mirror of
https://github.com/clearml/dropbear
synced 2025-01-31 02:46:58 +00:00
60 lines
1.7 KiB
Markdown
60 lines
1.7 KiB
Markdown
## Tips for a small system
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If you only want server functionality, compile with
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```
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make PROGRAMS=dropbear
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```
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rather than just
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```
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make dropbear
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```
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so that client functionality in shared portions of Dropbear won't be included.
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The same applies for `PROGRAMS=dbclient`.
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---
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The following are set in `localoptions.h`. See `default_options.h` for possibilities.
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You can disable either password or public-key authentication.
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Various algorithms can be disabled if they are not required by any connecting SSH clients/servers.
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Disabling many is fine for a local install, though
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builds for public consumption require more consideration.
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You can disable x11, tcp and agent forwarding as desired. None of these are essential (depending on use cases).
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---
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If you are compiling statically, you may want to disable zlib, as it will use a few tens of kB of binary size
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```
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./configure --disable-zlib
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```
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You can create a combined binary, see the file [MULTI.md](MULTI.md), which will put all the functions into one binary, avoiding repeated code.
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If you're compiling with gcc, you might want to look at gcc's options for stripping unused code.
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The relevant vars to set before configure are:
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```
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LDFLAGS=-Wl,--gc-sections
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CFLAGS="-ffunction-sections -fdata-sections"
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```
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You can also experiment with optimisation flags such as `-Os`. Note that in some cases these flags actually seem to increase size, so experiment before
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deciding.
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Of course using small C libraries such as musl can also help.
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---
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Libtommath has its own default `CFLAGS` to improve speed. You can use
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```
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./configure LTM_CFLAGS=-Os
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```
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to reduce size at the expense of speed.
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If you have any queries, mail me and I'll see if I can help.
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