Messages in this thread | | | Date | Thu, 19 Nov 2020 10:41:09 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v4 2/4] tools/bootconfig: Fix to check the write failure correctly |
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On Wed, 18 Nov 2020 11:04:37 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 19 Nov 2020 00:35:35 +0900 > Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > 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. > > > > 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> > > Tested-by: Chen Yu <yu.chen.surf@gmail.com> > > --- > > tools/bootconfig/main.c | 27 +++++++++++++++++++++++---- > > 1 file changed, 23 insertions(+), 4 deletions(-) > > > > diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c > > index 52eb2bbe8966..905bfaefae35 100644 > > --- a/tools/bootconfig/main.c > > +++ b/tools/bootconfig/main.c > > @@ -337,6 +337,7 @@ static int delete_xbc(const char *path) > > > > static int apply_xbc(const char *path, const char *xbc_path) > > { > > + struct stat stat; > > u32 size, csum; > > char *buf, *data; > > int ret, fd; > > @@ -394,16 +395,26 @@ static int apply_xbc(const char *path, const char *xbc_path) > > return ret; > > } > > /* 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: > > @@ -411,6 +422,14 @@ static int apply_xbc(const char *path, const char *xbc_path) > > free(data); > > > > return ret; > > + > > +out_rollback: > > + if (ftruncate(fd, stat.st_size) < 0) { > > If the first write fails (doesn't modify the initrd), and then this fails, > you will show a message of: "may be corrupted. Recommend to rebuild", when > that would not be the case. Should a test of the size be done again, to see > if it is already the same?
Please see the above 2 write error check. You can find
if (ret < 0) goto out;
only in the first check. (I know, it might a bit misleadable) So, the first write is failed with error message, it doesn't call rollback.
> > out_rollback: > old_size = stat.st_size; > if (stat(fd, &stat) < 0) /* Shouldn't happen, it worked once before */ > goto print_error; > > if (old_size < stat.st_size) > if (ftruncate(fd, old_size) < 0) > goto print_error;
If the old_size is current size, ftruncate must do nothing, doesn't it?
Thank you,
> > goto out; > > print_error: > > > + 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; > > } > > > > static int usage(void) > > -- Steve
-- Masami Hiramatsu <mhiramat@kernel.org>
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