/* posix-io.c - Posix I/O functions * Copyright (C) 2000 Werner Koch (dd9jn) * Copyright (C) 2001, 2002, 2004, 2005, 2007, 2010 g10 Code GmbH * * This file is part of GPGME. * * GPGME 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. * * GPGME 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, see . * SPDX-License-Identifier: LGPL-2.1-or-later */ #ifdef HAVE_CONFIG_H #include #endif #include #include #ifdef HAVE_STDINT_H # include #endif #include #include #include #include #include #ifdef HAVE_UNISTD_H # include #endif #ifdef HAVE_SYS_TIME_H # include #endif #ifdef HAVE_SYS_TYPES_H # include #endif #include #ifdef HAVE_SYS_UIO_H # include #endif #include #include #ifdef USE_LINUX_GETDENTS # include # include # include #endif /*USE_LINUX_GETDENTS*/ #include "util.h" #include "priv-io.h" #include "sema.h" #include "ath.h" #include "debug.h" #ifdef USE_LINUX_GETDENTS /* This is not declared in public headers; getdents64(2) says that we must * define it ourselves. */ struct linux_dirent64 { ino64_t d_ino; off64_t d_off; unsigned short d_reclen; unsigned char d_type; char d_name[]; }; # define DIR_BUF_SIZE 1024 #endif /*USE_LINUX_GETDENTS*/ /* Return true if FD is valid file descriptor. */ #if 0 int _gpgme_is_fd_valid (int fd) { int dir_fd; char dir_buf[DIR_BUF_SIZE]; struct linux_dirent64 *dir_entry; int r, pos, x; const char *s; int result = 0; dir_fd = open ("/proc/self/fd", O_RDONLY | O_DIRECTORY); if (dir_fd != -1) { for (;;) { r = syscall(SYS_getdents64, dir_fd, dir_buf, DIR_BUF_SIZE); if (r == -1) break; /* Ooops */ if (r == 0) break; for (pos = 0; pos < r; pos += dir_entry->d_reclen) { dir_entry = (struct linux_dirent64 *) (dir_buf + pos); s = dir_entry->d_name; if (*s < '0' || *s > '9') continue; /* atoi is not guaranteed to be async-signal-safe. */ for (x = 0; *s >= '0' && *s <= '9'; s++) x = x * 10 + (*s - '0'); if (*s) continue; /* Does not look like a file descriptor. */ if (x == fd) { result = 1; goto leave; } } } leave: close (dir_fd); } return result; } #endif /*0*/ void _gpgme_io_subsystem_init (void) { 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); } } /* Write the printable version of FD to the buffer BUF of length BUFLEN. The printable version is the representation on the command line that the child process expects. */ int _gpgme_io_fd2str (char *buf, int buflen, int fd) { return snprintf (buf, buflen, "%d", fd); } /* The table to hold notification handlers. We use a linear search and extend the table as needed. */ struct notify_table_item_s { int fd; /* -1 indicates an unused entry. */ _gpgme_close_notify_handler_t handler; void *value; }; typedef struct notify_table_item_s *notify_table_item_t; static notify_table_item_t notify_table; static size_t notify_table_size; DEFINE_STATIC_LOCK (notify_table_lock); int _gpgme_io_read (int fd, void *buffer, size_t count) { int nread; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_read", NULL, "fd=%d buffer=%p count=%zu", fd, buffer, count); do { nread = _gpgme_ath_read (fd, buffer, count); } while (nread == -1 && errno == EINTR); TRACE_LOGBUFX (buffer, nread); return TRACE_SYSRES (nread); } int _gpgme_io_write (int fd, const void *buffer, size_t count) { int nwritten; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_write", NULL, "fd=%d buffer=%p count=%zu", fd, buffer, count); TRACE_LOGBUFX (buffer, count); do { nwritten = _gpgme_ath_write (fd, buffer, count); } while (nwritten == -1 && errno == EINTR); return TRACE_SYSRES (nwritten); } int _gpgme_io_pipe (int filedes[2], int inherit_idx) { int saved_errno; int err; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_pipe", NULL, "inherit_idx=%i (GPGME uses it for %s)", inherit_idx, inherit_idx ? "reading" : "writing"); err = pipe (filedes); if (err < 0) return TRACE_SYSRES (err); /* FIXME: Should get the old flags first. */ err = fcntl (filedes[1 - inherit_idx], F_SETFD, FD_CLOEXEC); saved_errno = errno; if (err < 0) { close (filedes[0]); close (filedes[1]); } errno = saved_errno; if (err) return TRACE_SYSRES (err); TRACE_SUC ("read fd=%d write fd=%d", filedes[0], filedes[1]); return 0; } int _gpgme_io_close (int fd) { int res; _gpgme_close_notify_handler_t handler = NULL; void *handler_value; int idx; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_close", NULL, "fd=%d", fd); if (fd == -1) { errno = EINVAL; return TRACE_SYSRES (-1); } /* First call the notify handler. */ LOCK (notify_table_lock); for (idx=0; idx < notify_table_size; idx++) { if (notify_table[idx].fd == fd) { handler = notify_table[idx].handler; handler_value = notify_table[idx].value; notify_table[idx].handler = NULL; notify_table[idx].value = NULL; notify_table[idx].fd = -1; /* Mark slot as free. */ break; } } UNLOCK (notify_table_lock); if (handler) { TRACE_LOG ("invoking close handler %p/%p", handler, handler_value); handler (fd, handler_value); } /* Then do the close. */ res = close (fd); return TRACE_SYSRES (res); } int _gpgme_io_set_close_notify (int fd, _gpgme_close_notify_handler_t handler, void *value) { int res = 0; int idx; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_set_close_notify", NULL, "fd=%d close_handler=%p/%p", fd, handler, value); assert (fd != -1); LOCK (notify_table_lock); for (idx=0; idx < notify_table_size; idx++) if (notify_table[idx].fd == -1) break; if (idx == notify_table_size) { /* We need to increase the size of the table. The approach we take is straightforward to minimize the risk of bugs. */ notify_table_item_t newtbl; size_t newsize = notify_table_size + 64; newtbl = calloc (newsize, sizeof *newtbl); if (!newtbl) { res = -1; goto leave; } for (idx=0; idx < notify_table_size; idx++) newtbl[idx] = notify_table[idx]; for (; idx < newsize; idx++) { newtbl[idx].fd = -1; newtbl[idx].handler = NULL; newtbl[idx].value = NULL; } free (notify_table); notify_table = newtbl; idx = notify_table_size; notify_table_size = newsize; } notify_table[idx].fd = fd; notify_table[idx].handler = handler; notify_table[idx].value = value; leave: UNLOCK (notify_table_lock); return TRACE_SYSRES (res); } int _gpgme_io_set_nonblocking (int fd) { int flags; int res; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_set_nonblocking", NULL, "fd=%d", fd); flags = fcntl (fd, F_GETFL, 0); if (flags == -1) return TRACE_SYSRES (-1); flags |= O_NONBLOCK; res = fcntl (fd, F_SETFL, flags); return TRACE_SYSRES (res); } static long int get_max_fds (void) { const char *source = NULL; long int fds = -1; int rc; /* Under Linux we can figure out the highest used file descriptor by * reading /proc/self/fd. This is in the common cases much faster * than for example doing 4096 close calls where almost all of them * will fail. * * We can't use the normal opendir/readdir/closedir interface between * fork and exec in a multi-threaded process because opendir uses * malloc and thus a mutex which may deadlock with