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-rw-r--r--lib/compat/vsnprintf.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/lib/compat/vsnprintf.c b/lib/compat/vsnprintf.c
new file mode 100644
index 0000000..5f709d9
--- /dev/null
+++ b/lib/compat/vsnprintf.c
@@ -0,0 +1,81 @@
+/*
+ * libcompat - system compatibility library
+ *
+ * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright © 2008-2012 Guillem Jover <guillem@debian.org>
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+
+#include <unistd.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "compat.h"
+
+int
+vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args)
+{
+ static FILE *file = NULL;
+ static pid_t file_pid;
+
+ size_t want, nr;
+ int total;
+
+ if (maxsize != 0 && buf == NULL)
+ return -1;
+
+ /* Avoid race conditions from children after a fork(2). */
+ if (file_pid > 0 && file_pid != getpid()) {
+ fclose(file);
+ file = NULL;
+ }
+
+ if (!file) {
+ file = tmpfile();
+ if (!file)
+ return -1;
+ file_pid = getpid();
+ } else {
+ if (fseek(file, 0, 0))
+ return -1;
+ if (ftruncate(fileno(file), 0))
+ return -1;
+ }
+
+ total = vfprintf(file, fmt, args);
+ if (total < 0)
+ return -1;
+ if (maxsize == 0)
+ return total;
+ if (total >= (int)maxsize)
+ want = maxsize - 1;
+ else
+ want = total;
+ if (fflush(file))
+ return -1;
+ if (fseek(file, 0, SEEK_SET))
+ return -1;
+
+ nr = fread(buf, 1, want, file);
+ if (nr != want)
+ return -1;
+ buf[want] = '\0';
+
+ return total;
+}