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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_probe.c

Version: ~ [ linux-5.12-rc1 ] ~ [ linux-5.11.2 ] ~ [ linux-5.10.19 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.101 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.177 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.222 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.258 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.258 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * Common code for probe-based Dynamic events.
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 as
  6  * published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  * GNU General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public License
 14  * along with this program; if not, write to the Free Software
 15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 16  *
 17  * This code was copied from kernel/trace/trace_kprobe.c written by
 18  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 19  *
 20  * Updates to make this generic:
 21  * Copyright (C) IBM Corporation, 2010-2011
 22  * Author:     Srikar Dronamraju
 23  */
 24 
 25 #include "trace_probe.h"
 26 
 27 const char *reserved_field_names[] = {
 28         "common_type",
 29         "common_flags",
 30         "common_preempt_count",
 31         "common_pid",
 32         "common_tgid",
 33         FIELD_STRING_IP,
 34         FIELD_STRING_RETIP,
 35         FIELD_STRING_FUNC,
 36 };
 37 
 38 /* Printing  in basic type function template */
 39 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt)                         \
 40 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 41                                 void *data, void *ent)                  \
 42 {                                                                       \
 43         trace_seq_printf(s, " %s=" fmt, name, *(type *)data);           \
 44         return !trace_seq_has_overflowed(s);                            \
 45 }                                                                       \
 46 const char PRINT_TYPE_FMT_NAME(type)[] = fmt;                           \
 47 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
 48 
 49 DEFINE_BASIC_PRINT_TYPE_FUNC(u8 , "0x%x")
 50 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "0x%x")
 51 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "0x%x")
 52 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "0x%Lx")
 53 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  "%d")
 54 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d")
 55 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%d")
 56 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%Ld")
 57 
 58 /* Print type function for string type */
 59 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
 60                                  void *data, void *ent)
 61 {
 62         int len = *(u32 *)data >> 16;
 63 
 64         if (!len)
 65                 trace_seq_printf(s, " %s=(fault)", name);
 66         else
 67                 trace_seq_printf(s, " %s=\"%s\"", name,
 68                                  (const char *)get_loc_data(data, ent));
 69         return !trace_seq_has_overflowed(s);
 70 }
 71 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
 72 
 73 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
 74 
 75 #define CHECK_FETCH_FUNCS(method, fn)                   \
 76         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
 77           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
 78           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
 79           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
 80           (FETCH_FUNC_NAME(method, string) == fn) ||    \
 81           (FETCH_FUNC_NAME(method, string_size) == fn)) \
 82          && (fn != NULL))
 83 
 84 /* Data fetch function templates */
 85 #define DEFINE_FETCH_reg(type)                                          \
 86 void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
 87 {                                                                       \
 88         *(type *)dest = (type)regs_get_register(regs,                   \
 89                                 (unsigned int)((unsigned long)offset)); \
 90 }                                                                       \
 91 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
 92 DEFINE_BASIC_FETCH_FUNCS(reg)
 93 /* No string on the register */
 94 #define fetch_reg_string        NULL
 95 #define fetch_reg_string_size   NULL
 96 
 97 #define DEFINE_FETCH_retval(type)                                       \
 98 void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,                \
 99                                    void *dummy, void *dest)             \
100 {                                                                       \
101         *(type *)dest = (type)regs_return_value(regs);                  \
102 }                                                                       \
103 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
104 DEFINE_BASIC_FETCH_FUNCS(retval)
105 /* No string on the retval */
106 #define fetch_retval_string             NULL
107 #define fetch_retval_string_size        NULL
108 
109 /* Dereference memory access function */
110 struct deref_fetch_param {
111         struct fetch_param      orig;
112         long                    offset;
113         fetch_func_t            fetch;
114         fetch_func_t            fetch_size;
115 };
116 
117 #define DEFINE_FETCH_deref(type)                                        \
118 void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,                 \
