Commit Graph

22 Commits

Author SHA1 Message Date
Michael Forney edbcc223ea libutil/recurse: Use a single path buffer, and directory fd
This way, we don't use PATH_MAX bytes on the stack per path component,
and don't have to keep copying the complete path around.
2020-03-05 00:45:53 -08:00
Michael Forney 039b54aa51 Use *at functions with appropriate flags instead of lstat/lchown 2020-03-05 00:45:53 -08:00
Michael Forney 60895834f0 libutil/recurse: Use while-loop instead of for-loop with only condition 2019-12-28 22:38:17 -08:00
Michael Forney 45b9b26cae libutil/recurse: Remove some unnecessary parentheses 2019-11-02 14:03:10 -07:00
David Phillips 69b9c2444b libutil/recurse: only opendir if recursing
Previous behaviour was to call opendir regardless of if we are actually going
to be recursing into the directory. Additionally, some utilities that use
DIRFIRST benefit from running the function pointed to by fn before the call
to opendir. One such example is `chmod [-R] 777 dir` on a directory with mode
000, where it will be expected for chmod to first give itself rwx before
optionally listing the directory to traverse it.
2017-10-01 09:34:47 -07:00
FRIGN f83d7bc647 Add SILENT flag to recurse()
recurse() is getting smarter every day. I expect it to pass the Turing
test in a few months.
Along the way, it was reported that "rm -f" on nonexistant files reports
their missing as an internal recurse()-error.
So recurse() knows when to shut up, I added the SILENT flag to fix all
these things.
2015-04-20 11:12:40 +01:00
FRIGN 7b2465c101 Add maxdepth to recurse()
This also makes more sense.
2015-04-20 11:12:40 +01:00
FRIGN e14d9412f8 Properly handle recursion in recurse()
The restructuring of recurse() in the last few weeks actually broke
the recursion-flags in different tools.
As a long-term goal, the recursor should have a field "maxdepth"
which should be "1" for the non-Rflag-case. "0" stands for unlimited.
2015-04-20 11:12:40 +01:00
FRIGN b6b977f63d Audit tar(1), add DIRFIRST-flag to recurse()
I've been wanting to do this for a while now, as tar(1) used to
be one of messiest and cruftiest tools.
First off, before walking through the audit, I'll talk about
what the DIRFIRST-flag for recurse() does.
It basically calls fn() on the first-level-dir before calling
it's subentries. It's necessary here, because else the order
of the tar-files would've been wrong (it would try to create
dir/file before creating dir/).

Now, to the audit:
1)  Update manpage, fix mistake that compression is also available
    for compressing. It's only available for extracting.
2)  Define the major, minor and makedev macros from glibc by ourselves.
    No need to rely on them, as they are common sense.

decomp()
3)  Simple refactorization.

putoctal()
4)  Add a truncation check for snprintf().

archive()
5)  BUGFIX: Add checks to any checkable function, don't blindly call
    them, this is harmful and there are 100 ways to exploit that.
6)  Use estrlcpy() instead of snprintf() wherever possible, fix
    alignment.
7)  BUGFIX: Terminate the result-buffer of readlink(), check if
    it even succeeded.
8)  Fix sizeof()-formatting.

unarchive()
9)  BUGFIX: Add checks to any checkable function, don't blindly call
    them, this is harmful and there are 100 ways to exploit that.
10) BUGFIX: strtoul can happily return negative numbers. Add checks
    for that and also if the full string has been processed.
11) Remove calls to perror(). We have eprintf, use it.
12) BUGFIX: "minor = strtoul(h->mode, 0, 8);". We need h->minor of
    course.
13) Fix typo "usupported", remove fprintf-call.

print()
14) Check fread().

xt()
15) Get rid of snprintf-magic. Use estrlcat().
16) BUGFIX: check for ferror() on the tarfile.

usage()
17) Update it. The old usage() was like 1000 years old.

main()
18) Add DIRFIRST-flag to the recursor.
19) Don't print usage() when a mode is re-set. We allow this in
    general.
20) Add function checks and fix error messages.
21) Add tarfilename-global for proper error-messages.
2015-03-21 01:30:47 +01:00
FRIGN 3111908b03 Refactor recurse() again
Okay, why yet another recurse()-refactor?
The last one added the recursor-struct, which simplified things
on the user-end, but there was still one thing that bugged me a lot:
Previously, all fn()'s were forced to (l)stat the paths themselves.
This does not work well when you try to keep up with H-, L- and P-
flags at the same time, as each utility-function would have to set
the right function-pointer for (l)stat every single time.

This is not desirable. Furthermore, recurse should be easy to use
and not involve trouble finding the right (l)stat-function to do it
right.
So, what we needed was a stat-argument for each fn(), so it is
directly accessible. This was impossible to do though when the
fn()'s are still directly called by the programs to "start" the
recurse.
Thus, the fundamental change is to make recurse() the function to
go, while designing the fn()'s in a way they can "live" with st
being NULL (we don't want a null-pointer-deref).

