From 052961eb2e8279f103c091e850c317da335c0207 Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Wed, 23 Jul 2014 13:47:32 +0800
Subject: lib: Move generic file-handling code to lib/

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
 lib/file/file.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 lib/file/file.c

(limited to 'lib/file/file.c')

diff --git a/lib/file/file.c b/lib/file/file.c
new file mode 100644
index 0000000..1bde9fb
--- /dev/null
+++ b/lib/file/file.c
@@ -0,0 +1,123 @@
+/*
+ *  Copyright (C) 2013 Jeremy Kerr <jk@ozlabs.org>
+ *
+ *  This program 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; version 2 of the License.
+ *
+ *  This program 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, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <talloc/talloc.h>
+
+#include "file.h"
+
+static const int max_file_size = 1024 * 1024;
+
+int read_file(void *ctx, const char *filename, char **bufp, int *lenp)
+{
+	struct stat statbuf;
+	int rc, fd, i, len;
+	char *buf;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	rc = fstat(fd, &statbuf);
+	if (rc < 0)
+		goto err_close;
+
+	len = statbuf.st_size;
+	if (len > max_file_size)
+		goto err_close;
+
+	buf = talloc_array(ctx, char, len + 1);
+	if (!buf)
+		goto err_close;
+
+	for (i = 0; i < len; i += rc) {
+		rc = read(fd, buf + i, len - i);
+
+		/* unexpected EOF: trim and return */
+		if (rc == 0) {
+			len = i;
+			break;
+		}
+
+		if (rc < 0)
+			goto err_free;
+
+	}
+
+	buf[len] = '\0';
+
+	close(fd);
+	*bufp = buf;
+	*lenp = len;
+	return 0;
+
+err_free:
+	talloc_free(buf);
+err_close:
+	close(fd);
+	return -1;
+}
+
+static int write_fd(int fd, char *buf, int len)
+{
+	int i, rc;
+
+	for (i = 0; i < len; i += rc) {
+		rc = write(fd, buf + i, len - i);
+		if (rc < 0 && errno != -EINTR)
+			return rc;
+	}
+
+	return 0;
+}
+
+int replace_file(const char *filename, char *buf, int len)
+{
+	char *tempfile;
+	mode_t oldmask;
+	int rc, fd;
+
+	tempfile = talloc_asprintf(NULL, "%s.XXXXXX", filename);
+
+	oldmask = umask(0644);
+	fd = mkstemp(tempfile);
+	umask(oldmask);
+	if (fd < 0) {
+		talloc_free(tempfile);
+		return fd;
+	}
+
+	rc = write_fd(fd, buf, len);
+	if (rc) {
+		unlink(tempfile);
+	} else {
+		rc = rename(tempfile, filename);
+	}
+
+	talloc_free(tempfile);
+
+	fchmod(fd, 0644);
+
+	close(fd);
+	return rc;
+}
-- 
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