a malloc in another * thread. However, the underlying getdents system call is safe. */ #ifdef USE_LINUX_GETDENTS { int dir_fd; char dir_buf[DIR_BUF_SIZE]; struct linux_dirent64 *dir_entry; int r, pos; const char *s; int x; dir_fd = open ("/proc/self/fd", O_RDONLY | O_DIRECTORY); if (dir_fd != -1) { for (;;) { r = syscall(SYS_getdents64, dir_fd, dir_buf, DIR_BUF_SIZE); if (r == -1) { /* Fall back to other methods. */ fds = -1; break; } if (r == 0) break; for (pos = 0; pos < r; pos += dir_entry->d_reclen) { dir_entry = (struct linux_dirent64 *) (dir_buf + pos); s = dir_entry->d_name; if (*s < '0' || *s > '9') continue; /* atoi is not guaranteed to be async-signal-safe. */ for (x = 0; *s >= '0' && *s <= '9'; s++) x = x * 10 + (*s - '0'); if (!*s && x > fds && x != dir_fd) fds = x; } } close (dir_fd); } if (fds != -1) { fds++; source = "/proc"; } } #endif /*USE_LINUX_GETDENTS*/ #ifdef RLIMIT_NOFILE if (fds == -1) { struct rlimit rl; rc = getrlimit (RLIMIT_NOFILE, &rl); if (rc == 0) { source = "RLIMIT_NOFILE"; fds = rl.rlim_max; } } #endif #ifdef RLIMIT_OFILE if (fds == -1) { struct rlimit rl; rc = getrlimit (RLIMIT_OFILE, &rl); if (rc == 0) { source = "RLIMIT_OFILE"; fds = rl.rlim_max; } } #endif #ifdef _SC_OPEN_MAX if (fds == -1) { long int scres; scres = sysconf (_SC_OPEN_MAX); if (scres >= 0) { source = "_SC_OPEN_MAX"; return scres; } } #endif #ifdef OPEN_MAX if (fds == -1) { source = "OPEN_MAX"; fds = OPEN_MAX; } #endif #if !defined(RLIMIT_NOFILE) && !defined(RLIMIT_OFILE) \ && !defined(_SC_OPEN_MAX) && !defined(OPEN_MAX) #warning "No known way to get the maximum number of file descriptors." #endif if (fds == -1) { source = "arbitrary"; /* Arbitrary limit. */ fds = 1024; } /* AIX returns INT32_MAX instead of a proper value. We assume that * this is always an error and use a more reasonable limit. */ #ifdef INT32_MAX if (fds == INT32_MAX) { source = "aix-fix"; fds = 1024; } #endif TRACE (DEBUG_SYSIO, "gpgme:max_fds", NULL, "max fds=%ld (%s)", fds, source); return fds; } int _gpgme_io_waitpid (int pid, int hang, int *r_status, int *r_signal) { int status; pid_t ret; *r_status = 0; *r_signal = 0; do ret = _gpgme_ath_waitpid (pid, &status, hang? 0 : WNOHANG); while (ret == (pid_t)(-1) && errno == EINTR); if (ret == pid) { if (WIFSIGNALED (status)) { *r_status = 4; /* Need some value here. */ *r_signal = WTERMSIG (status); } else if (WIFEXITED (status)) *r_status = WEXITSTATUS (status); else *r_status = 4; /* Oops. */ return 1; } return 0; } /* Returns 0 on success, -1 on error. */ int _gpgme_io_spawn (const char *path, char *const argv[], unsigned int flags, struct spawn_fd_item_s *fd_list, void (*atfork) (void *opaque, int reserved), void *atforkvalue, pid_t *r_pid) { pid_t pid; int i; int status; int signo; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_spawn", NULL, "path=%s", path); i = 0; while (argv[i]) { TRACE_LOG ("argv[%2i] = %s", i, argv[i]); i++; } for (i = 0; fd_list[i].fd != -1; i++) { if (fd_list[i].dup_to == -1) TRACE_LOG ("fd[%i] = 0x%x", i, fd_list[i].fd); else TRACE_LOG ("fd[%i] = 0x%x -> 0x%x", i,fd_list[i].fd,fd_list[i].dup_to); } pid = fork (); if (pid == -1) return TRACE_SYSRES (-1); if (!pid) { /* Intermediate child to prevent zombie processes. */ if ((pid = fork ()) == 0) { /* Child. */ int max_fds = -1; int fd; int seen_stdin = 0; int seen_stdout = 0; int seen_stderr = 0; if (atfork) atfork (atforkvalue, 0); /* First close all fds which