93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
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//
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// An implementation of shm_open(), shm_unlink() from the GNU C Library
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//
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// Copyright (C) 2001,2002,2005 Free Software Foundation, Inc.
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// Copyright (C) 2018 Leonid Plyushch
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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//
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef __ANDROID__
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#define SHMDIR "/data/data/com.termux/files/usr/tmp/"
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#else
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#define SHMDIR "/dev/shm/"
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#endif
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int shm_open(const char *name, int oflag, mode_t mode) {
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size_t namelen;
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char *fname;
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int fd;
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/* Construct the filename. */
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while (name[0] == '/') ++name;
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if (name[0] == '\0') {
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/* The name "/" is not supported. */
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errno = EINVAL;
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return -1;
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}
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namelen = strlen(name);
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fname = (char *) alloca(sizeof(SHMDIR) - 1 + namelen + 1);
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memcpy(fname, SHMDIR, sizeof(SHMDIR) - 1);
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memcpy(fname + sizeof(SHMDIR) - 1, name, namelen + 1);
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fd = open(fname, oflag, mode);
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if (fd != -1) {
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/* We got a descriptor. Now set the FD_CLOEXEC bit. */
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int flags = fcntl(fd, F_GETFD, 0);
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flags |= FD_CLOEXEC;
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flags = fcntl(fd, F_SETFD, flags);
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if (flags == -1) {
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/* Something went wrong. We cannot return the descriptor. */
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int save_errno = errno;
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close(fd);
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fd = -1;
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errno = save_errno;
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}
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}
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return fd;
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}
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int shm_unlink(const char *name) {
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size_t namelen;
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char *fname;
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/* Construct the filename. */
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while (name[0] == '/') ++name;
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if (name[0] == '\0') {
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/* The name "/" is not supported. */
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errno = EINVAL;
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return -1;
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}
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namelen = strlen(name);
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fname = (char *) alloca(sizeof(SHMDIR) - 1 + namelen + 1);
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memcpy(fname, SHMDIR, sizeof(SHMDIR) - 1);
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memcpy(fname + sizeof(SHMDIR) - 1, name, namelen + 1);
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return unlink(fname);
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}
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