On 11.12.21 07:39, Yafang Shao wrote:
> A new macro TASK_COMM_LEN_16 is introduced for the old hard-coded 16 to
> make it more grepable. As explained above this marco, the difference
> between TASK_COMM_LEN and TASK_COMM_LEN_16 is that TASK_COMM_LEN_16 must
> be a fixed size 16 and can't be changed.
>
> Suggested-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx>
> Cc: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
> Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> Cc: Michal Miroslaw <mirq-linux@xxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> ---
> include/linux/elfcore-compat.h | 8 ++------
> include/linux/elfcore.h | 9 ++-------
> include/linux/sched.h | 5 +++++
> 3 files changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
> index 54feb64e9b5d..69fa1a728964 100644
> --- a/include/linux/elfcore-compat.h
> +++ b/include/linux/elfcore-compat.h
> @@ -5,6 +5,7 @@
> #include <linux/elf.h>
> #include <linux/elfcore.h>
> #include <linux/compat.h>
> +#include <linux/sched.h>
>
> /*
> * Make sure these layouts match the linux/elfcore.h native definitions.
> @@ -43,12 +44,7 @@ struct compat_elf_prpsinfo
> __compat_uid_t pr_uid;
> __compat_gid_t pr_gid;
> compat_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
> - /*
> - * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be
> - * changed as it is exposed to userspace. We'd better make it hard-coded
> - * here.
> - */
> - char pr_fname[16];
> + char pr_fname[TASK_COMM_LEN_16];
> char pr_psargs[ELF_PRARGSZ];
> };
>
> diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
> index 746e081879a5..d3bb4bd3c985 100644
> --- a/include/linux/elfcore.h
> +++ b/include/linux/elfcore.h
> @@ -65,13 +65,8 @@ struct elf_prpsinfo
> __kernel_gid_t pr_gid;
> pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
> /* Lots missing */
> - /*
> - * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be
> - * changed as it is exposed to userspace. We'd better make it hard-coded
> - * here.
> - */
> - char pr_fname[16]; /* filename of executable */
> - char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
> + char pr_fname[TASK_COMM_LEN_16]; /* filename of executable */
> + char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
> };
>
> static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index c79bd7ee6029..8d963a50a2a8 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -279,6 +279,11 @@ struct task_group;
> * BPF programs.
> */
> enum {
> + /*
> + * For the old hard-coded 16, which is exposed to userspace and can't
> + * be changed.
> + */
> + TASK_COMM_LEN_16 = 16,
> TASK_COMM_LEN = 16,
> };
>
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