What you can see in this commit is the result of this work. Why
all this trouble instead of using nftw?
The special thing about recurse() is that you tell the function
when to recurse() in your fn(). You don't need special flags to
tell nftw() to skip the subtree, just to give an example.

The only single downside to this is that now, you are not allowed
to unconditionally call recurse() from your fn(). It has to be
a directory.
However, that is a cost I think is easily weighed up by the
advantages.

Another thing is the history: I added a procedure at the end of
the outmost recurse to free the history. This way we don't leak
memory.

A simple optimization on the side:

-		if (h->dev == st.st_dev && h->ino == st.st_ino)
+		if (h->ino == st.st_ino && h->dev == st.st_dev)

First compare the likely difference in inode-numbers instead of
checking the unlikely condition that the device-numbers are
different.
2015-03-19 01:08:19 +01:00
FRIGN 93fd817536 Add estrlcat() and estrlcpy()
It has become a common idiom in sbase to check strlcat() and strlcpy()
using

if (strl{cat, cpy}(dst, src, siz) >= siz)
        eprintf("path too long\n");

However, this was not carried out consistently and to this very day,
some tools employed unchecked calls to these functions, effectively
allowing silent truncations to happen, which in turn may lead to
security issues.
To finally put an end to this, the e*-functions detect truncation
automatically and the caller can lean back and enjoy coding without
trouble. :)
2015-03-17 11:24:49 +01:00
FRIGN 9fd4a745f8 Add history and config-struct to recurse
For loop detection, a history is mandatory. In the process of also
adding a flexible struct to recurse, the recurse-definition was moved
to fs.h.
The motivation behind the struct is to allow easy extensions to the
recurse-function without having to change the prototypes of all
functions in the process.
Adding flags is really simple as well now.

Using the recursor-struct, it's also easier to see which defaults
apply to a program (for instance, which type of follow, ...).

Another change was to add proper stat-lstat-usage in recurse. It
was wrong before.
2015-03-13 00:29:48 +01:00
FRIGN af61ba738c Refactor recurse()
Instead of allocating a buffer on each run, build a buf on the stack.
2015-03-12 13:22:37 +01:00
FRIGN 01de5df8e6 Audit du(1) and refactor recurse()
While auditing du(1) I realized that there's no way the over 100 lines
of procedures in du() would pass the audit.
Instead, I decided to rewrite this section using recurse() from libutil.
However, the issue was that you'd need some kind of payload to count
the number of bytes in the subdirectories and use them in the higher
hierarchies.
The solution is to add a "void *data" data pointer to each recurse-
function-prototype, which we might also be able to use in other
recurse-applications.
recurse() itself had to be augmented with a recurse_samedev-flag, which
basically prevents recurse from leaving the current device.

Now, let's take a closer look at the audit:
1) Removing the now unnecessary util-functions push, pop, xrealpath,
   rename print() to printpath(), localize some global variables.
2) Only pass the block count to nblks instead of the entire stat-
   pointer.
3) Fix estrtonum to use the minimum of LLONG_MAX and SIZE_MAX.
4) Use idiomatic argv+argc-loop
5) Report proper exit-status.
2015-03-11 23:21:52 +01:00
FRIGN 0b9c02cd22 Use path[len] instead of *(path + len)
Maybe it's time to go to bed...
2015-03-03 00:31:27 +01:00
FRIGN 903d43bbb8 Use dynamic array in recurse() instead of PATH_MAX-array
Thanks Evan!
2015-03-03 00:11:41 +01:00
FRIGN 8dc92fbd6c Refactor enmasse() and recurse() to reflect depth
The HLP-changes to sbase have been a great addition of functionality,
but they kind of "polluted" the enmasse() and recurse() prototypes.
As this will come in handy in the future, knowing at which "depth"
you are inside a recursing function is an important functionality.

Instead of having a special HLP-flag passed to enmasse, each sub-
function needs to provide it on its own and can calculate results
based on the current depth (for instance, 'H' implies 'P' at
depth > 0).
A special case is recurse(), because it actually depends on the
follow-type. A new flag "recurse_follow" brings consistency into
what used to be spread across different naming conventions (fflag,
HLP_flag, ...).

This also fixes numerous bugs with the behaviour of HLP in the
tools using it.
2015-03-02 22:50:38 +01:00
sin 8f068589fb Fix recurse() prototype and convert char to int flags 2015-02-16 16:23:12 +00:00
Tai Chi Minh Ralph Eastwood 0cf6a18f6f recurse: change char follow to int follow 2015-02-16 15:53:58 +00:00
Tai Chi Minh Ralph Eastwood 82bc92da51 recurse: add symlink derefencing flags -H and -L 2015-02-16 15:53:55 +00:00
FRIGN 1436518f9d Use < 0 instead of == -1 2014-11-19 20:09:29 +00:00
sin 027052f5e5 Rename util/ to libutil/ 2014-11-17 16:48:34 +00:00