/* assuan-pipe-connect.c - Establish a pipe connection (client) * Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc. * * This file is part of Assuan. * * Assuan is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * Assuan 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include #include #include #include #include #include #include "assuan-defs.h" #ifdef _POSIX_OPEN_MAX #define MAX_OPEN_FDS _POSIX_OPEN_MAX #else #define MAX_OPEN_FDS 20 #endif #define LOG(format, args...) \ fprintf (assuan_get_assuan_log_stream (), \ assuan_get_assuan_log_prefix (), \ "%s" format , ## args) static int writen (int fd, const char *buffer, size_t length) { while (length) { int nwritten = write (fd, buffer, length); if (nwritten < 0) { if (errno == EINTR) continue; return -1; /* write error */ } length -= nwritten; buffer += nwritten; } return 0; /* okay */ } static int do_finish (ASSUAN_CONTEXT ctx) { if (ctx->inbound.fd != -1) { close (ctx->inbound.fd); ctx->inbound.fd = -1; } if (ctx->outbound.fd != -1) { close (ctx->outbound.fd); ctx->outbound.fd = -1; } if (ctx->pid != -1 && ctx->pid) { waitpid (ctx->pid, NULL, 0); /* FIXME Check return value. */ ctx->pid = -1; } return 0; } static void do_deinit (ASSUAN_CONTEXT ctx) { do_finish (ctx); } /* Connect to a server over a pipe, creating the assuan context and returning it in CTX. The server filename is NAME, the argument vector in ARGV. FD_CHILD_LIST is a -1 terminated list of file descriptors not to close in the child. ATFORK is called in the child right after the fork; ATFORKVALUE is passed as the first argument and 0 is passed as the second argument. The ATFORK function should only act if the second value is 0. */ AssuanError assuan_pipe_connect2 (ASSUAN_CONTEXT *ctx, const char *name, char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue) { static int fixed_signals = 0; AssuanError err; int rp[2]; int wp[2]; char mypidstr[50]; if (!ctx || !name || !argv || !argv[0]) return ASSUAN_Invalid_Value; if (!fixed_signals) { struct sigaction act; sigaction (SIGPIPE, NULL, &act); if (act.sa_handler == SIG_DFL) { act.sa_handler = SIG_IGN; sigemptyset (&act.sa_mask); act.sa_flags = 0; sigaction (SIGPIPE, &act, NULL); } fixed_signals = 1; /* FIXME: This is not MT safe */ } sprintf (mypidstr, "%lu", (unsigned long)getpid ()); if (pipe (rp) < 0) return ASSUAN_General_Error; if (pipe (wp) < 0) { close (rp[0]); close (rp[1]); return ASSUAN_General_Error; } err = _assuan_new_context (ctx); if (err) { close (rp[0]); close (rp[1]); close (wp[0]); close (wp[1]); return err; } (*ctx)->pipe_mode = 1; (*ctx)->inbound.fd = rp[0]; /* Our inbound is read end of read pipe. */ (*ctx)->outbound.fd = wp[1]; /* Our outbound is write end of write pipe. */ (*ctx)->deinit_handler = do_deinit; (*ctx)->finish_handler = do_finish; (*ctx)->pid = fork (); if ((*ctx)->pid < 0) { close (rp[0]); close (rp[1]); close (wp[0]); close (wp[1]); _assuan_release_context (*ctx); return ASSUAN_General_Error; } if ((*ctx)->pid == 0) { int i, n; char errbuf[512]; int *fdp; if (atfork) atfork (atforkvalue, 0); /* Dup handles to stdin/stdout. */ if (rp[1] != STDOUT_FILENO) { if (dup2 (rp[1], STDOUT_FILENO) == -1) { LOG ("dup2 failed in child: %s\n", strerror (errno)); _exit (4); } } if (wp[0] != STDIN_FILENO) { if (dup2 (wp[0], STDIN_FILENO) == -1) { LOG ("dup2 failed in child: %s\n", strerror (errno)); _exit (4); } } /* Dup stderr to /dev/null unless it is in the list of FDs to be passed to the child. */ fdp = fd_child_list; if (fdp) { for (; *fdp != -1 && *fdp != STDERR_FILENO; fdp++) ; } if (!fdp || *fdp == -1) { int fd = open ("/dev/null", O_WRONLY); if (fd == -1) { LOG ("can't open `/dev/null': %s\n", strerror (errno)); _exit (4); } if (dup2 (fd, STDERR_FILENO) == -1) { LOG ("dup2(dev/null, 2) failed: %s\n", strerror (errno)); _exit (4); } } /* Close all files which will not be duped and are not in the fd_child_list. */ n = sysconf (_SC_OPEN_MAX); if (n < 0) n = MAX_OPEN_FDS; for (i=0; i < n; i++) { if ( i == STDIN_FILENO || i == STDOUT_FILENO || i == STDERR_FILENO) continue; fdp = fd_child_list; if (fdp) { while (*fdp != -1 && *fdp != i) fdp++; } if (!(fdp && *fdp != -1)) close(i); } errno = 0; /* We store our parents pid in the environment so that the execed assuan server is able to read the actual pid of the client. The server can't use getppid becuase it might have been double forked before the assuan server has been initialized. */ setenv ("_assuan_pipe_connect_pid", mypidstr, 1); execv (name, argv); /* oops - use the pipe to tell the parent about it */ snprintf (errbuf, sizeof(errbuf)-1, "ERR %d can't exec `%s': %.50s\n", ASSUAN_Problem_Starting_Server, name, strerror (errno)); errbuf[sizeof(errbuf)-1] = 0; writen (1, errbuf, strlen (errbuf)); _exit (4); } close (rp[1]); close (wp[0]); /* initial handshake */ { int okay, off; err = _assuan_read_from_server (*ctx, &okay, &off); if (err) LOG ("can't connect server: %s\n", assuan_strerror (err)); else if (okay != 1) { LOG ("can't connect server: `%s'\n", (*ctx)->inbound.line); err = ASSUAN_Connect_Failed; } } if (err) { assuan_disconnect (*ctx); *ctx = NULL; } return err; } /* Connect to a server over a pipe, creating the assuan context and returning it in CTX. The server filename is NAME, the argument vector in ARGV. FD_CHILD_LIST is a -1 terminated list of file descriptors not to close in the child. */ AssuanError assuan_pipe_connect (ASSUAN_CONTEXT *ctx, const char *name, char *const argv[], int *fd_child_list) { return assuan_pipe_connect2 (ctx, name, argv, fd_child_list, NULL, NULL); }