Merge branch 'tr/fd-gotcha-fixes'

Two places we did not check return value (expected to be a file
descriptor) correctly.

* tr/fd-gotcha-fixes:
  run-command: dup_devnull(): guard against syscalls failing
  git_mkstemps: correctly test return value of open()

run-command.c

@@ -76,7 +76,10 @@ static inline void close_pair(int fd[2])
 static inline void dup_devnull(int to)
 {
 	int fd = open("/dev/null", O_RDWR);
-	dup2(fd, to);
+	if (fd < 0)
+		die_errno(_("open /dev/null failed"));
+	if (dup2(fd, to) < 0)
+		die_errno(_("dup2(%d,%d) failed"), fd, to);
 	close(fd);
 }
 #endif

wrapper.c

@@ -322,7 +322,7 @@ int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 		template[5] = letters[v % num_letters]; v /= num_letters;
 
 		fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
-		if (fd > 0)
+		if (fd >= 0)
 			return fd;
 		/*
 		 * Fatal error (EPERM, ENOSPC etc).