[tl-append] / tl-append-test.c

#define _POSIX_C_SOURCE 2
#define _XOPEN_SOURCE
#define _GNU_SOURCE
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/file.h>
#include <time.h>
#include <unistd.h>

#include "common.h"

const size_t TIMESTAMP_LEN = 19;

typedef struct expectation {
  time_t a, b;
  const char *message;
} ex_t;

const ex_t END = {((time_t)-1), ((time_t)-1), NULL};
const ex_t CONSUMED = {((time_t)-2), ((time_t)-2), NULL};
static int is_end(ex_t exp) {
  return exp.a == END.a && exp.b == END.b && exp.message == END.message;
}
static void consume(ex_t *exp) {
  exp->a = CONSUMED.a;
  exp->b = CONSUMED.b;
}
static int is_consumed(ex_t exp) {
  return exp.a == CONSUMED.a && exp.b == CONSUMED.b;
}
static ex_t expectation(time_t a, time_t b, const char *message) {
  ex_t exp;
  exp.a = a;
  exp.b = b;
  exp.message = message;
  return exp;
}

static void remove_logfile() {
  if (remove(FILENAME) != 0) {
    if (errno != ENOENT) {
      die_err("Error removing log file");
    }
  }
}

static ex_t write_to_tl_append(const char *content) {
  FILE *p = popen("./tl-append", "w");
  if (p == NULL)
    die_err("Couldn't run tl-append");
  time_t start = time(NULL);
  if (fputs(content, p) == EOF)
    die("Couldn't write to pipe");
  int status = pclose(p);
  time_t end = time(NULL);
  if (status < 0)
    die_err("Error closing pipe");
  if (status != 0)
    die("tl-append exited abnormally");
  return expectation(start, end, content);
}

static char *timestamp_problem(const ex_t *ex, const char *line) {
  struct tm tm;

  /* localtime_r to set tm's timezone */
  time_t now_time = time(NULL);
  if (localtime_r(&now_time, &tm) == NULL)
    return "Can't unpack current time?";

  const char *strptime_result = strptime(line, "%Y %m %d %H %M %S", &tm);
  if (strptime_result == NULL || strptime_result != &line[TIMESTAMP_LEN])
    return "Wrong contents in log file: Couldn't parse timestamp";
  time_t t = mktime(&tm);
  int t_in_range = ex->a <= t && t <= ex->b;
  if (!t_in_range)
    return "Wrong contents in log file: Wrong time";
  return NULL;
}

static char *line_problem(const ex_t *ex, const char *line) {
  size_t line_len = strlen(line);
  if (line_len < TIMESTAMP_LEN + 1)
    return "Wrong contents in log file: Line too short";
  char *trouble = timestamp_problem(ex, line);
  if (trouble)
    return trouble;
  if (line[TIMESTAMP_LEN] != ' ')
    return "Wrong contents in log file: Bad format";
  if (strncmp(ex->message, &line[TIMESTAMP_LEN + 1], strlen(ex->message) + 1) !=
      0)
    return "Wrong contents in log file";
  return NULL;
}

static void verify_line(const ex_t *ex, const char *line) {
  char *trouble = line_problem(ex, line);
  if (trouble)
    die(trouble);
}

static void verify_log_contents(const ex_t exps[]) {
  FILE *f = fopen(FILENAME, "r");
  if (f == NULL)
    die_err("Error opening log file");
  for (size_t i = 0; !is_end(exps[i]); i++) {
    size_t len = TIMESTAMP_LEN + 1 + strlen(exps[i].message);
    if (len > INT_MAX - 1)
      die("message too long");
    char *buf = (char *)malloc(len + 2);
    if (fgets(buf, len + 1, f) == NULL)
      die("Error reading log file");
    if (ferror(f))
      die("Error reading log file");
    verify_line(&exps[i], buf);
    free(buf);
  }
  if (fclose(f) != 0)
    die_err("Error closing log file");
}

static void consume_expectation(ex_t exps[], const char *line) {
  for (size_t i = 0; !is_end(exps[i]); i++) {
    if (line_problem(&exps[i], line) == NULL) {
      consume(&exps[i]);
      return;
    }
  }
  die("Wrong contents in log file: Line didn't match any expectation");
}

