- Do not write `foo ()`, write `foo()`.
-- Preferably allocate local variables on the top of the block:
+## Code Organization and Semantics
- ```c
- {
- int a, b;
+- Please name structures in `PascalCase` (with exceptions, such as public API
+ structs), variables and functions in `snake_case`.
- a = 5;
- b = a;
- }
- ```
+- Avoid static variables, except for caches and very few other cases. Think
+ about thread-safety! While most of our code is never used in threaded
+ environments, at least the library code should make sure it works correctly
+ in them. Instead of doing a lot of locking for that, we tend to prefer using
+ TLS to do per-thread caching (which only works for small, fixed-size cache
+ objects), or we disable caching for any thread that is not the main
+ thread. Use `is_main_thread()` to detect whether the calling thread is the
+ main thread.
-## Other
+- Do not write functions that clobber call-by-reference variables on
+ failure. Use temporary variables for these cases and change the passed in
+ variables only on success.
-- Variables and functions **must** be static, unless they have a
- prototype, and are supposed to be exported.
+- The order in which header files are included doesn't matter too
+ much. systemd-internal headers must not rely on an include order, so it is
+ safe to include them in any order possible. However, to not clutter global
+ includes, and to make sure internal definitions will not affect global
+ headers, please always include the headers of external components first
+ (these are all headers enclosed in <>), followed by our own exported headers
+ (usually everything that's prefixed by `sd-`), and then followed by internal
+ headers. Furthermore, in all three groups, order all includes alphabetically
+ so duplicate includes can easily be detected.
-- structs in `PascalCase` (with exceptions, such as public API structs),
- variables and functions in `snake_case`.
+- Please avoid using global variables as much as you can. And if you do use
+ them make sure they are static at least, instead of exported. Especially in
+ library-like code it is important to avoid global variables. Why are global
+ variables bad? They usually hinder generic reusability of code (since they
+ break in threaded programs, and usually would require locking there), and as
+ the code using them has side-effects make programs non-transparent. That
+ said, there are many cases where they explicitly make a lot of sense, and are
+ OK to use. For example, the log level and target in `log.c` is stored in a
+ global variable, and that's OK and probably expected by most. Also in many
+ cases we cache data in global variables. If you add more caches like this,
+ please be careful however, and think about threading. Only use static
+ variables if you are sure that thread-safety doesn't matter in your
+ case. Alternatively, consider using TLS, which is pretty easy to use with
+ gcc's `thread_local` concept. It's also OK to store data that is inherently
+ global in global variables, for example data parsed from command lines, see
+ below.
-- The destructors always deregister the object from the next bigger
- object, not the other way around.
+- You might wonder what kind of common code belongs in `src/shared/` and what
+ belongs in `src/basic/`. The split is like this: anything that is used to
+ implement the public shared object we provide (sd-bus, sd-login, sd-id128,
+ nss-systemd, nss-mymachines, nss-resolve, nss-myhostname, pam_systemd), must
+ be located in `src/basic` (those objects are not allowed to link to
+ libsystemd-shared.so). Conversely, anything which is shared between multiple
+ components and does not need to be in `src/basic/`, should be in
+ `src/shared/`.
-- To minimize strict aliasing violations, we prefer unions over casting.
+ To summarize:
-- For robustness reasons, destructors should be able to destruct
- half-initialized objects, too.
+ `src/basic/`
+ - may be used by all code in the tree
+ - may not use any code outside of `src/basic/`
-- Error codes are returned as negative `Exxx`. e.g. `return -EINVAL`. There
- are some exceptions: for constructors, it is OK to return `NULL` on
- OOM. For lookup functions, `NULL` is fine too for "not found".
+ `src/libsystemd/`
+ - may be used by all code in the tree, except for code in `src/basic/`
+ - may not use any code outside of `src/basic/`, `src/libsystemd/`
- Be strict with this. When you write a function that can fail due to
- more than one cause, it *really* should have an `int` as the return value
- for the error code.
+ `src/shared/`
+ - may be used by all code in the tree, except for code in `src/basic/`,
+ `src/libsystemd/`, `src/nss-*`, `src/login/pam_systemd.*`, and files under
+ `src/journal/` that end up in `libjournal-client.a` convenience library.
