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Steven Rostedt 011ea0501d tracing: Display some syscall arrays as strings
Some of the system calls that read a fixed length of memory from the user
space address are not arrays but strings. Take a bit away from the nb_args
field in the syscall meta data to use as a flag to denote that the system
call's user_arg_size is being used as a string. The nb_args should never
be more than 6, so 7 bits is plenty to hold that number. When the
user_arg_is_str flag that, when set, will display the data array from the
user space address as a string and not an array.

This will allow the output to look like this:

  sys_sethostname(name: 0x5584310eb2a0 "debian", len: 6)

Cc: Masami Hiramatsu <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Takaya Saeki <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Douglas Raillard <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Steven Rostedt (Google) <[email protected]>
2025-10-28 20:10:58 -04:00

58 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _TRACE_SYSCALL_H
#define _TRACE_SYSCALL_H
#include <linux/tracepoint.h>
#include <linux/unistd.h>
#include <linux/trace_events.h>
#include <linux/thread_info.h>
#include <asm/ptrace.h>
/*
* A syscall entry in the ftrace syscalls array.
*
* @name: name of the syscall
* @syscall_nr: number of the syscall
* @nb_args: number of parameters it takes
* @user_arg_is_str: set if the arg for @user_arg_size is a string
* @user_arg_size: holds @arg that has size of the user space to read
* @user_mask: mask of @args that will read user space
* @types: list of types as strings
* @args: list of args as strings (args[i] matches types[i])
* @enter_fields: list of fields for syscall_enter trace event
* @enter_event: associated syscall_enter trace event
* @exit_event: associated syscall_exit trace event
*/
struct syscall_metadata {
const char *name;
int syscall_nr;
u8 nb_args:7;
u8 user_arg_is_str:1;
s8 user_arg_size;
short user_mask;
const char **types;
const char **args;
struct list_head enter_fields;
struct trace_event_call *enter_event;
struct trace_event_call *exit_event;
};
#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS)
static inline void syscall_tracepoint_update(struct task_struct *p)
{
if (test_syscall_work(SYSCALL_TRACEPOINT))
set_task_syscall_work(p, SYSCALL_TRACEPOINT);
else
clear_task_syscall_work(p, SYSCALL_TRACEPOINT);
}
#else
static inline void syscall_tracepoint_update(struct task_struct *p)
{
}
#endif
#endif /* _TRACE_SYSCALL_H */