On Friday 04 April 2008 11:27, Michele Sanges wrote:
> Il giorno ven, 28/03/2008 alle 09.06 -0400, Paul Fox ha scritto:
> > is the proper solution simply to open it twice, once for reading,
> > and once for writing? this guarantees a writer (which will never
> > write anything).
>
> Following the suggestion of Paul, now I open the fifo twice to use the
> opportunity to make the read blocking.
This seems to be a good idea. I am committing the attached patch
to svn. Saves ~70 bytes.
--
vda
diff -d -urpN busybox.6/miscutils/fbsplash.c busybox.7/miscutils/fbsplash.c
--- busybox.6/miscutils/fbsplash.c 2008-03-31 21:26:17.000000000 +0200
+++ busybox.7/miscutils/fbsplash.c 2008-04-04 22:32:36.000000000 +0200
@@ -360,6 +360,8 @@ int fbsplash_main(int argc ATTRIBUTE_UNU
{
const char *fb_device, *cfg_filename, *fifo_filename;
FILE *fp = fp; // for compiler
+ char *num_buf;
+ unsigned num;
bool bCursorOff;
INIT_G();
@@ -392,49 +394,7 @@ int fbsplash_main(int argc ATTRIBUTE_UNU
return EXIT_SUCCESS;
fp = xfopen_stdin(fifo_filename);
-
- while (1) {
- struct stat statbuf;
- unsigned num;
- char *num_buf;
-
- fb_drawprogressbar(0);
- // Block on read, waiting for some input.
- // Use of <stdio.h> style I/O allows to correctly
- // handle a case when we have many buffered lines
- // already in the pipe
- while ((num_buf = xmalloc_fgetline(fp)) != NULL) {
- if (strncmp(num_buf, "exit", 4) == 0) {
- DEBUG_MESSAGE("exit");
- exit_cmd:
- if (bCursorOff) {
- // restore cursor
- full_write(STDOUT_FILENO, "\x1b" "[?25h", 6);
- }
- return EXIT_SUCCESS;
- }
- num = atoi(num_buf);
- if (isdigit(num_buf[0]) && (num <= 100)) {
-#if DEBUG
- char strVal[10];
- sprintf(strVal, "%d", num);
- DEBUG_MESSAGE(strVal);
-#endif
- fb_drawprogressbar(num);
- }
- free(num_buf);
- }
- // We got EOF/error on fp
- if (ferror(fp))
- goto exit_cmd;
- fclose(fp);
- if (LONE_DASH(fifo_filename)
- || stat(fifo_filename, &statbuf) != 0
- || !S_ISFIFO(statbuf.st_mode)
- ) {
- goto exit_cmd;
- }
- // It's really a named pipe!
+ if (fp != stdin) {
// For named pipes, we want to support this:
// mkfifo cmd_pipe
// fbsplash -f cmd_pipe .... &
@@ -442,10 +402,37 @@ int fbsplash_main(int argc ATTRIBUTE_UNU
// echo 33 >cmd_pipe
// ...
// echo 66 >cmd_pipe
- // This means that on EOF, we need to close/open cmd_pipe
- // (just reading again works too, but it hogs CPU)
- fp = xfopen_stdin(fifo_filename); // blocks on open
- } // end of while (1)
+ // This means that we don't want fbsplash to get EOF
+ // when last writer closes input end.
+ // The simplest way is to open fifo for writing too
+ // and become an additional writer :)
+ open(fifo_filename, O_WRONLY); // errors are ignored
+ }
+
+ fb_drawprogressbar(0);
+ // Block on read, waiting for some input.
+ // Use of <stdio.h> style I/O allows to correctly
+ // handle a case when we have many buffered lines
+ // already in the pipe
+ while ((num_buf = xmalloc_fgetline(fp)) != NULL) {
+ if (strncmp(num_buf, "exit", 4) == 0) {
+ DEBUG_MESSAGE("exit");
+ break;
+ }
+ num = atoi(num_buf);
+ if (isdigit(num_buf[0]) && (num <= 100)) {
+#if DEBUG
+ char strVal[10];
+ sprintf(strVal, "%d", num);
+ DEBUG_MESSAGE(strVal);
+#endif
+ fb_drawprogressbar(num);
+ }
+ free(num_buf);
+ }
+
+ if (bCursorOff) // restore cursor
+ full_write(STDOUT_FILENO, "\x1b" "[?25h", 6);
return EXIT_SUCCESS;
}
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