+ - may not use any code outside of `src/basic/`, `src/libsystemd/`, `src/shared/`
-- Do not bother with error checking whether writing to stdout/stderr
- worked.
+- Our focus is on the GNU libc (glibc), not any other libcs. If other libcs are
+ incompatible with glibc it's on them. However, if there are equivalent POSIX
+ and Linux/GNU-specific APIs, we generally prefer the POSIX APIs. If there
+ aren't, we are happy to use GNU or Linux APIs, and expect non-GNU
+ implementations of libc to catch up with glibc.
-- Do not log errors from "library" code, only do so from "main
- program" code. (With one exception: it is OK to log with DEBUG level
- from any code, with the exception of maybe inner loops).
+## Using C Constructs
-- Do not issue NSS requests (that includes user name and host name
- lookups) from PID 1 as this might trigger deadlocks when those
- lookups involve synchronously talking to services that we would need
- to start up.
+- Preferably allocate local variables on the top of the block:
-- Do not synchronously talk to any other service from PID 1, due to
- risk of deadlocks.
+ ```c
+ {
+ int a, b;
-- Be exceptionally careful when formatting and parsing floating point
- numbers. Their syntax is locale dependent (i.e. `5.000` in en_US is
- generally understood as 5, while in de_DE as 5000.).
+ a = 5;
+ b = a;
+ }
+ ```
-- Do not mix function invocations with variable definitions in one
- line. Wrong:
+- Do not mix function invocations with variable definitions in one line. Wrong:
```c
{
}
```
-- Use `goto` for cleaning up, and only use it for that. i.e. you may
- only jump to the end of a function, and little else. Never jump
- backwards!
-
-- Public API calls (i.e. functions exported by our shared libraries)
- must be marked `_public_` and need to be prefixed with `sd_`. No
- other functions should be prefixed like that.
+- Use `goto` for cleaning up, and only use it for that. i.e. you may only jump
+ to the end of a function, and little else. Never jump backwards!
-- In public API calls, you **must** validate all your input arguments for
- programming error with `assert_return()` and return a sensible return
- code. In all other calls, it is recommended to check for programming
- errors with a more brutal `assert()`. We are more forgiving to public
- users than for ourselves! Note that `assert()` and `assert_return()`
- really only should be used for detecting programming errors, not for
- runtime errors. `assert()` and `assert_return()` by usage of `_likely_()`
- inform the compiler that he should not expect these checks to fail,
- and they inform fellow programmers about the expected validity and
- range of parameters.
-
-- For every function you add, think about whether it is a "logging"
- function or a "non-logging" function. "Logging" functions do logging
- on their own, "non-logging" function never log on their own and
- expect their callers to log. All functions in "library" code,
- i.e. in `src/shared/` and suchlike must be "non-logging". Every time a
- "logging" function calls a "non-logging" function, it should log
- about the resulting errors. If a "logging" function calls another
- "logging" function, then it should not generate log messages, so
- that log messages are not generated twice for the same errors.
+- To minimize strict aliasing violations, we prefer unions over casting.
-- If possible, do a combined log & return operation:
+- Instead of using `memzero()`/`memset()` to initialize structs allocated on
+ the stack, please try to use c99 structure initializers. It's short, prettier
+ and actually even faster at execution. Hence:
```c
- r = operation(...);
- if (r < 0)
- return log_(error|warning|notice|...)_errno(r, "Failed to ...: %m");
+ struct foobar t = {
+ .foo = 7,
+ .bar = "bazz",
+ };
```
- If the error value is "synthetic", i.e. it was not received from
- the called function, use `SYNTHETIC_ERRNO` wrapper to tell the logging
- system to not log the errno value, but still return it:
+ instead of:
```c
- n = read(..., s, sizeof s);
- if (n != sizeof s)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read ...");
+ struct foobar t;
+ zero(t);
+ t.foo = 7;
+ t.bar = "bazz";
```
-- Avoid static variables, except for caches and very few other
- cases. Think about thread-safety! While most of our code is never
- used in threaded environments, at least the library code should make
- sure it works correctly in them. Instead of doing a lot of locking
- for that, we tend to prefer using TLS to do per-thread caching (which
- only works for small, fixed-size cache objects), or we disable
- caching for any thread that is not the main thread. Use
- `is_main_thread()` to detect whether the calling thread is the main
- thread.