static void verify_log_contents_unordered(ex_t exps[]) {
  FILE *f = fopen(FILENAME, "r");
  if (f == NULL)
    die_err("Error opening log file");
  for (;;) {
    const int MAX_LEN = 9999;
    char buf[MAX_LEN];
    if (fgets(buf, MAX_LEN, f) == NULL) {
      if (feof(f))
        break;
      die("Error reading log file");
    }
    if (ferror(f))
      die("Error reading log file");
    consume_expectation(exps, buf);
  }
  if (fclose(f) != 0)
    die_err("Error closing log file");
  for (size_t i = 0; !is_end(exps[i]); i++) {
    if (!is_consumed(exps[i]))
      die("Wrong contents in log file: Unconsumed expectation");
  }
}

static void test_encode_time() {
  /* localtime_r to set tm's timezone */
  time_t now_time = time(NULL);
  struct tm tm;
  if (localtime_r(&now_time, &tm) == NULL)
    die_err("Can't unpack current time?");

  const char *strptime_result = strptime("2011-12-13 14:15:16", "%F %T", &tm);
  if (strptime_result == NULL || *strptime_result != '\0')
    die("Couldn't parse time?");
  time_t tt = mktime(&tm);
  if (tt == (time_t)-1)
    die_err("Can't pack time?");

  char *encoded = encode_time(tt);
  /* Loose check to allow for daylight savings time changes between the current
   * time and the target time.  :( */
  assert(encoded[0] == '2');
  assert(encoded[1] == '0');
  assert(encoded[2] == '1');
  assert(encoded[3] == '1');
  assert(encoded[4] == ' ');
  assert(encoded[5] == '1');
  assert(encoded[6] == '2');
  assert(encoded[7] == ' ');
  assert(encoded[8] == '1');
  assert(encoded[9] == '3');
  assert(encoded[10] == ' ');
  assert(encoded[11] == '1');
  assert(isdigit(encoded[12]));
  assert(encoded[13] == ' ');
  assert(isdigit(encoded[14]));
  assert(isdigit(encoded[15]));
  assert(encoded[16] == ' ');
  assert(encoded[17] == '1');
  assert(encoded[18] == '6');
  assert(encoded[19] == '\0');
  free(encoded);
}

static FILE *take_lock(FILE *f, char *lock_type) {
  int fd = fileno(f);
  if (fd == -1)
    die_err("Couldn't get file descriptor for locking");
  if (strcmp(lock_type, "fcntl") == 0) {
    if (fcntl(fd, F_SETLK,
              &(struct flock){.l_type = F_WRLCK,
                              .l_whence = SEEK_SET,
                              .l_start = 0,
                              .l_len = 0}) == -1)
      die_err("Couldn't take fcntl lock");
  } else if (strcmp(lock_type, "flock") == 0) {
    if (flock(fd, LOCK_EX) == -1)
      die_err("Couldn't take flock lock");
  } else {
    die("Bad lock type");
  }
  return f;
}

static void release_lock(FILE *f) {
  if (fclose(f) != 0)
    die_err("Error releasing lock");
}

static void *release_lock_after_delay(void *f) {
  sleep(1);
  release_lock((FILE *)f);
  return NULL;
}

static void *writer_thread(void *start_signal) {
  ex_t *ex = (ex_t *)malloc(sizeof(ex_t));
  if (ex == NULL)
    die_err("Couldn't allocate memory");
  char *message;
  if (asprintf(&message, "Hello from thread %lu\n", pthread_self()) == -1)
    die("Couldn't prepare message");
  pthread_rwlock_rdlock((pthread_rwlock_t *)start_signal);
  *ex = write_to_tl_append(message);
  return ex;
}

static void write_and_read_line() {
  remove_logfile();
  ex_t e = write_to_tl_append("foo\n");
  verify_log_contents((ex_t[]){e, END});
}

static void write_and_read_two_lines() {
  remove_logfile();
  ex_t e1 = write_to_tl_append("foo\n");
  ex_t e2 = write_to_tl_append("bar\n");
  verify_log_contents((ex_t[]){e1, e2, END});
}

