From 429dcd8d6a215be133a0b587b69516197922b9ff Mon Sep 17 00:00:00 2001
Message-Id: <429dcd8d6a215be133a0b587b69516197922b9ff.1714632328.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Sat, 13 Feb 2016 19:33:40 +0000
Subject: [PATCH] Properly log fatal errors encountered after program startup.
Organization: Straylight/Edgeware

From: Mark Wooding <mdw@distorted.org.uk>

The code used to use mLib's `die', which reports to stderr, but we ought
properly to report errors to syslog if that's been requested.  So
introduce and use a new function `fatal' which does the right thing, and
use it in the places where it's necessary.
---
 linux.c | 10 +++++-----
 yaid.c  | 11 +++++++++++
 yaid.h  |  3 +++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/linux.c b/linux.c
index ecd43a1..571b179 100644
--- a/linux.c
+++ b/linux.c
@@ -47,8 +47,8 @@ void fill_random(void *p, size_t sz)
   ssize_t n;
 
   n = read(randfd, p, sz);
-  if (n < 0) die(1, "error reading `/dev/urandom': %s", strerror(errno));
-  else if (n < sz) die(1, "unexpected short read from `/dev/urandom'");
+  if (n < 0) fatal("error reading `/dev/urandom': %s", strerror(errno));
+  else if (n < sz) fatal("unexpected short read from `/dev/urandom'");
 }
 
 /*----- Address-type operations -------------------------------------------*/
@@ -118,7 +118,7 @@ static int get_default_gw(int af, union addr *a)
 
   /* Open a netlink socket for interrogating the kernel. */
   if ((fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
-    die(1, "failed to create netlink socket: %s", strerror(errno));
+    fatal("failed to create netlink socket: %s", strerror(errno));
 
   /* We want to read the routing table.  There doesn't seem to be a good way
    * to do this without just crawling through the whole thing.
@@ -135,14 +135,14 @@ static int get_default_gw(int af, union addr *a)
   rtgen->rtgen_family = af;
 
   if (write(fd, nlmsg, nlmsg->nlmsg_len) < 0)
-    die(1, "failed to send RTM_GETROUTE request: %s", strerror(errno));
+    fatal("failed to send RTM_GETROUTE request: %s", strerror(errno));
 
   /* Now we try to parse the answer. */
   for (;;) {
 
     /* Not finished yet, so read another chunk of answer. */
     if ((n = read(fd, buf, sizeof(buf))) < 0)
-      die(1, "failed to read RTM_GETROUTE response: %s", strerror(errno));
+      fatal("failed to read RTM_GETROUTE response: %s", strerror(errno));
 
     /* Start at the beginning of the response. */
     nlmsg = (struct nlmsghdr *)buf;
diff --git a/yaid.c b/yaid.c
index d2244b6..7de374d 100644
--- a/yaid.c
+++ b/yaid.c
@@ -264,6 +264,17 @@ void logmsg(const struct query *q, int prio, const char *msg, ...)
   va_end(ap);
 }
 
+/* Format and report MSG as a fatal error, and exit. */
+void fatal(const char *msg, ...)
+{
+  va_list ap;
+
+  va_start(ap, msg);
+  vlogmsg(0, LOG_CRIT, msg, &ap);
+  va_end(ap);
+  exit(1);
+}
+
 /* Fix up a socket FD so that it won't bite us.  Returns zero on success, or
  * nonzero on error.
  */
diff --git a/yaid.h b/yaid.h
index a148743..eb874cb 100644
--- a/yaid.h
+++ b/yaid.h
@@ -252,6 +252,9 @@ struct query {
 extern void PRINTF_LIKE(3, 4)
   logmsg(const struct query */*q*/, int /*prio*/, const char */*msg*/, ...);
 
+/* Format and report MSG as a fatal error, and exit. */
+extern void PRINTF_LIKE(1, 2) fatal(const char */*msg*/, ...);
+
 /*----- System-specific connection identification code --------------------*/
 
 /* Find out who is responsible for the connection described in the query Q.
-- 
[mdw]