-
-- Command line option parsing:
- - Do not print full `help()` on error, be specific about the error.
- - Do not print messages to stdout on error.
- - Do not POSIX_ME_HARDER unless necessary, i.e. avoid `+` in option string.
-
-- Do not write functions that clobber call-by-reference variables on
- failure. Use temporary variables for these cases and change the
- passed in variables only on success.
-
-- When you invoke certain calls like `unlink()`, or `mkdir_p()` and you
- know it is safe to ignore the error it might return (because a later
- call would detect the failure anyway, or because the error is in an
- error path and you thus couldn't do anything about it anyway), then
- make this clear by casting the invocation explicitly to `(void)`. Code
- checks like Coverity understand that, and will not complain about
- ignored error codes. Hence, please use this:
+- To implement an endless loop, use `for (;;)` rather than `while (1)`. The
+ latter is a bit ugly anyway, since you probably really meant `while
+ (true)`. To avoid the discussion what the right always-true expression for an
+ infinite while loop is, our recommendation is to simply write it without any
+ such expression by using `for (;;)`.
- ```c
- (void) unlink("/foo/bar/baz");
- ```
+- To determine the length of a constant string `"foo"`, don't bother with
+ `sizeof("foo")-1`, please use `strlen()` instead (both gcc and clang optimize
+ the call away for fixed strings). The only exception is when declaring an
+ array. In that case use STRLEN, which evaluates to a static constant and
+ doesn't force the compiler to create a VLA.
- instead of just this:
+## Destructors
- ```c
- unlink("/foo/bar/baz");
- ```
+- The destructors always deregister the object from the next bigger object, not
+ the other way around.
- Don't cast function calls to `(void)` that return no error
- conditions. Specifically, the various `xyz_unref()` calls that return a `NULL`
- object shouldn't be cast to `(void)`, since not using the return value does not
- hide any errors.
+- For robustness reasons, destructors should be able to destruct
+ half-initialized objects, too.
-- When you define a destructor or `unref()` call for an object, please
- accept a `NULL` object and simply treat this as NOP. This is similar
- to how libc `free()` works, which accepts `NULL` pointers and becomes a
- NOP for them. By following this scheme a lot of `if` checks can be
- removed before invoking your destructor, which makes the code
- substantially more readable and robust.
+- When you define a destructor or `unref()` call for an object, please accept a
+ `NULL` object and simply treat this as NOP. This is similar to how libc
+ `free()` works, which accepts `NULL` pointers and becomes a NOP for them. By
+ following this scheme a lot of `if` checks can be removed before invoking
+ your destructor, which makes the code substantially more readable and robust.
- Related to this: when you define a destructor or `unref()` call for an
- object, please make it return the same type it takes and always
- return `NULL` from it. This allows writing code like this:
+ object, please make it return the same type it takes and always return `NULL`
+ from it. This allows writing code like this:
```c
p = foobar_unref(p);
```
- which will always work regardless if `p` is initialized or not, and
+ which will always work regardless if `p` is initialized or not,x and
guarantees that `p` is `NULL` afterwards, all in just one line.
-- Instead of using `memzero()`/`memset()` to initialize structs allocated
- on the stack, please try to use c99 structure initializers. It's
- short, prettier and actually even faster at execution. Hence:
+## Error Handling
- ```c
- struct foobar t = {
- .foo = 7,
- .bar = "bazz",
- };
- ```
-
- instead of:
+- Error codes are returned as negative `Exxx`. e.g. `return -EINVAL`. There are
+ some exceptions: for constructors, it is OK to return `NULL` on OOM. For
+ lookup functions, `NULL` is fine too for "not found".
- ```c
- struct foobar t;
- zero(t);
- t.foo = 7;
- t.bar = "bazz";
- ```
+ Be strict with this. When you write a function that can fail due to more than
+ one cause, it *really* should have an `int` as the return value for the error
+ code.
-- When returning a return code from `main()`, please preferably use
- `EXIT_FAILURE` and `EXIT_SUCCESS` as defined by libc.
+- Do not bother with error checking whether writing to stdout/stderr worked.
-- The order in which header files are included doesn't matter too
- much. systemd-internal headers must not rely on an include order, so
- it is safe to include them in any order possible.