119                                   void *data, void *dest)               \
120 {                                                                       \
121         struct deref_fetch_param *dprm = data;                          \
122         unsigned long addr;                                             \
123         call_fetch(&dprm->orig, regs, &addr);                           \
124         if (addr) {                                                     \
125                 addr += dprm->offset;                                   \
126                 dprm->fetch(regs, (void *)addr, dest);                  \
127         } else                                                          \
128                 *(type *)dest = 0;                                      \
129 }                                                                       \
130 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
131 DEFINE_BASIC_FETCH_FUNCS(deref)
132 DEFINE_FETCH_deref(string)
133 
134 void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
135                                          void *data, void *dest)
136 {
137         struct deref_fetch_param *dprm = data;
138         unsigned long addr;
139 
140         call_fetch(&dprm->orig, regs, &addr);
141         if (addr && dprm->fetch_size) {
142                 addr += dprm->offset;
143                 dprm->fetch_size(regs, (void *)addr, dest);
144         } else
145                 *(string_size *)dest = 0;
146 }
147 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
148 
149 static void update_deref_fetch_param(struct deref_fetch_param *data)
150 {
151         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
152                 update_deref_fetch_param(data->orig.data);
153         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
154                 update_symbol_cache(data->orig.data);
155 }
156 NOKPROBE_SYMBOL(update_deref_fetch_param);
157 
158 static void free_deref_fetch_param(struct deref_fetch_param *data)
159 {
160         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
161                 free_deref_fetch_param(data->orig.data);
162         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
163                 free_symbol_cache(data->orig.data);
164         kfree(data);
165 }
166 NOKPROBE_SYMBOL(free_deref_fetch_param);
167 
168 /* Bitfield fetch function */
169 struct bitfield_fetch_param {
170         struct fetch_param      orig;
171         unsigned char           hi_shift;
172         unsigned char           low_shift;
173 };
174 
175 #define DEFINE_FETCH_bitfield(type)                                     \
176 void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,              \
177                                      void *data, void *dest)            \
178 {                                                                       \
179         struct bitfield_fetch_param *bprm = data;                       \
180         type buf = 0;                                                   \
181         call_fetch(&bprm->orig, regs, &buf);                            \
182         if (buf) {                                                      \
183                 buf <<= bprm->hi_shift;                                 \
184                 buf >>= bprm->low_shift;                                \
185         }                                                               \
186         *(type *)dest = buf;                                            \
187 }                                                                       \
188 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
189 DEFINE_BASIC_FETCH_FUNCS(bitfield)
190 #define fetch_bitfield_string           NULL
191 #define fetch_bitfield_string_size      NULL
192 
193 static void
194 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
195 {
196         /*
197          * Don't check the bitfield itself, because this must be the
198          * last fetch function.
199          */
200         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
201                 update_deref_fetch_param(data->orig.data);
202         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
203                 update_symbol_cache(data->orig.data);
204 }
205 
206 static void
207 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
208 {
209         /*
210          * Don't check the bitfield itself, because this must be the
211          * last fetch function.
212          */
213         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
214                 free_deref_fetch_param(data->orig.data);
215         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
216                 free_symbol_cache(data->orig.data);
217 
218         kfree(data);
219 }
220 
221 static const struct fetch_type *find_fetch_type(const char *type,
222                                                 const struct fetch_type *ftbl)
223 {
224         int i;
225 
226         if (!type)
227                 type = DEFAULT_FETCH_TYPE_STR;
228 
229         /* Special case: bitfield */
230         if (*type == 'b') {
231                 unsigned long bs;
232 
233                 type = strchr(type, '/');
234                 if (!type)
235                         goto fail;
236 
237                 type++;
238                 if (kstrtoul(type, 0, &bs))
239                         goto fail;
240 
241                 switch (bs) {
242                 case 8:
243                         return find_fetch_type("u8", ftbl);
244                 case 16:
245                         return find_fetch_type("u16", ftbl);
246                 case 32:
247                         return find_fetch_type("u32", ftbl);
