ref: 9ca327dd06c30341d984bff84727ea451b428db7
dir: /emu/Linux/cmd.c/
#include <sys/types.h> #include <signal.h> #include <pwd.h> #include <sys/resource.h> #include <sys/wait.h> #include <fcntl.h> #include "dat.h" #include "fns.h" #include "error.h" enum { Debug = 0 }; /* * os-specific devcmd support. * this version should be reasonably portable across Unix systems. */ typedef struct Targ Targ; struct Targ { int fd[3]; /* fd[0] is standard input, fd[1] is standard output, fd[2] is standard error */ char** args; char* dir; int pid; int wfd; /* child writes errors that occur after the fork or on exec */ int uid; int gid; }; extern int gidnobody; extern int uidnobody; static int childproc(Targ *t) { int i, nfd; if(Debug) print("devcmd: '%s'", t->args[0]); nfd = getdtablesize(); for(i = 0; i < nfd; i++) if(i != t->fd[0] && i != t->fd[1] && i != t->fd[2] && i != t->wfd) close(i); dup2(t->fd[0], 0); dup2(t->fd[1], 1); dup2(t->fd[2], 2); close(t->fd[0]); close(t->fd[1]); close(t->fd[2]); /* should have an auth file to do host-specific authorisation? */ if(t->gid != -1){ if(setgid(t->gid) < 0 && getegid() == 0){ fprint(t->wfd, "can't set gid %d: %s", t->gid, strerror(errno)); _exit(1); } } if(t->uid != -1){ if(setuid(t->uid) < 0 && geteuid() == 0){ fprint(t->wfd, "can't set uid %d: %s", t->uid, strerror(errno)); _exit(1); } } if(t->dir != nil && chdir(t->dir) < 0){ fprint(t->wfd, "can't chdir to %s: %s", t->dir, strerror(errno)); _exit(1); } signal(SIGPIPE, SIG_DFL); execvp(t->args[0], t->args); if(Debug) print("execvp: %s\n",strerror(errno)); fprint(t->wfd, "exec failed: %s", strerror(errno)); _exit(1); } void* oscmd(char **args, int nice, char *dir, int *fd) { Targ *t; int r, fd0[2], fd1[2], fd2[2], wfd[2], n, pid; t = mallocz(sizeof(*t), 1); if(t == nil) return nil; fd0[0] = fd0[1] = -1; fd1[0] = fd1[1] = -1; fd2[0] = fd2[1] = -1; wfd[0] = wfd[1] = -1; if(pipe(fd0) < 0 || pipe(fd1) < 0 || pipe(fd2) < 0 || pipe(wfd) < 0) goto Error; if(fcntl(wfd[1], F_SETFD, FD_CLOEXEC) < 0) /* close on exec to give end of file on success */ goto Error; t->fd[0] = fd0[0]; t->fd[1] = fd1[1]; t->fd[2] = fd2[1]; t->wfd = wfd[1]; t->args = args; t->dir = dir; t->gid = up->env->gid; if(t->gid == -1) t->gid = gidnobody; t->uid = up->env->uid; if(t->uid == -1) t->uid = uidnobody; signal(SIGCHLD, SIG_DFL); switch(pid = fork()) { case -1: goto Error; case 0: setpgrp(); if(nice) setpriority(PRIO_PROCESS, 0, 19); childproc(t); _exit(1); default: t->pid = pid; if(Debug) print("cmd pid %d\n", t->pid); 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]); free(t); up->genbuf[n] = 0; if(Debug) print("oscmd: bad exec: %q\n", up->genbuf); error(up->genbuf); return nil; } fd[0] = fd0[1]; fd[1] = fd1[0]; fd[2] = fd2[0]; return t; Error: r = errno; if(Debug) print("oscmd: %q\n",strerror(r)); close(fd0[0]); close(fd0[1]); close(fd1[0]); close(fd1[1]); close(fd2[0]); close(fd2[1]); close(wfd[0]); close(wfd[1]); error(strerror(r)); return nil; } int oscmdkill(void *a) { Targ *t = a; if(Debug) print("kill: %d\n", t->pid); return kill(-t->pid, SIGTERM); } int oscmdwait(void *a, char *buf, int n) { Targ *t = a; int s; if(waitpid(t->pid, &s, 0) == -1){ if(Debug) print("wait error: %d [in %d] %q\n", t->pid, getpid(), strerror(errno)); return -1; } if(WIFEXITED(s)){ if(WEXITSTATUS(s) == 0) return snprint(buf, n, "%d 0 0 0 ''", t->pid); return snprint(buf, n, "%d 0 0 0 'exit: %d'", t->pid, WEXITSTATUS(s)); } if(WIFSIGNALED(s)){ if(WTERMSIG(s) == SIGTERM || WTERMSIG(s) == SIGKILL) return snprint(buf, n, "%d 0 0 0 killed", t->pid); return snprint(buf, n, "%d 0 0 0 'signal: %d'", t->pid, WTERMSIG(s)); } return snprint(buf, n, "%d 0 0 0 'odd status: 0x%x'", t->pid, s); } void oscmdfree(void *a) { free(a); }