Put error msg in buffer instead of exiting on read errors

diff --git a/x5/khatus.c b/x5/khatus.c
index 293b346..b21336d 100644 (file)
--- a/x5/khatus.c
+++ b/x5/khatus.c
@@ -18,6 +18,11 @@
 #define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
 #define usage(args...) {print_usage(); fatal("[usage] " args);}
 
+#define ERRMSG "ERROR"
+
+static const char errmsg[] = ERRMSG;
+static const int  errlen   = sizeof(ERRMSG) - 1;
+
 char *argv0;
 
 /* TODO: Convert fifo list to fifo array. */
@@ -243,6 +248,22 @@ opts_parse(Config *cfg, int argc, char *argv[])
        }
 }
 
+void
+read_error(Fifo *f, char *buf)
+{
+       char *b;
+       int i;
+
+       b = buf + f->pos;
+       /* Copy as much of the error message as possible.
+        * EXCLUDING the reminating \0. */
+       for (i = 0; i < errlen && i < f->width; i++)
+               b[i] = errmsg[i];
+       /* Any remaining slots: */
+       for (; i < f->width; i++)
+               b[i] = '_';
+}
+
 void
 read_one(Fifo *f, char *buf)
 {
@@ -259,8 +280,10 @@ read_one(Fifo *f, char *buf)
        memset(b, ' ', f->width);
        while ((current = read(f->fd, &c, 1)) && c != '\n' && c != '\0' && total++ < f->width)
                *b++ = c;
-       if (current == -1)
+       if (current == -1) {
                error("Failed to read: \"%s\". Error: %s\n", f->name, strerror(errno));
+               read_error(f, buf);
+       }
        /* TODO Record timestamp read */
        close(f->fd);
        f->fd = -1;
@@ -278,16 +301,25 @@ read_all(Config *cfg, char *buf)
        /* TODO: Check TTL */
        for (Fifo *f = cfg->fifos; f; f = f->next) {
                /* TODO: Create the FIFO if it doesn't already exist. */
-               if (lstat(f->name, &st) < 0)
-                       fatal("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
-               if (!(st.st_mode & S_IFIFO))
-                       fatal("\"%s\" is not a FIFO\n", f->name);
+               if (lstat(f->name, &st) < 0) {
+                       error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
+                       read_error(f, buf);
+                       continue;
+               }
+               if (!(st.st_mode & S_IFIFO)) {
+                       error("\"%s\" is not a FIFO\n", f->name);
+                       read_error(f, buf);
+                       continue;
+               }
                debug("opening: %s\n", f->name);
                if (f->fd < 0)
                        f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
-               if (f->fd == -1)
+               if (f->fd == -1) {
                        /* TODO: Consider backing off retries for failed fifos. */
-                       fatal("Failed to open \"%s\"\n", f->name);
+                       error("Failed to open \"%s\"\n", f->name);
+                       read_error(f, buf);
+                       continue;
+               }
                if (f->fd > maxfd)
                        maxfd = f->fd;
                FD_SET(f->fd, &fds);
@@ -313,10 +345,12 @@ main(int argc, char *argv[])
        int nfifos = 0;
        int seplen = 0;
        int prefix = 0;
+       int errors = 0;
        char *buf;
        Config cfg0 = defaults;
        Config *cfg = &cfg0;
        Display *display = NULL;
+       struct stat st;
 
        argv0 = argv[0];
 
@@ -326,10 +360,26 @@ main(int argc, char *argv[])
        if (cfg->fifos == NULL)
                usage("No fifo specs were given!\n");
 
+       /* 1st pass to check file existence and type */
+       for (Fifo *f = cfg->fifos; f; f = f->next) {
+               if (lstat(f->name, &st) < 0) {
+                       error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
+                       errors++;
+                       continue;
+               }
+               if (!(st.st_mode & S_IFIFO)) {
+                       error("\"%s\" is not a FIFO\n", f->name);
+                       errors++;
+                       continue;
+               }
+       }
+       if (errors)
+               fatal("Encountered errors with the given file paths. See log.\n");
+
        width  = cfg->total_width;
        seplen = strlen(cfg->separator);
 
-       /* 1st pass to make space for separators */
+       /* 2nd pass to make space for separators */
        for (Fifo *f = cfg->fifos; f; f = f->next) {
                f->pos += prefix;
                prefix += seplen;
@@ -341,7 +391,7 @@ main(int argc, char *argv[])
                fatal("[memory] Failed to allocate buffer of %d bytes", width);
        memset(buf, ' ', width);
        buf[width] = '\0';
-       /* 2nd pass to set the separators */
+       /* 3rd pass to set the separators */
        for (Fifo *f = cfg->fifos; f; f = f->next) {
                if (f->pos) {  /* Skip the first, left-most */
                        /* Copying only seplen ensures we omit the '\0' byte. */