libkern/libkern.h Kernel.framework

Returns the larger of two signed integers.

Returns the smaller of two signed integers.

Returns the larger of two longs.

Returns the smaller of two longs.

Returns the larger of two unsigned integers.

Returns the smaller of two unsigned integers.

Returns the larger of two u_int32_t values.

Returns the smaller of two u_int32_t values.

Scans the byte string cp of length size, stopping at the first byte whose entry in the 256-byte lookup table has any of the bits in mask set (table[*cp] & mask != 0). Returns the number of bytes remaining in the string, counting the matching byte; returns 0 if no byte matched. 4.4BSD utility used by tty and expansion code.

Decodes percent-encoded (%XX) escape sequences in the string, in place. Each escape whose decoded value is a printable character replaces the sequence and the remainder of the string is shifted down; escapes that decode to non-printable characters are left untouched. Does nothing if str is NULL.

Formats into the buffer like snprintf, but returns the number of characters actually written, excluding the terminating NUL, rather than the length the full formatted string would have had. Returns 0 when count is 0 and count - 1 on truncation, so the result is always safe to use as an offset for appending.

Formats into dst with vsnprintf semantics, then returns a __null_terminated pointer to dst, or NULL if count was 0. Provided to "finalize" a char array into a NUL-terminated string under -fbounds-safety; the character data must not be aliased after finalization. va_list form of tsnprintf.

Kernel printf. Formats the arguments and delivers the result both to the kernel log (visible through os_log/syslog) and to the console. Supports the usual integer, character and string conversions with width and precision, plus the kernel extensions %b (decode a register value against a bit-name string) and %D (hex dump with separator); %e, %f and %g are not implemented. The return value is always 0 and carries no meaning.

Computes the CRC-32 checksum (IEEE 802.3 polynomial 0xedb88320, as used by zlib and POSIX cksum) of the len bytes at bufp, using a byte-at-a-time table lookup. The crc argument is the running checksum from a previous call, permitting incremental computation over discontiguous buffers; pass 0 to start. Pre- and post-inversion of the CRC register is handled internally. Returns the updated checksum.

Copies a NUL-terminated string between two kernel addresses, copying at most len bytes. Returns 0 on success, or ENAMETOOLONG if the string did not fit; if done is non-NULL it receives the number of bytes copied, including the terminating NUL. For new code strlcpy is preferred.

Copies a NUL-terminated string from the user address uaddr of the current task into the kernel buffer kaddr, copying at most len bytes. Returns 0 on success, EFAULT if the user address is invalid or faults, and ENAMETOOLONG if len bytes were exhausted before a NUL was found (len of 0 also returns ENAMETOOLONG). *done receives the number of bytes copied, including the terminating NUL. The result must be checked (OS_WARN_RESULT).

Copies the NUL-terminated kernel string kaddr out to the user address udaddr of the current task, copying at most len bytes. Returns 0 on success, EFAULT if the user address faults, or ENAMETOOLONG if the string and its NUL exceed len (the first len bytes are still copied). If done is non-NULL it receives the number of bytes copied.

va_list form of the kernel printf. Formats the message and delivers it to the kernel log (os_log) and the console. Always returns 0.

Scaled-down kernel version of vsnprintf(3). Formats at most size - 1 characters into str and NUL-terminates when size is at least 1. Returns the length the fully formatted string would have had, even if it did not fit; use vscnprintf to obtain the number of bytes actually written.

va_list form of scnprintf. Formats into buf like vsnprintf but returns the number of characters actually written, excluding the terminating NUL: 0 when size is 0, and size - 1 when the output was truncated.

Invalidates the instruction cache for the given address range so subsequently executed instructions are fetched from memory; call after writing instructions (e.g. code modification). addr is a kernel virtual address, or a physical address if phys is nonzero. A no-op on x86, where instruction caches are coherent with data accesses.

Cleans and invalidates (writes back to memory and discards) the data cache for the given address range, to the point of coherency. addr is a kernel virtual address, or a physical address if phys is nonzero. Used around DMA on platforms with non-coherent I/O; a no-op on x86 and on ARM systems built with coherent I/O.

Variant of invalidate_icache taking a 64-bit addr64_t address. Invalidates the instruction cache for the range; a physical address is indicated by a nonzero phys argument. On arm64 it is an alias of invalidate_icache; a no-op on x86.

Variant of flush_dcache taking a 64-bit addr64_t address. Cleans and invalidates the data cache for the range, treating addr as physical if phys is nonzero. On arm64 it is an alias of flush_dcache; on x86 it flushes cache lines with clflush when given a virtual range.

Counts the number of leading zero bits in the 32-bit argument. Defined for an input of 0, returning 32: on ARM the builtin already returns the type width, and on Intel, where __builtin_clz(0) is undefined, the zero case is checked explicitly.