static void write_to_locked_log(char *lock_types[]) {
  remove_logfile();
  ex_t e1 = write_to_tl_append("begin\n");
  FILE *f = fopen(FILENAME, "ae");
  if (f == NULL)
    die_err("Couldn't open file for locking");
  for (int i = 0; lock_types[i]; i++)
    take_lock(f, lock_types[0]);
  pthread_t unlock_thread;
  int create_ret =
      pthread_create(&unlock_thread, NULL, &release_lock_after_delay, f);
  if (create_ret != 0) {
    errno = create_ret;
    die_err("Couldn't start thread");
  }
  ex_t e2 = write_to_tl_append("delayed\n");
  int join_ret = pthread_join(unlock_thread, NULL);
  if (join_ret != 0) {
    errno = join_ret;
    die_err("Couldn't join thread");
  }
  verify_log_contents((ex_t[]){e1, e2, END});
}

static void write_concurrently() {
  remove_logfile();
  const int PARALLELISM = 250;
  pthread_t threads[PARALLELISM];
  pthread_rwlock_t start_signal;
  pthread_rwlock_init(&start_signal, NULL);
  for (int i = 0; i < PARALLELISM; i++) {
    int create_ret =
        pthread_create(&threads[i], NULL, &writer_thread, &start_signal);
    if (create_ret != 0) {
      errno = create_ret;
      die_err("Couldn't start thread");
    }
  }
  pthread_rwlock_unlock(&start_signal);
  ex_t results[PARALLELISM + 1];
  for (int i = 0; i < PARALLELISM; i++) {
    ex_t *ex;
    int join_ret = pthread_join(threads[i], (void **)&ex);
    if (join_ret != 0) {
      errno = join_ret;
      die_err("Couldn't join thread");
    }
    results[i] = *ex;
    free(ex);
  }
  results[PARALLELISM] = END;
  verify_log_contents_unordered(results);
  for (int i = 0; i < PARALLELISM; i++) {
    free((void *)results[i].message);
  }
}

