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API Documentation

Important Note

When using functions like mkpath(), makepath(), and makefifo(), make sure your umask() is correct so you do not accidentally create files and directories accessible to other users than intended.

Helper Macros

  • atonum(str)

    Convert string to natural number, works for 32-bit non-negative integers. Returns -1 on error. (Uses strtonum() internally.)

  • blkdev(dev)

    Create block device

  • chardev(dev)

    Create character device

  • erase(path)

    Erase file/directory with remove(). Errors on stderr

  • erasef(fmt, ...)

    Like erase() but takes a formatted printf-like string as argument.

  • makedir(path)

    Create directory, like mkdir(). Errors on stderr

  • makefifo(path)

    Create a FIFO, like mkfifo(). Errors on stderr

  • min(a,b)/max(a,b)

    These macros take care to avoid double evaluation.

  • touch(path)

    Create a file, or update mtime. Errors on stderr

  • touchf(fmt, ...)

    Like touch() but takes a formatted printf-like string as argument.

  • S_ISEXEC(mode_t m)

    Mysteriously missing from GLIBC

  • ISCLR(word,bit)

    Is bit in (integer) word cleared?

  • ISSET(word,bit)

    Is bit in (integer) word set?

  • ISOTHER(word,bit)

    Are any other bits, except bit, in (integer) word set?

  • SETBIT(word,bit)

    Set bit in (integer) word.

  • CLRBIT(word,bit)

    Clear bit in (integer) word.

  • NELEMS(array)

    Returns the number of elements in an array. From the great book, The Practice of Programming, by Kernighan and Pike.

Generic Functions

  • chomp(str)

    Perl like chomp function, chop off last char if newline.

  • copyfile(src, dst, len, opt)

    Like the shell cp(1) and dd(1),, can also copy symlinks and preserve the mtime of the source file. The opt argument can be a mask of:

    • LITE_FOPT_COPYFILE_SYM (0x01)
    • LITE_FOPT_KEEP_MTIME (0x02)

    In releases prior to v2.0 the opt argument was called symlink. The APIs are 100% compatible if the value 1 was used to enable the symlink option.

  • dir(dir, ext, filter, list, strip)

    Wrapper for scandir() with optional filter. Returns a list of names: files and directories that must be freed after use. See the unit test for an example, or take a look at glob(3), it's probably what you want anyway.

  • fcopyfile(src, dst)

    Like copyfile() but uses already open FILE * pointers. Copies from current file positions to current file positions until EOF.

  • fexist(file)

    Check for the existence of a file, returns True(1) or False(0).

  • fisdir(path)

    Check for the existence of a directory, returns True(1) or False(0).

  • fopenf(mode, fmt, ...) and vfopenf(mode, fmt, ap)

    Like fopen(), but takes a formatted string as argument. This greatly simplifies operations that usually consist of composing a filename from parts into a dynamic buffer before actually opening the file.

    Notice: the swapped order of pathname and mode!

  • fremove(fmt, ...)

    Like remove(), but takes a formatted string as argument. This greatly simplifies operations that usually consist of composing a filename from parts into a dynamic buffer before actually removing the file.

  • fsendfile(src, dst, len)

    Copy data between file streams, very similar to fcopyfile(), but dst is allowed to be NULL to be able to read and discard len bytes from src.

  • ifconfig(ifname, addr, mask, up)

    Basic ifconfig like operations on an interface. Only supports IPv4 addresses. Note that mask is not CIDR notation.

  • lfopen(file, sep), lfclose(lf)

    LITE file API for parsing UNIX style configuration files like /etc/protocols and /etc/services.

  • lftok(lf)

    Read tokens, delimited by sep, from file opened with lfopen().

  • lfgetkey(lf, key)

    Find key in file opened with lfopen(), return value/argument.

  • lfgetint(lf, key)

    Wrapper for lfgetkey(), returns positive integer value to key, or -1 if key is not found.

  • fgetint(file, sep, key)

    Wrapper for lfopen(), lfgetint(), and lfclose(). Useful for when only reading a single key from a file.

  • makepath(dir)

    Create all components of the specified directory.

  • mkpath(dir, mode)

    Like makepath(), but also takes a mode_t permission mode argument.

  • fmkpath(mode, fmt, ...)

    Like mkpath(), but takes a formatted string as argument.

    Notice: the swapped order of pathname and mode!

  • movefile(src, dst)

    Like copyfile(), but renames src to dst, or recreates symlink with the dst name. On successful operation the source is removed and the function returns POSIX OK (0).

  • pidfile(name)

    Create a daemon PID file using either the name as a full path, if name starts with /, or in _PATH_VARRUN using name as the basename of the application. If name is NULL, then __progname is used as the basename. The resulting file name is available to the user as a read-only pointer:

      extern char *__pidfile_name;

    Use this function to create a PID file for your daemon when it is ready to receive signals. A client application may poll for the existence of this file, so make sure to have your signal handlers properly setup before calling this function.

    The PID file is removed when the program exits, using an atexit() handler. However, depending on how the program terminates the file may still exist even though the program is no longer running.

    Calling this function multiple times updates the mtime of the file. Only one atexit() handler is created, regardless of the amount of times the function is called. If the file is removed, subsequent calls to this function will recreate the file.

    See below for a link to OpenBSD man page.