will not be inherited. If we * have closefrom(2) we first figure out the highest fd we * do not want to close, then call closefrom, and on success * use the regular code to close all fds up to the start * point of closefrom. Note that Solaris' and FreeBSD's closefrom do * not return errors. */ #ifdef HAVE_CLOSEFROM { fd = -1; for (i = 0; fd_list[i].fd != -1; i++) if (fd_list[i].fd > fd) fd = fd_list[i].fd; fd++; #if defined(__sun) || defined(__FreeBSD__) || defined(__GLIBC__) closefrom (fd); max_fds = fd; #else /*!__sun */ while ((i = closefrom (fd)) && errno == EINTR) ; if (!i || errno == EBADF) max_fds = fd; #endif /*!__sun*/ } #endif /*HAVE_CLOSEFROM*/ if (max_fds == -1) max_fds = get_max_fds (); for (fd = 0; fd < max_fds; fd++) { for (i = 0; fd_list[i].fd != -1; i++) if (fd_list[i].fd == fd) break; if (fd_list[i].fd == -1) close (fd); } /* And now dup and close those to be duplicated. */ for (i = 0; fd_list[i].fd != -1; i++) { int child_fd; int res; if (fd_list[i].dup_to != -1) child_fd = fd_list[i].dup_to; else child_fd = fd_list[i].fd; if (child_fd == 0) seen_stdin = 1; else if (child_fd == 1) seen_stdout = 1; else if (child_fd == 2) seen_stderr = 1; if (fd_list[i].dup_to == -1) continue; res = dup2 (fd_list[i].fd, fd_list[i].dup_to); if (res < 0) { #if 0 /* FIXME: The debug file descriptor is not dup'ed anyway, so we can't see this. */ TRACE_LOG ("dup2 failed in child: %s\n", strerror (errno)); #endif _exit (8); } close (fd_list[i].fd); } if (! seen_stdin || ! seen_stdout || !seen_stderr) { fd = open ("/dev/null", O_RDWR); if (fd == -1) { /* The debug file descriptor is not dup'ed, so we can't do a trace output. */ _exit (8); } /* Make sure that the process has connected stdin. */ if (! seen_stdin && fd != 0) { if (dup2 (fd, 0) == -1) _exit (8); } if (! seen_stdout && fd != 1) { if (dup2 (fd, 1) == -1) _exit (8); } if (! seen_stderr && fd != 2) { if (dup2 (fd, 2) == -1) _exit (8); } if (fd != 0 && fd != 1 && fd != 2) close (fd); } execv (path, (char *const *) argv); /* Hmm: in that case we could write a special status code to the status-pipe. */ _exit (8); /* End child. */ } if (pid == -1) _exit (1); else _exit (0); } TRACE_LOG ("waiting for child process pid=%i", pid); _gpgme_io_waitpid (pid, 1, &status, &signo); if (status) return TRACE_SYSRES (-1); for (i = 0; fd_list[i].fd != -1; i++) { if (! (flags & IOSPAWN_FLAG_NOCLOSE)) _gpgme_io_close (fd_list[i].fd); /* No handle translation. */ fd_list[i].peer_name = fd_list[i].fd; } if (r_pid) *r_pid = pid; return TRACE_SYSRES (0); } /* Select on the list of fds. Returns: -1 = error, 0 = timeout or nothing to select, > 0 = number of signaled fds. */ int _gpgme_io_select (struct io_select_fd_s *fds, size_t nfds, int nonblock) { fd_set readfds; fd_set writefds; unsigned int i; int any; int max_fd; int n; int count; /* Use a 1s timeout. */ struct timeval timeout = { 1, 0 }; void *dbg_help = NULL; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_select", NULL, "nfds=%zu, nonblock=%u", nfds, nonblock); FD_ZERO (&readfds); FD_ZERO (&writefds); max_fd = 0; if (nonblock) timeout.tv_sec = 0; TRACE_SEQ (dbg_help, "select on [ "); any = 0; for (i = 0; i < nfds; i++) { if (fds[i].fd == -1) continue; if (fds[i].for_read) { if (fds[i].fd >= FD_SETSIZE) { TRACE_END (dbg_help, " -BAD- ]"); gpg_err_set_errno (EMFILE); return TRACE_SYSRES (-1); } assert (!FD_ISSET (fds[i].fd, &readfds)); FD_SET (fds[i].fd, &readfds); if (fds[i].fd > max_fd) max_fd = fds[i].fd; TRACE_ADD1 (dbg_help, "r=%d ", fds[i].fd); any = 1; } else if (fds[i].for_write) { if (fds[i].fd >= FD_SETSIZE) { TRACE_END (dbg_help, " -BAD- ]"); gpg_err_set_errno (EMFILE); return TRACE_SYSRES (-1); } assert (!FD_ISSET (fds[i].fd, &writefds)); FD_SET (fds[i].fd, &writefds); if (fds[i].fd > max_fd) max_fd = fds[i].fd; TRACE_ADD1 (dbg_help, "w=%d ", fds[i].fd); any = 1; } fds[i].signaled = 0; } TRACE_END (dbg_help, "]"); if (!any) return TRACE_SYSRES (0); do { count = _gpgme_ath_select (max_fd + 1, &readfds, &writefds, NULL, &timeout); } while (count < 0 && errno == EINTR); if (count < 0) return TRACE_SYSRES (-1); TRACE_SEQ (dbg_help, "select OK [ "); if (TRACE_ENABLED (dbg_help)) { for (i = 0; i <= max_fd; i++) { if (FD_ISSET (i, &readfds)) TRACE_ADD1 (dbg_help, "r=%d ", i); if (FD_ISSET (i, &writefds)) TRACE_ADD1 (dbg_help, "w=%d ", i); } TRACE_END (dbg_help, "]"); } /* The variable N is used to optimize it a little bit. */ for (n = count, i = 0; i < nfds && n; i++) { if (fds[i].fd == -1) ; else if (fds[i].for_read) { if (FD_ISSET (fds[i].fd, &readfds)) { fds[i].signaled = 1; n--; } } else if (fds[i].for_write) { if (FD_ISSET (fds[i].fd, &writefds)) { fds[i].signaled = 1; n--; } } } return TRACE_SYSRES (count); } int _gpgme_io_recvmsg (int fd, struct msghdr *msg, int flags) { int nread; int saved_errno; struct iovec *iov; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_recvmsg", NULL, "fd=%d msg=%p flags=%i", fd, msg, flags); nread = 0; iov = msg->msg_iov; while (iov < msg->msg_iov + msg->msg_iovlen) { nread += iov->iov_len; iov++; } TRACE_LOG ("about to receive %d bytes", nread); do { nread = _gpgme_ath_recvmsg (fd, msg, flags); } while (nread == -1 && errno == EINTR); saved_errno = errno; if (nread > 0) { int nr = nread; iov = msg->msg_iov; while (nr > 0) { int len = nr > iov->iov_len ? iov->iov_len : nr; TRACE_LOGBUFX (msg->msg_iov->iov_base, len); iov++; nr -= len; } } errno = saved_errno; return TRACE_SYSRES (nread); } int _gpgme_io_sendmsg (int fd, const struct msghdr *msg, int flags) { int nwritten; struct iovec *iov; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_sendmsg", NULL, "fd=%d msg=%p flags=%i", fd, msg, flags); nwritten = 0; iov = msg->msg_iov; while (iov < msg->msg_iov + msg->msg_iovlen) { nwritten += iov->iov_len; iov++; } TRACE_LOG ("about to receive %d bytes", nwritten); iov = msg->msg_iov; while (nwritten > 0) { int len = nwritten > iov->iov_len ? iov->iov_len : nwritten; TRACE_LOGBUFX (msg->msg_iov->iov_base, len); iov++; nwritten -= len; } do { nwritten = _gpgme_ath_sendmsg (fd, msg, flags); } while (nwritten == -1 && errno == EINTR); return TRACE_SYSRES (nwritten); } int _gpgme_io_dup (int fd) { int new_fd; do new_fd = dup (fd); while (new_fd == -1 && errno == EINTR); TRACE (DEBUG_SYSIO, "_gpgme_io_dup", NULL, "fd=%d -> fd=%d", fd, new_fd); return new_fd; } int _gpgme_io_socket (int domain, int type, int proto) { int res; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_socket", NULL, "domain=%d type=%i proto=%i", domain, type, proto); res = socket (domain, type, proto); return TRACE_SYSRES (res); } int _gpgme_io_connect (int fd, struct sockaddr *addr, int addrlen) { int res; TRACE_BEG (DEBUG_SYSIO, "_gpgme_io_connect", NULL, "fd=%d addr=%p addrlen=%i", fd, addr, addrlen); do res = ath_connect (fd, addr, addrlen); while (res == -1 && errno == EINTR); return TRACE_SYSRES (res); }