcp, 2);
> +	return RVAL_FD;
>  }

I'd rather change do_dup2 to return RVAL_FD rather than change its users.

>  
>  #if defined(ALPHA)
> diff --git a/file.c b/file.c
> index c322242..92a5873 100644
> --- a/file.c
> +++ b/file.c
> @@ -309,6 +309,12 @@ decode_open(struct tcb *tcp, int offset)
>  int
>  sys_open(struct tcb *tcp)
>  {
> +	decode_open(tcp, 0);
> +	return RVAL_FD;
> +}
> +

Same here, lets change decode_open to return RVAL_FD instead.

> +int sys_delete_module(struct tcb *tcp)
> +{
>  	return decode_open(tcp, 0);
>  }

btw, it's not right for sys_delete_module to use decode_open,
but that's a subject for another patch.


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