devdup.c 2.3 KB

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  1. #include "u.h"
  2. #include "../port/lib.h"
  3. #include "mem.h"
  4. #include "dat.h"
  5. #include "fns.h"
  6. #include "../port/error.h"
  7. /* Qid is (2*fd + (file is ctl))+1 */
  8. static int
  9. dupgen(Chan *c, char *, Dirtab*, int, int s, Dir *dp)
  10. {
  11. Fgrp *fgrp = up->fgrp;
  12. Chan *f;
  13. static int perm[] = { 0400, 0200, 0600, 0 };
  14. int p;
  15. Qid q;
  16. if(s == DEVDOTDOT){
  17. devdir(c, c->qid, ".", 0, eve, DMDIR|0555, dp);
  18. return 1;
  19. }
  20. if(s == 0)
  21. return 0;
  22. s--;
  23. if(s/2 > fgrp->maxfd)
  24. return -1;
  25. if((f=fgrp->fd[s/2]) == nil)
  26. return 0;
  27. if(s & 1){
  28. p = 0400;
  29. sprint(up->genbuf, "%dctl", s/2);
  30. }else{
  31. p = perm[f->mode&3];
  32. sprint(up->genbuf, "%d", s/2);
  33. }
  34. mkqid(&q, s+1, 0, QTFILE);
  35. devdir(c, q, up->genbuf, 0, eve, p, dp);
  36. return 1;
  37. }
  38. static Chan*
  39. dupattach(char *spec)
  40. {
  41. return devattach('d', spec);
  42. }
  43. static Walkqid*
  44. dupwalk(Chan *c, Chan *nc, char **name, int nname)
  45. {
  46. return devwalk(c, nc, name, nname, (Dirtab *)0, 0, dupgen);
  47. }
  48. static int
  49. dupstat(Chan *c, uchar *db, int n)
  50. {
  51. return devstat(c, db, n, (Dirtab *)0, 0L, dupgen);
  52. }
  53. static Chan*
  54. dupopen(Chan *c, int omode)
  55. {
  56. Chan *f;
  57. int fd, twicefd;
  58. if(c->qid.type & QTDIR){
  59. if(omode != 0)
  60. error(Eisdir);
  61. c->mode = 0;
  62. c->flag |= COPEN;
  63. c->offset = 0;
  64. return c;
  65. }
  66. if(c->qid.type & QTAUTH)
  67. error(Eperm);
  68. twicefd = c->qid.path - 1;
  69. fd = twicefd/2;
  70. if((twicefd & 1)){
  71. /* ctl file */
  72. f = c;
  73. f->mode = openmode(omode);
  74. f->flag |= COPEN;
  75. f->offset = 0;
  76. }else{
  77. /* fd file */
  78. f = fdtochan(fd, openmode(omode), 0, 1);
  79. cclose(c);
  80. }
  81. if(omode & OCEXEC)
  82. f->flag |= CCEXEC;
  83. return f;
  84. }
  85. static void
  86. dupclose(Chan*)
  87. {
  88. }
  89. static long
  90. dupread(Chan *c, void *va, long n, vlong offset)
  91. {
  92. char *a = va;
  93. char buf[256];
  94. int fd, twicefd;
  95. if(c->qid.type == QTDIR)
  96. return devdirread(c, a, n, (Dirtab *)0, 0L, dupgen);
  97. twicefd = c->qid.path - 1;
  98. fd = twicefd/2;
  99. if(twicefd & 1){
  100. c = fdtochan(fd, -1, 0, 1);
  101. procfdprint(c, fd, 0, buf, sizeof buf);
  102. cclose(c);
  103. return readstr((ulong)offset, va, n, buf);
  104. }
  105. panic("dupread");
  106. return 0;
  107. }
  108. static long
  109. dupwrite(Chan*, void*, long, vlong)
  110. {
  111. error(Eperm);
  112. return 0; /* not reached */
  113. }
  114. Dev dupdevtab = {
  115. 'd',
  116. "dup",
  117. devreset,
  118. devinit,
  119. devshutdown,
  120. dupattach,
  121. dupwalk,
  122. dupstat,
  123. dupopen,
  124. devcreate,
  125. dupclose,
  126. dupread,
  127. devbread,
  128. dupwrite,
  129. devbwrite,
  130. devremove,
  131. devwstat,
  132. };