Switch from regular files to fifos

diff --git a/x5/khatus.c b/x5/khatus.c
index 34ac42f..a41351a 100644 (file)
--- a/x5/khatus.c
+++ b/x5/khatus.c
@@ -1,19 +1,14 @@
-/*
-
-- [ ] Switch from regular files to named pipes
-       - [ ] poll with select
-
-*/
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/select.h>
 
 #include <assert.h>
 #include <ctype.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include <fcntl.h>
-#include <unistd.h>
-
 #define debug(args...) {fprintf(stderr, "[debug] " args);}
 #define info( args...) {fprintf(stderr, "[info] "  args);}
 #define error(args...) {fprintf(stderr, "[error] " args);}
@@ -37,19 +32,68 @@ typedef struct Config Config;
 struct Config {
        int    interval;
        char * separator;
-       char * timefmt;
        File * files;
        int    file_count;
        int    total_width;
 } defaults = {
        .interval    = 1,
        .separator   = "|",
-       .timefmt     = "%Y-%m-%d %H:%M:%S",
        .files       = NULL,
        .file_count  = 0,
        .total_width = 0,
 };
 
+void
+file_print_one(File *f)
+{
+       debug(
+               "File "
+               "{"
+                       " name = %s,"
+                       " fd = %d,"
+                       " width = %d,"
+                       " last_read = %d,"
+                       " ttl = %d,"
+                       " pos = %d,"
+                       " next = %p,"
+               " }\n",
+               f->name,
+               f->fd,
+               f->width,
+               f->last_read,
+               f->ttl,
+               f->pos,
+               f->next
+       );
+}
+
+void
+file_print_all(File *head)
+{
+       for (File *f = head; f; f = f->next) {
+               file_print_one(f);
+       }
+}
+
+void
+config_print(Config *c)
+{
+       debug(
+               "Config "
+               "{"
+                       " interval = %d,"
+                       " separator = %s,"
+                       " file_count = %d,"
+                       " total_width = %d,"
+                       " files = ..."
+               " }\n",
+               c->interval,
+               c->separator,
+               c->file_count,
+               c->total_width
+       );
+       file_print_all(c->files);
+}
 
 int
 is_pos_num(char *s)
@@ -119,25 +163,12 @@ parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
        }
 }
 
-void
-parse_opts_opt_t(Config *cfg, int argc, char *argv[], int i)
-{
-       if (i < argc) {
-               cfg->timefmt = calloc((strlen(argv[i]) + 1), sizeof(char));
-               strcpy(cfg->timefmt, argv[i]);
-               opts_parse_any(cfg, argc, argv, ++i);
-       } else {
-               usage("Option -t parameter is missing.\n");
-       }
-}
-
 void
 parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
 {
        switch (argv[i][1]) {
                case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break;  /* TODO: Generic set_int */
                case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break;  /* TODO: Generic set_str */
-               case 't': parse_opts_opt_t(cfg, argc, argv, ++i); break;  /* TODO: Generic set_str */
                default : usage("Option \"%s\" is invalid\n", argv[i]);
        }
 }
@@ -201,23 +232,65 @@ opts_parse(Config *cfg, int argc, char *argv[], int i)
        }
 }
 
+void
+read_one(File *f, char *buf)
+{
+       ssize_t n;
+       char *b;
+
+       b = buf + f->pos;
+       memset(b, ' ', f->width);
+       while ((n = read(f->fd, b, f->width)) > 0) {
+               b += n;
+               debug("read %zd from %s\n", n, f->name);
+       }
+
+       if (n > -1) {
+               if (*(b - 1) == '\n')
+                       *(b - 1) = ' ';
+       } else {
+               error(
+                       "Failed to read: \"%s\". Error: %s\n",
+                       f->name,
+                       strerror(errno)
+               );
+       }
+
+       close(f->fd);
+       f->fd = -1;
+}
+
 void
 read_all(Config *cfg, char *buf)
 {
+       fd_set fds;
+       int maxfd;
+       int ready;
+
+       FD_ZERO(&fds);
+
        /* TODO: stat then check TTL */
        for (File *f = cfg->files; f; f = f->next) {
+               debug("opening: %s\n", f->name);
                if (f->fd < 0)
-                       f->fd = open(f->name, O_RDONLY);
-               if (f->fd == -1) {
+                       f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
+               if (f->fd == -1)
                        /* TODO: Consider backing off retries for failed files. */
                        fatal("Failed to open \"%s\"\n", f->name);
-               } else {
-                       lseek(f->fd, 0, 0);
-                       ssize_t n = read(f->fd, buf + f->pos, f->width);
-                       int lasti = n + f->pos - 1;
-                       char lastc = buf[lasti];
-                       if (lastc == '\n')
-                               buf[lasti] = ' ';
+               if (f->fd > maxfd)
+                       maxfd = f->fd;
+               FD_SET(f->fd, &fds);
+       }
+       debug("selecting...\n");
+       ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
+       debug("ready: %d\n", ready);
+       assert(ready != 0);
+       if (ready < 0)
+               fatal("%s", strerror(errno));
+       for (File *f = cfg->files; f; f = f->next) {
+               if (FD_ISSET(f->fd, &fds)) {
+                       debug("reading: %s\n", f->name);
+                       read_one(f, buf);
                }
        }
 }
@@ -236,29 +309,9 @@ main(int argc, char *argv[])
 
        opts_parse(cfg, argc, argv, 1);
        debug("argv0 = %s\n", argv0);
-       debug("[config] interval    = %d\n", cfg->interval);
-       debug("[config] separator   = %s\n", cfg->separator);
-       debug("[config] file_count  = %d\n", cfg->file_count);
-       debug("[config] total_width = %d\n", cfg->total_width);
+       config_print(cfg);
        if (cfg->files == NULL)
                usage("No file specs were given!\n");
-       for (File *f = cfg->files; f; f = f->next) {
-               debug(
-                       "[config] file = "
-                       "{"
-                               " name = %s,"
-                               " pos = %d,"
-                               " width = %d,"
-                               " ttl = %d,"
-                               " last_read = %d,"
-                       " }\n",
-                       f->name,
-                       f->pos,
-                       f->width,
-                       f->ttl,
-                       f->last_read
-               );
-       }
 
        width  = cfg->total_width;
        seplen = strlen(cfg->separator);
@@ -278,14 +331,15 @@ main(int argc, char *argv[])
        /* 2nd pass to set the separators */
        for (File *f = cfg->files; f; f = f->next) {
                if (f->pos) {  /* Skip the first, left-most */
-                       strcpy(buf + (f->pos - seplen), cfg->separator);
+                       /* Copying only seplen ensures we omit the '\0' byte. */
+                       strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
                }
        }
 
+       printf("%s\n", buf);
        /* TODO: nanosleep and nano time diff */
        for (;;) {
                read_all(cfg, buf);
                printf("%s\n", buf);
-               sleep(cfg->interval);
        }
 }