xio-pty.c

   1 /* source: xio-pty.c */
   2 /* Copyright Gerhard Rieger and contributors (see file CHANGES) */
   3 /* Published under the GNU General Public License V.2, see file COPYING */
   4
   5 /* this file contains the source for creating pty addresses */
   6
   7 #include "xiosysincludes.h"
   8 #include "xioopen.h"
   9
  10 #include "xio-named.h"
  11 #include "xio-termios.h"
  12
  13
  14 #if WITH_PTY
  15
  16 /* here define the preferred polling intervall, in seconds */
  17 #define PTY_INTERVALL 1,0       /* for struct timespec */
  18
  19 #define MAXPTYNAMELEN 64
  20
  21 static int xioopen_pty(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *fd, const struct addrdesc *addrdesc);
  22
  23 const struct addrdesc xioaddr_pty = { "PTY",   3, xioopen_pty, GROUP_NAMED|GROUP_FD|GROUP_TERMIOS|GROUP_PTY, 0, 0, 0 HELP("") };
  24
  25 const struct optdesc opt_symbolic_link = { "symbolic-link", "link", OPT_SYMBOLIC_LINK, GROUP_PTY, PH_LATE, TYPE_FILENAME, OFUNC_SPEC, 0, 0 };
  26 #if HAVE_POLL
  27 const struct optdesc opt_pty_wait_slave = { "pty-wait-slave", "wait-slave", OPT_PTY_WAIT_SLAVE, GROUP_PTY, PH_EARLY, TYPE_BOOL,   OFUNC_SPEC, 0, 0 };
  28 const struct optdesc opt_pty_intervall  = { "pty-interval",  NULL,         OPT_PTY_INTERVALL,  GROUP_PTY, PH_EARLY, TYPE_TIMESPEC, OFUNC_SPEC, 0, 0 };
  29 #endif /* HAVE_POLL */
  30
  31 static int xioopen_pty(
  32         int argc,
  33         const char *argv[],
  34         struct opt *opts,
  35         int xioflags,
  36         xiofile_t *xfd,
  37         const struct addrdesc *addrdesc)
  38 {
  39    /* we expect the form: filename */
  40    struct single *sfd = &xfd->stream;
  41    int ptyfd = -1;      /* master */
  42    int ttyfd = -1;      /* slave */
  43 #if defined(HAVE_DEV_PTMX) || defined(HAVE_DEV_PTC)
  44    bool useptmx = false;        /* use /dev/ptmx or equivalent */
  45 #endif
  46 #if HAVE_OPENPTY
  47    bool useopenpty = false;     /* try only openpty */
  48 #endif  /* HAVE_OPENPTY */
  49    char ptyname[MAXPTYNAMELEN];
  50    char *tn = NULL;
  51    char *linkname = NULL;
  52    bool opt_unlink_close = true;        /* remove symlink afterwards */
  53    bool wait_slave = false;     /* true would be better for many platforms, but
  54                                    some OSes cannot handle this, and for common
  55                                    default behaviour as well as backward
  56                                    compatibility we choose "no" as default */
  57    struct timespec pollintv = { PTY_INTERVALL };
  58
  59    if (argc != 1) {
  60       xio_syntax(argv[0], 0, argc-1, addrdesc->syntax);
  61       return STAT_NORETRY;
  62    }
  63
  64    if (sfd->howtoend == END_UNSPEC)
  65       sfd->howtoend = END_CLOSE;
  66
  67    if (applyopts_single(sfd, opts, PH_INIT) < 0)  return -1;
  68    applyopts(sfd, -1, opts, PH_INIT);
  69
  70    retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);
  71
  72    /* trying to set user-early, perm-early etc. here might be useless because
  73       file system entry is eventually available only past pty creation */
