summaryrefslogtreecommitdiff
path: root/src/udev/util.h
blob: b9230e38bcd12468779c323dff6dbf61674be84d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

#pragma once

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <inttypes.h>
#include <time.h>
#include <sys/time.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <sched.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <sys/resource.h>
#include <stddef.h>

#include "macro.h"

typedef uint64_t usec_t;
typedef uint64_t nsec_t;

typedef struct dual_timestamp {
        usec_t realtime;
        usec_t monotonic;
} dual_timestamp;

union dirent_storage {
        struct dirent de;
        uint8_t storage[offsetof(struct dirent, d_name) +
                        ((NAME_MAX + 1 + sizeof(long)) & ~(sizeof(long) - 1))];
};

#define MSEC_PER_SEC  1000ULL
#define USEC_PER_SEC  1000000ULL
#define USEC_PER_MSEC 1000ULL
#define NSEC_PER_SEC  1000000000ULL
#define NSEC_PER_MSEC 1000000ULL
#define NSEC_PER_USEC 1000ULL

#define USEC_PER_MINUTE (60ULL*USEC_PER_SEC)
#define NSEC_PER_MINUTE (60ULL*NSEC_PER_SEC)
#define USEC_PER_HOUR (60ULL*USEC_PER_MINUTE)
#define NSEC_PER_HOUR (60ULL*NSEC_PER_MINUTE)
#define USEC_PER_DAY (24ULL*USEC_PER_HOUR)
#define NSEC_PER_DAY (24ULL*NSEC_PER_HOUR)
#define USEC_PER_WEEK (7ULL*USEC_PER_DAY)
#define NSEC_PER_WEEK (7ULL*NSEC_PER_DAY)
#define USEC_PER_MONTH (2629800ULL*USEC_PER_SEC)
#define NSEC_PER_MONTH (2629800ULL*NSEC_PER_SEC)
#define USEC_PER_YEAR (31557600ULL*USEC_PER_SEC)
#define NSEC_PER_YEAR (31557600ULL*NSEC_PER_SEC)

/* What is interpreted as whitespace? */
#define WHITESPACE " \t\n\r"
#define NEWLINE "\n\r"
#define QUOTES "\"\'"
#define COMMENTS "#;\n"

#define FORMAT_TIMESTAMP_MAX (5+11+9+4+1)
#define FORMAT_TIMESTAMP_PRETTY_MAX 256
#define FORMAT_TIMESPAN_MAX 64
#define FORMAT_BYTES_MAX 8

#define ANSI_HIGHLIGHT_ON "\x1B[1;39m"
#define ANSI_HIGHLIGHT_RED_ON "\x1B[1;31m"
#define ANSI_HIGHLIGHT_GREEN_ON "\x1B[1;32m"
#define ANSI_HIGHLIGHT_YELLOW_ON "\x1B[1;33m"
#define ANSI_HIGHLIGHT_OFF "\x1B[0m"

bool is_efiboot(void);

usec_t now(clockid_t clock);

dual_timestamp* dual_timestamp_get(dual_timestamp *ts);
dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u);

#define dual_timestamp_is_set(ts) ((ts)->realtime > 0)

usec_t timespec_load(const struct timespec *ts);
struct timespec *timespec_store(struct timespec *ts, usec_t u);

usec_t timeval_load(const struct timeval *tv);
struct timeval *timeval_store(struct timeval *tv, usec_t u);

size_t page_size(void);
#define PAGE_ALIGN(l) ALIGN_TO((l), page_size())

#define streq(a,b) (strcmp((a),(b)) == 0)
#define strneq(a, b, n) (strncmp((a), (b), (n)) == 0)

bool streq_ptr(const char *a, const char *b);

#define new(t, n) ((t*) malloc_multiply(sizeof(t), (n)))

#define new0(t, n) ((t*) calloc((n), sizeof(t)))

#define newa(t, n) ((t*) alloca(sizeof(t)*(n)))

#define newdup(t, p, n) ((t*) memdup_multiply(p, sizeof(t), (n)))

