| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | #include "boot_id.h" |
| 4 | #include "libnetdata/libnetdata.h" |
| 5 | |
| 6 | static ND_UUID cached_boot_id = { 0 }; |
| 7 | static SPINLOCK spinlock = SPINLOCK_INITIALIZER; |
| 8 | |
| 9 | #if defined(OS_LINUX) |
| 10 | |
| 11 | static ND_UUID get_boot_id(void) { |
| 12 | ND_UUID boot_id = { 0 }; |
| 13 | char buf[UUID_STR_LEN]; |
| 14 | |
| 15 | char filename[FILENAME_MAX + 1]; |
| 16 | snprintfz(filename, sizeof(filename), "%s/proc/sys/kernel/random/boot_id", |
| 17 | netdata_configured_host_prefix ? netdata_configured_host_prefix : ""); |
| 18 | |
| 19 | // Try reading the official boot_id first |
| 20 | if (read_txt_file(filename, buf, sizeof(buf)) == 0) { |
| 21 | if (uuid_parse(trim(buf), boot_id.uuid) == 0) |
| 22 | return boot_id; |
| 23 | } |
| 24 | |
| 25 | // Fallback to boottime-based ID |
| 26 | time_t boottime = os_boottime(); |
| 27 | if(boottime > 0) { |
| 28 | boot_id.parts.low64 = (uint64_t)boottime; |
| 29 | // parts.hig64 remains 0 to indicate this is a synthetic boot_id |
| 30 | } |
| 31 | |
| 32 | return boot_id; |
| 33 | } |
| 34 | |
| 35 | #else // !OS_LINUX |
| 36 | |
| 37 | static ND_UUID get_boot_id(void) { |
| 38 | ND_UUID boot_id = { 0 }; |
| 39 | |
| 40 | time_t boottime = os_boottime(); |
| 41 | if(boottime > 0) { |
| 42 | boot_id.parts.low64 = (uint64_t)boottime; |
| 43 | // parts.hig64 remains 0 to indicate this is a synthetic boot_id |
| 44 | } |
| 45 | |
| 46 | return boot_id; |
| 47 | } |
| 48 | |
| 49 | #endif // OS_LINUX |
| 50 | |
| 51 | ND_UUID os_boot_id(void) { |
| 52 | // Fast path - return cached value if available |
| 53 | if(!UUIDiszero(cached_boot_id)) |
| 54 | return cached_boot_id; |
| 55 | |
| 56 | spinlock_lock(&spinlock); |
| 57 | |
| 58 | // Check again under lock in case another thread set it |
| 59 | if(UUIDiszero(cached_boot_id)) { |
| 60 | cached_boot_id = get_boot_id(); |
| 61 | } |
| 62 | |
| 63 | spinlock_unlock(&spinlock); |
| 64 | return cached_boot_id; |
| 65 | } |
| 66 | |
| 67 | bool os_boot_ids_match(ND_UUID a, ND_UUID b) { |
| 68 | if(UUIDeq(a, b)) |
| 69 | return true; |
| 70 | |
| 71 | if(a.parts.hig64 == 0 && b.parts.hig64 == 0) { |
| 72 | uint64_t diff = a.parts.low64 > b.parts.low64 ? a.parts.low64 - b.parts.low64 : b.parts.low64 - a.parts.low64; |
| 73 | if(diff <= 3) |
| 74 | return true; |
| 75 | } |
| 76 | |
| 77 | return false; |
| 78 | } |