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 //applet:IF_DUMPLEASES(APPLET(dumpleases, BB_DIR_USR_BIN, BB_SUID_DROP))
   6
   7 //kbuild:lib-$(CONFIG_DUMPLEASES) += dumpleases.o
   8
   9 //usage:#define dumpleases_trivial_usage
  10 //usage:       "[-r|-a] [-d] [-f LEASEFILE]"
  11 //usage:#define dumpleases_full_usage "\n\n"
  12 //usage:       "Display DHCP leases granted by udhcpd\n"
  13 //usage:        IF_LONG_OPTS(
  14 //usage:     "\n        -f,--file FILE  Lease file"
  15 //usage:     "\n        -r,--remaining  Show remaining time"
  16 //usage:     "\n        -a,--absolute   Show expiration time"
  17 //usage:     "\n        -d,--decimal    Show time in seconds"
  18 //usage:        )
  19 //usage:        IF_NOT_LONG_OPTS(
  20 //usage:     "\n        -f FILE Lease file"
  21 //usage:     "\n        -r      Show remaining time"
  22 //usage:     "\n        -a      Show expiration time"
  23 //usage:     "\n        -d      Show time in seconds"
  24 //usage:        )
  25
  26 #include "common.h"
  27 #include "dhcpd.h"
  28 #include "unicode.h"
  29
  30 int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  31 int dumpleases_main(int argc UNUSED_PARAM, char **argv)
  32 {
  33         int fd;
  34         int i;
  35         unsigned opt;
  36         int64_t written_at, curr;
  37         const char *file = LEASES_FILE;
  38         struct dyn_lease lease;
  39
  40         enum {
  41                 OPT_a = 0x1, // -a
  42                 OPT_r = 0x2, // -r
  43                 OPT_f = 0x4, // -f
  44                 OPT_d = 0x8, // -d
  45         };
  46 #if ENABLE_LONG_OPTS
  47         static const char dumpleases_longopts[] ALIGN1 =
  48                 "absolute\0"  No_argument       "a"
  49                 "remaining\0" No_argument       "r"
  50                 "file\0"      Required_argument "f"
  51                 "decimal\0"   No_argument       "d"
  52                 ;
  53
  54         applet_long_options = dumpleases_longopts;
  55 #endif
  56         init_unicode();
  57
  58         opt_complementary = "=0:a--r:r--a";
  59         opt = getopt32(argv, "arf:d", &file);
  60
  61         fd = xopen(file, O_RDONLY);
  62
  63         /*     "123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 */
  64         /*     "00:00:00:00:00:00 255.255.255.255 ABCDEFGHIJKLMNOPQRS Wed Jun 30 21:49:08 1993" */
  65         printf("Mac %-14s"       "IP %-13s"      "Host %-15s"        "Expires %s\n",
  66                 "Address", "Address", "Name",
  67                 (opt & OPT_a) ? "at" : "in"
  68         );
  69
  70         xread(fd, &written_at, sizeof(written_at));
  71         written_at = SWAP_BE64(written_at);
  72         curr = time(NULL);
  73         if (curr < written_at)
  74                 written_at = curr; /* lease file from future! :) */
  75
  76         while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
  77                 struct in_addr addr;
  78                 int64_t expires_abs;
  79
  80                 const char *fmt = ":%02x" + 1;
  81                 for (i = 0; i < 6; i++) {
  82                         printf(fmt, lease.lease_mac[i]);
  83                         fmt = ":%02x";
  84                 }
  85                 addr.s_addr = lease.lease_nip;
  86 #if ENABLE_UNICODE_SUPPORT
  87                 {
  88                         char *uni_name = unicode_conv_to_printable_fixedwidth(/*NULL,*/ lease.hostname, 19);
  89                         printf(" %-16s%s ", inet_ntoa(addr), uni_name);
  90                         free(uni_name);
  91                 }
  92 #else
  93                 /* actually, 15+1 and 19+1, +1 is a space between columns */
  94                 /* lease.hostname is char[20] and is always NUL terminated */
  95                 printf(" %-16s%-20s", inet_ntoa(addr), lease.hostname);
  96 #endif
  97                 expires_abs = ntohl(lease.expires) + written_at;
  98                 if (expires_abs <= curr) {
  99                         puts("expired");
 100                         continue;
 101                 }
 102                 if (opt & OPT_d) {
 103                         /* -d: decimal time */
 104                         if (!(opt & OPT_a))
 105                                 expires_abs -= curr;
 106                         printf("%llu\n", (unsigned long long) expires_abs);
 107                         continue;
 108                 }
 109                 if (!(opt & OPT_a)) { /* no -a */
 110                         unsigned d, h, m;
 111                         unsigned expires = expires_abs - curr;
 112                         d = expires / (24*60*60); expires %= (24*60*60);
 113                         h = expires / (60*60); expires %= (60*60);
 114                         m = expires / 60; expires %= 60;
 115                         if (d)
 116                                 printf("%u days ", d);
 117                         printf("%02u:%02u:%02u\n", h, m, (unsigned)expires);
 118                 } else { /* -a */
 119                         time_t t = expires_abs;
 120                         fputs(ctime(&t), stdout);
 121                 }
 122         }
 123         /* close(fd); */
 124
 125         return 0;
 126 }