#define malloc0(n) (calloc((n), 1))

static inline const char* yes_no(bool b) {
        return b ? "yes" : "no";
}

static inline const char* strempty(const char *s) {
        return s ? s : "";
}

static inline const char* strnull(const char *s) {
        return s ? s : "(null)";
}

static inline const char *strna(const char *s) {
        return s ? s : "n/a";
}

static inline bool isempty(const char *p) {
        return !p || !p[0];
}

char *endswith(const char *s, const char *postfix);
char *startswith(const char *s, const char *prefix);
char *startswith_no_case(const char *s, const char *prefix);

bool first_word(const char *s, const char *word);

int close_nointr(int fd);
void close_nointr_nofail(int fd);
void close_many(const int fds[], unsigned n_fd);

int parse_boolean(const char *v);
int parse_usec(const char *t, usec_t *usec);
int parse_nsec(const char *t, nsec_t *nsec);
int parse_bytes(const char *t, off_t *bytes);
int parse_pid(const char *s, pid_t* ret_pid);
int parse_uid(const char *s, uid_t* ret_uid);
#define parse_gid(s, ret_uid) parse_uid(s, ret_uid)

int safe_atou(const char *s, unsigned *ret_u);
int safe_atoi(const char *s, int *ret_i);

int safe_atollu(const char *s, unsigned long long *ret_u);
int safe_atolli(const char *s, long long int *ret_i);

#if __WORDSIZE == 32
static inline int safe_atolu(const char *s, unsigned long *ret_u) {
        assert_cc(sizeof(unsigned long) == sizeof(unsigned));
        return safe_atou(s, (unsigned*) ret_u);
}
static inline int safe_atoli(const char *s, long int *ret_u) {
        assert_cc(sizeof(long int) == sizeof(int));
        return safe_atoi(s, (int*) ret_u);
}
#else
static inline int safe_atolu(const char *s, unsigned long *ret_u) {
        assert_cc(sizeof(unsigned long) == sizeof(unsigned long long));
        return safe_atollu(s, (unsigned long long*) ret_u);
}
static inline int safe_atoli(const char *s, long int *ret_u) {
        assert_cc(sizeof(long int) == sizeof(long long int));
        return safe_atolli(s, (long long int*) ret_u);
}
#endif

static inline int safe_atou32(const char *s, uint32_t *ret_u) {
        assert_cc(sizeof(uint32_t) == sizeof(unsigned));
        return safe_atou(s, (unsigned*) ret_u);
}

static inline int safe_atoi32(const char *s, int32_t *ret_i) {
        assert_cc(sizeof(int32_t) == sizeof(int));
        return safe_atoi(s, (int*) ret_i);
}

static inline int safe_atou64(const char *s, uint64_t *ret_u) {
        assert_cc(sizeof(uint64_t) == sizeof(unsigned long long));
        return safe_atollu(s, (unsigned long long*) ret_u);
}

static inline int safe_atoi64(const char *s, int64_t *ret_i) {
        assert_cc(sizeof(int64_t) == sizeof(long long int));
        return safe_atolli(s, (long long int*) ret_i);
}

char *split(const char *c, size_t *l, const char *separator, char **state);
char *split_quoted(const char *c, size_t *l, char **state);

#define FOREACH_WORD(word, length, s, state)                            \
        for ((state) = NULL, (word) = split((s), &(length), WHITESPACE, &(state)); (word); (word) = split((s), &(length), WHITESPACE, &(state)))

#define FOREACH_WORD_SEPARATOR(word, length, s, separator, state)       \
        for ((state) = NULL, (word) = split((s), &(length), (separator), &(state)); (word); (word) = split((s), &(length), (separator), &(state)))

#define FOREACH_WORD_QUOTED(word, length, s, state)                     \
        for ((state) = NULL, (word) = split_quoted((s), &(length), &(state)); (word); (word) = split_quoted((s), &(length), &(state)))

pid_t get_parent_of_pid(pid_t pid, pid_t *ppid);
int get_starttime_of_pid(pid_t pid, unsigned long long *st);

int write_one_line_file(const char *fn, const char *line);
int write_one_line_file_atomic(const char *fn, const char *line);
int read_one_line_file(const char *fn, char **line);
int read_full_file(const char *fn, char **contents, size_t *size);

