ref: dc952dad295700a836cf91ec66b1c443e5bbb4b7
dir: /sys/src/cmd/upas/imap4d/quota.c/
#include "imap4d.h" static int openpipe(int *pip, char *cmd, char *av[]) { int pid, fd[2]; if(pipe(fd) != 0) sysfatal("pipe: %r"); pid = fork(); switch(pid){ case -1: return -1; case 0: close(1); dup(fd[1], 1); if(fd[1] != 1) close(fd[1]); if(fd[0] != 0) close(fd[0]); exec(cmd, av); ilog("exec: %r"); _exits("b0rked"); return -1; default: *pip = fd[0]; close(fd[1]); return pid; } } static int closepipe(int pid, int fd) { int nz, wpid; Waitmsg *w; close(fd); while(w = wait()){ nz = !w->msg || !w->msg[0]; wpid = w->pid; free(w); if(wpid == pid) return nz? 0: -1; } return -1; } static char dupath[Pathlen]; static char *duav[] = { "du", "-s", dupath, 0}; vlong getquota(void) { char buf[Pathlen + 128], *f[3]; int fd, pid; werrstr(""); memset(buf, 0, sizeof buf); snprint(dupath, sizeof dupath, "%s", mboxdir); pid = openpipe(&fd, "/bin/du", duav); if(pid == -1) return -1; if(read(fd, buf, sizeof buf) < 4){ closepipe(pid, fd); return -1; } if(closepipe(pid, fd) == -1) return -1; if(getfields(buf, f, 2, 1, "\t") != 2) return -1; return strtoull(f[0], 0, 0); }