diff options
Diffstat (limited to 'src/libutil/util.hh')
| -rw-r--r-- | src/libutil/util.hh | 509 |
1 files changed, 360 insertions, 149 deletions
diff --git a/src/libutil/util.hh b/src/libutil/util.hh index 5a3976d02..040fed68f 100644 --- a/src/libutil/util.hh +++ b/src/libutil/util.hh @@ -1,4 +1,5 @@ #pragma once +///@file #include "types.hh" #include "error.hh" @@ -31,78 +32,114 @@ namespace nix { struct Sink; struct Source; +void initLibUtil(); -/* The system for which Nix is compiled. */ +/** + * The system for which Nix is compiled. + */ extern const std::string nativeSystem; -/* Return an environment variable. */ +/** + * @return an environment variable. + */ std::optional<std::string> getEnv(const std::string & key); -/* Return a non empty environment variable. Returns nullopt if the env -variable is set to "" */ +/** + * @return a non empty environment variable. Returns nullopt if the env + * variable is set to "" + */ std::optional<std::string> getEnvNonEmpty(const std::string & key); -/* Get the entire environment. */ +/** + * Get the entire environment. + */ std::map<std::string, std::string> getEnv(); -/* Clear the environment. */ +/** + * Clear the environment. + */ void clearEnv(); -/* Return an absolutized path, resolving paths relative to the - specified directory, or the current directory otherwise. The path - is also canonicalised. */ +/** + * @return An absolutized path, resolving paths relative to the + * specified directory, or the current directory otherwise. The path + * is also canonicalised. + */ Path absPath(Path path, std::optional<PathView> dir = {}, bool resolveSymlinks = false); -/* Canonicalise a path by removing all `.' or `..' components and - double or trailing slashes. Optionally resolves all symlink - components such that each component of the resulting path is *not* - a symbolic link. */ +/** + * Canonicalise a path by removing all `.` or `..` components and + * double or trailing slashes. Optionally resolves all symlink + * components such that each component of the resulting path is *not* + * a symbolic link. + */ Path canonPath(PathView path, bool resolveSymlinks = false); -/* Return the directory part of the given canonical path, i.e., - everything before the final `/'. If the path is the root or an - immediate child thereof (e.g., `/foo'), this means `/' - is returned.*/ +/** + * @return The directory part of the given canonical path, i.e., + * everything before the final `/`. If the path is the root or an + * immediate child thereof (e.g., `/foo`), this means `/` + * is returned. + */ Path dirOf(const PathView path); -/* Return the base name of the given canonical path, i.e., everything - following the final `/' (trailing slashes are removed). */ +/** + * @return the base name of the given canonical path, i.e., everything + * following the final `/` (trailing slashes are removed). + */ std::string_view baseNameOf(std::string_view path); -/* Perform tilde expansion on a path. */ +/** + * Perform tilde expansion on a path. + */ std::string expandTilde(std::string_view path); -/* Check whether 'path' is a descendant of 'dir'. Both paths must be - canonicalized. */ +/** + * Check whether 'path' is a descendant of 'dir'. Both paths must be + * canonicalized. + */ bool isInDir(std::string_view path, std::string_view dir); -/* Check whether 'path' is equal to 'dir' or a descendant of - 'dir'. Both paths must be canonicalized. */ +/** + * Check whether 'path' is equal to 'dir' or a descendant of + * 'dir'. Both paths must be canonicalized. + */ bool isDirOrInDir(std::string_view path, std::string_view dir); -/* Get status of `path'. */ +/** + * Get status of `path`. + */ struct stat stat(const Path & path); struct stat lstat(const Path & path); -/* Return true iff the given path exists. */ +/** + * @return true iff the given path exists. + */ bool pathExists(const Path & path); -/* Read the contents (target) of a symbolic link. The result is not - in any way canonicalised. */ +/** + * Read the contents (target) of a symbolic link. The result is not + * in any way canonicalised. + */ Path readLink(const Path & path); bool isLink(const Path & path); -/* Read the contents of a directory. The entries `.' and `..' are - removed. */ +/** + * Read the contents of a directory. The entries `.