/* 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 <https://gnu.org/licenses/>.
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <sys/wait.h>
#ifdef HAVE_SYS_UIO_H
# include <sys/uio.h>
#endif
#include <ctype.h>
#include <sys/resource.h>
#ifdef USE_LINUX_GETDENTS
# include <sys/syscall.h>
# include <sys/types.h>
# include <dirent.h>
#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__)
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);
}