/* Unix SMB/CIFS mplementation. run a child command Copyright (C) Andrew Tridgell 2010 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* this runs a child command with stdout and stderr going to the Samba log */ #include "includes.h" #include "system/filesys.h" #include "lib/tevent/tevent.h" #include "lib/util/tevent_unix.h" struct samba_runcmd_state { int stdout_log_level; int stderr_log_level; struct tevent_fd *fde_stdout; struct tevent_fd *fde_stderr; int fd_stdout, fd_stderr; char *arg0; pid_t pid; char buf[1024]; uint16_t buf_used; }; static int samba_runcmd_state_destructor(struct samba_runcmd_state *state) { if (state->pid > 0) { kill(state->pid, SIGKILL); waitpid(state->pid, NULL, 0); state->pid = -1; } return 0; } static void samba_runcmd_io_handler(struct tevent_context *ev, struct tevent_fd *fde, uint16_t flags, void *private_data); /* run a command as a child process, with a timeout. any stdout/stderr from the child will appear in the Samba logs with the specified log levels */ struct tevent_req *samba_runcmd_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, struct timeval endtime, int stdout_log_level, int stderr_log_level, const char * const *argv0, ...) { struct tevent_req *req; struct samba_runcmd_state *state; int p1[2], p2[2]; char **argv; int ret; va_list ap; req = tevent_req_create(mem_ctx, &state, struct samba_runcmd_state); if (req == NULL) { return NULL; } state->stdout_log_level = stdout_log_level; state->stderr_log_level = stderr_log_level; state->arg0 = talloc_strdup(state, argv0[0]); if (tevent_req_nomem(state->arg0, req)) { return tevent_req_post(req, ev); } if (pipe(p1) != 0) { tevent_req_error(req, errno); return tevent_req_post(req, ev); } if (pipe(p2) != 0) { close(p1[0]); close(p1[1]); tevent_req_error(req, errno); return tevent_req_post(req, ev); } state->pid = fork(); if (state->pid == (pid_t)-1) { close(p1[0]); close(p1[1]); close(p2[0]); close(p2[1]); tevent_req_error(req, errno); return tevent_req_post(req, ev); } if (state->pid != 0) { /* the parent */ close(p1[1]); close(p2[1]); state->fd_stdout = p1[0]; state->fd_stderr = p2[0]; set_blocking(state->fd_stdout, false); set_blocking(state->fd_stderr, false); talloc_set_destructor(state, samba_runcmd_state_destructor); state->fde_stdout = tevent_add_fd(ev, state, state->fd_stdout, TEVENT_FD_READ, samba_runcmd_io_handler, req); if (tevent_req_nomem(state->fde_stdout, req)) { close(p1[0]); close(p2[0]); return tevent_req_post(req, ev); } tevent_fd_set_auto_close(state->fde_stdout); state->fde_stderr = tevent_add_fd(ev, state, state->fd_stderr, TEVENT_FD_READ, samba_runcmd_io_handler, req); if (tevent_req_nomem(state->fde_stdout, req)) { close(p2[0]); return tevent_req_post(req, ev); } tevent_fd_set_auto_close(state->fde_stderr); if (!timeval_is_zero(&endtime)) { tevent_req_set_endtime(req, ev, endtime); } return req; } /* the child */ close(p1[0]); close(p2[0]); close(0); close(1); close(2); /* we want to ensure that all of the network sockets we had open are closed */ tevent_re_initialise(ev); /* setup for logging to go to the parents debug log */ open("/dev/null", O_RDONLY); /* for stdin */ dup2(p1[1], 1); dup2(p2[1], 2); argv = str_list_copy(state, discard_const_p(const char *, argv0)); if (!argv) { fprintf(stderr, "Out of memory in child\n"); _exit(255); } va_start(ap, argv0); while (1) { char *arg = va_arg(ap, char *); if (arg == NULL) break; argv = discard_const_p(char *, str_list_add((const char **)argv, arg)); if (!argv) { fprintf(stderr, "Out of memory in child\n"); _exit(255); } } va_end(ap); ret = execvp(state->arg0, argv); fprintf(stderr, "Failed to exec child - %s\n", strerror(errno)); _exit(255); return NULL; } /* handle stdout/stderr from the child */ static void samba_runcmd_io_handler(struct tevent_context *ev, struct tevent_fd *fde, uint16_t flags, void *private_data) { struct tevent_req *req = talloc_get_type_abort(private_data, struct tevent_req); struct samba_runcmd_state *state = tevent_req_data(req, struct samba_runcmd_state); int level; char *p; int n, fd; if (fde == state->fde_stdout) { level = state->stdout_log_level; fd = state->fd_stdout; } else { level = state->stderr_log_level; fd = state->fd_stderr; } if (!(flags & TEVENT_FD_READ)) { return; } n = read(fd, &state->buf[state->buf_used], sizeof(state->buf) - state->buf_used); if (n > 0) { state->buf_used += n; } else if (n == 0) { if (fde == state->fde_stdout) { talloc_free(fde); state->fde_stdout = NULL; } if (fde == state->fde_stderr) { talloc_free(fde); state->fde_stderr = NULL; } if (state->fde_stdout == NULL && state->fde_stderr == NULL) { int status; /* the child has closed both stdout and * stderr, assume its dead */ pid_t pid = waitpid(state->pid, &status, 0); if (pid != state->pid) { if (errno == ECHILD) { /* this happens when the parent has set SIGCHLD to SIG_IGN. In that case we can only get error information for the child via its logging. We should stop using SIG_IGN on SIGCHLD in the standard process model. */ tevent_req_done(req); return; } DEBUG(0,("Error in waitpid() for child %s - %s \n", state->arg0, strerror(errno))); if (errno == 0) { errno = ECHILD; } tevent_req_error(req, errno); return; } status = WEXITSTATUS(status); DEBUG(3,("Child %s exited with status %d - %s\n", state->arg0, status, strerror(status))); if (status != 0) { tevent_req_error(req, status); return; } tevent_req_done(req); return; } return; } while (state->buf_used > 0 && (p = (char *)memchr(state->buf, '\n', state->buf_used)) != NULL) { int n1 = (p - state->buf)+1; int n2 = n1 - 1; /* swallow \r from child processes */ if (n2 > 0 && state->buf[n2-1] == '\r') { n2--; } DEBUG(level,("%s: %*.*s\n", state->arg0, n2, n2, state->buf)); memmove(state->buf, p+1, sizeof(state->buf) - n1); state->buf_used -= n1; } /* the buffer could have completely filled - unfortunately we have no choice but to dump it out straight away */ if (state->buf_used == sizeof(state->buf)) { DEBUG(level,("%s: %*.*s\n", state->arg0, state->buf_used, state->buf_used, state->buf)); state->buf_used = 0; } } int samba_runcmd_recv(struct tevent_req *req, int *perrno) { if (tevent_req_is_unix_error(req, perrno)) { tevent_req_received(req); return -1; } tevent_req_received(req); return 0; }