- However, to not clutter global includes, and to make sure internal
- definitions will not affect global headers, please always include the
- headers of external components first (these are all headers enclosed
- in <>), followed by our own exported headers (usually everything
- that's prefixed by `sd-`), and then followed by internal headers.
- Furthermore, in all three groups, order all includes alphabetically
- so duplicate includes can easily be detected.
+- Do not log errors from "library" code, only do so from "main program"
+ code. (With one exception: it is OK to log with DEBUG level from any code,
+ with the exception of maybe inner loops).
-- To implement an endless loop, use `for (;;)` rather than `while (1)`.
- The latter is a bit ugly anyway, since you probably really
- meant `while (true)`. To avoid the discussion what the right
- always-true expression for an infinite while loop is, our
- recommendation is to simply write it without any such expression by
- using `for (;;)`.
-
-- Commit message subject lines should be prefixed with an appropriate
- component name of some kind. For example "journal: ", "nspawn: " and
- so on.
-
-- Do not use "Signed-Off-By:" in your commit messages. That's a kernel
- thing we don't do in the systemd project.
-
-- Avoid leaving long-running child processes around, i.e. `fork()`s that
- are not followed quickly by an `execv()` in the child. Resource
- management is unclear in this case, and memory CoW will result in
- unexpected penalties in the parent much, much later on.
-
-- Don't block execution for arbitrary amounts of time using `usleep()`
- or a similar call, unless you really know what you do. Just "giving
- something some time", or so is a lazy excuse. Always wait for the
- proper event, instead of doing time-based poll loops.
-
-- To determine the length of a constant string `"foo"`, don't bother with
- `sizeof("foo")-1`, please use `strlen()` instead (both gcc and clang optimize
- the call away for fixed strings). The only exception is when declaring an
- array. In that case use STRLEN, which evaluates to a static constant and
- doesn't force the compiler to create a VLA.
-
-- Please avoid using global variables as much as you can. And if you
- do use them make sure they are static at least, instead of
- exported. Especially in library-like code it is important to avoid
- global variables. Why are global variables bad? They usually hinder
- generic reusability of code (since they break in threaded programs,
- and usually would require locking there), and as the code using them
- has side-effects make programs non-transparent. That said, there are
- many cases where they explicitly make a lot of sense, and are OK to
- use. For example, the log level and target in `log.c` is stored in a
- global variable, and that's OK and probably expected by most. Also
- in many cases we cache data in global variables. If you add more
- caches like this, please be careful however, and think about
- threading. Only use static variables if you are sure that
- thread-safety doesn't matter in your case. Alternatively, consider
- using TLS, which is pretty easy to use with gcc's `thread_local`
- concept. It's also OK to store data that is inherently global in
- global variables, for example data parsed from command lines, see
- below.
+- In public API calls, you **must** validate all your input arguments for
+ programming error with `assert_return()` and return a sensible return
+ code. In all other calls, it is recommended to check for programming errors
+ with a more brutal `assert()`. We are more forgiving to public users than for
+ ourselves! Note that `assert()` and `assert_return()` really only should be
+ used for detecting programming errors, not for runtime errors. `assert()` and
+ `assert_return()` by usage of `_likely_()` inform the compiler that he should
+ not expect these checks to fail, and they inform fellow programmers about the
+ expected validity and range of parameters.
+
+- When you invoke certain calls like `unlink()`, or `mkdir_p()` and you know it
+ is safe to ignore the error it might return (because a later call would
+ detect the failure anyway, or because the error is in an error path and you
+ thus couldn't do anything about it anyway), then make this clear by casting
+ the invocation explicitly to `(void)`. Code checks like Coverity understand
+ that, and will not complain about ignored error codes. Hence, please use
+ this:
-- If you parse a command line, and want to store the parsed parameters
- in global variables, please consider prefixing their names with
- `arg_`. We have been following this naming rule in most of our
- tools, and we should continue to do so, as it makes it easy to
- identify command line parameter variables, and makes it clear why it
- is OK that they are global variables.
+ ```c
+ (void) unlink("/foo/bar/baz");
+ ```
-- When exposing public C APIs, be careful what function parameters you make
- `const`. For example, a parameter taking a context object should probably not
- be `const`, even if you are writing an otherwise read-only accessor function
- for it. The reason is that making it `const` fixates the contract that your
- call won't alter the object ever, as part of the API. However, that's often
- quite a promise, given that this even prohibits object-internal caching or
- lazy initialization of object variables. Moreover, it's usually not too useful
- for client applications. Hence, please be careful and avoid `const` on object
- parameters, unless you are very sure `const` is appropriate.
