Allow file locking to be turned off

[tl-append] / tl-append.c

diff --git a/tl-append.c b/tl-append.c
index 0650721f3fc90c32ee5d43d7449901bbe188cd90..1b3a9d0c6fc45572f16c775eae148a09d6d4150c 100644 (file)
--- a/tl-append.c
+++ b/tl-append.c
@@ -21,19 +21,26 @@ const struct timespec ACKNOWLEDGE_DELAY = {0, 300000000};
 
 typedef struct {
   int interactive;
+  int fcntl_lock;
 } conf_t;
 
 conf_t parse_command_line(int argc, char *argv[]) {
-  conf_t conf = {0};
-
-  if (argc == 2 && strcmp(argv[1], "-i") == 0 && isatty(2))
-    conf.interactive = 1;
+  conf_t conf;
+  conf.interactive = 0;
+  conf.fcntl_lock = 1;
+
+  for (int i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "-i") == 0 && isatty(2))
+      conf.interactive = 1;
+    if (strcmp(argv[i], "--no-fnctl-lock") == 0)
+      conf.fcntl_lock = 0;
+  }
 
   return conf;
 }
 
-static void read_line(conf_t conf, char *buf) {
-  if (conf.interactive)
+static void read_line(conf_t *conf, char *buf) {
+  if (conf->interactive)
     if (fputs(PROMPT, stderr) == EOF)
       die("I/O error writing prompt");
   if (fgets(buf, BUF_SIZE, stdin) == NULL) {
@@ -58,7 +65,9 @@ static void write_line(const char *now, FILE *f, const char *line) {
     die("Error writing to output file");
 }
 
-static void take_lock(FILE *f) {
+static void take_lock(conf_t *conf, FILE *f) {
+  if (!conf->fcntl_lock)
+    return;
   struct flock lock;
   lock.l_type = F_WRLCK;
   lock.l_whence = SEEK_SET;
@@ -78,8 +87,8 @@ static void take_lock(FILE *f) {
   die_err("Couldn't take lock");
 }
 
-static void write_acknowledgment(conf_t conf) {
-  if (conf.interactive) {
+static void write_acknowledgment(conf_t *conf) {
+  if (conf->interactive) {
     if (fputs(ACKNOWLEDGE, stderr) == EOF)
       die("Error writing acknowledgment");
     if (nanosleep(&ACKNOWLEDGE_DELAY, NULL) == -1 && errno != EINTR)
@@ -87,11 +96,11 @@ static void write_acknowledgment(conf_t conf) {
   }
 }
 
-static void lock_and_write_line(conf_t conf, const char *line) {
+static void lock_and_write_line(conf_t *conf, const char *line) {
   const char *now = encode_time(time(NULL));
   FILE *f = fopen(FILENAME, "a");
 
-  take_lock(f);
+  take_lock(conf, f);
   write_line(now, f, line);
 
   if (fclose(f) != 0)
@@ -103,8 +112,8 @@ static void lock_and_write_line(conf_t conf, const char *line) {
 int main(int argc, char *argv[]) {
   conf_t conf = parse_command_line(argc, argv);
   char buf[BUF_SIZE];
-  for (read_line(conf, buf); buf[0]; read_line(conf, buf)) {
-    lock_and_write_line(conf, buf);
+  for (read_line(&conf, buf); buf[0]; read_line(&conf, buf)) {
+    lock_and_write_line(&conf, buf);
   }
   return 0;
 }