From b750101eb236130cf056c675997decbac904cc49 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:35:18 +0200 Subject: Adding upstream version 252.22. Signed-off-by: Daniel Baumann --- man/sd-id128.xml | 283 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 283 insertions(+) create mode 100644 man/sd-id128.xml (limited to 'man/sd-id128.xml') diff --git a/man/sd-id128.xml b/man/sd-id128.xml new file mode 100644 index 0000000..c869943 --- /dev/null +++ b/man/sd-id128.xml @@ -0,0 +1,283 @@ + + + + + + + + sd-id128 + systemd + + + + sd-id128 + 3 + + + + sd-id128 + SD_ID128_ALLF + SD_ID128_CONST_STR + SD_ID128_FORMAT_STR + SD_ID128_FORMAT_VAL + SD_ID128_MAKE + SD_ID128_MAKE_STR + SD_ID128_MAKE_UUID_STR + SD_ID128_NULL + SD_ID128_UUID_FORMAT_STR + sd_id128_equal + sd_id128_string_equal + sd_id128_in_set + sd_id128_in_set_sentinel + sd_id128_in_setv + sd_id128_is_allf + sd_id128_is_null + sd_id128_t + APIs for processing 128-bit IDs + + + + + #include <systemd/sd-id128.h> + + + SD_ID128_ALLF + + + SD_ID128_NULL + + + SD_ID128_CONST_STR(id) + + + SD_ID128_FORMAT_STR + + + SD_ID128_FORMAT_VAL(id) + + + SD_ID128_MAKE(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_MAKE_STR(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_MAKE_UUID_STR(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_UUID_FORMAT_STR + + + + int sd_id128_equal + sd_id128_t a + sd_id128_t b + + + + int sd_id128_string_equal + const char *a + sd_id128_t b + + + + int sd_id128_is_null + sd_id128_t id + + + + int sd_id128_is_allf + sd_id128_t id + + + + int sd_id128_in_setv + sd_id128_t id + va_list ap + + + + int sd_id128_in_set_sentinel + sd_id128_t id + … + SD_ID128_NULL + + + + int sd_id128_in_set + sd_id128_t id + … + + + + + pkg-config --cflags --libs libsystemd + + + + + + Description + + sd-id128.h provides APIs to generate, convert, and compare 128-bit ID values. + The 128-bit ID values processed and generated by these APIs are a generalization of OSF UUIDs as defined + by RFC 4122 but use a simpler string format. + These functions impose no structure on the used IDs, much unlike OSF UUIDs or Microsoft GUIDs, but are + mostly compatible with those types of IDs. + + + A 128-bit ID is implemented as the following + union type: + + typedef union sd_id128 { + uint8_t bytes[16]; + uint64_t qwords[2]; +} sd_id128_t; + + This union type allows accessing the 128-bit ID as 16 separate bytes or two 64-bit words. It is + generally safer to access the ID components by their 8-bit array to avoid endianness issues. This union + is intended to be passed by value (as opposed to pass-by-reference) and may be directly manipulated by + clients. + + A couple of macros are defined to denote and decode 128-bit + IDs: + + SD_ID128_MAKE() is used to write a constant ID in source code. A commonly used + idiom is to assign a name to an ID using this macro: + + #define SD_MESSAGE_COREDUMP SD_ID128_MAKE(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1) + + SD_ID128_NULL defines an ID consisting of only NUL bytes + (i.e. all bits off). + + SD_ID128_ALLF defines an ID consisting of only 0xFF bytes + (i.e. all bits on). + + SD_ID128_MAKE_STR() is similar to SD_ID128_MAKE(), but + creates a const char* expression that can be conveniently used in message formats and + such: + + #include <stdio.h> +#define SD_MESSAGE_COREDUMP_STR SD_ID128_MAKE_STR(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1) + +int main(int argc, char **argv) { + puts("Match for coredumps: MESSAGE_ID=" SD_MESSAGE_COREDUMP_STR); +} + + SD_ID128_CONST_STR() converts