| 1 | /* |
| 2 | * uxsel.c |
| 3 | * |
| 4 | * This module is a sort of all-purpose interchange for file |
| 5 | * descriptors. At one end it talks to uxnet.c and pty.c and |
| 6 | * anything else which might have one or more fds that need |
| 7 | * select()-type things doing to them during an extended program |
| 8 | * run; at the other end it talks to pterm.c or uxplink.c or |
| 9 | * anything else which might have its own means of actually doing |
| 10 | * those select()-type things. |
| 11 | */ |
| 12 | |
| 13 | #include <assert.h> |
| 14 | |
| 15 | #include "putty.h" |
| 16 | #include "tree234.h" |
| 17 | |
| 18 | struct fd { |
| 19 | int fd; |
| 20 | int rwx; /* 4=except 2=write 1=read */ |
| 21 | uxsel_callback_fn callback; |
| 22 | int id; /* for uxsel_input_remove */ |
| 23 | }; |
| 24 | |
| 25 | static tree234 *fds; |
| 26 | |
| 27 | static int uxsel_fd_cmp(void *av, void *bv) |
| 28 | { |
| 29 | struct fd *a = (struct fd *)av; |
| 30 | struct fd *b = (struct fd *)bv; |
| 31 | if (a->fd < b->fd) |
| 32 | return -1; |
| 33 | if (a->fd > b->fd) |
| 34 | return +1; |
| 35 | return 0; |
| 36 | } |
| 37 | static int uxsel_fd_findcmp(void *av, void *bv) |
| 38 | { |
| 39 | int *a = (int *)av; |
| 40 | struct fd *b = (struct fd *)bv; |
| 41 | if (*a < b->fd) |
| 42 | return -1; |
| 43 | if (*a > b->fd) |
| 44 | return +1; |
| 45 | return 0; |
| 46 | } |
| 47 | |
| 48 | void uxsel_init(void) |
| 49 | { |
| 50 | fds = newtree234(uxsel_fd_cmp); |
| 51 | } |
| 52 | |
| 53 | /* |
| 54 | * Here is the interface to fd-supplying modules. They supply an |
| 55 | * fd, a set of read/write/execute states, and a callback function |
| 56 | * for when the fd satisfies one of those states. Repeated calls to |
| 57 | * uxsel_set on the same fd are perfectly legal and serve to change |
| 58 | * the rwx state (typically you only want to select an fd for |
| 59 | * writing when you actually have pending data you want to write to |
| 60 | * it!). |
| 61 | */ |
| 62 | |
| 63 | void uxsel_set(int fd, int rwx, uxsel_callback_fn callback) |
| 64 | { |
| 65 | struct fd *newfd = snew(struct fd); |
| 66 | struct fd *oldfd; |
| 67 | |
| 68 | newfd->fd = fd; |
| 69 | newfd->rwx = rwx; |
| 70 | newfd->callback = callback; |
| 71 | |
| 72 | oldfd = find234(fds, newfd, NULL); |
| 73 | if (oldfd) { |
| 74 | uxsel_input_remove(oldfd->id); |
| 75 | del234(fds, oldfd); |
| 76 | sfree(oldfd); |
| 77 | } |
| 78 | |
| 79 | add234(fds, newfd); |
| 80 | newfd->id = uxsel_input_add(fd, rwx); |
| 81 | } |
| 82 | |
| 83 | void uxsel_del(int fd) |
| 84 | { |
| 85 | struct fd *oldfd = find234(fds, &fd, uxsel_fd_findcmp); |
| 86 | if (oldfd) { |
| 87 | uxsel_input_remove(oldfd->id); |
| 88 | del234(fds, oldfd); |
| 89 | sfree(oldfd); |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /* |
| 94 | * And here is the interface to select-functionality-supplying |
| 95 | * modules. |
| 96 | */ |
| 97 | |
| 98 | int next_fd(int *state, int *rwx) |
| 99 | { |
| 100 | struct fd *fd; |
| 101 | fd = index234(fds, (*state)++); |
| 102 | if (fd) { |
| 103 | *rwx = fd->rwx; |
| 104 | return fd->fd; |
| 105 | } else |
| 106 | return -1; |
| 107 | } |
| 108 | |
| 109 | int first_fd(int *state, int *rwx) |
| 110 | { |
| 111 | *state = 0; |
| 112 | return next_fd(state, rwx); |
| 113 | } |
| 114 | |
| 115 | int select_result(int fd, int event) |
| 116 | { |
| 117 | struct fd *fdstruct = find234(fds, &fd, uxsel_fd_findcmp); |
| 118 | /* |
| 119 | * Apparently this can sometimes be NULL. Can't see how, but I |
| 120 | * assume it means I need to ignore the event since it's on an |
| 121 | * fd I've stopped being interested in. Sigh. |
| 122 | */ |
| 123 | if (fdstruct) |
| 124 | return fdstruct->callback(fd, event); |
| 125 | else |
| 126 | return 1; |
| 127 | } |