int main() {
  test_encode_time();
  write_and_read_line();
  write_and_read_two_lines();
  write_to_locked_log((char *[]){NULL});
  write_to_locked_log((char *[]){"fcntl", NULL});
  write_to_locked_log((char *[]){"flock", NULL});
  write_to_locked_log((char *[]){"flock", "fcntl", NULL}); /* Deadlock risk! */
  write_to_locked_log((char *[]){"fcntl", "flock", NULL});
  write_concurrently();
}
Commit	Line	Data
b3d5ed96	1	#define _POSIX_C_SOURCE 2
bab98a3a	2	#define _XOPEN_SOURCE
8559ce11	3	#define _GNU_SOURCE
bab98a3a SW	4	#include <assert.h>
bab98a3a SW	5	#include <ctype.h>
27dfbfeb	6	#include <errno.h>
8559ce11	7	#include <fcntl.h>
90df84eb	8	#include <limits.h>
8559ce11	9	#include <pthread.h>
b3d5ed96 SW	10	#include <stdio.h>
	11	#include <stdlib.h>
	12	#include <string.h>
a1160bb5	13	#include <sys/file.h>
853b83c4	14	#include <time.h>
8559ce11	15	#include <unistd.h>
b3d5ed96	16
d522116b SW	17	#include "common.h"
d522116b SW	18
2998af81 SW	19	const size_t TIMESTAMP_LEN = 19;
2998af81 SW	20
71a7e5c5	21	typedef struct expectation {
853b83c4	22	time_t a, b;
eaaa0046	23	const char *message;
71a7e5c5	24	} ex_t;
eaaa0046	25
853b83c4	26	const ex_t END = {((time_t)-1), ((time_t)-1), NULL};
8559ce11	27	const ex_t CONSUMED = {((time_t)-2), ((time_t)-2), NULL};
853b83c4 SW	28	static int is_end(ex_t exp) {
	29	return exp.a == END.a && exp.b == END.b && exp.message == END.message;
	30	}
ee028f60 SW	31	static void consume(ex_t *exp) {
	32	exp->a = CONSUMED.a;
	33	exp->b = CONSUMED.b;
	34	}
8559ce11	35	static int is_consumed(ex_t exp) {
ee028f60	36	return exp.a == CONSUMED.a && exp.b == CONSUMED.b;
8559ce11	37	}
853b83c4	38	static ex_t expectation(time_t a, time_t b, const char *message) {
71a7e5c5	39	ex_t exp;
853b83c4 SW	40	exp.a = a;
853b83c4 SW	41	exp.b = b;
eaaa0046 SW	42	exp.message = message;
	43	return exp;
	44	}
	45
27dfbfeb	46	static void remove_logfile() {
d522116b	47	if (remove(FILENAME) != 0) {
27dfbfeb SW	48	if (errno != ENOENT) {
	49	die_err("Error removing log file");
	50	}
	51	}
	52	}
	53
71a7e5c5	54	static ex_t write_to_tl_append(const char *content) {
b3d5ed96 SW	55	FILE *p = popen("./tl-append", "w");
	56	if (p == NULL)
	57	die_err("Couldn't run tl-append");
d753115a	58	time_t start = time(NULL);
aacfb261	59	if (fputs(content, p) == EOF)
b3d5ed96 SW	60	die("Couldn't write to pipe");
b3d5ed96 SW	61	int status = pclose(p);
d753115a	62	time_t end = time(NULL);
b3d5ed96 SW	63	if (status < 0)
	64	die_err("Error closing pipe");
	65	if (status != 0)
	66	die("tl-append exited abnormally");
d753115a	67	return expectation(start, end, content);
aacfb261 SW	68	}
aacfb261 SW	69
8559ce11	70	static char timestamp_problem(const ex_t ex, const char *line) {
2998af81 SW	71	struct tm tm;
	72
	73	/* localtime_r to set tm's timezone */
	74	time_t now_time = time(NULL);
	75	if (localtime_r(&now_time, &tm) == NULL)
8559ce11	76	return "Can't unpack current time?";
2998af81 SW	77
	78	const char *strptime_result = strptime(line, "%Y %m %d %H %M %S", &tm);
	79	if (strptime_result == NULL \|\| strptime_result != &line[TIMESTAMP_LEN])
8559ce11	80	return "Wrong contents in log file: Couldn't parse timestamp";
2998af81 SW	81	time_t t = mktime(&tm);
	82	int t_in_range = ex->a <= t && t <= ex->b;
	83	if (!t_in_range)
8559ce11 SW	84	return "Wrong contents in log file: Wrong time";
8559ce11 SW	85	return NULL;
2998af81 SW	86	}
2998af81 SW	87
8559ce11	88	static char line_problem(const ex_t ex, const char *line) {
2998af81 SW	89	size_t line_len = strlen(line);
2998af81 SW	90	if (line_len < TIMESTAMP_LEN + 1)
8559ce11 SW	91	return "Wrong contents in log file: Line too short";
	92	char *trouble = timestamp_problem(ex, line);
	93	if (trouble)
	94	return trouble;
2998af81	95	if (line[TIMESTAMP_LEN] != ' ')
8559ce11	96	return "Wrong contents in log file: Bad format";
2998af81 SW	97	if (strncmp(ex->message, &line[TIMESTAMP_LEN + 1], strlen(ex->message) + 1) !=