int parse_env_file(const char *fname, const char *separator, ...) _sentinel_;
int load_env_file(const char *fname, char ***l);
int write_env_file(const char *fname, char **l);

char *strappend(const char *s, const char *suffix);
char *strnappend(const char *s, const char *suffix, size_t length);

char *replace_env(const char *format, char **env);
char **replace_env_argv(char **argv, char **env);

int readlink_malloc(const char *p, char **r);
int readlink_and_make_absolute(const char *p, char **r);
int readlink_and_canonicalize(const char *p, char **r);

int reset_all_signal_handlers(void);

char *strstrip(char *s);
char *delete_chars(char *s, const char *bad);
char *truncate_nl(char *s);

char *file_in_same_dir(const char *path, const char *filename);

int rmdir_parents(const char *path, const char *stop);

int get_process_comm(pid_t pid, char **name);
int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line);
int get_process_exe(pid_t pid, char **name);
int get_process_uid(pid_t pid, uid_t *uid);
int get_process_gid(pid_t pid, gid_t *gid);

char hexchar(int x);
int unhexchar(char c);
char octchar(int x);
int unoctchar(char c);
char decchar(int x);
int undecchar(char c);

char *cescape(const char *s);
char *cunescape(const char *s);
char *cunescape_length(const char *s, size_t length);
char *cunescape_length_with_prefix(const char *s, size_t length, const char *prefix);

char *xescape(const char *s, const char *bad);

char *bus_path_escape(const char *s);
char *bus_path_unescape(const char *s);

char *ascii_strlower(char *path);

bool dirent_is_file(const struct dirent *de);
bool dirent_is_file_with_suffix(const struct dirent *de, const char *suffix);

bool ignore_file(const char *filename);

bool chars_intersect(const char *a, const char *b);

char *format_timestamp(char *buf, size_t l, usec_t t);
char *format_timestamp_pretty(char *buf, size_t l, usec_t t);
char *format_timespan(char *buf, size_t l, usec_t t);

int make_stdio(int fd);
int make_null_stdio(void);
int make_console_stdio(void);

unsigned long long random_ull(void);

/* For basic lookup tables with strictly enumerated entries */
#define __DEFINE_STRING_TABLE_LOOKUP(name,type,scope)                   \
        scope const char *name##_to_string(type i) {                    \
                if (i < 0 || i >= (type) ELEMENTSOF(name##_table))      \
                        return NULL;                                    \
                return name##_table[i];                                 \
        }                                                               \
        scope type name##_from_string(const char *s) {                  \
                type i;                                                 \
                assert(s);                                              \
                for (i = 0; i < (type)ELEMENTSOF(name##_table); i++)    \
                        if (name##_table[i] &&                          \
                            streq(name##_table[i], s))                  \
                                return i;                               \
                return (type) -1;                                       \
        }                                                               \
        struct __useless_struct_to_allow_trailing_semicolon__

#define DEFINE_STRING_TABLE_LOOKUP(name,type) __DEFINE_STRING_TABLE_LOOKUP(name,type,)
#define DEFINE_PRIVATE_STRING_TABLE_LOOKUP(name,type) __DEFINE_STRING_TABLE_LOOKUP(name,type,static)

/* For string conversions where numbers are also acceptable */
#define DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(name,type,max)         \
        int name##_to_string_alloc(type i, char **str) {                \
                char *s;                                                \
                int r;                                                  \
                if (i < 0 || i > max)                                   \
                        return -ERANGE;                                 \
                if (i < (type) ELEMENTSOF(name##_table)) {              \
                        s = strdup(name##_table[i]);                    \
                        if (!s)                                         \
                                return log_oom();                       \
                } else {                                                \
                        r = asprintf(&s, "%u", i);                      \
                        if (r < 0)                                      \
                                return log_oom();                       \
                }                                                       \
                *str = s;                                               \
                return 0;                                               \
        }                                                               \
        type name##_from_string(const char *s) {                        \
                type i;                                                 \
                unsigned u = 0;                                         \
                assert(s);                                              \
                for (i = 0; i < (type)ELEMENTSOF(name##_table); i++)    \
                        if (name##_table[i] &&                          \
                            streq(name##_table[i], s))                  \
                                return i;                               \
                if (safe_atou(s, &u) >= 0 && u <= max)                  \
                        return (type) u;                                \
                return (type) -1;                                       \
        }                                                               \
        struct __useless_struct_to_allow_trailing_semicolon__

