GNU Linux-libre 4.9.306-gnu1
[releases.git] / kernel / trace / trace_probe.c
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(tname, type, fmt)                  \
40 int PRINT_TYPE_FUNC_NAME(tname)(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(tname)[] = fmt;                          \
47 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname));
48
49 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
56 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
57 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
58 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
59 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
60 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
61
62 /* Print type function for string type */
63 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
64                                  void *data, void *ent)
65 {
66         int len = *(u32 *)data >> 16;
67
68         if (!len)
69                 trace_seq_printf(s, " %s=(fault)", name);
70         else
71                 trace_seq_printf(s, " %s=\"%s\"", name,
72                                  (const char *)get_loc_data(data, ent));
73         return !trace_seq_has_overflowed(s);
74 }
75 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
76
77 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
78
79 #define CHECK_FETCH_FUNCS(method, fn)                   \
80         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
81           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
82           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
83           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
84           (FETCH_FUNC_NAME(method, string) == fn) ||    \
85           (FETCH_FUNC_NAME(method, string_size) == fn)) \
86          && (fn != NULL))
87
88 /* Data fetch function templates */
89 #define DEFINE_FETCH_reg(type)                                          \
90 void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
91 {                                                                       \
92         *(type *)dest = (type)regs_get_register(regs,                   \
93                                 (unsigned int)((unsigned long)offset)); \
94 }                                                                       \
95 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
96 DEFINE_BASIC_FETCH_FUNCS(reg)
97 /* No string on the register */
98 #define fetch_reg_string        NULL
99 #define fetch_reg_string_size   NULL
100
101 #define DEFINE_FETCH_retval(type)                                       \
102 void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,                \
103                                    void *dummy, void *dest)             \
104 {                                                                       \
105         *(type *)dest = (type)regs_return_value(regs);                  \
106 }                                                                       \
107 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
108 DEFINE_BASIC_FETCH_FUNCS(retval)
109 /* No string on the retval */
110 #define fetch_retval_string             NULL
111 #define fetch_retval_string_size        NULL
112
113 /* Dereference memory access function */
114 struct deref_fetch_param {
115         struct fetch_param      orig;
116         long                    offset;
117         fetch_func_t            fetch;
118         fetch_func_t            fetch_size;
119 };
120
121 #define DEFINE_FETCH_deref(type)                                        \
122 void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,                 \
123                                   void *data, void *dest)               \
124 {                                                                       \
125         struct deref_fetch_param *dprm = data;                          \
126         unsigned long addr;                                             \
127         call_fetch(&dprm->orig, regs, &addr);                           \
128         if (addr) {                                                     \
129                 addr += dprm->offset;                                   \
130                 dprm->fetch(regs, (void *)addr, dest);                  \
131         } else                                                          \
132                 *(type *)dest = 0;                                      \
133 }                                                                       \
134 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
135 DEFINE_BASIC_FETCH_FUNCS(deref)
136 DEFINE_FETCH_deref(string)
137
138 void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
139                                          void *data, void *dest)
140 {
141         struct deref_fetch_param *dprm = data;
142         unsigned long addr;
143
144         call_fetch(&dprm->orig, regs, &addr);
145         if (addr && dprm->fetch_size) {
146                 addr += dprm->offset;
147                 dprm->fetch_size(regs, (void *)addr, dest);
148         } else
149                 *(string_size *)dest = 0;
150 }
151 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
152
153 static void update_deref_fetch_param(struct deref_fetch_param *data)
154 {
155         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
156                 update_deref_fetch_param(data->orig.data);
157         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
158                 update_symbol_cache(data->orig.data);
159 }
160 NOKPROBE_SYMBOL(update_deref_fetch_param);
161
162 static void free_deref_fetch_param(struct deref_fetch_param *data)
163 {
164         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
165                 free_deref_fetch_param(data->orig.data);
166         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
167                 free_symbol_cache(data->orig.data);
168         kfree(data);
169 }
170 NOKPROBE_SYMBOL(free_deref_fetch_param);
171
172 /* Bitfield fetch function */
173 struct bitfield_fetch_param {
174         struct fetch_param      orig;
175         unsigned char           hi_shift;
176         unsigned char           low_shift;
177 };
178
179 #define DEFINE_FETCH_bitfield(type)                                     \
180 void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,              \
181                                      void *data, void *dest)            \
182 {                                                                       \
183         struct bitfield_fetch_param *bprm = data;                       \
184         type buf = 0;                                                   \
185         call_fetch(&bprm->orig, regs, &buf);                            \
186         if (buf) {                                                      \
187                 buf <<= bprm->hi_shift;                                 \
188                 buf >>= bprm->low_shift;                                \
189         }                                                               \
190         *(type *)dest = buf;                                            \
191 }                                                                       \
192 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
193 DEFINE_BASIC_FETCH_FUNCS(bitfield)
194 #define fetch_bitfield_string           NULL
195 #define fetch_bitfield_string_size      NULL
196
197 static void
198 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
199 {
200         /*
201          * Don't check the bitfield itself, because this must be the
202          * last fetch function.
