tools/bootconfig: Fix to check the write failure correctly

[ Upstream commit a995e6bc0524450adfd6181dfdcd9d0520cfaba5 ]

Fix to check the write(2) failure including partial write
correctly and try to rollback the partial write, because
if there is no BOOTCONFIG_MAGIC string, we can not remove it.

Link: https://lkml.kernel.org/r/160576521135.320071.3883101436675969998.stgit@devnote2
Fixes: 85c46b78da58 ("bootconfig: Add bootconfig magic word for indicating bootconfig explicitly")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index e0878f5f74b1b8cdaae27fe366b2a38ebe2ab097..ffd6a358925da7db0e81b5a77c66557ca337fdf4 100644 (file)
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -274,6 +274,7 @@ static void show_xbc_error(const char *data, const char *msg, int pos)
 
 int apply_xbc(const char *path, const char *xbc_path)
 {
+       struct stat stat;
        u32 size, csum;
        char *buf, *data;
        int ret, fd;
@@ -330,16 +331,26 @@ int apply_xbc(const char *path, const char *xbc_path)
                return fd;
        }
        /* TODO: Ensure the @path is initramfs/initrd image */
+       if (fstat(fd, &stat) < 0) {
+               pr_err("Failed to get the size of %s\n", path);
+               goto out;
+       }
        ret = write(fd, data, size + 8);
-       if (ret < 0) {
+       if (ret < size + 8) {
+               if (ret < 0)
+                       ret = -errno;
                pr_err("Failed to apply a boot config: %d\n", ret);
-               goto out;
+               if (ret < 0)
+                       goto out;
+               goto out_rollback;
        }
        /* Write a magic word of the bootconfig */
        ret = write(fd, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
-       if (ret < 0) {
+       if (ret < BOOTCONFIG_MAGIC_LEN) {
+               if (ret < 0)
+                       ret = -errno;
                pr_err("Failed to apply a boot config magic: %d\n", ret);
-               goto out;
+               goto out_rollback;
        }
        ret = 0;
 out:
@@ -347,6 +358,17 @@ out:
        free(data);
 
        return ret;
+
+out_rollback:
+       /* Map the partial write to -ENOSPC */
+       if (ret >= 0)
+               ret = -ENOSPC;
+       if (ftruncate(fd, stat.st_size) < 0) {
+               ret = -errno;
+               pr_err("Failed to rollback the write error: %d\n", ret);
+               pr_err("The initrd %s may be corrupted. Recommend to rebuild.\n", path);
+       }
+       goto out;
 }
 
 int usage(void)