int fd_nonblock(int fd, bool nonblock);
int fd_cloexec(int fd, bool cloexec);

int close_all_fds(const int except[], unsigned n_except);

bool fstype_is_network(const char *fstype);

int chvt(int vt);

int read_one_char(FILE *f, char *ret, usec_t timeout, bool *need_nl);
int ask(char *ret, const char *replies, const char *text, ...);

int reset_terminal_fd(int fd, bool switch_to_text);
int reset_terminal(const char *name);

int open_terminal(const char *name, int mode);
int acquire_terminal(const char *name, bool fail, bool force, bool ignore_tiocstty_eperm, usec_t timeout);
int release_terminal(void);

int flush_fd(int fd);

int ignore_signals(int sig, ...);
int default_signals(int sig, ...);
int sigaction_many(const struct sigaction *sa, ...);

int close_pipe(int p[]);
int fopen_temporary(const char *path, FILE **_f, char **_temp_path);

ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll);
ssize_t loop_write(int fd, const void *buf, size_t nbytes, bool do_poll);

bool is_device_path(const char *path);

int dir_is_empty(const char *path);

void rename_process(const char name[8]);

void sigset_add_many(sigset_t *ss, ...);

bool hostname_is_set(void);

char* gethostname_malloc(void);
char* getlogname_malloc(void);
char* getusername_malloc(void);

int getttyname_malloc(int fd, char **r);
int getttyname_harder(int fd, char **r);

int get_ctty_devnr(pid_t pid, dev_t *d);
int get_ctty(pid_t, dev_t *_devnr, char **r);

int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid);
int fchmod_and_fchown(int fd, mode_t mode, uid_t uid, gid_t gid);

int rm_rf_children(int fd, bool only_dirs, bool honour_sticky, struct stat *root_dev);
int rm_rf_children_dangerous(int fd, bool only_dirs, bool honour_sticky, struct stat *root_dev);
int rm_rf(const char *path, bool only_dirs, bool delete_root, bool honour_sticky);
int rm_rf_dangerous(const char *path, bool only_dirs, bool delete_root, bool honour_sticky);

int pipe_eof(int fd);

cpu_set_t* cpu_set_malloc(unsigned *ncpus);

int status_vprintf(const char *status, bool ellipse, const char *format, va_list ap);
int status_printf(const char *status, bool ellipse, const char *format, ...);
int status_welcome(void);

int fd_columns(int fd);
unsigned columns(void);
int fd_lines(int fd);
unsigned lines(void);
void columns_lines_cache_reset(int _unused_ signum);

bool on_tty(void);

int running_in_chroot(void);

char *ellipsize(const char *s, size_t length, unsigned percent);
char *ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent);

int touch(const char *path);

char *unquote(const char *s, const char *quotes);
char *normalize_env_assignment(const char *s);

int wait_for_terminate(pid_t pid, siginfo_t *status);
int wait_for_terminate_and_warn(const char *name, pid_t pid);

_noreturn_ void freeze(void);

bool null_or_empty(struct stat *st);
int null_or_empty_path(const char *fn);

DIR *xopendirat(int dirfd, const char *name, int flags);

void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t);
void dual_timestamp_deserialize(const char *value, dual_timestamp *t);

char *fstab_node_to_udev_node(const char *p);

bool tty_is_vc(const char *tty);
bool tty_is_vc_resolve(const char *tty);
bool tty_is_console(const char *tty);
int vtnr_from_tty(const char *tty);
const char *default_term_for_tty(const char *tty);

int execute_command(const char *command, char *const argv[]);
void execute_directory(const char *directory, DIR *_d, char *argv[]);

int kill_and_sigcont(pid_t pid, int sig);

bool nulstr_contains(const char*nulstr, const char *needle);

bool plymouth_running(void);

bool hostname_is_valid(const char *s);
char* hostname_cleanup(char *s);

char* strshorten(char *s, size_t l);

int terminal_vhangup_fd(int fd);
int terminal_vhangup(const char *name);

int vt_disallocate(const char *name);