  74    /* name not yet known; umask should not be handled with this function! */
  75    /* umask does not affect resulting mode, on Linux 2.4 */
  76    applyopts_named("", opts, PH_EARLY); /* umask! */
  77
  78 #if defined(HAVE_DEV_PTMX) || defined(HAVE_DEV_PTC)
  79    retropt_bool(opts, OPT_PTMX, &useptmx);
  80 #endif
  81 #if HAVE_OPENPTY
  82    retropt_bool(opts, OPT_OPENPTY, &useopenpty);
  83 #endif
  84
  85 #if (defined(HAVE_DEV_PTMX) || defined(HAVE_DEV_PTC))
  86 #  if  HAVE_OPENPTY
  87    useopenpty = !useptmx;
  88 #  else /* !HAVE_OPENPTY */
  89    useptmx = true;
  90 #  endif /* !HAVE_OPENPTY */
  91 #else
  92 # if HAVE_OPENPTY
  93    useopenpty = true;
  94 # endif /* HAVE_OPENPTY */
  95 #endif /* ! (defined(HAVE_DEV_PTMX) || defined(HAVE_DEV_PTC)) */
  96
  97 #if HAVE_POLL
  98    retropt_bool(opts, OPT_PTY_WAIT_SLAVE, &wait_slave);
  99    retropt_timespec(opts, OPT_PTY_INTERVALL, &pollintv);
 100 #endif /* HAVE_POLL */
 101
 102    if (applyopts_single(sfd, opts, PH_INIT) < 0)  return -1;
 103    applyopts2(sfd, -1, opts, PH_INIT, PH_EARLY);
 104
 105    applyopts(sfd, -1, opts, PH_PREBIGEN);
 106
 107 #if HAVE_OPENPTY
 108    if (ptyfd < 0) {
 109       int result;
 110       if ((result = Openpty(&ptyfd, &ttyfd, ptyname, NULL, NULL)) < 0) {
 111          Error4("openpty(%p, %p, %p, NULL, NULL): %s",
 112                 &ptyfd, &ttyfd, ptyname, strerror(errno));
 113          return -1;
 114       }
 115       Notice1("PTY is %s", ptyname);
 116    }
 117 #endif /* HAVE_OPENPTY */
 118
 119 #if defined(HAVE_DEV_PTMX)
 120 #  define PTMX "/dev/ptmx"      /* Linux */
 121 #elif HAVE_DEV_PTC
 122 #  define PTMX "/dev/ptc"       /* AIX 4.3.3 */
 123 #endif
 124 #if HAVE_DEV_PTMX || HAVE_DEV_PTC
 125    if (useptmx || ptyfd < 0) {
 126       if ((ptyfd = Open(PTMX, O_RDWR|O_NOCTTY, 0620)) < 0) {
 127          Warn1("open(\""PTMX"\", O_RDWR|O_NOCTTY, 0620): %s",
 128                strerror(errno));
 129          /*!*/
 130       } else {
 131          ;/*0 Info1("open(\""PTMX"\", O_RDWR|O_NOCTTY, 0620) -> %d", ptyfd);*/
 132       }
 133       if (ptyfd >= 0) {
 134          /* we used PTMX before forking */
 135          /*0 extern char *ptsname(int);*/
 136 #if HAVE_GRANTPT        /* AIX, not Linux */
 137          if (Grantpt(ptyfd)/*!*/ < 0) {
 138             Warn2("grantpt(%d): %s", ptyfd, strerror(errno));
 139          }
 140 #endif /* HAVE_GRANTPT */
 141 #if HAVE_UNLOCKPT
 142          if (Unlockpt(ptyfd)/*!*/ < 0) {
 143             Warn2("unlockpt(%d): %s", ptyfd, strerror(errno));
 144          }
 145 #endif /* HAVE_UNLOCKPT */
 146 #if HAVE_PROTOTYPE_LIB_ptsname  /* AIX, not Linux */
 147          if ((tn = Ptsname(ptyfd)) == NULL) {
 148             Warn2("ptsname(%d): %s", ptyfd, strerror(errno));
 149          } else {
 150             Notice1("PTY is %s", tn);
 151          }
 152 #endif /* HAVE_PROTOTYPE_LIB_ptsname */
 153          if (tn == NULL) {
 154             if ((tn = Ttyname(ptyfd)) == NULL) {
 155                Warn2("ttyname(%d): %s", ptyfd, strerror(errno));
 156             }
 157          }
 158          ptyname[0] = '\0'; strncat(ptyname, tn, MAXPTYNAMELEN-1);
