include/instrumentation/syscalls/lttng-syscalls-extractor/lttng-syscalls-extractor.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-syscalls-extractor.c
   4  *
   5  * Dump syscall metadata to console.
   6  *
   7  * Copyright 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  * Copyright 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/list.h>
  15 #include <linux/err.h>
  16 #include <linux/slab.h>
  17 #include <linux/kallsyms.h>
  18 #include <linux/dcache.h>
  19 #include <linux/trace_events.h>
  20 #include <trace/syscall.h>
  21 #include <asm/syscall.h>
  22
  23 #ifndef CONFIG_FTRACE_SYSCALLS
  24 #error "You need to set CONFIG_FTRACE_SYSCALLS=y"
  25 #endif
  26
  27 #ifndef CONFIG_KALLSYMS_ALL
  28 #error "You need to set CONFIG_KALLSYMS_ALL=y"
  29 #endif
  30
  31 /*
  32  * The 'ident' parameter is prepended to each printk line to help
  33  * extract the proper lines from dmesg.
  34  */
  35 static char *ident = "";
  36 module_param(ident, charp, 0);
  37
  38 static struct syscall_metadata **__start_syscalls_metadata;
  39 static struct syscall_metadata **__stop_syscalls_metadata;
  40
  41 static __init
  42 struct syscall_metadata *find_syscall_meta(unsigned long syscall)
  43 {
  44         struct syscall_metadata **iter;
  45
  46         for (iter = __start_syscalls_metadata;
  47                         iter < __stop_syscalls_metadata; iter++) {
  48                 if ((*iter)->syscall_nr == syscall)
  49                         return (*iter);
  50         }
  51         return NULL;
  52 }
  53
  54 int init_module(void)
  55 {
  56         struct syscall_metadata *meta;
  57         int i;
  58
  59         __start_syscalls_metadata = (void *) kallsyms_lookup_name("__start_syscalls_metadata");
  60         __stop_syscalls_metadata = (void *) kallsyms_lookup_name("__stop_syscalls_metadata");
  61
  62         printk("%s---START---\n", ident);
  63         for (i = 0; i < NR_syscalls; i++) {
  64                 int j;
  65
  66                 meta = find_syscall_meta(i);
  67                 if (!meta)
  68                         continue;
  69                 printk("%ssyscall %s nr %d nbargs %d ",
  70                         ident, meta->name, meta->syscall_nr, meta->nb_args);
  71                 printk(KERN_CONT "types: (");
  72                 for (j = 0; j < meta->nb_args; j++) {
  73                         if (j > 0)
  74                                 printk(KERN_CONT ", ");
  75                         printk(KERN_CONT "%s", meta->types[j]);
  76                 }
  77                 printk(KERN_CONT ") ");
  78                 printk(KERN_CONT "args: (");
  79                 for (j = 0; j < meta->nb_args; j++) {
  80                         if (j > 0)
  81                                 printk(KERN_CONT ", ");
  82                         printk(KERN_CONT "%s", meta->args[j]);
  83                 }
  84                 printk(KERN_CONT ")\n");
  85         }
  86         printk("%s---END---\n", ident);
  87
  88         /*
  89          * This module always fails to load.
  90          */
  91         return -1;
  92 }
  93
  94 void cleanup_module(void)
  95 {
  96 }
  97
  98 MODULE_LICENSE("GPL");