networking/udhcp/dumpleases.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   4  */
   5
   6 #include "common.h"
   7 #include "dhcpd.h"
   8 #include "unicode.h"
   9
  10 #if BB_LITTLE_ENDIAN
  11 static inline uint64_t hton64(uint64_t v)
  12 {
  13         return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
  14 }
  15 #else
  16 #define hton64(v) (v)
  17 #endif
  18 #define ntoh64(v) hton64(v)
  19
  20
  21 int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  22 int dumpleases_main(int argc UNUSED_PARAM, char **argv)
  23 {
  24         int fd;
  25         int i;
  26         unsigned opt;
  27         int64_t written_at, curr, expires_abs;
  28         const char *file = LEASES_FILE;
  29         struct dyn_lease lease;
  30         struct in_addr addr;
  31
  32         enum {
  33                 OPT_a   = 0x1,  // -a
  34                 OPT_r   = 0x2,  // -r
  35                 OPT_f   = 0x4,  // -f
  36         };
  37 #if ENABLE_LONG_OPTS
  38         static const char dumpleases_longopts[] ALIGN1 =
  39                 "absolute\0"  No_argument       "a"
  40                 "remaining\0" No_argument       "r"
  41                 "file\0"      Required_argument "f"
  42                 ;
  43
  44         applet_long_options = dumpleases_longopts;
  45 #endif
  46         check_unicode_in_env();
  47
  48         opt_complementary = "=0:a--r:r--a";
  49         opt = getopt32(argv, "arf:", &file);
  50
  51         fd = xopen(file, O_RDONLY);
  52
  53         printf("Mac Address       IP Address      Host Name           Expires %s\n", (opt & OPT_a) ? "at" : "in");
  54         /*     "00:00:00:00:00:00 255.255.255.255 ABCDEFGHIJKLMNOPQRS Wed Jun 30 21:49:08 1993" */
  55         /*     "123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 */
  56
  57         if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
  58                 return 0;
  59         written_at = ntoh64(written_at);
  60         curr = time(NULL);
  61         if (curr < written_at)
  62                 written_at = curr; /* lease file from future! :) */
  63
  64         while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
  65                 const char *fmt = ":%02x" + 1;
  66                 for (i = 0; i < 6; i++) {
  67                         printf(fmt, lease.lease_mac[i]);
  68                         fmt = ":%02x";
  69                 }
  70                 addr.s_addr = lease.lease_nip;
  71                 /* actually, 15+1 and 19+1, +1 is a space between columns */
  72                 /* lease.hostname is char[20] and is always NUL terminated */
  73 #if ENABLE_FEATURE_ASSUME_UNICODE
  74                 printf(" %-16s%s%*s", inet_ntoa(addr), lease.hostname,
  75                         20 - (int)bb_mbstrlen(lease.hostname), "");
  76 #else
  77                 printf(" %-16s%-20s", inet_ntoa(addr), lease.hostname);
  78 #endif
  79                 expires_abs = ntohl(lease.expires) + written_at;
  80                 if (expires_abs <= curr) {
  81                         puts("expired");
  82                         continue;
  83                 }
  84                 if (!(opt & OPT_a)) { /* no -a */
  85                         unsigned d, h, m;
  86                         unsigned expires = expires_abs - curr;
  87                         d = expires / (24*60*60); expires %= (24*60*60);
  88                         h = expires / (60*60); expires %= (60*60);
  89                         m = expires / 60; expires %= 60;
  90                         if (d)
  91                                 printf("%u days ", d);
  92                         printf("%02u:%02u:%02u\n", h, m, (unsigned)expires);
  93                 } else { /* -a */
  94                         time_t t = expires_abs;
  95                         fputs(ctime(&t), stdout);
  96                 }
  97         }
  98         /* close(fd); */
  99
 100         return 0;
 101 }