+ instead of just this:
-- Make sure to enforce limits on every user controllable resource. If the user
- can allocate resources in your code, your code must enforce some form of
- limits after which it will refuse operation. It's fine if it is hard-coded (at
- least initially), but it needs to be there. This is particularly important
- for objects that unprivileged users may allocate, but also matters for
- everything else any user may allocated.
+ ```c
+ unlink("/foo/bar/baz");
+ ```
-- You might wonder what kind of common code belongs in `src/shared/` and what
- belongs in `src/basic/`. The split is like this: anything that is used to
- implement the public shared object we provide (sd-bus, sd-login, sd-id128,
- nss-systemd, nss-mymachines, nss-resolve, nss-myhostname, pam_systemd), must
- be located in `src/basic` (those objects are not allowed to link to
- libsystemd-shared.so). Conversely, anything which is shared between multiple
- components and does not need to be in `src/basic/`, should be in
- `src/shared/`.
+ Don't cast function calls to `(void)` that return no error
+ conditions. Specifically, the various `xyz_unref()` calls that return a
+ `NULL` object shouldn't be cast to `(void)`, since not using the return value
+ does not hide any errors.
- To summarize:
+- When returning a return code from `main()`, please preferably use
+ `EXIT_FAILURE` and `EXIT_SUCCESS` as defined by libc.
- `src/basic/`
- - may be used by all code in the tree
- - may not use any code outside of `src/basic/`
+## Logging
- `src/libsystemd/`
- - may be used by all code in the tree, except for code in `src/basic/`
- - may not use any code outside of `src/basic/`, `src/libsystemd/`
+- For every function you add, think about whether it is a "logging" function or
+ a "non-logging" function. "Logging" functions do logging on their own,
+ "non-logging" function never log on their own and expect their callers to
+ log. All functions in "library" code, i.e. in `src/shared/` and suchlike must
+ be "non-logging". Every time a "logging" function calls a "non-logging"
+ function, it should log about the resulting errors. If a "logging" function
+ calls another "logging" function, then it should not generate log messages,
+ so that log messages are not generated twice for the same errors.
- `src/shared/`
- - may be used by all code in the tree, except for code in `src/basic/`,
- `src/libsystemd/`, `src/nss-*`, `src/login/pam_systemd.*`, and files under
- `src/journal/` that end up in `libjournal-client.a` convenience library.
- - may not use any code outside of `src/basic/`, `src/libsystemd/`, `src/shared/`
+- If possible, do a combined log & return operation:
-- Our focus is on the GNU libc (glibc), not any other libcs. If other libcs are
- incompatible with glibc it's on them. However, if there are equivalent POSIX
- and Linux/GNU-specific APIs, we generally prefer the POSIX APIs. If there
- aren't, we are happy to use GNU or Linux APIs, and expect non-GNU
- implementations of libc to catch up with glibc.
+ ```c
+ r = operation(...);
+ if (r < 0)
+ return log_(error|warning|notice|...)_errno(r, "Failed to ...: %m");
+ ```
-- Whenever installing a signal handler, make sure to set `SA_RESTART` for it, so
- that interrupted system calls are automatically restarted, and we minimize
- hassles with handling `EINTR` (in particular as `EINTR` handling is pretty broken
- on Linux).
+ If the error value is "synthetic", i.e. it was not received from
+ the called function, use `SYNTHETIC_ERRNO` wrapper to tell the logging
+ system to not log the errno value, but still return it:
-- When applying C-style unescaping as well as specifier expansion on the same
- string, always apply the C-style unescaping fist, followed by the specifier
- expansion. When doing the reverse, make sure to escape `%` in specifier-style
- first (i.e. `%` → `%%`), and then do C-style escaping where necessary.
+ ```c
+ n = read(..., s, sizeof s);
+ if (n != sizeof s)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read ...");
+ ```
## Memory Allocation
matters particularly in inner loops (but note that `strjoina()` cannot be
used there).