248                 case 64:
249                         return find_fetch_type("u64", ftbl);
250                 default:
251                         goto fail;
252                 }
253         }
254 
255         for (i = 0; ftbl[i].name; i++) {
256                 if (strcmp(type, ftbl[i].name) == 0)
257                         return &ftbl[i];
258         }
259 
260 fail:
261         return NULL;
262 }
263 
264 /* Special function : only accept unsigned long */
265 static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
266 {
267         *(unsigned long *)dest = kernel_stack_pointer(regs);
268 }
269 NOKPROBE_SYMBOL(fetch_kernel_stack_address);
270 
271 static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
272 {
273         *(unsigned long *)dest = user_stack_pointer(regs);
274 }
275 NOKPROBE_SYMBOL(fetch_user_stack_address);
276 
277 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
278                                             fetch_func_t orig_fn,
279                                             const struct fetch_type *ftbl)
280 {
281         int i;
282 
283         if (type != &ftbl[FETCH_TYPE_STRING])
284                 return NULL;    /* Only string type needs size function */
285 
286         for (i = 0; i < FETCH_MTD_END; i++)
287                 if (type->fetch[i] == orig_fn)
288                         return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
289 
290         WARN_ON(1);     /* This should not happen */
291 
292         return NULL;
293 }
294 
295 /* Split symbol and offset. */
296 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
297 {
298         char *tmp;
299         int ret;
300 
301         if (!offset)
302                 return -EINVAL;
303 
304         tmp = strchr(symbol, '+');
305         if (tmp) {
306                 /* skip sign because kstrtoul doesn't accept '+' */
307                 ret = kstrtoul(tmp + 1, 0, offset);
308                 if (ret)
309                         return ret;
310 
311                 *tmp = '\0';
312         } else
313                 *offset = 0;
314 
315         return 0;
316 }
317 
318 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
319 
320 static int parse_probe_vars(char *arg, const struct fetch_type *t,
321                             struct fetch_param *f, bool is_return,
322                             bool is_kprobe)
323 {
324         int ret = 0;
325         unsigned long param;
326 
327         if (strcmp(arg, "retval") == 0) {
328                 if (is_return)
329                         f->fn = t->fetch[FETCH_MTD_retval];
330                 else
331                         ret = -EINVAL;
332         } else if (strncmp(arg, "stack", 5) == 0) {
333                 if (arg[5] == '\0') {
334                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
335                                 return -EINVAL;
336 
337                         if (is_kprobe)
338                                 f->fn = fetch_kernel_stack_address;
339                         else
340                                 f->fn = fetch_user_stack_address;
341                 } else if (isdigit(arg[5])) {
342                         ret = kstrtoul(arg + 5, 10, &param);
343                         if (ret || (is_kprobe && param > PARAM_MAX_STACK))
344                                 ret = -EINVAL;
345                         else {
346                                 f->fn = t->fetch[FETCH_MTD_stack];
347                                 f->data = (void *)param;
348                         }
349                 } else
350                         ret = -EINVAL;
351         } else
352                 ret = -EINVAL;
353 
354         return ret;
355 }
356 
357 /* Recursive argument parser */
358 static int parse_probe_arg(char *arg, const struct fetch_type *t,
359                      struct fetch_param *f, bool is_return, bool is_kprobe)
360 {
361         const struct fetch_type *ftbl;
362         unsigned long param;
363         long offset;
364         char *tmp;
365         int ret = 0;
366 
367         ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
368         BUG_ON(ftbl == NULL);
369 
370         switch (arg[0]) {
371         case '$':
372                 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
373                 break;
374 
375         case '%':       /* named register */
376                 ret = regs_query_register_offset(arg + 1);
377                 if (ret >= 0) {
378                         f->fn = t->fetch[FETCH_MTD_reg];
379                         f->data = (void *)(unsigned long)ret;
380                         ret = 0;
381                 }
382                 break;
383 
384         case '@':       /* memory, file-offset or symbol */
385                 if (isdigit(arg[1])) {
386                         ret = kstrtoul(arg + 1, 0, &param);
387                         if (ret)
388                                 break;
389 
390                         f->fn = t->fetch[FETCH_MTD_memory];
391                         f->data = (void *)param;
392                 } else if (arg[1] == '+') {
393                         /* kprobes don't support file offsets */
394                         if (is_kprobe)
395                                 return -EINVAL;
396 
397                         ret = kstrtol(arg + 2, 0, &offset);
398                         if (ret)
399                                 break;
400 
401                         f->fn = t->fetch[FETCH_MTD_file_offset];
402                         f->data = (void *)offset;
403                 } else {
404                         /* uprobes don't support symbols */
405                         if (!is_kprobe)
