networking/udhcp/dumpleases.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   4  */
   5
   6 //usage:#define dumpleases_trivial_usage
   7 //usage:       "[-r|-a] [-f LEASEFILE]"
   8 //usage:#define dumpleases_full_usage "\n\n"
   9 //usage:       "Display DHCP leases granted by udhcpd\n"
  10 //usage:        IF_LONG_OPTS(
  11 //usage:     "\n        -f,--file=FILE  Lease file"
  12 //usage:     "\n        -r,--remaining  Show remaining time"
  13 //usage:     "\n        -a,--absolute   Show expiration time"
  14 //usage:        )
  15 //usage:        IF_NOT_LONG_OPTS(
  16 //usage:     "\n        -f FILE Lease file"
  17 //usage:     "\n        -r      Show remaining time"
  18 //usage:     "\n        -a      Show expiration time"
  19 //usage:        )
  20
  21 #include "common.h"
  22 #include "dhcpd.h"
  23 #include "unicode.h"
  24
  25 int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  26 int dumpleases_main(int argc UNUSED_PARAM, char **argv)
  27 {
  28         int fd;
  29         int i;
  30         unsigned opt;
  31         int64_t written_at, curr, expires_abs;
  32         const char *file = LEASES_FILE;
  33         struct dyn_lease lease;
  34         struct in_addr addr;
  35
  36         enum {
  37                 OPT_a = 0x1, // -a
  38                 OPT_r = 0x2, // -r
  39                 OPT_f = 0x4, // -f
  40         };
  41 #if ENABLE_LONG_OPTS
  42         static const char dumpleases_longopts[] ALIGN1 =
  43                 "absolute\0"  No_argument       "a"
  44                 "remaining\0" No_argument       "r"
  45                 "file\0"      Required_argument "f"
  46                 ;
  47
  48         applet_long_options = dumpleases_longopts;
  49 #endif
  50         init_unicode();
  51
  52         opt_complementary = "=0:a--r:r--a";
  53         opt = getopt32(argv, "arf:", &file);
  54
  55         fd = xopen(file, O_RDONLY);
  56
  57         printf("Mac Address       IP Address      Host Name           Expires %s\n", (opt & OPT_a) ? "at" : "in");
  58         /*     "00:00:00:00:00:00 255.255.255.255 ABCDEFGHIJKLMNOPQRS Wed Jun 30 21:49:08 1993" */
  59         /*     "123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 */
  60
  61         xread(fd, &written_at, sizeof(written_at));
  62         written_at = SWAP_BE64(written_at);
  63         curr = time(NULL);
  64         if (curr < written_at)
  65                 written_at = curr; /* lease file from future! :) */
  66
  67         while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
  68                 const char *fmt = ":%02x" + 1;
  69                 for (i = 0; i < 6; i++) {
  70                         printf(fmt, lease.lease_mac[i]);
  71                         fmt = ":%02x";
  72                 }
  73                 addr.s_addr = lease.lease_nip;
  74 #if ENABLE_UNICODE_SUPPORT
  75                 {
  76                         char *uni_name = unicode_conv_to_printable_fixedwidth(/*NULL,*/ lease.hostname, 19);
  77                         printf(" %-16s%s ", inet_ntoa(addr), uni_name);
  78                         free(uni_name);
  79                 }
  80 #else
  81                 /* actually, 15+1 and 19+1, +1 is a space between columns */
  82                 /* lease.hostname is char[20] and is always NUL terminated */
  83                 printf(" %-16s%-20s", inet_ntoa(addr), lease.hostname);
  84 #endif
  85                 expires_abs = ntohl(lease.expires) + written_at;
  86                 if (expires_abs <= curr) {
  87                         puts("expired");
  88                         continue;
  89                 }
  90                 if (!(opt & OPT_a)) { /* no -a */
  91                         unsigned d, h, m;
  92                         unsigned expires = expires_abs - curr;
  93                         d = expires / (24*60*60); expires %= (24*60*60);
  94                         h = expires / (60*60); expires %= (60*60);
  95                         m = expires / 60; expires %= 60;
  96                         if (d)
  97                                 printf("%u days ", d);
  98                         printf("%02u:%02u:%02u\n", h, m, (unsigned)expires);
  99                 } else { /* -a */
 100                         time_t t = expires_abs;
 101                         fputs(ctime(&t), stdout);
 102                 }
 103         }
 104         /* close(fd); */
 105
 106         return 0;
 107 }