| 1 | /************************************************* |
| 2 | * Exim - an Internet mail transport agent * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* Copyright (c) University of Cambridge 1997 - 2014 */ |
| 6 | /* See the file NOTICE for conditions of use and distribution. */ |
| 7 | |
| 8 | /* Linux-specific code. This is concatenated onto the generic |
| 9 | src/os.c file. */ |
| 10 | |
| 11 | |
| 12 | /************************************************* |
| 13 | * Load average computation * |
| 14 | *************************************************/ |
| 15 | |
| 16 | /*Linux has an apparently unique way of getting the load average, so we provide |
| 17 | a unique function here, and define OS_LOAD_AVERAGE to stop src/os.c trying to |
| 18 | provide the function. However, when compiling os.c for utilities, we may not |
| 19 | want this at all, so check that it isn't set first. */ |
| 20 | |
| 21 | #if !defined(OS_LOAD_AVERAGE) && defined(__linux__) |
| 22 | #define OS_LOAD_AVERAGE |
| 23 | |
| 24 | /* Linux has 2 ways of returning load average: |
| 25 | |
| 26 | (1) Do a read on /proc/loadavg |
| 27 | (2) Use the sysinfo library function and syscall |
| 28 | |
| 29 | The latter is simpler but in Linux 2.0 - 2.2 (and probably later releases) is |
| 30 | exceptionally slow - 10-50ms per call is not unusual and about 100x slow the |
| 31 | first method. This cripples high performance mail servers by increasing CPU |
| 32 | utilisation by 3-5x. |
| 33 | |
| 34 | In Exim's very early days, it used the 1st method. Later, it switched to the |
| 35 | 2nd method. Now it tries the 1st method and falls back to the 2nd if /proc is |
| 36 | unavailable. */ |
| 37 | |
| 38 | #include <sys/sysinfo.h> |
| 39 | |
| 40 | static int |
| 41 | linux_slow_getloadavg(void) |
| 42 | { |
| 43 | struct sysinfo s; |
| 44 | double avg; |
| 45 | if (sysinfo(&s) < 0) return -1; |
| 46 | avg = (double) (s.loads[0]) / (1<<SI_LOAD_SHIFT); |
| 47 | return (int)(avg * 1000.0); |
| 48 | } |
| 49 | |
| 50 | int |
| 51 | os_getloadavg(void) |
| 52 | { |
| 53 | char buffer[40]; |
| 54 | double avg; |
| 55 | int count; |
| 56 | int fd = open ("/proc/loadavg", O_RDONLY); |
| 57 | if (fd == -1) return linux_slow_getloadavg(); |
| 58 | count = read (fd, buffer, sizeof(buffer)); |
| 59 | (void)close (fd); |
| 60 | if (count <= 0) return linux_slow_getloadavg(); |
| 61 | count = sscanf (buffer, "%lf", &avg); |
| 62 | if (count < 1) return linux_slow_getloadavg(); |
| 63 | return (int)(avg * 1000.0); |
| 64 | } |
| 65 | #endif /* OS_LOAD_AVERAGE */ |
| 66 | |
| 67 | |
| 68 | |
| 69 | |
| 70 | |
| 71 | /************************************************* |
| 72 | * Finding interface addresses * |
| 73 | *************************************************/ |
| 74 | |
| 75 | /* This function is not required for utilities; we cut it out if |
| 76 | FIND_RUNNING_INTERFACES is already defined. */ |
| 77 | |
| 78 | #ifndef FIND_RUNNING_INTERFACES |
| 79 | |
| 80 | /* This code, contributed by Jason Gunthorpe, appears to be the current |
| 81 | way of finding IPv6 interfaces in Linux. It first calls the common function in |
| 82 | order to find IPv4 interfaces, then grobbles around to find the others. Jason |
| 83 | said, "This is so horrible, don't look. Slightly ripped from net-tools |
| 84 | ifconfig." It gets called by virtue of os_find_running_interfaces being defined |
| 85 | as a macro for os_find_running_interfaces_linux in the os.h-Linux file. */ |
| 86 | |
| 87 | ip_address_item * |
| 88 | os_find_running_interfaces_linux(void) |
| 89 | { |
| 90 | ip_address_item *yield = NULL; |
| 91 | |
| 92 | #if HAVE_IPV6 |
| 93 | ip_address_item *last = NULL; |
| 94 | ip_address_item *next; |
| 95 | char addr6p[8][5]; |
| 96 | unsigned int plen, scope, dad_status, if_idx; |
| 97 | char devname[20+1]; |
| 98 | FILE *f; |
| 99 | #endif |
| 100 | |
| 101 | yield = os_common_find_running_interfaces(); |
| 102 | |
| 103 | #if HAVE_IPV6 |
| 104 | |
| 105 | /* Open the /proc file; give up if we can't. */ |
| 106 | |
| 107 | if ((f = fopen("/proc/net/if_inet6", "r")) == NULL) return yield; |
| 108 | |
| 109 | /* Pick out the data from within the file, and add it on to the chain */ |
| 110 | |
| 111 | last = yield; |
| 112 | if (last != NULL) while (last->next != NULL) last = last->next; |
| 113 | |
| 114 | while (fscanf(f, "%4s%4s%4s%4s%4s%4s%4s%4s %02x %02x %02x %02x %20s\n", |
| 115 | addr6p[0], addr6p[1], addr6p[2], addr6p[3], |
| 116 | addr6p[4], addr6p[5], addr6p[6], addr6p[7], |
| 117 | &if_idx, &plen, &scope, &dad_status, devname) != EOF) |
| 118 | { |
| 119 | struct sockaddr_in6 addr; |
| 120 | |
| 121 | /* This data has to survive for ever, so use malloc. */ |
| 122 | |
| 123 | next = store_malloc(sizeof(ip_address_item)); |
| 124 | next->next = NULL; |
| 125 | next->port = 0; |
| 126 | sprintf(CS next->address, "%s:%s:%s:%s:%s:%s:%s:%s", |
| 127 | addr6p[0], addr6p[1], addr6p[2], addr6p[3], |
| 128 | addr6p[4], addr6p[5], addr6p[6], addr6p[7]); |
| 129 | |
| 130 | /* Normalize the representation */ |
| 131 | |
| 132 | inet_pton(AF_INET6, CS next->address, &addr.sin6_addr); |
| 133 | inet_ntop(AF_INET6, &addr.sin6_addr, CS next->address, sizeof(next->address)); |
| 134 | |
| 135 | if (yield == NULL) yield = last = next; else |
| 136 | { |
| 137 | last->next = next; |
| 138 | last = next; |
| 139 | } |
| 140 | |
| 141 | DEBUG(D_interface) |
| 142 | debug_printf("Actual local interface address is %s (%s)\n", last->address, |
| 143 | devname); |
| 144 | } |
| 145 | fclose(f); |
| 146 | #endif /* HAVE_IPV6 */ |
| 147 | |
| 148 | return yield; |
| 149 | } |
| 150 | |
| 151 | #endif /* FIND_RUNNING_INTERFACES */ |
| 152 | |
| 153 | /* End of os.c-Linux */ |