` and `..` are + * removed. + */ struct DirEntry { std::string name; ino_t ino; - unsigned char type; // one of DT_* + /** + * one of DT_* + */ + unsigned char type; DirEntry(std::string name, ino_t ino, unsigned char type) : name(std::move(name)), ino(ino), type(type) { } }; @@ -113,74 +150,110 @@ DirEntries readDirectory(const Path & path); unsigned char getFileType(const Path & path); -/* Read the contents of a file into a string. */ +/** + * Read the contents of a file into a string. + */ std::string readFile(int fd); std::string readFile(const Path & path); void readFile(const Path & path, Sink & sink); -/* Write a string to a file. */ +/** + * Write a string to a file. + */ void writeFile(const Path & path, std::string_view s, mode_t mode = 0666, bool sync = false); void writeFile(const Path & path, Source & source, mode_t mode = 0666, bool sync = false); -/* Flush a file's parent directory to disk */ +/** + * Flush a file's parent directory to disk + */ void syncParent(const Path & path); -/* Read a line from a file descriptor. */ +/** + * Read a line from a file descriptor. + */ std::string readLine(int fd); -/* Write a line to a file descriptor. */ +/** + * Write a line to a file descriptor. + */ void writeLine(int fd, std::string s); -/* Delete a path; i.e., in the case of a directory, it is deleted - recursively. It's not an error if the path does not exist. The - second variant returns the number of bytes and blocks freed. */ +/** + * Delete a path; i.e., in the case of a directory, it is deleted + * recursively. It's not an error if the path does not exist. The + * second variant returns the number of bytes and blocks freed. + */ void deletePath(const Path & path); void deletePath(const Path & path, uint64_t & bytesFreed); std::string getUserName(); -/* Return the given user's home directory from /etc/passwd. */ +/** + * @return the given user's home directory from /etc/passwd. + */ Path getHomeOf(uid_t userId); -/* Return $HOME or the user's home directory from /etc/passwd. */ +/** + * @return $HOME or the user's home directory from /etc/passwd. + */ Path getHome(); -/* Return $XDG_CACHE_HOME or $HOME/.cache. */ +/** + * @return $XDG_CACHE_HOME or $HOME/.cache. + */ Path getCacheDir(); -/* Return $XDG_CONFIG_HOME or $HOME/.config. */ +/** + * @return $XDG_CONFIG_HOME or $HOME/.config. + */ Path getConfigDir(); -/* Return the directories to search for user configuration files */ +/** + * @return the directories to search for user configuration files + */ std::vector<Path> getConfigDirs(); -/* Return $XDG_DATA_HOME or $HOME/.local/share. */ +/** + * @return $XDG_DATA_HOME or $HOME/.local/share. + */ Path getDataDir(); -/* Return the path of the current executable. */ +/** + * @return the path of the current executable. + */ std::optional<Path> getSelfExe(); -/* Return $XDG_STATE_HOME or $HOME/.local/state. */ +/** + * @return $XDG_STATE_HOME or $HOME/.local/state. + */ Path getStateDir(); -/* Create the Nix state directory and return the path to it. */ +/** + * Create the Nix state directory and return the path to it. + */ Path createNixStateDir(); -/* Create a directory and all its parents, if necessary. Returns the - list of created directories, in order of creation. */ +/** + * Create a directory and all its parents, if necessary. Returns the + * list of created directories, in order of creation. + */ Paths createDirs(const Path & path); inline Paths createDirs(PathView path) { return createDirs(Path(path)); } -/* Create a symlink. */ +/** + * Create a symlink. + */ void createSymlink(const Path & target, const Path & link, std::optional<time_t> mtime = {}); -/* Atomically create or replace a symlink. */ +/** + * Atomically create or replace a symlink. + */ void replaceSymlink(const Path & target, const Path & link, std::optional<time_t> mtime = {}); @@ -196,24 +269,32 @@ void renameFile(const Path & src, const Path & dst); void moveFile(const Path & src, const Path & dst); -/* Wrappers arount read()/write() that read/write exactly the - requested number of bytes. */ +/** + * Wrappers arount read()/write() that read/write exactly the + * requested number of bytes. + */ void readFull(int fd, char * buf, size_t count); void writeFull(int fd, std::string_view s, bool allowInterrupts = true); MakeError(EndOfFile, Error); -/* Read a file descriptor until EOF occurs. */ +/** + * Read a file descriptor until EOF occurs. + */ std::string drainFD(int fd, bool block = true, const size_t reserveSize=0); void drainFD(int fd, Sink & sink, bool block = true); -/* If cgroups are active, attempt to calculate the number of CPUs available. - If cgroups are unavailable or if cpu.max is set to "max", return 0. */ +/** + * If cgroups are active, attempt to calculate the number of CPUs available. + * If cgroups are unavailable or if cpu.max is set to "max", return 0. + */ unsigned int getMaxCPU(); -/* Automatic cleanup of resources. */ +/** + * Automatic cleanup of resources. + */ class AutoDelete @@ -251,11 +332,15 @@ public: }; -/* Create a temporary directory. */ +/** + * Create a temporary directory. + */ Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix", bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755); -/* Create a temporary file, returning a file handle and its path. */ +/** + * Create a temporary file, returning a file handle and its path. + */ std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix = "nix"); @@ -298,27 +383,36 @@ public: }; -/* Kill all processes running under the specified uid by sending them - a SIGKILL. */ +/** + * Kill all processes running under the specified uid by sending them + * a SIGKILL. + */ void killUser(uid_t uid); -/* Fork a process that runs the given function, and return the child - pid to the caller. */ +/** + * Fork a process that runs the given function, and return the child + * pid to the caller. + */ struct ProcessOptions { std::string errorPrefix = ""; bool dieWithParent = true; bool runExitHandlers = false; bool allowVfork = false; - int cloneFlags = 0; // use clone() with the specified flags (Linux only) + /** + * use clone() with the specified flags (Linux only) + */ + int cloneFlags = 0; }; pid_t startProcess(std::function<void()> fun, const ProcessOptions & options = ProcessOptions()); -/* Run a program and return its stdout in a string (i.e., like the - shell backtick operator). */ +/** + * Run a program and return its stdout in a string (i.e., like the + * shell backtick operator). + */ std::string runProgram(Path program, bool searchPath = false, const Strings & args = Strings(), const std::optional<std::string> & input = {}); @@ -343,25 +437,37 @@ std::pair<int, std::string> runProgram(RunOptions && options); void runProgram2(const RunOptions & options); -/* Change the stack size. */ +/** + * Change the stack size. + */ void setStackSize(size_t stackSize); -/* Restore the original inherited Unix process context (such as signal - masks, stack size). */ +/** + * Restore the original inherited Unix process context (such as signal + * masks, stack size). + + * See startSignalHandlerThread(), saveSignalMask(). + */ void restoreProcessContext(bool restoreMounts = true); -/* Save the current mount namespace. Ignored if called more than - once. */ +/** + * Save the current mount namespace. Ignored if called more than + * once. + */ void saveMountNamespace(); -/* Restore the mount namespace saved by saveMountNamespace(). Ignored - if saveMountNamespace() was never called. */ +/** + * Restore the mount namespace saved by saveMountNamespace(). Ignored + * if saveMountNamespace() was never called. + */ void restoreMountNamespace(); -/* Cause this thread to not share any FS attributes with the main - thread, because this causes setns() in restoreMountNamespace() to - fail. */ +/** + * Cause this thread to not share any FS attributes with the main + * thread, because this causes setns() in restoreMountNamespace() to + * fail. + */ void unshareFilesystem(); @@ -376,16 +482,22 @@ public: { } }; -/* Convert a list of strings to a null-terminated vector of char - *'s. The result must not be accessed beyond the lifetime of the - list of strings. */ +/** + * Convert a list of strings to a null-terminated vector of `char + * *`s. The result must not be accessed beyond the lifetime of the + * list of strings. + */ std::vector<char *> stringsToCharPtrs(const Strings & ss); -/* Close