X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/aaf70a50e13231ba06df17d79147ac0d7fed6d91..9322ba2854211794c27fae9468768b80b767c211:/sbr/error.c?ds=sidebyside

diff --git a/sbr/error.c b/sbr/error.c
index 184c9509..b33eae54 100644
--- a/sbr/error.c
+++ b/sbr/error.c
@@ -13,11 +13,10 @@
 #include <sys/uio.h>
 
 
-/*
- * print out error message
- */
+/* advise calls advertise() with no tail to print fmt, and perhaps what,
+ * to stderr. */
 void
-advise (char *what, char *fmt, ...)
+advise (const char *what, const char *fmt, ...)
 {
     va_list ap;
 
@@ -27,11 +26,14 @@ advise (char *what, char *fmt, ...)
 }
 
 
-/*
- * print out error message and exit
- */
+/* adios calls advertise() with no tail to print fmt, and perhaps what,
+ * to stderr, and "ends" the program with an error exit status.  The
+ * route to exit is via the done function pointer and may not be
+ * straightforward, e.g. longjmp(3), but it must not return to adios().
+ * If it does then it's a bug and adios() will abort(3) as callers do
+ * not expect execution to continue. */
 void
-adios (char *what, const char *fmt, ...)
+adios (const char *what, const char *fmt, ...)
 {
     va_list ap;
 
@@ -39,12 +41,12 @@ adios (char *what, const char *fmt, ...)
     advertise (what, NULL, fmt, ap);
     va_end(ap);
     done (1);
+    abort();
 }
 
 
-/*
- * admonish the user
- */
+/* admonish calls advertise() with a tail indicating the program
+ * continues. */
 void
 admonish (char *what, char *fmt, ...)
 {
@@ -56,57 +58,72 @@ admonish (char *what, char *fmt, ...)
 }
 
 
-/*
- * main routine for printing error messages.
- */
+/* advertise prints fmt and ap to stderr after flushing stdout.
+ * If invo_name isn't NULL or empty, it precedes the output seperated by ": ".
+ * If what isn't NULL, errno as a string is appended.
+ * A non-empty what separates fmt from errno, surrounded by " " and ": ".
+ * BUG: No space separator before errno if what is "".
+ * If tail isn't NULL or empty then ", " and tail are appended
+ * before the finishing "\n".
+ * In summary: "invo_name: fmt what: errno, tail\n". */
 void
-advertise (char *what, char *tail, const char *fmt, va_list ap)
+advertise (const char *what, char *tail, const char *fmt, va_list ap)
 {
     int	eindex = errno;
-    char buffer[BUFSIZ], err[BUFSIZ];
-    struct iovec iob[20], *iov;
-
-    fflush (stdout);
+    char buffer[NMH_BUFSIZ], errbuf[NMH_BUFSIZ], *err;
+    struct iovec iob[10], *iov;
+    size_t niov;
 
-    fflush (stderr);
     iov = iob;
 
+#define APPEND_IOV(p, len) \
+    iov->iov_base = (p); \
+    iov->iov_len = (len); \
+    iov++
+
+#define ADD_LITERAL(s) APPEND_IOV((s), LEN(s))
+#define ADD_VAR(s) APPEND_IOV((s), strlen(s))
+
     if (invo_name && *invo_name) {
-	iov->iov_len = strlen (iov->iov_base = invo_name);
-	iov++;
-	iov->iov_len = strlen (iov->iov_base = ": ");
-	iov++;
+        ADD_VAR(invo_name);
+	ADD_LITERAL(": ");
     }
     
     vsnprintf (buffer, sizeof(buffer), fmt, ap);
-    iov->iov_len = strlen (iov->iov_base = buffer);
-    iov++;
+    ADD_VAR(buffer);
     if (what) {
 	if (*what) {
-	    iov->iov_len = strlen (iov->iov_base = " ");
-	    iov++;
-	    iov->iov_len = strlen (iov->iov_base = what);
-	    iov++;
-	    iov->iov_len = strlen (iov->iov_base = ": ");
-	    iov++;
+            ADD_LITERAL(" ");
+            ADD_VAR((void *)what);
+            ADD_LITERAL(": ");
 	}
-        if (!(iov->iov_base = strerror (eindex))) {
+        err = strerror(eindex);
+        if (!err) {
 	    /* this shouldn't happen, but we'll test for it just in case */
-	    snprintf (err, sizeof(err), "Error %d", eindex);
-	    iov->iov_base = err;
+	    snprintf(errbuf, sizeof(errbuf), "Error %d", eindex);
+            err = errbuf;
 	}
-	iov->iov_len = strlen (iov->iov_base);
-	iov++;
+        ADD_VAR(err);
     }
     if (tail && *tail) {
-	iov->iov_len = strlen (iov->iov_base = ", ");
-	iov++;
-	iov->iov_len = strlen (iov->iov_base = tail);
-	iov++;
+        ADD_LITERAL(", ");
+        ADD_VAR(tail);
     }
-    iov->iov_len = strlen (iov->iov_base = "\n");
-    iov++;
-    if (writev (fileno (stderr), iob, iov - iob) < 0) {
-	advise ("stderr", "writev");
+    ADD_LITERAL("\n");
+
+#undef ADD_LITERAL
+#undef ADD_VAR
+
+    niov = iov - iob;
+    assert(niov <= DIM(iob));
+
+    fflush (stdout);
+    fflush (stderr);
+    if (writev(fileno(stderr), iob, niov) == -1) {
+        snprintf(buffer, sizeof buffer, "%s: write stderr failed: %d\n",
+            invo_name && *invo_name ? invo_name : "nmh", errno);
+        if (write(2, buffer, strlen(buffer)) == -1) {
+            /* Ignore.  if-statement needed to shut up compiler. */
+        }
     }
 }