2998af81 SW	98	0)
8559ce11 SW	99	return "Wrong contents in log file";
8559ce11 SW	100	return NULL;
83acbf7e SW	101	}
83acbf7e SW	102
8559ce11 SW	103	static void verify_line(const ex_t ex, const char line) {
	104	char *trouble = line_problem(ex, line);
	105	if (trouble)
	106	die(trouble);
	107	}
b3d5ed96	108
8559ce11	109	static void verify_log_contents(const ex_t exps[]) {
d522116b	110	FILE *f = fopen(FILENAME, "r");
b3d5ed96 SW	111	if (f == NULL)
b3d5ed96 SW	112	die_err("Error opening log file");
71a7e5c5	113	for (size_t i = 0; !is_end(exps[i]); i++) {
2998af81	114	size_t len = TIMESTAMP_LEN + 1 + strlen(exps[i].message);
90df84eb SW	115	if (len > INT_MAX - 1)
90df84eb SW	116	die("message too long");
71a7e5c5 SW	117	char buf = (char )malloc(len + 2);
	118	if (fgets(buf, len + 1, f) == NULL)
	119	die("Error reading log file");
	120	if (ferror(f))
	121	die("Error reading log file");
83acbf7e	122	verify_line(&exps[i], buf);
71a7e5c5 SW	123	free(buf);
71a7e5c5 SW	124	}
b3d5ed96 SW	125	if (fclose(f) != 0)
	126	die_err("Error closing log file");
	127	}
	128
8559ce11 SW	129	static void consume_expectation(ex_t exps[], const char *line) {
	130	for (size_t i = 0; !is_end(exps[i]); i++) {
	131	if (line_problem(&exps[i], line) == NULL) {
ee028f60	132	consume(&exps[i]);
8559ce11 SW	133	return;
	134	}
	135	}
	136	die("Wrong contents in log file: Line didn't match any expectation");
	137	}
	138
	139	static void verify_log_contents_unordered(ex_t exps[]) {
	140	FILE *f = fopen(FILENAME, "r");
	141	if (f == NULL)
	142	die_err("Error opening log file");
	143	for (;;) {
	144	const int MAX_LEN = 9999;
	145	char buf[MAX_LEN];
	146	if (fgets(buf, MAX_LEN, f) == NULL) {
	147	if (feof(f))
	148	break;
	149	die("Error reading log file");
	150	}
	151	if (ferror(f))
	152	die("Error reading log file");
	153	consume_expectation(exps, buf);
	154	}
	155	if (fclose(f) != 0)
	156	die_err("Error closing log file");
	157	for (size_t i = 0; !is_end(exps[i]); i++) {
	158	if (!is_consumed(exps[i]))
	159	die("Wrong contents in log file: Unconsumed expectation");
	160	}
	161	}
	162
bab98a3a SW	163	static void test_encode_time() {
	164	/* localtime_r to set tm's timezone */
	165	time_t now_time = time(NULL);
	166	struct tm tm;
	167	if (localtime_r(&now_time, &tm) == NULL)
	168	die_err("Can't unpack current time?");
	169
	170	const char *strptime_result = strptime("2011-12-13 14:15:16", "%F %T", &tm);
	171	if (strptime_result == NULL \|\| *strptime_result != '\0')
	172	die("Couldn't parse time?");
	173	time_t tt = mktime(&tm);
	174	if (tt == (time_t)-1)
	175	die_err("Can't pack time?");
	176
9b76e9d2	177	char *encoded = encode_time(tt);
bab98a3a SW	178	/* Loose check to allow for daylight savings time changes between the current
	179	* time and the target time. :( */
	180	assert(encoded[0] == '2');
	181	assert(encoded[1] == '0');
	182	assert(encoded[2] == '1');
	183	assert(encoded[3] == '1');
	184	assert(encoded[4] == ' ');
	185	assert(encoded[5] == '1');
	186	assert(encoded[6] == '2');
	187	assert(encoded[7] == ' ');
	188	assert(encoded[8] == '1');
	189	assert(encoded[9] == '3');
	190	assert(encoded[10] == ' ');
	191	assert(encoded[11] == '1');
	192	assert(isdigit(encoded[12]));
	193	assert(encoded[13] == ' ');
	194	assert(isdigit(encoded[14]));
	195	assert(isdigit(encoded[15]));
	196	assert(encoded[16] == ' ');
	197	assert(encoded[17] == '1');
	198	assert(encoded[18] == '6');
	199	assert(encoded[19] == '\0');
9b76e9d2	200	free(encoded);
bab98a3a SW	201	}
bab98a3a SW	202
a1160bb5	203	static FILE take_lock(FILE f, char *lock_type) {
8559ce11 SW	204	int fd = fileno(f);
	205	if (fd == -1)
	206	die_err("Couldn't get file descriptor for locking");
a1160bb5 SW	207	if (strcmp(lock_type, "fcntl") == 0) {
	208	if (fcntl(fd, F_SETLK,
	209	&(struct flock){.l_type = F_WRLCK,
	210	.l_whence = SEEK_SET,
	211	.l_start = 0,
