ref: 53d55013598d7cd214d01cbf0b026844fe7ca8d2
dir: /sys/src/cmd/os.c/
#include <u.h> #include <libc.h> enum { Fstdin, Fstdout, Fstderr, Fwait, Fctl, Nfd, }; enum { Pcopyin, Pcopyout, Pcopyerr, Preadwait, Npid, }; char *mnt = "/mnt/term/cmd"; char *dir = nil; char buf[8192]; int fd[Nfd] = {-1}; int pid[Npid]; int nice, foreground = 1; void killstdin(void) { if(pid[Pcopyin] != 0) postnote(PNPROC, pid[Pcopyin], "kill"); } void killproc(void) { if(fd[Fctl] >= 0) write(fd[Fctl], "kill", 4); } int catch(void*, char *msg) { if(strcmp(msg, "interrupt") == 0 || strcmp(msg, "hangup") == 0 || strcmp(msg, "kill") == 0){ killproc(); return 1; } return 0; } void fd01(int fd0, int fd1) { int i; if(fd0 >= 0 && fd0 != 0){ if(dup(fd0, 0) < 0) sysfatal("dup: %r"); } if(fd1 >= 0 && fd1 != 1){ if(dup(fd1, 1) < 0) sysfatal("dup: %r"); } for(i = 0; i<Nfd; i++){ if(fd[i] > 2) close(fd[i]); if(fd[i] == fd0) fd[i] = 0; else if(fd[i] == fd1) fd[i] = 1; else fd[i] = -1; } } void copy(void) { int n; while((n = read(0, buf, sizeof(buf))) > 0) if(write(1, buf, n) != n) break; } void usage(void) { fprint(2, "%s: [ -b ] [ -m mountpoint ] [ -d dir ] [ -n ] [ -N level ] cmd [ arg... ]\n", argv0); exits("usage"); } void main(int argc, char **argv) { Waitmsg *w; char *s; int n; quotefmtinstall(); ARGBEGIN { case 'b': foreground = 0; break; case 'm': mnt = cleanname(EARGF(usage())); break; case 'd': dir = EARGF(usage()); break; case 'n': nice = 1; break; case 'N': nice = atoi(EARGF(usage())); break; default: usage(); } ARGEND; if(argc < 1) usage(); seprint(buf, &buf[sizeof(buf)], "%s/clone", mnt); if((fd[Fctl] = open(buf, ORDWR)) < 0) sysfatal("open: %r"); s = &buf[strlen(mnt)+1]; if((n = read(fd[Fctl], s, &buf[sizeof(buf)-1]-s)) < 0) sysfatal("read clone: %r"); while(n > 0 && buf[n-1] == '\n') n--; s += n; seprint(s, &buf[sizeof(buf)], "/wait"); if((fd[Fwait] = open(buf, OREAD)) < 0) sysfatal("open: %r"); if(foreground){ seprint(s, &buf[sizeof(buf)], "/data"); if((fd[Fstdin] = open(buf, OWRITE)) < 0) sysfatal("open: %r"); seprint(s, &buf[sizeof(buf)], "/data"); if((fd[Fstdout] = open(buf, OREAD)) < 0) sysfatal("open: %r"); seprint(s, &buf[sizeof(buf)], "/stderr"); if((fd[Fstderr] = open(buf, OREAD)) < 0) sysfatal("open: %r"); } if(dir != nil){ if(fprint(fd[Fctl], "dir %q", dir) < 0) sysfatal("cannot change directory: %r"); } else { /* * try to automatically change directory if we are in * /mnt/term or /mnt/term/root, but unlike -d flag, * do not error when the dir ctl command fails. */ if((s = strrchr(mnt, '/')) != nil){ n = s - mnt; dir = getwd(buf, sizeof(buf)); if(strncmp(dir, mnt, n) == 0 && (dir[n] == 0 || dir[n] == '/')){ dir += n; if(strncmp(dir, "/root", 5) == 0 && (dir[5] == 0 || dir[5] == '/')) dir += 5; if(*dir == 0) dir = "/"; /* hack for win32: /C:... -> C:/... */ if(dir[1] >= 'A' && dir[1] <= 'Z' && dir[2] == ':') dir[0] = dir[1], dir[1] = ':', dir[2] = '/'; fprint(fd[Fctl], "dir %q", dir); } } } if(nice != 0) fprint(fd[Fctl], "nice %d", nice); if(foreground) fprint(fd[Fctl], "killonclose"); s = seprint(buf, &buf[sizeof(buf)], "exec"); while(*argv != nil){ s = seprint(s, &buf[sizeof(buf)], " %q", *argv++); if(s >= &buf[sizeof(buf)-1]) sysfatal("too many arguments"); } if(write(fd[Fctl], buf, s - buf) < 0) sysfatal("write: %r"); if((pid[Preadwait] = fork()) == -1) sysfatal("fork: %r"); if(pid[Preadwait] == 0){ fd01(fd[Fwait], 2); if((n = read(0, buf, sizeof(buf)-1)) < 0) rerrstr(buf, sizeof(buf)); else { char *f[5]; while(n > 0 && buf[n-1] == '\n') n--; buf[n] = 0; if(tokenize(buf, f, 5) == 5) exits(f[4]); } exits(buf); } if(foreground){ if((pid[Pcopyerr] = fork()) == -1) sysfatal("fork: %r"); if(pid[Pcopyerr] == 0){ fd01(fd[Fstderr], 2); copy(); rerrstr(buf, sizeof(buf)); exits(buf); } if((pid[Pcopyout] = fork()) == -1) sysfatal("fork: %r"); if(pid[Pcopyout] == 0){ fd01(fd[Fstdout], 1); copy(); rerrstr(buf, sizeof(buf)); exits(buf); } if((pid[Pcopyin] = fork()) == -1) sysfatal("fork: %r"); if(pid[Pcopyin] == 0){ fd01(0, fd[Fstdin]); copy(); rerrstr(buf, sizeof(buf)); exits(buf); } } fd01(fd[Fctl], 2); atexit(killstdin); atnotify(catch, 1); while((w = wait()) != nil){ if((s = strstr(w->msg, ": ")) == nil) s = w->msg; else s += 2; for(n = 0; n < Npid; n++){ if(pid[n] == w->pid){ pid[n] = 0; break; } } if(n == Preadwait) exits(s); free(w); } }