all file descriptors except those listed in the given set. - Good practice in child processes. */ +/** + * Close all file descriptors except those listed in the given set. + * Good practice in child processes. + */ void closeMostFDs(const std::set<int> & exceptions); -/* Set the close-on-exec flag for the given file descriptor. */ +/** + * Set the close-on-exec flag for the given file descriptor. + */ void closeOnExec(int fd); @@ -411,12 +523,16 @@ MakeError(Interrupted, BaseError); MakeError(FormatError, Error); -/* String tokenizer. */ +/** + * String tokenizer. + */ template<class C> C tokenizeString(std::string_view s, std::string_view separators = " \t\n\r"); -/* Concatenate the given strings with a separator between the - elements. */ +/** + * Concatenate the given strings with a separator between the + * elements. + */ template<class C> std::string concatStringsSep(const std::string_view sep, const C & ss) { @@ -441,7 +557,9 @@ auto concatStrings(Parts && ... parts) } -/* Add quotes around a collection of strings. */ +/** + * Add quotes around a collection of strings. + */ template<class C> Strings quoteStrings(const C & c) { Strings res; @@ -450,16 +568,23 @@ template<class C> Strings quoteStrings(const C & c) return res; } -/* Remove trailing whitespace from a string. FIXME: return - std::string_view. */ +/** + * Remove trailing whitespace from a string. + * + * \todo return std::string_view. + */ std::string chomp(std::string_view s); -/* Remove whitespace from the start and end of a string. */ +/** + * Remove whitespace from the start and end of a string. + */ std::string trim(std::string_view s, std::string_view whitespace = " \n\r\t"); -/* Replace all occurrences of a string inside another string. */ +/** + * Replace all occurrences of a string inside another string. + */ std::string replaceStrings( std::string s, std::string_view from, @@ -469,14 +594,18 @@ std::string replaceStrings( std::string rewriteStrings(std::string s, const StringMap & rewrites); -/* Convert the exit status of a child as returned by wait() into an - error string. */ +/** + * Convert the exit status of a child as returned by wait() into an + * error string. + */ std::string statusToString(int status); bool statusOk(int status); -/* Parse a string into an integer. */ +/** + * Parse a string into an integer. + */ template<class N> std::optional<N> string2Int(const std::string_view s) { @@ -489,8 +618,10 @@ std::optional<N> string2Int(const std::string_view s) } } -/* Like string2Int(), but support an optional suffix 'K', 'M', 'G' or - 'T' denoting a binary unit prefix. */ +/** + * Like string2Int(), but support an optional suffix 'K', 'M', 'G' or + * 'T' denoting a binary unit prefix. + */ template<class N> N string2IntWithUnitPrefix(std::string_view s) { @@ -511,7 +642,9 @@ N string2IntWithUnitPrefix(std::string_view s) throw UsageError("'%s' is not an integer", s); } -/* Parse a string into a float. */ +/** + * Parse a string into a float. + */ template<class N> std::optional<N> string2Float(const std::string_view s) { @@ -523,7 +656,9 @@ std::optional<N> string2Float(const std::string_view s) } -/* Convert a little-endian integer to host order. */ +/** + * Convert a little-endian integer to host order. + */ template<typename T> T readLittleEndian(unsigned char * p) { @@ -535,66 +670,90 @@ T readLittleEndian(unsigned char * p) } -/* Return true iff `s' starts with `prefix'. */ +/** + * @return true iff `s` starts with `prefix`. + */ bool hasPrefix(std::string_view s, std::string_view prefix); -/* Return true iff `s' ends in `suffix'. */ +/** + * @return true iff `s` ends in `suffix`. + */ bool hasSuffix(std::string_view s, std::string_view suffix); -/* Convert a string to lower case. */ +/** + * Convert a string to lower case. + */ std::string toLower(const std::string & s); -/* Escape a string as a shell word. */ +/** + * Escape a string as a shell word. + */ std::string shellEscape(const std::string_view s); -/* Exception handling in destructors: print an error message, then - ignore the exception. */ +/** + * Exception handling in destructors: print an error message, then + * ignore the exception. + */ void ignoreException(Verbosity lvl = lvlError); -/* Tree