203          */
204         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
205                 update_deref_fetch_param(data->orig.data);
206         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
207                 update_symbol_cache(data->orig.data);
208 }
209
210 static void
211 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
212 {
213         /*
214          * Don't check the bitfield itself, because this must be the
215          * last fetch function.
216          */
217         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
218                 free_deref_fetch_param(data->orig.data);
219         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
220                 free_symbol_cache(data->orig.data);
221
222         kfree(data);
223 }
224
225 void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
226                                           void *data, void *dest)
227 {
228         int maxlen = get_rloc_len(*(u32 *)dest);
229         u8 *dst = get_rloc_data(dest);
230         long ret;
231
232         if (!maxlen)
233                 return;
234
235         ret = strlcpy(dst, current->comm, maxlen);
236         *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
237 }
238 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
239
240 void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
241                                                void *data, void *dest)
242 {
243         *(u32 *)dest = strlen(current->comm) + 1;
244 }
245 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
246
247 static const struct fetch_type *find_fetch_type(const char *type,
248                                                 const struct fetch_type *ftbl)
249 {
250         int i;
251
252         if (!type)
253                 type = DEFAULT_FETCH_TYPE_STR;
254
255         /* Special case: bitfield */
256         if (*type == 'b') {
257                 unsigned long bs;
258
259                 type = strchr(type, '/');
260                 if (!type)
261                         goto fail;
262
263                 type++;
264                 if (kstrtoul(type, 0, &bs))
265                         goto fail;
266
267                 switch (bs) {
268                 case 8:
269                         return find_fetch_type("u8", ftbl);
270                 case 16:
271                         return find_fetch_type("u16", ftbl);
272                 case 32:
273                         return find_fetch_type("u32", ftbl);
274                 case 64:
275                         return find_fetch_type("u64", ftbl);
276                 default:
277                         goto fail;
278                 }
279         }
280
281         for (i = 0; ftbl[i].name; i++) {
282                 if (strcmp(type, ftbl[i].name) == 0)
283                         return &ftbl[i];
284         }
285
286 fail:
287         return NULL;
288 }
289
290 /* Special function : only accept unsigned long */
291 static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
292 {
293         *(unsigned long *)dest = kernel_stack_pointer(regs);
294 }
295 NOKPROBE_SYMBOL(fetch_kernel_stack_address);
296
297 static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
298 {
299         *(unsigned long *)dest = user_stack_pointer(regs);
300 }
301 NOKPROBE_SYMBOL(fetch_user_stack_address);
302
303 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
304                                             fetch_func_t orig_fn,
305                                             const struct fetch_type *ftbl)
306 {
307         int i;
308
309         if (type != &ftbl[FETCH_TYPE_STRING])
310                 return NULL;    /* Only string type needs size function */
311
312         for (i = 0; i < FETCH_MTD_END; i++)
313                 if (type->fetch[i] == orig_fn)
314                         return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
315
316         WARN_ON(1);     /* This should not happen */
317
318         return NULL;
319 }
320
321 /* Split symbol and offset. */
322 int traceprobe_split_symbol_offset(char *symbol, long *offset)
323 {
324         char *tmp;
325         int ret;
326
327         if (!offset)
328                 return -EINVAL;
329
330         tmp = strpbrk(symbol, "+-");
331         if (tmp) {
332                 ret = kstrtol(tmp, 0, offset);
333                 if (ret)
334                         return ret;
335                 *tmp = '\0';
336         } else
337                 *offset = 0;
338
339         return 0;
340 }
341
342 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
343
344 static int parse_probe_vars(char *arg, const struct fetch_type *t,
345                             struct fetch_param *f, bool is_return,
346                             bool is_kprobe)
347 {
348         int ret = 0;
349         unsigned long param;
350
351         if (strcmp(arg, "retval") == 0) {
352                 if (is_return)