	212	.l_len = 0}) == -1)
	213	die_err("Couldn't take fcntl lock");
	214	} else if (strcmp(lock_type, "flock") == 0) {
	215	if (flock(fd, LOCK_EX) == -1)
	216	die_err("Couldn't take flock lock");
	217	} else {
	218	die("Bad lock type");
	219	}
8559ce11 SW	220	return f;
	221	}
	222
	223	static void release_lock(FILE *f) {
	224	if (fclose(f) != 0)
	225	die_err("Error releasing lock");
	226	}
	227
	228	static void release_lock_after_delay(void f) {
a1160bb5	229	sleep(1);
8559ce11 SW	230	release_lock((FILE *)f);
	231	return NULL;
	232	}
	233
	234	static void writer_thread(void start_signal) {
	235	ex_t ex = (ex_t )malloc(sizeof(ex_t));
	236	if (ex == NULL)
	237	die_err("Couldn't allocate memory");
	238	char *message;
	239	if (asprintf(&message, "Hello from thread %lu\n", pthread_self()) == -1)
	240	die("Couldn't prepare message");
	241	pthread_rwlock_rdlock((pthread_rwlock_t *)start_signal);
	242	*ex = write_to_tl_append(message);
	243	return ex;
	244	}
	245
aacfb261	246	static void write_and_read_line() {
27dfbfeb	247	remove_logfile();
71a7e5c5 SW	248	ex_t e = write_to_tl_append("foo\n");
71a7e5c5 SW	249	verify_log_contents((ex_t[]){e, END});
aacfb261 SW	250	}
aacfb261 SW	251
27dfbfeb SW	252	static void write_and_read_two_lines() {
27dfbfeb SW	253	remove_logfile();
71a7e5c5 SW	254	ex_t e1 = write_to_tl_append("foo\n");
	255	ex_t e2 = write_to_tl_append("bar\n");
	256	verify_log_contents((ex_t[]){e1, e2, END});
27dfbfeb SW	257	}
27dfbfeb SW	258
a1160bb5	259	static void write_to_locked_log(char *lock_types[]) {
8559ce11 SW	260	remove_logfile();
8559ce11 SW	261	ex_t e1 = write_to_tl_append("begin\n");
d212cd99	262	FILE *f = fopen(FILENAME, "ae");
a1160bb5 SW	263	if (f == NULL)
	264	die_err("Couldn't open file for locking");
	265	for (int i = 0; lock_types[i]; i++)
	266	take_lock(f, lock_types[0]);
8559ce11 SW	267	pthread_t unlock_thread;
8559ce11 SW	268	int create_ret =
a1160bb5	269	pthread_create(&unlock_thread, NULL, &release_lock_after_delay, f);
8559ce11 SW	270	if (create_ret != 0) {
	271	errno = create_ret;
	272	die_err("Couldn't start thread");
	273	}
	274	ex_t e2 = write_to_tl_append("delayed\n");
	275	int join_ret = pthread_join(unlock_thread, NULL);
	276	if (join_ret != 0) {
	277	errno = join_ret;
	278	die_err("Couldn't join thread");
	279	}
	280	verify_log_contents((ex_t[]){e1, e2, END});
	281	}
	282
	283	static void write_concurrently() {
	284	remove_logfile();
	285	const int PARALLELISM = 250;
	286	pthread_t threads[PARALLELISM];
	287	pthread_rwlock_t start_signal;
	288	pthread_rwlock_init(&start_signal, NULL);
	289	for (int i = 0; i < PARALLELISM; i++) {
	290	int create_ret =
	291	pthread_create(&threads[i], NULL, &writer_thread, &start_signal);
	292	if (create_ret != 0) {
	293	errno = create_ret;
	294	die_err("Couldn't start thread");
	295	}
	296	}
	297	pthread_rwlock_unlock(&start_signal);
	298	ex_t results[PARALLELISM + 1];
	299	for (int i = 0; i < PARALLELISM; i++) {
	300	ex_t *ex;
	301	int join_ret = pthread_join(threads[i], (void **)&ex);
	302	if (join_ret != 0) {
	303	errno = join_ret;
	304	die_err("Couldn't join thread");
	305	}
	306	results[i] = *ex;
	307	free(ex);
	308	}
	309	results[PARALLELISM] = END;
	310	verify_log_contents_unordered(results);
ee028f60 SW	311	for (int i = 0; i < PARALLELISM; i++) {
	312	free((void *)results[i].message);
	313	}
8559ce11 SW	314	}
8559ce11 SW	315
27dfbfeb	316	int main() {
bab98a3a	317	test_encode_time();
27dfbfeb SW	318	write_and_read_line();
27dfbfeb SW	319	write_and_read_two_lines();
a1160bb5 SW	320	write_to_locked_log((char *[]){NULL});
	321	write_to_locked_log((char *[]){"fcntl", NULL});
	322	write_to_locked_log((char *[]){"flock", NULL});
d212cd99	323	write_to_locked_log((char []){"flock", "fcntl", NULL}); / Deadlock risk! */
a1160bb5	324	write_to_locked_log((char *[]){"fcntl", "flock", NULL});
8559ce11	325	write_concurrently();
27dfbfeb	326	}