406                                 return -EINVAL;
407 
408                         ret = traceprobe_split_symbol_offset(arg + 1, &offset);
409                         if (ret)
410                                 break;
411 
412                         f->data = alloc_symbol_cache(arg + 1, offset);
413                         if (f->data)
414                                 f->fn = t->fetch[FETCH_MTD_symbol];
415                 }
416                 break;
417 
418         case '+':       /* deref memory */
419                 arg++;  /* Skip '+', because kstrtol() rejects it. */
420         case '-':
421                 tmp = strchr(arg, '(');
422                 if (!tmp)
423                         break;
424 
425                 *tmp = '\0';
426                 ret = kstrtol(arg, 0, &offset);
427 
428                 if (ret)
429                         break;
430 
431                 arg = tmp + 1;
432                 tmp = strrchr(arg, ')');
433 
434                 if (tmp) {
435                         struct deref_fetch_param        *dprm;
436                         const struct fetch_type         *t2;
437 
438                         t2 = find_fetch_type(NULL, ftbl);
439                         *tmp = '\0';
440                         dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
441 
442                         if (!dprm)
443                                 return -ENOMEM;
444 
445                         dprm->offset = offset;
446                         dprm->fetch = t->fetch[FETCH_MTD_memory];
447                         dprm->fetch_size = get_fetch_size_function(t,
448                                                         dprm->fetch, ftbl);
449                         ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
450                                                         is_kprobe);
451                         if (ret)
452                                 kfree(dprm);
453                         else {
454                                 f->fn = t->fetch[FETCH_MTD_deref];
455                                 f->data = (void *)dprm;
456                         }
457                 }
458                 break;
459         }
460         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
461                 pr_info("%s type has no corresponding fetch method.\n", t->name);
462                 ret = -EINVAL;
463         }
464 
465         return ret;
466 }
467 
468 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
469 
470 /* Bitfield type needs to be parsed into a fetch function */
471 static int __parse_bitfield_probe_arg(const char *bf,
472                                       const struct fetch_type *t,
473                                       struct fetch_param *f)
474 {
475         struct bitfield_fetch_param *bprm;
476         unsigned long bw, bo;
477         char *tail;
478 
479         if (*bf != 'b')
480                 return 0;
481 
482         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
483         if (!bprm)
484                 return -ENOMEM;
485 
486         bprm->orig = *f;
487         f->fn = t->fetch[FETCH_MTD_bitfield];
488         f->data = (void *)bprm;
489         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
490 
491         if (bw == 0 || *tail != '@')
492                 return -EINVAL;
493 
494         bf = tail + 1;
495         bo = simple_strtoul(bf, &tail, 0);
496 
497         if (tail == bf || *tail != '/')
498                 return -EINVAL;
499 
500         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
501         bprm->low_shift = bprm->hi_shift + bo;
502 
503         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
504 }
505 
506 /* String length checking wrapper */
507 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
508                 struct probe_arg *parg, bool is_return, bool is_kprobe)
509 {
510         const struct fetch_type *ftbl;
511         const char *t;
512         int ret;
513 
514         ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
515         BUG_ON(ftbl == NULL);
516 
517         if (strlen(arg) > MAX_ARGSTR_LEN) {
518                 pr_info("Argument is too long.: %s\n",  arg);
519                 return -ENOSPC;
520         }
521         parg->comm = kstrdup(arg, GFP_KERNEL);
522         if (!parg->comm) {
523                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
524                 return -ENOMEM;
525         }
526         t = strchr(parg->comm, ':');
527         if (t) {
528                 arg[t - parg->comm] = '\0';
529                 t++;
530         }
531         parg->type = find_fetch_type(t, ftbl);
532         if (!parg->type) {
533                 pr_info("Unsupported type: %s\n", t);
534                 return -EINVAL;
535         }
536         parg->offset = *size;
537         *size += parg->type->size;
538         ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
539 
540         if (ret >= 0 && t != NULL)
541                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
542 
543         if (ret >= 0) {
544                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
545                                                               parg->fetch.fn,
546                                                               ftbl);
547                 parg->fetch_size.data = parg->fetch.data;
548         }
549 
550         return ret;
551 }
552 
553 /* Return 1 if name is reserved or already used by another argument */
554 int traceprobe_conflict_field_name(const char *name,
555                                struct probe_arg *args, int narg)
556 {
557         int i;
558 
559         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