 159       }
 160    }
 161 #endif /* HAVE_DEV_PTMX || HAVE_DEV_PTC */
 162
 163    if (!retropt_string(opts, OPT_SYMBOLIC_LINK, &linkname)) {
 164       xio_unlink(linkname, E_ERROR);
 165       if (Symlink(ptyname, linkname) < 0) {
 166          Error3("symlink(\"%s\", \"%s\"): %s",
 167                 ptyname, linkname, strerror(errno));
 168       }
 169       if (opt_unlink_close) {
 170          if ((sfd->unlink_close = strdup(linkname)) == NULL) {
 171             Error1("strdup(\"%s\"): out of memory", linkname);
 172          }
 173          sfd->opt_unlink_close = true;
 174       }
 175    }
 176
 177    applyopts_named(ptyname, opts, PH_PASTOPEN);
 178    applyopts_named(ptyname, opts, PH_FD);
 179
 180    applyopts_cloexec(ptyfd, opts);/*!*/
 181    sfd->dtype    = XIODATA_PTY;
 182
 183    applyopts(sfd, ttyfd, opts, PH_FD);
 184
 185    {
 186       /* special handling of user-late etc.; with standard behaviour (up to
 187          1.7.1.1) they affected /dev/ptmx instead of /dev/pts/N */
 188       uid_t uid = -1, gid = -1;
 189       mode_t perm;
 190
 191       bool dont;
 192       dont = retropt_uid(opts, OPT_USER_LATE, &uid);
 193       dont &= retropt_gid(opts, OPT_GROUP_LATE, &gid);
 194
 195       if (!dont) {
 196          if (Chown(ptyname, uid, gid) < 0) {
 197             Error4("chown(\"%s\", %d, %d): %s",
 198                    ptyname, uid, gid, strerror(errno));
 199          }
 200       }
 201
 202       if (retropt_mode(opts, OPT_PERM_LATE, &perm) == 0) {
 203          if (Chmod(ptyname, perm) < 0) {
 204             Error3("chmod(\"%s\", %03o): %s",
 205                    ptyname, perm, strerror(errno));
 206          }
 207       }
 208
 209    }
 210
 211    sfd->fd = ptyfd;
 212    applyopts(sfd, -1, opts, PH_LATE);
 213    if (applyopts_single(sfd, opts, PH_LATE) < 0)
 214       return -1;
 215
 216 #if HAVE_POLL
 217    /* if you can and wish: */
 218    if (wait_slave) {
 219       /* try to wait until someone opens the slave side of the pty */
 220       /* we want to get a HUP (hangup) condition on the pty */
 221 #if HAVE_DEV_PTMX || HAVE_DEV_PTC
 222       if (useptmx) {
 223          ttyfd = Open(tn, O_RDWR|O_NOCTTY, 0620);
 224          Close(ttyfd);
 225       }
 226 #endif
 227 #if HAVE_OPENPTY
 228       if (useopenpty) {
 229          Close(ttyfd);
 230       }
 231 #endif /* HAVE_OPENPTY */
 232
 233       /* now we poll until the HUP vanishes - this indicates a slave conn. */
 234       while (true) {
 235          struct pollfd ufd;
 236          ufd.fd = ptyfd;
 237          ufd.events = (POLLHUP);
 238          if (Poll(&ufd, 1, 0) < 0) {
 239             Error3("poll({%d, 0x%04hu,}, 1, 0): %s",
 240                    ufd.fd, ufd.events, strerror(errno));
 241             /*! close something */
 242             return -1;
 243          }
 244          if (!(ufd.revents & POLLHUP)) {
 245             break;
 246          }
 247          Nanosleep(&pollintv, NULL);
 248          continue;
 249       }
 250    }
 251 #endif /* HAVE_POLL */
 252
 253    return STAT_OK;
 254 }
 255 #endif /* WITH_PTY */