353                         f->fn = t->fetch[FETCH_MTD_retval];
354                 else
355                         ret = -EINVAL;
356         } else if (strncmp(arg, "stack", 5) == 0) {
357                 if (arg[5] == '\0') {
358                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
359                                 return -EINVAL;
360
361                         if (is_kprobe)
362                                 f->fn = fetch_kernel_stack_address;
363                         else
364                                 f->fn = fetch_user_stack_address;
365                 } else if (isdigit(arg[5])) {
366                         ret = kstrtoul(arg + 5, 10, &param);
367                         if (ret || (is_kprobe && param > PARAM_MAX_STACK))
368                                 ret = -EINVAL;
369                         else {
370                                 f->fn = t->fetch[FETCH_MTD_stack];
371                                 f->data = (void *)param;
372                         }
373                 } else
374                         ret = -EINVAL;
375         } else if (strcmp(arg, "comm") == 0) {
376                 if (strcmp(t->name, "string") != 0 &&
377                     strcmp(t->name, "string_size") != 0)
378                         return -EINVAL;
379                 f->fn = t->fetch[FETCH_MTD_comm];
380         } else
381                 ret = -EINVAL;
382
383         return ret;
384 }
385
386 /* Recursive argument parser */
387 static int parse_probe_arg(char *arg, const struct fetch_type *t,
388                      struct fetch_param *f, bool is_return, bool is_kprobe,
389                      const struct fetch_type *ftbl)
390 {
391         unsigned long param;
392         long offset;
393         char *tmp;
394         int ret = 0;
395
396         switch (arg[0]) {
397         case '$':
398                 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
399                 break;
400
401         case '%':       /* named register */
402                 ret = regs_query_register_offset(arg + 1);
403                 if (ret >= 0) {
404                         f->fn = t->fetch[FETCH_MTD_reg];
405                         f->data = (void *)(unsigned long)ret;
406                         ret = 0;
407                 }
408                 break;
409
410         case '@':       /* memory, file-offset or symbol */
411                 if (isdigit(arg[1])) {
412                         ret = kstrtoul(arg + 1, 0, &param);
413                         if (ret)
414                                 break;
415
416                         f->fn = t->fetch[FETCH_MTD_memory];
417                         f->data = (void *)param;
418                 } else if (arg[1] == '+') {
419                         /* kprobes don't support file offsets */
420                         if (is_kprobe)
421                                 return -EINVAL;
422
423                         ret = kstrtol(arg + 2, 0, &offset);
424                         if (ret)
425                                 break;
426
427                         f->fn = t->fetch[FETCH_MTD_file_offset];
428                         f->data = (void *)offset;
429                 } else {
430                         /* uprobes don't support symbols */
431                         if (!is_kprobe)
432                                 return -EINVAL;
433
434                         ret = traceprobe_split_symbol_offset(arg + 1, &offset);
435                         if (ret)
436                                 break;
437
438                         f->data = alloc_symbol_cache(arg + 1, offset);
439                         if (f->data)
440                                 f->fn = t->fetch[FETCH_MTD_symbol];
441                 }
442                 break;
443
444         case '+':       /* deref memory */
445                 arg++;  /* Skip '+', because kstrtol() rejects it. */
446         case '-':
447                 tmp = strchr(arg, '(');
448                 if (!tmp)
449                         break;
450
451                 *tmp = '\0';
452                 ret = kstrtol(arg, 0, &offset);
453
454                 if (ret)
455                         break;
456
457                 arg = tmp + 1;
458                 tmp = strrchr(arg, ')');
459
460                 if (tmp) {
461                         struct deref_fetch_param        *dprm;
462                         const struct fetch_type         *t2;
463
464                         t2 = find_fetch_type(NULL, ftbl);
465                         *tmp = '\0';
466                         dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
467
468                         if (!dprm)
469                                 return -ENOMEM;
470
471                         dprm->offset = offset;
472                         dprm->fetch = t->fetch[FETCH_MTD_memory];
473                         dprm->fetch_size = get_fetch_size_function(t,