  • pidfile_read(pidfile)

    Read PID from pid file created by pidfile().

  • pidfile_signal(pidfile, signal)

    Send signal to PID found in pid file created by pidfile().

  • progress(percent, max_width)

    Simple ASCII progress bar with a spinner. Start it with percent=0 and set the max_width=chars to indicate width of the progress bar. Called multiple times with the same percentage value cause spinner to spin.

  • rsync(src, dst, opt, *filter())

    Very simple rsync() to copy files and directories recursively. It supports pruning files from the destination tree that do not exist in the source tree and preserving the mtime of the source files. The opt argument can be a mask of:

    • LITE_FOPT_RSYNC_DELETE (0x01)
    • LITE_FOPT_KEEP_MTIME (0x02)

    In releases prior to v2.0 the argument controlling pruning was called delete, it is now called opt. The APIs are 100% compatible if the value 1 was used.

  • runbg(cmd, delay)

    Run a command in the background, after delay microseconds, essentially a background execvp() with a delay. The function employs double-fork to prevent zombies and closes all open files, including stdio.

    char *cmd[] = { "sh", "-c", "echo 'hej' >/tmp/foo", NULL};

    runbg(cmd, 200000); /* Create /tmp/foo after 200 millisec */
    /* Execution continues here immediately */

  • strmatch(str, list), strnmatch(str, list, len)

    Find matching string in an array of strings. Returns index in array on match, or -1 on error or not found. strnmatch() takes an extra arg to compare only len number of characters from str.

  • strtrim(str)

    Trims a string from any leading and trailing white-space, returns the trimmed result in the same buffer.

  • systemf(fmt, ...)

    Like system(), but takes a formatted string as argument. This greatly simplifies operations that usually consist of composing a command from parts into a dynamic buffer before calling it.

  • telnet_open(addr, port), telnet_close(ctx), telnet_expect(ctx, script, output)

    Poor mans telnet expect in C. Opens connection to a Telnet service; FTP, Telnet, similar, and run an expect-like script.

  • telnet_session(addr, port, script output)

    Wrapper for the above three in one API.

  • tempfile()

    Secure replacement for tmpfile(). Creates an invisible temporary file in /tmp that is removed when the returned FILE pointer is closed.

    Note: Requires Linux v3.11, or later, will fall back to the old and unsafe tmpfile() on older systems.

  • truncatef(length, fmt, ...)

    Like truncate(), but takes a formatted string as argument. This simplifies some operations when the filename otherwise have to be composed from parts into a separate array before calling the real function.

  • which(cmd), whichp(cmd)

    C implementation of UNIX which(1). Returns a malloc'ed string with the full path to cmd on success, otherwise NULL.

    whichp() is a predicate function, returns TRUE or FALSE.

    Note: which("/bin/ps aux") will return /bin/ps, or TRUE, provided of course /bin/ps exists.

  • yorn(fmt, ...)

    Pose a question to user, appended with (y/N)?, returns TRUE for yes (both y and Y are handled) and FALSE for everything else.

Procfile Functions

These functions can be used to simplify access to data in /proc and /sys on a Linux system.

String Functions

  • readsnf(line, len, fmt, ...)

    Read first line from a file composed from fmt, with optional args. At most len bytes from the file are stored in line.

    On success this function returns line with any trailing newlines chomp()ed off. On error NULL is returned.

  • vreadsnf(line, len, fmt, ap)

    Similar to readsnf() but takes a va_list argument instead.

  • writesf(str, mode, fmt, ...)

    Write the string buffer str, with an additional newline, to a file composed from fmt, with optional args. The file is opened with the given mode, e.g. "w+", which allows for both replacing and appending file content.

    The function returns POSIX OK(0) on success or -1 on failure with the errno variable set to a value from either fopen() or fclose().

Integer Functions

Read and write 32-bit and 64-bit signed values from/to files.

  • vreadllf(value, fmt, ap) and readllf(value, fmt, ...)

    Only the first line is read. If the line has newline that is stripped before calling strtoll() on the line. The arguments to the latter function is such that it can convert also from a hexadecimal value.

    This function may fail and return -1 on opening the file, reading a line, or if the strtoll() function fails. All of which set the errno variable. Otherwise this function return POSIX OK(0).

  • readdf(value, fmt, ...)

    Read a signed 32-bit value from a file composed from fmt, with optional args. This function use vreadllf() with an additional range checking for INT_MIN and INT_MAX. Values outside that cause this function to return -1 with errno set to ERANGE.

  • writedf(value, mode, fmt, ...)

    Write a signed 32-bit value to a file composed from fmt, with optional args. The file is opened with the given mode, e.g. "w+", which allows for both replacing and appending file content.

    The function returns POSIX OK(0) on success or -1 on failure with the errno variable set to a value from either fopen() or fclose().

  • writellf(value, mode, fmt, ...)

    Write a signed 64-bit value to a file composed from fmt, with optional args. The file is opened with the given mode, e.g. "w+", which allows for both replacing and appending file content.

    The function returns POSIX OK(0) on success or -1 on failure with the errno variable set to a value from either fopen() or fclose().

GNU Functions

The following are useful GNU functions, that do not exist on *BSD, and some other platforms.

OpenBSD/NetBSD/FreeBSD Functions

The following are popular functions and highly useful macros from the *BSD world of UNIX that are sadly missing on Linux.