runit/runsvdir.c

   1 /* Busyboxed by Denis Vlasenko <vda.linux@googlemail.com> */
   2 /* TODO: depends on runit_lib.c - review and reduce/eliminate */
   3
   4 #include <sys/poll.h>
   5 #include <sys/file.h>
   6 #include "busybox.h"
   7 #include "runit_lib.h"
   8
   9 #define MAXSERVICES 1000
  10
  11 static char *svdir;
  12 static unsigned long dev;
  13 static unsigned long ino;
  14 static struct service {
  15         unsigned long dev;
  16         unsigned long ino;
  17         int pid;
  18         int isgone;
  19 } *sv;
  20 static int svnum;
  21 static int check = 1;
  22 static char *rplog;
  23 static int rploglen;
  24 static int logpipe[2];
  25 static iopause_fd io[1];
  26 static struct taia stamplog;
  27 static int exitsoon;
  28 static int pgrp;
  29
  30 #define usage() bb_show_usage()
  31 static void fatal2_cannot(const char *m1, const char *m2)
  32 {
  33         bb_perror_msg_and_die("%s: fatal: cannot %s%s", svdir, m1, m2);
  34         /* was exiting 100 */
  35 }
  36 static void warn3x(const char *m1, const char *m2, const char *m3)
  37 {
  38         bb_error_msg("%s: warning: %s%s%s", svdir, m1, m2, m3);
  39 }
  40 static void warn2_cannot(const char *m1, const char *m2)
  41 {
  42         warn3x("cannot ", m1, m2);
  43 }
  44 static void warnx(const char *m1)
  45 {
  46         warn3x(m1, "", "");
  47 }
  48
  49 static void s_term(int sig_no)
  50 {
  51         exitsoon = 1;
  52 }
  53 static void s_hangup(int sig_no)
  54 {
  55         exitsoon = 2;
  56 }
  57
  58 static void runsv(int no, const char *name)
  59 {
  60         int pid = fork();
  61
  62         if (pid == -1) {
  63                 warn2_cannot("fork for ", name);
  64                 return;
  65         }
  66         if (pid == 0) {
  67                 /* child */
  68                 char *prog[3];
  69
  70                 prog[0] = (char*)"runsv";
  71                 prog[1] = (char*)name;
  72                 prog[2] = NULL;
  73                 sig_uncatch(SIGHUP);
  74                 sig_uncatch(SIGTERM);
  75                 if (pgrp) setsid();
  76                 execvp(prog[0], prog);
  77                 //pathexec_run(*prog, prog, (char* const*)environ);
  78                 fatal2_cannot("start runsv ", name);
  79         }
  80         sv[no].pid = pid;
  81 }
  82
  83 static void runsvdir(void)
  84 {
  85         DIR *dir;
  86         direntry *d;
  87         int i;
  88         struct stat s;
  89
  90         dir = opendir(".");
  91         if (!dir) {
  92                 warn2_cannot("open directory ", svdir);
  93                 return;
  94         }
  95         for (i = 0; i < svnum; i++)
  96                 sv[i].isgone = 1;
  97         errno = 0;
  98         while ((d = readdir(dir))) {
  99                 if (d->d_name[0] == '.') continue;
 100                 if (stat(d->d_name, &s) == -1) {
 101                         warn2_cannot("stat ", d->d_name);
 102                         errno = 0;
 103                         continue;
 104                 }
 105                 if (!S_ISDIR(s.st_mode)) continue;
 106                 for (i = 0; i < svnum; i++) {
 107                         if ((sv[i].ino == s.st_ino) && (sv[i].dev == s.st_dev)) {
 108                                 sv[i].isgone = 0;
 109                                 if (!sv[i].pid)
 110                                         runsv(i, d->d_name);
 111                                 break;
 112                         }
 113                 }
 114                 if (i == svnum) {
 115                         /* new service */
 116                         struct service *svnew = realloc(sv, (i+1) * sizeof(*sv));
 117                         if (!svnew) {
 118                                 warn3x("cannot start runsv ", d->d_name,
 119                                                 " too many services");
 120                                 continue;
 121                         }
 122                         sv = svnew;
 123                         svnum++;
 124                         memset(&sv[i], 0, sizeof(sv[i]));
 125                         sv[i].ino = s.st_ino;
 126                         sv[i].dev = s.st_dev;
 127                         //sv[i].pid = 0;
 128                         //sv[i].isgone = 0;
 129                         runsv(i, d->d_name);
 130                         check = 1;
 131                 }
 132         }
 133         if (errno) {
 134                 warn2_cannot("read directory ", svdir);
 135                 closedir(dir);
 136                 check = 1;
 137                 return;
 138         }
 139         closedir(dir);
 140
 141         /* SIGTERM removed runsv's */
 142         for (i = 0; i < svnum; i++) {
 143                 if (!sv[i].isgone)
 144                         continue;
 145                 if (sv[i].pid)
 146                         kill(sv[i].pid, SIGTERM);
 147                 sv[i] = sv[--svnum];
 148                 check = 1;
 149         }
 150 }
 151
 152 static int setup_log(void)
 153 {
 154         rploglen = strlen(rplog);
 155         if (rploglen < 7) {
 156                 warnx("log must have at least seven characters");
 157                 return 0;
 158         }
 159         if (pipe(logpipe) == -1) {
 160                 warnx("cannot create pipe for log");
 161                 return -1;
 162         }
 163         coe(logpipe[1]);
 164         coe(logpipe[0]);
 165         ndelay_on(logpipe[0]);
 166         ndelay_on(logpipe[1]);
 167         if (fd_copy(2, logpipe[1]) == -1) {
 168                 warnx("cannot set filedescriptor for log");
 169                 return -1;
 170         }
 171         io[0].fd = logpipe[0];
 172         io[0].events = IOPAUSE_READ;