constant IDs into constant strings for + output. The following example code will output the string "fc2e22bc6ee647b6b90729ab34a250b1": + int main(int argc, char *argv[]) { + puts("Match for coredumps: %s", SD_ID128_CONST_STR(SD_MESSAGE_COREDUMP)); +} + + SD_ID128_FORMAT_STR and SD_ID128_FORMAT_VAL() is used to + format an ID in a printf3 format + string, as shown in the following example: + + int main(int argc, char *argv[]) { + sd_id128_t id; + id = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07); + printf("The ID encoded in this C file is " SD_ID128_FORMAT_STR ".\n", SD_ID128_FORMAT_VAL(id)); + return 0; +} + + SD_ID128_UUID_FORMAT_STR and SD_ID128_MAKE_UUID_STR() + are similar to + SD_ID128_FORMAT_STR and SD_ID128_MAKE_STR(), + but include separating hyphens to conform to the + "canonical representation". + They format the string based on RFC4122 Variant 1 rules, i.e. converting from Big + Endian byte order. This matches behaviour of most other Linux userspace infrastructure. It's probably + best to avoid UUIDs of other variants, in order to avoid unnecessary ambiguities. All 128-bit IDs + generated by the sd-id128 APIs strictly conform to Variant 1 Version 4 UUIDs, as per RFC 4122. + + sd_id128_equal() compares two 128-bit IDs: + + int main(int argc, char *argv[]) { + sd_id128_t a, b, c; + a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07); + b = SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e); + c = a; + assert(sd_id128_equal(a, c)); + assert(!sd_id128_equal(a, b)); + return 0; +} + + sd_id128_string_equal() is similar to sd_id128_equal(), + but the first ID is formatted as const char*. The same restrictions apply as to the first + argument of sd_id128_from_string(). + + sd_id128_is_null() checks if an ID consists of only NUL + bytes: + + assert(sd_id128_is_null(SD_ID128_NULL)); + + Similarly, sd_id128_is_allf() checks if an ID consists of only + 0xFF bytes (all bits on): + + assert(sd_id128_is_allf(SD_ID128_ALLF)); + + sd_id128_in_set_sentinel() takes a list of IDs and returns true if the first + argument is equal to any of the subsequent arguments. The argument list is terminated by an + SD_ID128_NULL sentinel, which must be present. + + sd_id128_in_set() is a convenience function that takes a list of IDs and + returns true if the first argument is equal to any of the subsequent arguments: + + int main(int argc, char *argv[]) { + sd_id12_t a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07); + assert(sd_id128_in_set(a, a)); + assert(sd_id128_in_set(a, a, a)); + assert(!sd_id128_in_set(a)); + assert(!sd_id128_in_set(a, + SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e) + SD_ID128_MAKE(2f,88,28,5f,9c,44,09,9d,d7,15,77,04,bc,85,7e,e3) + SD_ID128_ALLF)); + return 0; +} + + + sd_id128_in_set() is defined as a macro over + sd_id128_in_set_sentinel(), adding the SD_ID128_NULL sentinel + automatically. Since sd_id128_in_set_sentinel() uses + SD_ID128_NULL as the sentinel, SD_ID128_NULL cannot be + otherwise placed in the argument list. + + sd_id128_in_setv() is similar to + sd_id128_in_set_sentinel(), but takes a struct varargs + argument. + + New randomized IDs may be generated with + systemd-id1281's + new command. + + See + sd_id128_to_string3, + sd_id128_randomize3 + and + sd_id128_get_machine3 + for information about other implemented functions. + + + + + + See Also + + systemd1, + sd_id128_to_string3, + sd_id128_randomize3, + sd_id128_get_machine3, + printf3, + journalctl1, + sd-journal7, + pkg-config1, + machine-id5 + + + + -- cgit v1.2.3