Cleanly handle select() returning EINTR.

[buftee] / buftee.c

diff --git a/buftee.c b/buftee.c
index 4b03eca..c31ba69 100644 (file)
--- a/buftee.c
+++ b/buftee.c
@@ -175,6 +175,10 @@ static void time_diff(const struct timespec* restrict start,
   assert(out->tv_nsec < 1000000000);
 }
 
+static int gettid(void) {
+  return (int)syscall(SYS_gettid);
+}
+
 static void warn_time(const char* desc,
                       const struct timespec* restrict start,
                       const struct timespec* restrict end) {
@@ -183,9 +187,8 @@ static void warn_time(const char* desc,
   if (diff.tv_sec > 0 || diff.tv_nsec > SLOW_NSEC) {
     char buf[128];
     extern char *__progname;  // This is where glibc stashes argv[0].
-    snprintf(buf, sizeof(buf), "%d: %s: %s took %d.%09d secs\n",
-            (int)getpid(), __progname, desc,
-            (int)diff.tv_sec, (int)diff.tv_nsec);
+    snprintf(buf, sizeof(buf), "%s:tid %d: %s took %d.%09d secs\n",
+            __progname, gettid(), desc, (int)diff.tv_sec, (int)diff.tv_nsec);
     // Best effort write to a non-blocking stderr.
     (void)write(STDERR_FILENO, buf, strlen(buf));
   }
@@ -242,12 +245,17 @@ static int xwrite(const int fd, struct buf* const buf) {
 static int max(const int a, const int b) { return (a > b) ? a : b; }
 
 static void wait_until_readable(const int fd) {
-  int select_ret;
   fd_set read_fds;
   FD_ZERO(&read_fds);
   FD_SET(fd, &read_fds);
-  if ((select_ret = select(fd + 1, &read_fds, NULL, NULL, NULL)) == -1)
+  int select_ret = select(fd + 1, &read_fds, NULL, NULL, NULL);
+  if (select_ret == -1) {
+    if (errno == EINTR) {
+      assert(stopping);  // that should have been SIGTERM
+      return;
+    }
     err(1, "select() failed");
+  }
   if (!FD_ISSET(fd, &read_fds))
     errx(1, "select() did not return readable fd = %d", fd);
 }