ref: caef73363f896a1405ce6b9b6435f91e47a9b188
dir: /emu/Plan9/cmd.c/
#include "dat.h" #include "fns.h" #include "error.h" extern void vstack(void*); /* * all this is for the benefit of devcmd. * i hope it's grateful. */ typedef struct Targ Targ; struct Targ { int fd[3]; /* standard input, output and error */ int wfd; int* spin; char** args; char* dir; int pid; int nice; }; /* * called by vstack once it has moved to * the unshared stack in the new process. */ void exectramp(Targ *t) { int *fd, i, nfd; char filename[128], err[ERRMAX], status[2*ERRMAX]; t->pid = getpid(); *t->spin = 0; /* allow parent to proceed: can't just rendezvous: see below */ fd = t->fd; snprint(filename, sizeof(filename), "#d/%d", t->wfd); t->wfd = open(filename, OWRITE|OCEXEC); /* if it failed, we'll manage */ nfd = MAXNFD; /* TO DO: should read from /fd */ for(i = 0; i < nfd; i++) if(i != fd[0] && i != fd[1] && i != fd[2] && i != t->wfd) close(i); if(fd[0] != 0){ dup(fd[0], 0); close(fd[0]); } if(fd[1] != 1){ dup(fd[1], 1); close(fd[1]); } if(fd[2] != 2){ dup(fd[2], 2); close(fd[2]); } if(t->dir != nil && chdir(t->dir) < 0){ if(t->wfd > 0) fprint(t->wfd, "chdir: %s: %r", t->dir); _exits("bad dir"); } if(t->nice) oslopri(); exec(t->args[0], t->args); err[0] = 0; errstr(err, sizeof(err)); if(t->args[0][0] != '/' && t->args[0][0] != '#' && strncmp(t->args[0], "../", 3) != 0 && strncmp(t->args[0], "./", 2) != 0 && strlen(t->args[0])+5 < sizeof(filename)){ snprint(filename, sizeof(filename), "/bin/%s", t->args[0]); exec(filename, t->args); errstr(err, sizeof(err)); } snprint(status, sizeof(status), "%s: can't exec: %s", t->args[0], err); if(t->wfd > 0) write(t->wfd, status, strlen(status)); _exits(status); } void* oscmd(char **args, int nice, char *dir, int *fd) { Targ *t; int spin, *spinptr, fd0[2], fd1[2], fd2[2], wfd[2], n; Dir *d; up->genbuf[0] = 0; t = mallocz(sizeof(*t), 1); if(t == nil) return nil; t->args = args; t->dir = dir; t->nice = nice; fd0[0] = fd0[1] = -1; fd1[0] = fd1[1] = -1; fd2[0] = fd2[1] = -1; wfd[0] = wfd[1] = -1; if(dir != nil){ d = dirstat(dir); if(d == nil) goto Error; free(d); } if(pipe(fd0) < 0 || pipe(fd1) < 0 || pipe(fd2) < 0 || pipe(wfd) < 0) goto Error; spinptr = &spin; spin = 1; t->fd[0] = fd0[0]; t->fd[1] = fd1[1]; t->fd[2] = fd2[1]; t->wfd = wfd[1]; t->spin = spinptr; switch(rfork(RFPROC|RFMEM|RFREND|RFNOTEG|RFFDG|RFNAMEG|RFENVG)) { case -1: goto Error; case 0: /* if child returns first from rfork, its call to vstack replaces ... */ vstack(t); /* ... parent's return address from rfork and parent returns here */ default: /* if parent returns first from rfork, it comes here */ /* can't call anything: on shared stack until child releases spin in exectramp */ while(*spinptr) ; break; } close(fd0[0]); close(fd1[1]); close(fd2[1]); close(wfd[1]); n = read(wfd[0], up->genbuf, sizeof(up->genbuf)-1); close(wfd[0]); if(n > 0){ close(fd0[1]); close(fd1[0]); close(fd2[0]); up->genbuf[n] = 0; errstr(up->genbuf, sizeof(up->genbuf)); free(t); return nil; } fd[0] = fd0[1]; fd[1] = fd1[0]; fd[2] = fd2[0]; return t; Error: errstr(up->genbuf, sizeof(up->genbuf)); /* save the message before close */ close(fd0[0]); close(fd0[1]); close(fd1[0]); close(fd1[1]); close(fd2[0]); close(fd2[1]); close(wfd[0]); close(wfd[1]); free(t); errstr(up->genbuf, sizeof(up->genbuf)); return nil; } int oscmdkill(void *a) { Targ *t = a; return postnote(PNGROUP, t->pid, "kill"); } int oscmdwait(void*, char *buf, int n) { return await(buf, n); } void oscmdfree(void *a) { free(a); }