formatting. */ +/** + * Tree formatting. + */ constexpr char treeConn[] = "├───"; constexpr char treeLast[] = "└───"; constexpr char treeLine[] = "│ "; constexpr char treeNull[] = " "; -/* Determine whether ANSI escape sequences are appropriate for the - present output. */ +/** + * Determine whether ANSI escape sequences are appropriate for the + * present output. + */ bool shouldANSI(); -/* Truncate a string to 'width' printable characters. If 'filterAll' - is true, all ANSI escape sequences are filtered out. Otherwise, - some escape sequences (such as colour setting) are copied but not - included in the character count. Also, tabs are expanded to - spaces. */ +/** + * Truncate a string to 'width' printable characters. If 'filterAll' + * is true, all ANSI escape sequences are filtered out. Otherwise, + * some escape sequences (such as colour setting) are copied but not + * included in the character count. Also, tabs are expanded to + * spaces. + */ std::string filterANSIEscapes(std::string_view s, bool filterAll = false, unsigned int width = std::numeric_limits<unsigned int>::max()); -/* Base64 encoding/decoding. */ +/** + * Base64 encoding/decoding. + */ std::string base64Encode(std::string_view s); std::string base64Decode(std::string_view s); -/* Remove common leading whitespace from the lines in the string - 's'. For example, if every line is indented by at least 3 spaces, - then we remove 3 spaces from the start of every line. */ +/** + * Remove common leading whitespace from the lines in the string + * 's'. For example, if every line is indented by at least 3 spaces, + * then we remove 3 spaces from the start of every line. + */ std::string stripIndentation(std::string_view s); -/* Get the prefix of 's' up to and excluding the next line break (LF - optionally preceded by CR), and the remainder following the line - break. */ +/** + * Get the prefix of 's' up to and excluding the next line break (LF + * optionally preceded by CR), and the remainder following the line + * break. + */ std::pair<std::string_view, std::string_view> getLine(std::string_view s); -/* Get a value for the specified key from an associate container. */ +/** + * Get a value for the specified key from an associate container. + */ template <class T> const typename T::mapped_type * get(const T & map, const typename T::key_type & key) { @@ -611,7 +770,9 @@ typename T::mapped_type * get(T & map, const typename T::key_type & key) return &i->second; } -/* Get a value for the specified key from an associate container, or a default value if the key isn't present. */ +/** + * Get a value for the specified key from an associate container, or a default value if the key isn't present. + */ template <class T> const typename T::mapped_type & getOr(T & map, const typename T::key_type & key, @@ -622,7 +783,9 @@ const typename T::mapped_type & getOr(T & map, return i->second; } -/* Remove and return the first item from a container. */ +/** + * Remove and return the first item from a container. + */ template <class T> std::optional<typename T::value_type> remove_begin(T & c) { @@ -634,7 +797,9 @@ std::optional<typename T::value_type> remove_begin(T & c) } -/* Remove and return the first item from a container. */ +/** + * Remove and return the first item from a container. + */ template <class T> std::optional<typename T::value_type> pop(T & c) { @@ -649,25 +814,48 @@ template<typename T> class Callback; -/* Start a thread that handles various signals. Also block those signals - on the current thread (and thus any threads created by it). */ +/** + * Start a thread that handles various signals. Also block those signals + * on the current thread (and thus any threads created by it). + * Saves the signal mask before changing the mask to block those signals. + * See saveSignalMask(). + */ void startSignalHandlerThread(); +/** + * Saves the signal mask, which is the signal mask that nix will restore + * before creating child processes. + * See setChildSignalMask() to set an arbitrary signal mask instead of the + * current mask. + */ +void saveSignalMask(); + +/** + * Sets the signal mask. Like saveSignalMask() but for a signal set that doesn't + * necessarily match the current thread's mask. + * See