 173         taia_now(&stamplog);
 174         return 1;
 175 }
 176
 177 int runsvdir_main(int argc, char **argv)
 178 {
 179         struct stat s;
 180         time_t mtime = 0;
 181         int wstat;
 182         int curdir;
 183         int pid;
 184         struct taia deadline;
 185         struct taia now;
 186         struct taia stampcheck;
 187         char ch;
 188         int i;
 189
 190         argv++;
 191         if (!argv || !*argv) usage();
 192         if (**argv == '-') {
 193                 switch (*(*argv + 1)) {
 194                 case 'P': pgrp = 1;
 195                 case '-': ++argv;
 196                 }
 197                 if (!argv || !*argv) usage();
 198         }
 199
 200         sig_catch(SIGTERM, s_term);
 201         sig_catch(SIGHUP, s_hangup);
 202         svdir = *argv++;
 203         if (argv && *argv) {
 204                 rplog = *argv;
 205                 if (setup_log() != 1) {
 206                         rplog = 0;
 207                         warnx("log service disabled");
 208                 }
 209         }
 210         curdir = open_read(".");
 211         if (curdir == -1)
 212                 fatal2_cannot("open current directory", "");
 213         coe(curdir);
 214
 215         taia_now(&stampcheck);
 216
 217         for (;;) {
 218                 /* collect children */
 219                 for (;;) {
 220                         pid = wait_nohang(&wstat);
 221                         if (pid <= 0) break;
 222                         for (i = 0; i < svnum; i++) {
 223                                 if (pid == sv[i].pid) {
 224                                         /* runsv has gone */
 225                                         sv[i].pid = 0;
 226                                         check = 1;
 227                                         break;
 228                                 }
 229                         }
 230                 }
 231
 232                 taia_now(&now);
 233                 if (now.sec.x < (stampcheck.sec.x - 3)) {
 234                         /* time warp */
 235                         warnx("time warp: resetting time stamp");
 236                         taia_now(&stampcheck);
 237                         taia_now(&now);
 238                         if (rplog) taia_now(&stamplog);
 239                 }
 240                 if (taia_less(&now, &stampcheck) == 0) {
 241                         /* wait at least a second */
 242                         taia_uint(&deadline, 1);
 243                         taia_add(&stampcheck, &now, &deadline);
 244
 245                         if (stat(svdir, &s) != -1) {
 246                                 if (check || s.st_mtime != mtime
 247                                  || s.st_ino != ino || s.st_dev != dev
 248                                 ) {
 249                                         /* svdir modified */
 250                                         if (chdir(svdir) != -1) {
 251                                                 mtime = s.st_mtime;
 252                                                 dev = s.st_dev;
 253                                                 ino = s.st_ino;
 254                                                 check = 0;
 255                                                 if (now.sec.x <= (4611686018427387914ULL + (uint64_t)mtime))
 256                                                         sleep(1);
 257                                                 runsvdir();
 258                                                 while (fchdir(curdir) == -1) {
 259                                                         warn2_cannot("change directory, pausing", "");
 260                                                         sleep(5);
 261                                                 }
 262                                         } else
 263                                                 warn2_cannot("change directory to ", svdir);
 264                                 }
 265                         } else
 266                                 warn2_cannot("stat ", svdir);
 267                 }
 268
 269                 if (rplog) {
 270                         if (taia_less(&now, &stamplog) == 0) {
 271                                 write(logpipe[1], ".", 1);
 272                                 taia_uint(&deadline, 900);
 273                                 taia_add(&stamplog, &now, &deadline);
 274                         }
 275                 }
 276                 taia_uint(&deadline, check ? 1 : 5);
 277                 taia_add(&deadline, &now, &deadline);
 278
 279                 sig_block(SIGCHLD);
 280                 if (rplog)
 281                         iopause(io, 1, &deadline, &now);
 282                 else
 283                         iopause(0, 0, &deadline, &now);
 284                 sig_unblock(SIGCHLD);
 285
 286                 if (rplog && (io[0].revents | IOPAUSE_READ))
 287                         while (read(logpipe[0], &ch, 1) > 0)
 288                                 if (ch) {
 289                                         for (i = 6; i < rploglen; i++)
 290                                                 rplog[i-1] = rplog[i];
 291                                         rplog[rploglen-1] = ch;
 292                                 }
 293
 294                 switch (exitsoon) {
 295                 case 1:
 296                         _exit(0);
 297                 case 2:
 298                         for (i = 0; i < svnum; i++)
 299                                 if (sv[i].pid)
 300                                         kill(sv[i].pid, SIGTERM);
 301                         _exit(111);
 302                 }
 303         }
 304         /* not reached */
 305         return 0;
 306 }