+## Runtime Behaviour
+
+- Avoid leaving long-running child processes around, i.e. `fork()`s that are
+ not followed quickly by an `execv()` in the child. Resource management is
+ unclear in this case, and memory CoW will result in unexpected penalties in
+ the parent much, much later on.
+
+- Don't block execution for arbitrary amounts of time using `usleep()` or a
+ similar call, unless you really know what you do. Just "giving something some
+ time", or so is a lazy excuse. Always wait for the proper event, instead of
+ doing time-based poll loops.
+
+- Whenever installing a signal handler, make sure to set `SA_RESTART` for it,
+ so that interrupted system calls are automatically restarted, and we minimize
+ hassles with handling `EINTR` (in particular as `EINTR` handling is pretty
+ broken on Linux).
+
+- When applying C-style unescaping as well as specifier expansion on the same
+ string, always apply the C-style unescaping fist, followed by the specifier
+ expansion. When doing the reverse, make sure to escape `%` in specifier-style
+ first (i.e. `%` → `%%`), and then do C-style escaping where necessary.
+
+- Be exceptionally careful when formatting and parsing floating point
+ numbers. Their syntax is locale dependent (i.e. `5.000` in en_US is generally
+ understood as 5, while in de_DE as 5000.).
+
+- Make sure to enforce limits on every user controllable resource. If the user
+ can allocate resources in your code, your code must enforce some form of
+ limits after which it will refuse operation. It's fine if it is hard-coded
+ (at least initially), but it needs to be there. This is particularly
+ important for objects that unprivileged users may allocate, but also matters
+ for everything else any user may allocated.
+
## Types
- Think about the types you use. If a value cannot sensibly be negative, do not
headers (i.e those in `src/systemd/sd-*.h`) use integers after all, as `bool`
is C99 and in our public APIs we try to stick to C89 (with a few extension).
+## Deadlocks
+
+- Do not issue NSS requests (that includes user name and host name lookups)
+ from PID 1 as this might trigger deadlocks when those lookups involve
+ synchronously talking to services that we would need to start up.
+
+- Do not synchronously talk to any other service from PID 1, due to risk of
+ deadlocks.
+
## File Descriptors
- When you allocate a file descriptor, it should be made `O_CLOEXEC` right from
effect on the regular file. If in doubt consider turning off `O_NONBLOCK`
again after opening.
+## Command Line
+
+- If you parse a command line, and want to store the parsed parameters in
+ global variables, please consider prefixing their names with `arg_`. We have
+ been following this naming rule in most of our tools, and we should continue
+ to do so, as it makes it easy to identify command line parameter variables,
+ and makes it clear why it is OK that they are global variables.
+
+- Command line option parsing:
+ - Do not print full `help()` on error, be specific about the error.
+ - Do not print messages to stdout on error.
+ - Do not POSIX_ME_HARDER unless necessary, i.e. avoid `+` in option string.
+
+## Exporting Symbols
+
+- Variables and functions **must** be static, unless they have a prototype, and
+ are supposed to be exported.
+
+- Public API calls (i.e. functions exported by our shared libraries)
+ must be marked `_public_` and need to be prefixed with `sd_`. No
+ other functions should be prefixed like that.
+
+- When exposing public C APIs, be careful what function parameters you make
+ `const`. For example, a parameter taking a context object should probably not
+ be `const`, even if you are writing an otherwise read-only accessor function
+ for it. The reason is that making it `const` fixates the contract that your
+ call won't alter the object ever, as part of the API. However, that's often
+ quite a promise, given that this even prohibits object-internal caching or
+ lazy initialization of object variables. Moreover, it's usually not too
+ useful for client applications. Hence, please be careful and avoid `const` on
+ object parameters, unless you are very sure `const` is appropriate.
+
## Referencing Concepts
- When referring to a configuration file option in the documentation and such,
only reason to include `libgen.h` is because `dirname()` is needed. Every
time you need that please immediately undefine `basename()`, and add a
comment about it, so that no code ever ends up using the POSIX version!
+
+# Committing to git
+
+- Commit message subject lines should be prefixed with an appropriate component
+ name of some kind. For example "journal: ", "nspawn: " and so on.
+
+- Do not use "Signed-Off-By:" in your commit messages. That's a kernel thing we
+ don't do in the systemd project.
projects / thirdparty / systemd.git / blobdiff