560                 if (strcmp(reserved_field_names[i], name) == 0)
561                         return 1;
562 
563         for (i = 0; i < narg; i++)
564                 if (strcmp(args[i].name, name) == 0)
565                         return 1;
566 
567         return 0;
568 }
569 
570 void traceprobe_update_arg(struct probe_arg *arg)
571 {
572         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
573                 update_bitfield_fetch_param(arg->fetch.data);
574         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
575                 update_deref_fetch_param(arg->fetch.data);
576         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
577                 update_symbol_cache(arg->fetch.data);
578 }
579 
580 void traceprobe_free_probe_arg(struct probe_arg *arg)
581 {
582         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
583                 free_bitfield_fetch_param(arg->fetch.data);
584         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
585                 free_deref_fetch_param(arg->fetch.data);
586         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
587                 free_symbol_cache(arg->fetch.data);
588 
589         kfree(arg->name);
590         kfree(arg->comm);
591 }
592 
593 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
594 {
595         char **argv;
596         int argc, ret;
597 
598         argc = 0;
599         ret = 0;
600         argv = argv_split(GFP_KERNEL, buf, &argc);
601         if (!argv)
602                 return -ENOMEM;
603 
604         if (argc)
605                 ret = createfn(argc, argv);
606 
607         argv_free(argv);
608 
609         return ret;
610 }
611 
612 #define WRITE_BUFSIZE  4096
613 
614 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
615                                 size_t count, loff_t *ppos,
616                                 int (*createfn)(int, char **))
617 {
618         char *kbuf, *tmp;
619         int ret = 0;
620         size_t done = 0;
621         size_t size;
622 
623         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
624         if (!kbuf)
625                 return -ENOMEM;
626 
627         while (done < count) {
628                 size = count - done;
629 
630                 if (size >= WRITE_BUFSIZE)
631                         size = WRITE_BUFSIZE - 1;
632 
633                 if (copy_from_user(kbuf, buffer + done, size)) {
634                         ret = -EFAULT;
635                         goto out;
636                 }
637                 kbuf[size] = '\0';
638                 tmp = strchr(kbuf, '\n');
639 
640                 if (tmp) {
641                         *tmp = '\0';
642                         size = tmp - kbuf + 1;
643                 } else if (done + size < count) {
644                         pr_warning("Line length is too long: "
645                                    "Should be less than %d.", WRITE_BUFSIZE);
646                         ret = -EINVAL;
647                         goto out;
648                 }
649                 done += size;
650                 /* Remove comments */
651                 tmp = strchr(kbuf, '#');
652 
653                 if (tmp)
654                         *tmp = '\0';
655 
656                 ret = traceprobe_command(kbuf, createfn);
657                 if (ret)
658                         goto out;
659         }
660         ret = done;
661 
662 out:
663         kfree(kbuf);
664 
665         return ret;
666 }
667 
668 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
669                            bool is_return)
670 {
671         int i;
672         int pos = 0;
673 
674         const char *fmt, *arg;
675 
676         if (!is_return) {
677                 fmt = "(%lx)";
678                 arg = "REC->" FIELD_STRING_IP;
679         } else {
680                 fmt = "(%lx <- %lx)";
681                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
682         }
683 
684         /* When len=0, we just calculate the needed length */
685 #define LEN_OR_ZERO (len ? len - pos : 0)
686 
687         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
688 
689         for (i = 0; i < tp->nr_args; i++) {
690                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
691                                 tp->args[i].name, tp->args[i].type->fmt);
692         }
693 
694         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
695 
696         for (i = 0; i < tp->nr_args; i++) {
697                 if (strcmp(tp->args[i].type->name, "string") == 0)
698                         pos += snprintf(buf + pos, LEN_OR_ZERO,
699                                         ", __get_str(%s)",
700                                         tp->args[i].name);
701                 else
702                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
703                                         tp->args[i].name);
704         }
705 
706 #undef LEN_OR_ZERO
707 
708         /* return the length of print_fmt */
709         return pos;
710 }
711 
712 int set_print_fmt(struct trace_probe *tp, bool is_return)
713 {
714         int len;
715         char *print_fmt;
716 
717         /* First: called with 0 length to calculate the needed length */
718         len = __set_print_fmt(tp, NULL, 0, is_return);
719         print_fmt = kmalloc(len + 1, GFP_KERNEL);
720         if (!print_fmt)
721                 return -ENOMEM;
722 
723         /* Second: actually write the @print_fmt */
724         __set_print_fmt(tp, print_fmt, len + 1, is_return);
725         tp->call.print_fmt = print_fmt;
726 
727         return 0;
728 }
729 

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