saveSignalMask() to set the saved mask to the current mask. + */ +void setChildSignalMask(sigset_t *sigs); + struct InterruptCallback { virtual ~InterruptCallback() { }; }; -/* Register a function that gets called on SIGINT (in a non-signal - context). */ +/** + * Register a function that gets called on SIGINT (in a non-signal + * context). + */ std::unique_ptr<InterruptCallback> createInterruptCallback( std::function<void()> callback); void triggerInterrupt(); -/* A RAII class that causes the current thread to receive SIGUSR1 when - the signal handler thread receives SIGINT. That is, this allows - SIGINT to be multiplexed to multiple threads. */ +/** + * A RAII class that causes the current thread to receive SIGUSR1 when + * the signal handler thread receives SIGINT. That is, this allows + * SIGINT to be multiplexed to multiple threads. + */ struct ReceiveInterrupts { pthread_t target; @@ -681,8 +869,10 @@ struct ReceiveInterrupts -/* A RAII helper that increments a counter on construction and - decrements it on destruction. */ +/** + * A RAII helper that increments a counter on construction and + * decrements it on destruction. + */ template<typename T> struct MaintainCount { @@ -693,33 +883,50 @@ struct MaintainCount }; -/* Return the number of rows and columns of the terminal. */ +/** + * @return the number of rows and columns of the terminal. + */ std::pair<unsigned short, unsigned short> getWindowSize(); -/* Used in various places. */ +/** + * Used in various places. + */ typedef std::function<bool(const Path & path)> PathFilter; extern PathFilter defaultPathFilter; -/* Common initialisation performed in child processes. */ +/** + * Common initialisation performed in child processes. + */ void commonChildInit(); -/* Create a Unix domain socket. */ +/** + * Create a Unix domain socket. + */ AutoCloseFD createUnixDomainSocket(); -/* Create a Unix domain socket in listen mode. */ +/** + * Create a Unix domain socket in listen mode. + */ AutoCloseFD createUnixDomainSocket(const Path & path, mode_t mode); -/* Bind a Unix domain socket to a path. */ +/** + * Bind a Unix domain socket to a path. + */ void bind(int fd, const std::string & path); -/* Connect to a Unix domain socket. */ +/** + * Connect to a Unix domain socket. + */ void connect(int fd, const std::string & path); -// A Rust/Python-like enumerate() iterator adapter. -// Borrowed from http://reedbeta.com/blog/python-like-enumerate-in-cpp17. +/** + * A Rust/Python-like enumerate() iterator adapter. + * + * Borrowed from http://reedbeta.com/blog/python-like-enumerate-in-cpp17. + */ template <typename T, typename TIter = decltype(std::begin(std::declval<T>())), typename = decltype(std::end(std::declval<T>()))> @@ -729,23 +936,25 @@ constexpr auto enumerate(T && iterable) { size_t i; TIter iter; - bool operator != (const iterator & other) const { return iter != other.iter; } - void operator ++ () { ++i; ++iter; } - auto operator * () const { return std::tie(i, *iter); } + constexpr bool operator != (const iterator & other) const { return iter != other.iter; } + constexpr void operator ++ () { ++i; ++iter; } + constexpr auto operator * () const { return std::tie(i, *iter); } }; struct iterable_wrapper { T iterable; - auto begin() { return iterator{ 0, std::begin(iterable) }; } - auto end() { return iterator{ 0, std::end(iterable) }; } + constexpr auto begin() { return iterator{ 0, std::begin(iterable) }; } + constexpr auto end() { return iterator{ 0, std::end(iterable) }; } }; return iterable_wrapper{ std::forward<T>(iterable) }; } -// C++17 std::visit boilerplate +/** + * C++17 std::visit boilerplate + */ template<class... Ts> struct overloaded : Ts... { using Ts::operator()...; }; template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>; @@ -753,8 +962,10 @@ template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>; std::string showBytes(uint64_t bytes); -/* Provide an addition operator between strings and string_views - inexplicably omitted from the standard library. */ +/** + * Provide an addition operator between strings and string_views + * inexplicably omitted from the standard library. + */ inline std::string operator + (const std::string & s1, std::string_view s2) { auto s = s1; |