src/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 EfficiOS Inc.
   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 <linux/kprobes.h>
  21 #include <trace/syscall.h>
  22 #include <asm/syscall.h>
  23 #include <wrapper/kallsyms.h>
  24
  25 #ifndef CONFIG_FTRACE_SYSCALLS
  26 #error "You need to set CONFIG_FTRACE_SYSCALLS=y"
  27 #endif
  28
  29 #ifndef CONFIG_KALLSYMS_ALL
  30 #error "You need to set CONFIG_KALLSYMS_ALL=y"
  31 #endif
  32
  33 /*
  34  * The 'ident' parameter is prepended to each printk line to help
  35  * extract the proper lines from dmesg.
  36  */
  37 static char *ident = "";
  38 module_param(ident, charp, 0);
  39
  40 static struct syscall_metadata **__start_syscalls_metadata;
  41 static struct syscall_metadata **__stop_syscalls_metadata;
  42
  43 static __init
  44 struct syscall_metadata *find_syscall_meta(unsigned long syscall)
  45 {
  46         struct syscall_metadata **iter;
  47
  48         for (iter = __start_syscalls_metadata;
  49                         iter < __stop_syscalls_metadata; iter++) {
  50                 if ((*iter)->syscall_nr == syscall)
  51                         return (*iter);
  52         }
  53         return NULL;
  54 }
  55
  56 int init_module(void)
  57 {
  58         struct syscall_metadata *meta;
  59         int i;
  60
  61         __start_syscalls_metadata = (void *) wrapper_kallsyms_lookup_name("__start_syscalls_metadata");
  62         __stop_syscalls_metadata = (void *) wrapper_kallsyms_lookup_name("__stop_syscalls_metadata");
  63
  64         printk("%s---START---\n", ident);
  65         for (i = 0; i < NR_syscalls; i++) {
  66                 int j;
  67
  68                 meta = find_syscall_meta(i);
  69                 if (!meta)
  70                         continue;
  71                 printk("%ssyscall %s nr %d nbargs %d ",
  72                         ident, meta->name, meta->syscall_nr, meta->nb_args);
  73                 printk(KERN_CONT "types: (");
  74                 for (j = 0; j < meta->nb_args; j++) {
  75                         if (j > 0)
  76                                 printk(KERN_CONT ", ");
  77                         printk(KERN_CONT "%s", meta->types[j]);
  78                 }
  79                 printk(KERN_CONT ") ");
  80                 printk(KERN_CONT "args: (");
  81                 for (j = 0; j < meta->nb_args; j++) {
  82                         if (j > 0)
  83                                 printk(KERN_CONT ", ");
  84                         printk(KERN_CONT "%s", meta->args[j]);
  85                 }
  86                 printk(KERN_CONT ")\n");
  87         }
  88         printk("%s---END---\n", ident);
  89
  90         /*
  91          * This module always fails to load.
  92          */
  93         return -1;
  94 }
  95
  96 void cleanup_module(void)
  97 {
  98 }
  99
 100 MODULE_LICENSE("GPL");