/* assuan-pipe-connect.c - Establish a pipe connection (client) * Copyright (C) 2001, 2002, 2003, 2005, 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include #include #include #include #include #ifndef HAVE_W32_SYSTEM #include #else #include #endif #include "assuan-defs.h" /* Hacks for Slowaris. */ #ifndef PF_LOCAL # ifdef PF_UNIX # define PF_LOCAL PF_UNIX # else # define PF_LOCAL AF_UNIX # endif #endif #ifndef AF_LOCAL # define AF_LOCAL AF_UNIX #endif #ifdef _POSIX_OPEN_MAX #define MAX_OPEN_FDS _POSIX_OPEN_MAX #else #define MAX_OPEN_FDS 20 #endif #ifdef HAVE_W32_SYSTEM /* We assume that a HANDLE can be represented by an int which should be true for all i386 systems (HANDLE is defined as void *) and these are the only systems for which Windows is available. Further we assume that -1 denotes an invalid handle. */ #define fd_to_handle(a) ((HANDLE)(a)) #define handle_to_fd(a) ((int)(a)) #define pid_to_handle(a) ((HANDLE)(a)) #define handle_to_pid(a) ((int)(a)) #endif /*HAVE_W32_SYSTEM*/ /* This should be called to make sure that SIGPIPE gets ignored. */ static void fix_signals (void) { #ifndef _ASSUAN_NO_FIXED_SIGNALS #ifndef HAVE_DOSISH_SYSTEM /* No SIGPIPE for these systems. */ static int fixed_signals; if (!fixed_signals) { struct sigaction act; sigaction (SIGPIPE, NULL, &act); if (act.sa_handler == SIG_DFL) { act.sa_handler = SIG_IGN; sigemptyset (&act.sa_tqmask); act.sa_flags = 0; sigaction (SIGPIPE, &act, NULL); } fixed_signals = 1; /* FIXME: This is not MT safe */ } #endif /*HAVE_DOSISH_SYSTEM*/ #endif /*!_ASSUAN_NO_FIXED_SIGNALS*/ } #ifndef HAVE_W32_SYSTEM 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 */ } #endif static int do_finish (assuan_context_t ctx) { if (ctx->inbound.fd != -1) { _assuan_close (ctx->inbound.fd); if (ctx->inbound.fd == ctx->outbound.fd) ctx->outbound.fd = -1; ctx->inbound.fd = -1; } if (ctx->outbound.fd != -1) { _assuan_close (ctx->outbound.fd); ctx->outbound.fd = -1; } if (ctx->pid != -1 && ctx->pid) { #ifndef HAVE_W32_SYSTEM #ifndef _ASSUAN_USE_DOUBLE_FORK if (!ctx->flags.no_waitpid) _assuan_waitpid (ctx->pid, NULL, 0); ctx->pid = -1; #endif #endif /*!HAVE_W32_SYSTEM*/ } return 0; } static void do_deinit (assuan_context_t ctx) { do_finish (ctx); } /* Helper for pipe_connect. */ static assuan_error_t initial_handshake (assuan_context_t *ctx) { int okay, off; assuan_error_t err; err = _assuan_read_from_server (*ctx, &okay, &off); if (err) _assuan_log_printf ("can't connect server: %s\n", assuan_strerror (err)); else if (okay != 1) { _assuan_log_printf ("can't connect server: `%s'\n", (*ctx)->inbound.line); err = _assuan_error (ASSUAN_Connect_Failed); } if (err) { assuan_disconnect (*ctx); *ctx = NULL; } return err; } #ifndef HAVE_W32_SYSTEM #define pipe_connect pipe_connect_unix /* Unix version of the pipe connection code. We use an extra macro to make ChangeLog entries easier. */ static assuan_error_t pipe_connect_unix (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue) { assuan_error_t err; int rp[2]; int wp[2]; char mypidstr[50]; if (!ctx || !name || !argv || !argv[0]) return _assuan_error (ASSUAN_Invalid_Value); fix_signals (); sprintf (mypidstr, "%lu", (unsigned long)getpid ()); if (pipe (rp) < 0) return _assuan_error (ASSUAN_General_Error); if (pipe (wp) < 0) { close (rp[0]); close (rp[1]); return _assuan_error (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; /* FIXME: For GPGME we should better use _gpgme_io_spawn. The PID stored here is actually soon useless. */ (*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_error (ASSUAN_General_Error); } if ((*ctx)->pid == 0) { #ifdef _ASSUAN_USE_DOUBLE_FORK pid_t pid; if ((pid = fork ()) == 0) #endif { 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) { _assuan_log_printf ("dup2 failed in child: %s\n", strerror (errno)); _exit (4); } } if (wp[0] != STDIN_FILENO) { if (dup2 (wp[0], STDIN_FILENO) == -1) { _assuan_log_printf ("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) { _assuan_log_printf ("can't open `/dev/null': %s\n", strerror (errno)); _exit (4); } if (dup2 (fd, STDERR_FILENO) == -1) { _assuan_log_printf ("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 because it might have been double forked before the assuan server has been initialized. */ setenv ("_assuan_pipe_connect_pid", mypidstr, 1); /* Make sure that we never pass a connection fd variable when using a simple pipe. */ unsetenv ("_assuan_connection_fd"); execv (name, (char *const *) 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_error (ASSUAN_Problem_Starting_Server), name, strerror (errno)); errbuf[sizeof(errbuf)-1] = 0; writen (1, errbuf, strlen (errbuf)); _exit (4); } #ifdef _ASSUAN_USE_DOUBLE_FORK if (pid == -1) _exit (1); else _exit (0); #endif } #ifdef _ASSUAN_USE_DOUBLE_FORK _assuan_waitpid ((*ctx)->pid, NULL, 0); (*ctx)->pid = -1; #endif close (rp[1]); close (wp[0]); return initial_handshake (ctx); } #endif /*!HAVE_W32_SYSTEM*/ #ifndef HAVE_W32_SYSTEM /* This function is similar to pipe_connect but uses a socketpair and sets the I/O up to use sendmsg/recvmsg. */ static assuan_error_t socketpair_connect (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue) { assuan_error_t err; int fds[2]; char mypidstr[50]; if (!ctx || (name && (!argv || !argv[0])) || (!name && argv)) return _assuan_error (ASSUAN_Invalid_Value); fix_signals (); sprintf (mypidstr, "%lu", (unsigned long)getpid ()); if ( socketpair (AF_LOCAL, SOCK_STREAM, 0, fds) ) { _assuan_log_printf ("socketpair failed: %s\n", strerror (errno)); return _assuan_error (ASSUAN_General_Error); } err = _assuan_new_context (ctx); if (err) { close (fds[0]); close (fds[1]); return err; } (*ctx)->pipe_mode = 1; (*ctx)->inbound.fd = fds[0]; (*ctx)->outbound.fd = fds[0]; _assuan_init_uds_io (*ctx); (*ctx)->deinit_handler = _assuan_uds_deinit; (*ctx)->finish_handler = do_finish; (*ctx)->pid = fork (); if ((*ctx)->pid < 0) { close (fds[0]); close (fds[1]); _assuan_release_context (*ctx); *ctx = NULL; return _assuan_error (ASSUAN_General_Error); } if ((*ctx)->pid == 0) { #ifdef _ASSUAN_USE_DOUBLE_FORK pid_t pid; if ((pid = fork ()) == 0) #endif { int fd, i, n; char errbuf[512]; int *fdp; if (atfork) atfork (atforkvalue, 0); /* Connect stdin and stdout to /dev/null. */ fd = open ("/dev/null", O_RDONLY); if (fd == -1 || dup2 (fd, STDIN_FILENO) == -1) { _assuan_log_printf ("dup2(dev/null) failed: %s\n", strerror (errno)); _exit (4); } fd = open ("/dev/null", O_WRONLY); if (fd == -1 || dup2 (fd, STDOUT_FILENO) == -1) { _assuan_log_printf ("dup2(dev/null) failed: %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) { fd = open ("/dev/null", O_WRONLY); if (fd == -1 || dup2 (fd, STDERR_FILENO) == -1) { _assuan_log_printf ("dup2(dev/null) failed: %s\n", strerror (errno)); _exit (4); } } /* Close all files which will not be duped, are not in the fd_child_list and are not the connection fd. */ 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 || i == fds[1]) 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); /* Now set the environment variable used to convey the connection's file descriptor. */ sprintf (mypidstr, "%d", fds[1]); if (setenv ("_assuan_connection_fd", mypidstr, 1)) { _assuan_log_printf ("setenv failed: %s\n", strerror (errno)); _exit (4); } if (!name && !argv) { /* No name and no args given, thus we don't do an exec but continue the forked process. */ _assuan_release_context (*ctx); *ctx = NULL; return 0; } execv (name, (char *const *) 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_error (ASSUAN_Problem_Starting_Server), name, strerror (errno)); errbuf[sizeof(errbuf)-1] = 0; writen (fds[1], errbuf, strlen (errbuf)); _exit (4); } #ifdef _ASSUAN_USE_DOUBLE_FORK if (pid == -1) _exit (1); else _exit (0); #endif } #ifdef _ASSUAN_USE_DOUBLE_FORK _assuan_waitpid ((*ctx)->pid, NULL, 0); (*ctx)->pid = -1; #endif close (fds[1]); return initial_handshake (ctx); } #endif /*!HAVE_W32_SYSTEM*/ #ifdef HAVE_W32_SYSTEM /* Build a command line for use with W32's CreateProcess. On success CMDLINE gets the address of a newly allocated string. */ static int build_w32_commandline (char * const *argv, char **cmdline) { int i, n; const char *s; char *buf, *p; *cmdline = NULL; n = 0; for (i=0; (s=argv[i]); i++) { n += strlen (s) + 1 + 2; /* (1 space, 2 quoting */ for (; *s; s++) if (*s == '\"') n++; /* Need to double inner quotes. */ } n++; buf = p = xtrymalloc (n); if (!buf) return -1; for (i=0; argv[i]; i++) { if (i) p = stpcpy (p, " "); if (!*argv[i]) /* Empty string. */ p = stpcpy (p, "\"\""); else if (strpbrk (argv[i], " \t\n\v\f\"")) { p = stpcpy (p, "\""); for (s=argv[i]; *s; s++) { *p++ = *s; if (*s == '\"') *p++ = *s; } *p++ = '\"'; *p = 0; } else p = stpcpy (p, argv[i]); } *cmdline= buf; return 0; } #endif /*HAVE_W32_SYSTEM*/ #ifdef HAVE_W32_SYSTEM /* Create pipe where one end end is inheritable. */ static int create_inheritable_pipe (int filedes[2], int for_write) { HANDLE r, w, h; SECURITY_ATTRIBUTES sec_attr; memset (&sec_attr, 0, sizeof sec_attr ); sec_attr.nLength = sizeof sec_attr; sec_attr.bInheritHandle = FALSE; if (!CreatePipe (&r, &w, &sec_attr, 0)) { _assuan_log_printf ("CreatePipe failed: %s\n", w32_strerror (-1)); return -1; } if (!DuplicateHandle (GetCurrentProcess(), for_write? r : w, GetCurrentProcess(), &h, 0, TRUE, DUPLICATE_SAME_ACCESS )) { _assuan_log_printf ("DuplicateHandle failed: %s\n", w32_strerror (-1)); CloseHandle (r); CloseHandle (w); return -1; } if (for_write) { CloseHandle (r); r = h; } else { CloseHandle (w); w = h; } filedes[0] = handle_to_fd (r); filedes[1] = handle_to_fd (w); return 0; } #endif /*HAVE_W32_SYSTEM*/ #ifdef HAVE_W32_SYSTEM #define pipe_connect pipe_connect_w32 /* W32 version of the pipe connection code. */ static assuan_error_t pipe_connect_w32 (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue) { assuan_error_t err; int rp[2]; int wp[2]; char mypidstr[50]; char *cmdline; SECURITY_ATTRIBUTES sec_attr; PROCESS_INFORMATION pi = { NULL, /* Returns process handle. */ 0, /* Returns primary thread handle. */ 0, /* Returns pid. */ 0 /* Returns tid. */ }; STARTUPINFO si; int fd, *fdp; HANDLE nullfd = INVALID_HANDLE_VALUE; if (!ctx || !name || !argv || !argv[0]) return _assuan_error (ASSUAN_Invalid_Value); fix_signals (); sprintf (mypidstr, "%lu", (unsigned long)getpid ()); /* Build the command line. */ if (build_w32_commandline (argv, &cmdline)) return _assuan_error (ASSUAN_Out_Of_Core); /* Create thew two pipes. */ if (create_inheritable_pipe (rp, 0)) { xfree (cmdline); return _assuan_error (ASSUAN_General_Error); } if (create_inheritable_pipe (wp, 1)) { CloseHandle (fd_to_handle (rp[0])); CloseHandle (fd_to_handle (rp[1])); xfree (cmdline); return _assuan_error (ASSUAN_General_Error); } err = _assuan_new_context (ctx); if (err) { CloseHandle (fd_to_handle (rp[0])); CloseHandle (fd_to_handle (rp[1])); CloseHandle (fd_to_handle (wp[0])); CloseHandle (fd_to_handle (wp[1])); xfree (cmdline); return _assuan_error (ASSUAN_General_Error); } (*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; /* fixme: Actually we should set the "_assuan_pipe_connect_pid" env variable. However this requires us to write a full environment handler, because the strings are expected in sorted order. The suggestion given in the MS Reference Library, to save the old value, changeit, create proces and restore it, is not thread safe. */ /* Start the process. */ memset (&sec_attr, 0, sizeof sec_attr ); sec_attr.nLength = sizeof sec_attr; sec_attr.bInheritHandle = FALSE; memset (&si, 0, sizeof si); si.cb = sizeof (si); si.dwFlags = STARTF_USESTDHANDLES; si.hStdInput = fd_to_handle (wp[0]); si.hStdOutput = fd_to_handle (rp[1]); /* Dup stderr to /dev/null unless it is in the list of FDs to be passed to the child. */ fd = fileno (stderr); fdp = fd_child_list; if (fdp) { for (; *fdp != -1 && *fdp != fd; fdp++) ; } if (!fdp || *fdp == -1) { nullfd = CreateFile ("nul", GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL); if (nullfd == INVALID_HANDLE_VALUE) { _assuan_log_printf ("can't open `nul': %s\n", w32_strerror (-1)); CloseHandle (fd_to_handle (rp[0])); CloseHandle (fd_to_handle (rp[1])); CloseHandle (fd_to_handle (wp[0])); CloseHandle (fd_to_handle (wp[1])); xfree (cmdline); _assuan_release_context (*ctx); return -1; } si.hStdError = nullfd; } else si.hStdError = fd_to_handle (_get_osfhandle (fd)); /* Note: We inherit all handles flagged as inheritable. This seems to be a security flaw but there seems to be no way of selecting handles to inherit. */ /* _assuan_log_printf ("CreateProcess, path=`%s' cmdline=`%s'\n", */ /* name, cmdline); */ if (!CreateProcess (name, /* Program to start. */ cmdline, /* Command line arguments. */ &sec_attr, /* Process security attributes. */ &sec_attr, /* Thread security attributes. */ TRUE, /* Inherit handles. */ (CREATE_DEFAULT_ERROR_MODE | GetPriorityClass (GetCurrentProcess ()) | CREATE_SUSPENDED), /* Creation flags. */ NULL, /* Environment. */ NULL, /* Use current drive/directory. */ &si, /* Startup information. */ &pi /* Returns process information. */ )) { _assuan_log_printf ("CreateProcess failed: %s\n", w32_strerror (-1)); CloseHandle (fd_to_handle (rp[0])); CloseHandle (fd_to_handle (rp[1])); CloseHandle (fd_to_handle (wp[0])); CloseHandle (fd_to_handle (wp[1])); if (nullfd != INVALID_HANDLE_VALUE) CloseHandle (nullfd); xfree (cmdline); _assuan_release_context (*ctx); return _assuan_error (ASSUAN_General_Error); } xfree (cmdline); cmdline = NULL; if (nullfd != INVALID_HANDLE_VALUE) { CloseHandle (nullfd); nullfd = INVALID_HANDLE_VALUE; } CloseHandle (fd_to_handle (rp[1])); CloseHandle (fd_to_handle (wp[0])); /* _assuan_log_printf ("CreateProcess ready: hProcess=%p hThread=%p" */ /* " dwProcessID=%d dwThreadId=%d\n", */ /* pi.hProcess, pi.hThread, */ /* (int) pi.dwProcessId, (int) pi.dwThreadId); */ ResumeThread (pi.hThread); CloseHandle (pi.hThread); (*ctx)->pid = 0; /* We don't use the PID. */ CloseHandle (pi.hProcess); /* We don't need to wait for the process. */ return initial_handshake (ctx); } #endif /*HAVE_W32_SYSTEM*/ /* 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. */ assuan_error_t assuan_pipe_connect (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list) { return pipe_connect (ctx, name, argv, fd_child_list, NULL, NULL); } assuan_error_t assuan_pipe_connect2 (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue) { return pipe_connect (ctx, name, argv, fd_child_list, atfork, atforkvalue); } /* Connect to a server over a full-duplex socket (i.e. created by socketpair), 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. For now FLAGS may either take the value 0 to behave like assuan_pipe_connect2 or 1 to enable the described full-duplex socket behaviour. If NAME as well as ARGV are NULL, no exec is done but the same process is continued. However all file descriptors are closed and some special environment variables are set. To let the caller detect whether the child or the parent continues, the child returns a CTX of NULL. */ assuan_error_t assuan_pipe_connect_ext (assuan_context_t *ctx, const char *name, const char *const argv[], int *fd_child_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue, unsigned int flags) { if ((flags & 1)) { #ifdef HAVE_W32_SYSTEM return _assuan_error (ASSUAN_Not_Implemented); #else return socketpair_connect (ctx, name, argv, fd_child_list, atfork, atforkvalue); #endif } else return pipe_connect (ctx, name, argv, fd_child_list, atfork, atforkvalue); }