int copy_file(const char *from, const char *to);

int symlink_atomic(const char *from, const char *to);

int fchmod_umask(int fd, mode_t mode);

bool display_is_local(const char *display);
int socket_from_display(const char *display, char **path);

int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home, const char **shell);
int get_group_creds(const char **groupname, gid_t *gid);

int in_group(const char *name);

int glob_exists(const char *path);

int dirent_ensure_type(DIR *d, struct dirent *de);

int in_search_path(const char *path, char **search);
int get_files_in_directory(const char *path, char ***list);

char *strjoin(const char *x, ...) _sentinel_;

bool is_main_thread(void);

bool in_charset(const char *s, const char* charset);

int block_get_whole_disk(dev_t d, dev_t *ret);

int file_is_priv_sticky(const char *p);

int strdup_or_null(const char *a, char **b);

#define NULSTR_FOREACH(i, l)                                    \
        for ((i) = (l); (i) && *(i); (i) = strchr((i), 0)+1)

#define NULSTR_FOREACH_PAIR(i, j, l)                             \
        for ((i) = (l), (j) = strchr((i), 0)+1; (i) && *(i); (i) = strchr((j), 0)+1, (j) = *(i) ? strchr((i), 0)+1 : (i))

int ioprio_class_to_string_alloc(int i, char **s);
int ioprio_class_from_string(const char *s);

const char *sigchld_code_to_string(int i);
int sigchld_code_from_string(const char *s);

int log_facility_unshifted_to_string_alloc(int i, char **s);
int log_facility_unshifted_from_string(const char *s);

int log_level_to_string_alloc(int i, char **s);
int log_level_from_string(const char *s);

int sched_policy_to_string_alloc(int i, char **s);
int sched_policy_from_string(const char *s);

const char *rlimit_to_string(int i);
int rlimit_from_string(const char *s);

int ip_tos_to_string_alloc(int i, char **s);
int ip_tos_from_string(const char *s);

const char *signal_to_string(int i);
int signal_from_string(const char *s);

int signal_from_string_try_harder(const char *s);

extern int saved_argc;
extern char **saved_argv;

bool kexec_loaded(void);

int prot_from_flags(int flags);

char *format_bytes(char *buf, size_t l, off_t t);

int fd_wait_for_event(int fd, int event, usec_t timeout);

void* memdup(const void *p, size_t l) _malloc_;

int is_kernel_thread(pid_t pid);

int fd_inc_sndbuf(int fd, size_t n);
int fd_inc_rcvbuf(int fd, size_t n);

int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *path, ...);

int setrlimit_closest(int resource, const struct rlimit *rlim);

int getenv_for_pid(pid_t pid, const char *field, char **_value);

int can_sleep(const char *type);
int can_sleep_disk(const char *type);

bool is_valid_documentation_url(const char *url);

bool in_initrd(void);

void warn_melody(void);

int get_shell(char **ret);
int get_home_dir(char **ret);

void freep(void *p);
void fclosep(FILE **f);
void closep(int *fd);
void closedirp(DIR **d);
void umaskp(mode_t *u);

_malloc_  static inline void *malloc_multiply(size_t a, size_t b) {
        if (_unlikely_(b == 0 || a > ((size_t) -1) / b))
                return NULL;

        return malloc(a * b);
}

_malloc_ static inline void *memdup_multiply(const void *p, size_t a, size_t b) {
        if (_unlikely_(b == 0 || a > ((size_t) -1) / b))
                return NULL;

        return memdup(p, a * b);
}

bool filename_is_safe(const char *p);
bool string_is_safe(const char *p);

int parse_timestamp(const char *t, usec_t *usec);

void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
                 int (*compar) (const void *, const void *, void *),
                 void *arg);

bool is_locale_utf8(void);

typedef enum DrawSpecialChar {
        DRAW_TREE_VERT,
        DRAW_TREE_BRANCH,
        DRAW_TREE_RIGHT,
        DRAW_TRIANGULAR_BULLET,
        _DRAW_SPECIAL_CHAR_MAX
} DrawSpecialChar;
const char *draw_special_char(DrawSpecialChar ch);

char *strreplace(const char *text, const char *old_string, const char *new_string);