474                                                         dprm->fetch, ftbl);
475                         ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
476                                                         is_kprobe, ftbl);
477                         if (ret)
478                                 kfree(dprm);
479                         else {
480                                 f->fn = t->fetch[FETCH_MTD_deref];
481                                 f->data = (void *)dprm;
482                         }
483                 }
484                 break;
485         }
486         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
487                 pr_info("%s type has no corresponding fetch method.\n", t->name);
488                 ret = -EINVAL;
489         }
490
491         return ret;
492 }
493
494 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
495
496 /* Bitfield type needs to be parsed into a fetch function */
497 static int __parse_bitfield_probe_arg(const char *bf,
498                                       const struct fetch_type *t,
499                                       struct fetch_param *f)
500 {
501         struct bitfield_fetch_param *bprm;
502         unsigned long bw, bo;
503         char *tail;
504
505         if (*bf != 'b')
506                 return 0;
507
508         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
509         if (!bprm)
510                 return -ENOMEM;
511
512         bprm->orig = *f;
513         f->fn = t->fetch[FETCH_MTD_bitfield];
514         f->data = (void *)bprm;
515         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
516
517         if (bw == 0 || *tail != '@')
518                 return -EINVAL;
519
520         bf = tail + 1;
521         bo = simple_strtoul(bf, &tail, 0);
522
523         if (tail == bf || *tail != '/')
524                 return -EINVAL;
525
526         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
527         bprm->low_shift = bprm->hi_shift + bo;
528
529         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
530 }
531
532 /* String length checking wrapper */
533 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
534                 struct probe_arg *parg, bool is_return, bool is_kprobe,
535                 const struct fetch_type *ftbl)
536 {
537         const char *t;
538         int ret;
539
540         if (strlen(arg) > MAX_ARGSTR_LEN) {
541                 pr_info("Argument is too long.: %s\n",  arg);
542                 return -ENOSPC;
543         }
544         parg->comm = kstrdup(arg, GFP_KERNEL);
545         if (!parg->comm) {
546                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
547                 return -ENOMEM;
548         }
549         t = strchr(parg->comm, ':');
550         if (t) {
551                 arg[t - parg->comm] = '\0';
552                 t++;
553         }
554         /*
555          * The default type of $comm should be "string", and it can't be
556          * dereferenced.
557          */
558         if (!t && strcmp(arg, "$comm") == 0)
559                 t = "string";
560         parg->type = find_fetch_type(t, ftbl);
561         if (!parg->type) {
562                 pr_info("Unsupported type: %s\n", t);
563                 return -EINVAL;
564         }
565         parg->offset = *size;
566         *size += parg->type->size;
567         ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
568                               is_kprobe, ftbl);
569
570         if (ret >= 0 && t != NULL)
571                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
572
573         if (ret >= 0) {
574                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
575                                                               parg->fetch.fn,
576                                                               ftbl);
577                 parg->fetch_size.data = parg->fetch.data;
578         }
579
580         return ret;
581 }
582
583 /* Return 1 if name is reserved or already used by another argument */
584 int traceprobe_conflict_field_name(const char *name,
585                                struct probe_arg *args, int narg)
586 {
587         int i;
588
589         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
590                 if (strcmp(reserved_field_names[i], name) == 0)
591                         return 1;
592
593         for (i = 0; i < narg; i++)
594                 if (strcmp(args[i].name, name) == 0)
595                         return 1;
596
597         return 0;
598 }
599
600 void traceprobe_update_arg(struct probe_arg *arg)
601 {
602         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
603                 update_bitfield_fetch_param(arg->fetch.data);
604         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
605                 update_deref_fetch_param(arg->fetch.data);
606         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
