| Message ID | 1458562991-6882-1-git-send-email-ahferroin7@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
Works for me, thanks. Martin Volf On Mon, Mar 21, 2016 at 1:23 PM, Austin S. Hemmelgarn <ahferroin7@gmail.com> wrote: > Currently, btrfs fi du uses open_file_or_dir(), which tries to open > it's argument with o_RDWR. Because of POSIX semantics, this fails for > non-root users when the file is read-only or is an executable that > is being run currently, or for all users (including root) when the > filesystem is read-only. THis results in a somewhat confusing 'Unknown > error -1' message when trying to check such files. Switch to using > open_file_or_dir3() with O_RDONLY passed in the flags, as this avoids > the limitations listed above, and we have no need to write to the files > anyway (and thus shouldn't be opening them writable). > > Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> > --- > Build and runtime tested on x86-64 with glibc. > > I intend to take the time at some point this week to audit all users of > open_file_or_dir() and similarly change any that don't need to write > to what they're opening, possibly adding a helper function to do a > read-only open. > > cmds-fi-du.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/cmds-fi-du.c b/cmds-fi-du.c > index 2ffd917..168fc72 100644 > --- a/cmds-fi-du.c > +++ b/cmds-fi-du.c > @@ -438,7 +438,7 @@ static int du_add_file(const char *filename, int dirfd, > ret = sprintf(pathp, "/%s", filename); > pathp += ret; > > - fd = open_file_or_dir(path, &dirstream); > + fd = open_file_or_dir3(path, &dirstream, O_RDONLY); > if (fd < 0) { > ret = fd; > goto out; > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 21, 2016 at 08:23:11AM -0400, Austin S. Hemmelgarn wrote: > Currently, btrfs fi du uses open_file_or_dir(), which tries to open > it's argument with o_RDWR. Because of POSIX semantics, this fails for > non-root users when the file is read-only or is an executable that > is being run currently, or for all users (including root) when the > filesystem is read-only. THis results in a somewhat confusing 'Unknown > error -1' message when trying to check such files. Switch to using > open_file_or_dir3() with O_RDONLY passed in the flags, as this avoids > the limitations listed above, and we have no need to write to the files > anyway (and thus shouldn't be opening them writable). > > Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> Applied, thanks. > --- > Build and runtime tested on x86-64 with glibc. > > I intend to take the time at some point this week to audit all users of > open_file_or_dir() and similarly change any that don't need to write > to what they're opening, possibly adding a helper function to do a > read-only open. Thanks. I think using open_file_or_dir3(path, &dirstream, O_RDONLY) is ok, no need for a helper. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2016-03-21 13:40, David Sterba wrote: > On Mon, Mar 21, 2016 at 08:23:11AM -0400, Austin S. Hemmelgarn wrote: >> Currently, btrfs fi du uses open_file_or_dir(), which tries to open >> it's argument with o_RDWR. Because of POSIX semantics, this fails for >> non-root users when the file is read-only or is an executable that >> is being run currently, or for all users (including root) when the >> filesystem is read-only. THis results in a somewhat confusing 'Unknown >> error -1' message when trying to check such files. Switch to using >> open_file_or_dir3() with O_RDONLY passed in the flags, as this avoids >> the limitations listed above, and we have no need to write to the files >> anyway (and thus shouldn't be opening them writable). >> >> Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> > > Applied, thanks. > >> --- >> Build and runtime tested on x86-64 with glibc. >> >> I intend to take the time at some point this week to audit all users of >> open_file_or_dir() and similarly change any that don't need to write >> to what they're opening, possibly adding a helper function to do a >> read-only open. > > Thanks. I think using open_file_or_dir3(path, &dirstream, O_RDONLY) is > ok, no need for a helper. > Agreed, especially since this appears to be the only place that used open_file_or_dir() that doesn't potentially need write access. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/cmds-fi-du.c b/cmds-fi-du.c index 2ffd917..168fc72 100644 --- a/cmds-fi-du.c +++ b/cmds-fi-du.c @@ -438,7 +438,7 @@ static int du_add_file(const char *filename, int dirfd, ret = sprintf(pathp, "/%s", filename); pathp += ret; - fd = open_file_or_dir(path, &dirstream); + fd = open_file_or_dir3(path, &dirstream, O_RDONLY); if (fd < 0) { ret = fd; goto out;
Currently, btrfs fi du uses open_file_or_dir(), which tries to open it's argument with o_RDWR. Because of POSIX semantics, this fails for non-root users when the file is read-only or is an executable that is being run currently, or for all users (including root) when the filesystem is read-only. THis results in a somewhat confusing 'Unknown error -1' message when trying to check such files. Switch to using open_file_or_dir3() with O_RDONLY passed in the flags, as this avoids the limitations listed above, and we have no need to write to the files anyway (and thus shouldn't be opening them writable). Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> --- Build and runtime tested on x86-64 with glibc. I intend to take the time at some point this week to audit all users of open_file_or_dir() and similarly change any that don't need to write to what they're opening, possibly adding a helper function to do a read-only open. cmds-fi-du.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)