ref: 6fa3e08412c49a188e2abe7d9ee54cd1f37a85f5
dir: /sys/src/cmd/cec/mux.c/
#include <u.h> #include <libc.h> #include "cec.h" typedef struct { char type; char pad[3]; Pkt p; } Muxmsg; typedef struct { int fd; int type; int pid; } Muxproc; struct Mux { Muxmsg m; Muxproc p[2]; int pfd[2]; int inuse; }; static Mux smux = { .inuse = -1, }; void muxcec(int, int cfd) { Muxmsg m; int l; m.type = Fcec; while((l = netget(&m.p, sizeof m.p)) > 0) if(write(cfd, &m, l+4) != l+4) break; exits(""); } void muxkbd(int kfd, int cfd) { Muxmsg m; m.type = Fkbd; while((m.p.len = read(kfd, m.p.data, sizeof m.p.data)) > 0) if(write(cfd, &m, m.p.len+22) != m.p.len+22) break; m.type = Ffatal; write(cfd, &m, 4); exits(""); } int muxproc(Mux *m, Muxproc *p, int fd, void (*f)(int, int), int type) { memset(p, 0, sizeof p); p->type = -1; switch(p->pid = rfork(RFPROC|RFFDG)){ case -1: return -1; case 0: close(m->pfd[0]); f(fd, m->pfd[1]); default: p->fd = fd; p->type = type; return p->pid; } } void muxfree(Mux *m) { close(m->pfd[0]); close(m->pfd[1]); postnote(PNPROC, m->p[0].pid, "this note goes to 11"); postnote(PNPROC, m->p[1].pid, "this note goes to 11"); waitpid(); waitpid(); memset(m, 0, sizeof *m); m->inuse = -1; } Mux* mux(int fd[2]) { Mux *m; if(smux.inuse != -1) sysfatal("mux in use"); m = &smux; m->inuse = 1; if(pipe(m->pfd) == -1) sysfatal("pipe: %r"); muxproc(m, m->p+0, fd[0], muxkbd, Fkbd); muxproc(m, m->p+1, fd[1], muxcec, Fcec); close(m->pfd[1]); return m; } int muxread(Mux *m, Pkt *p) { if(read(m->pfd[0], &m->m, sizeof m->m) == -1) return -1; memcpy(p, &m->m.p, sizeof *p); return m->m.type; }