607                 update_symbol_cache(arg->fetch.data);
608 }
609
610 void traceprobe_free_probe_arg(struct probe_arg *arg)
611 {
612         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
613                 free_bitfield_fetch_param(arg->fetch.data);
614         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
615                 free_deref_fetch_param(arg->fetch.data);
616         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
617                 free_symbol_cache(arg->fetch.data);
618
619         kfree(arg->name);
620         kfree(arg->comm);
621 }
622
623 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
624 {
625         char **argv;
626         int argc, ret;
627
628         argc = 0;
629         ret = 0;
630         argv = argv_split(GFP_KERNEL, buf, &argc);
631         if (!argv)
632                 return -ENOMEM;
633
634         if (argc)
635                 ret = createfn(argc, argv);
636
637         argv_free(argv);
638
639         return ret;
640 }
641
642 #define WRITE_BUFSIZE  4096
643
644 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
645                                 size_t count, loff_t *ppos,
646                                 int (*createfn)(int, char **))
647 {
648         char *kbuf, *tmp;
649         int ret = 0;
650         size_t done = 0;
651         size_t size;
652
653         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
654         if (!kbuf)
655                 return -ENOMEM;
656
657         while (done < count) {
658                 size = count - done;
659
660                 if (size >= WRITE_BUFSIZE)
661                         size = WRITE_BUFSIZE - 1;
662
663                 if (copy_from_user(kbuf, buffer + done, size)) {
664                         ret = -EFAULT;
665                         goto out;
666                 }
667                 kbuf[size] = '\0';
668                 tmp = strchr(kbuf, '\n');
669
670                 if (tmp) {
671                         *tmp = '\0';
672                         size = tmp - kbuf + 1;
673                 } else if (done + size < count) {
674                         pr_warn("Line length is too long: Should be less than %d\n",
675                                 WRITE_BUFSIZE);
676                         ret = -EINVAL;
677                         goto out;
678                 }
679                 done += size;
680                 /* Remove comments */
681                 tmp = strchr(kbuf, '#');
682
683                 if (tmp)
684                         *tmp = '\0';
685
686                 ret = traceprobe_command(kbuf, createfn);
687                 if (ret)
688                         goto out;
689         }
690         ret = done;
691
692 out:
693         kfree(kbuf);
694
695         return ret;
696 }
697
698 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
699                            bool is_return)
700 {
701         int i;
702         int pos = 0;
703
704         const char *fmt, *arg;
705
706         if (!is_return) {
707                 fmt = "(%lx)";
708                 arg = "REC->" FIELD_STRING_IP;
709         } else {
710                 fmt = "(%lx <- %lx)";
711                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
712         }
713
714         /* When len=0, we just calculate the needed length */
715 #define LEN_OR_ZERO (len ? len - pos : 0)
716
717         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
718
719         for (i = 0; i < tp->nr_args; i++) {
720                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
721                                 tp->args[i].name, tp->args[i].type->fmt);
722         }
723
724         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
725
726         for (i = 0; i < tp->nr_args; i++) {
727                 if (strcmp(tp->args[i].type->name, "string") == 0)
728                         pos += snprintf(buf + pos, LEN_OR_ZERO,
729                                         ", __get_str(%s)",
730                                         tp->args[i].name);
731                 else
732                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
733                                         tp->args[i].name);
734         }
735
736 #undef LEN_OR_ZERO
737
738         /* return the length of print_fmt */
739         return pos;
740 }
741
742 int set_print_fmt(struct trace_probe *tp, bool is_return)
743 {
744         int len;
745         char *print_fmt;
746
747         /* First: called with 0 length to calculate the needed length */
748         len = __set_print_fmt(tp, NULL, 0, is_return);
749         print_fmt = kmalloc(len + 1, GFP_KERNEL);
750         if (!print_fmt)
751                 return -ENOMEM;
752
753         /* Second: actually write the @print_fmt */
754         __set_print_fmt(tp, print_fmt, len + 1, is_return);
755         tp->call.print_fmt = print_fmt;
756
757         return 0;
758 }