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; Add 2024 to copyright years # Conflicts: # doc/misc/modus-themes.org # doc/misc/texinfo.tex # etc/NEWS # etc/refcards/ru-refcard.tex # etc/themes/modus-operandi-theme.el # etc/themes/modus-themes.el # etc/themes/modus-vivendi-theme.el # lib/alloca.in.h # lib/binary-io.h # lib/c-ctype.h # lib/c-strcasecmp.c # lib/c-strncasecmp.c # lib/careadlinkat.c # lib/cloexec.c # lib/close-stream.c # lib/diffseq.h # lib/dup2.c # lib/filemode.h # lib/fpending.c # lib/fpending.h # lib/fsusage.c # lib/getgroups.c # lib/getloadavg.c # lib/gettext.h # lib/gettime.c # lib/gettimeofday.c # lib/group-member.c # lib/malloc.c # lib/md5-stream.c # lib/md5.c # lib/md5.h # lib/memmem.c # lib/memrchr.c # lib/nanosleep.c # lib/save-cwd.h # lib/sha1.c # lib/sig2str.c # lib/stdlib.in.h # lib/strtoimax.c # lib/strtol.c # lib/strtoll.c # lib/time_r.c # lib/xalloc-oversized.h # lisp/auth-source-pass.el # lisp/emacs-lisp/lisp-mnt.el # lisp/emacs-lisp/timer.el # lisp/info-look.el # lisp/jit-lock.el # lisp/loadhist.el # lisp/mail/rmail.el # lisp/net/ntlm.el # lisp/net/webjump.el # lisp/progmodes/asm-mode.el # lisp/progmodes/project.el # lisp/progmodes/sh-script.el # lisp/textmodes/flyspell.el # lisp/textmodes/reftex-toc.el # lisp/textmodes/reftex.el # lisp/textmodes/tex-mode.el # lisp/url/url-gw.el # m4/alloca.m4 # m4/clock_time.m4 # m4/d-type.m4 # m4/dirent_h.m4 # m4/dup2.m4 # m4/euidaccess.m4 # m4/fchmodat.m4 # m4/filemode.m4 # m4/fsusage.m4 # m4/getgroups.m4 # m4/getloadavg.m4 # m4/getrandom.m4 # m4/gettime.m4 # m4/gettimeofday.m4 # m4/gnulib-common.m4 # m4/group-member.m4 # m4/inttypes.m4 # m4/malloc.m4 # m4/manywarnings.m4 # m4/mempcpy.m4 # m4/memrchr.m4 # m4/mkostemp.m4 # m4/mktime.m4 # m4/nproc.m4 # m4/nstrftime.m4 # m4/pathmax.m4 # m4/pipe2.m4 # m4/pselect.m4 # m4/pthread_sigmask.m4 # m4/readlink.m4 # m4/realloc.m4 # m4/sig2str.m4 # m4/ssize_t.m4 # m4/stat-time.m4 # m4/stddef_h.m4 # m4/stdint.m4 # m4/stdio_h.m4 # m4/stdlib_h.m4 # m4/stpcpy.m4 # m4/strnlen.m4 # m4/strtoimax.m4 # m4/strtoll.m4 # m4/time_h.m4 # m4/timegm.m4 # m4/timer_time.m4 # m4/timespec.m4 # m4/unistd_h.m4 # m4/warnings.m4 # nt/configure.bat # nt/preprep.c # test/lisp/register-tests.el
155 lines
4.8 KiB
C
155 lines
4.8 KiB
C
/* Create /proc/self/fd-related names for subfiles of open directories.
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Copyright (C) 2006, 2009-2024 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Paul Eggert. */
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#include <config.h>
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#include "openat-priv.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.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 __KLIBC__ /* OS/2 */
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# include <InnoTekLIBC/backend.h>
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#endif
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#ifdef __MVS__ /* z/OS */
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# include <termios.h>
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#endif
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#include "intprops.h"
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/* Set BUF to the name of the subfile of the directory identified by
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FD, where the subfile is named FILE. If successful, return BUF if
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the result fits in BUF, dynamically allocated memory otherwise.
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Return NULL (setting errno) on error. */
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char *
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openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file)
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{
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char *result = buf;
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int dirlen;
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/* Make sure the caller gets ENOENT when appropriate. */
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if (!*file)
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{
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buf[0] = '\0';
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return buf;
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}
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#if !(defined __KLIBC__ || defined __MVS__)
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/* Generic code for Linux, Solaris, and similar platforms. */
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# define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/"
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{
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enum {
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PROC_SELF_FD_DIR_SIZE_BOUND
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= (sizeof PROC_SELF_FD_FORMAT - (sizeof "%d" - 1)
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+ INT_STRLEN_BOUND (int))
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};
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static int proc_status = 0;
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if (! proc_status)
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{
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/* Set PROC_STATUS to a positive value if /proc/self/fd is
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reliable, and a negative value otherwise. Solaris 10
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/proc/self/fd mishandles "..", and any file name might expand
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to ".." after symbolic link expansion, so avoid /proc/self/fd
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if it mishandles "..". Solaris 10 has openat, but this
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problem is exhibited on code that built on Solaris 8 and
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running on Solaris 10. */
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int proc_self_fd =
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open ("/proc/self/fd",
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O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK | O_CLOEXEC);
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if (proc_self_fd < 0)
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proc_status = -1;
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else
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{
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/* Detect whether /proc/self/fd/%i/../fd exists, where %i is the
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number of a file descriptor open on /proc/self/fd. On Linux,
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that name resolves to /proc/self/fd, which was opened above.
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However, on Solaris, it may resolve to /proc/self/fd/fd, which
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cannot exist, since all names in /proc/self/fd are numeric. */
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char dotdot_buf[PROC_SELF_FD_DIR_SIZE_BOUND + sizeof "../fd" - 1];
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sprintf (dotdot_buf, PROC_SELF_FD_FORMAT "../fd", proc_self_fd);
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proc_status = access (dotdot_buf, F_OK) ? -1 : 1;
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close (proc_self_fd);
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}
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}
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if (proc_status < 0)
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return NULL;
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else
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{
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size_t bufsize = PROC_SELF_FD_DIR_SIZE_BOUND + strlen (file);
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if (OPENAT_BUFFER_SIZE < bufsize)
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{
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result = malloc (bufsize);
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if (! result)
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return NULL;
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}
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dirlen = sprintf (result, PROC_SELF_FD_FORMAT, fd);
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}
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}
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#else /* (defined __KLIBC__ || defined __MVS__), i.e. OS/2 or z/OS */
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/* OS/2 kLIBC provides a function to retrieve a path from a fd. */
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{
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size_t bufsize;
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# ifdef __KLIBC__
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char dir[_MAX_PATH];
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if (__libc_Back_ioFHToPath (fd, dir, sizeof dir))
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return NULL;
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# endif
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# ifdef __MVS__
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char dir[_XOPEN_PATH_MAX];
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/* Documentation:
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https://www.ibm.com/docs/en/zos/2.2.0?topic=functions-w-ioctl-w-pioctl-control-devices */
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if (w_ioctl (fd, _IOCC_GPN, sizeof dir, dir) < 0)
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return NULL;
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/* Documentation:
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https://www.ibm.com/docs/en/zos/2.2.0?topic=functions-e2a-l-convert-characters-from-ebcdic-ascii */
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dirlen = __e2a_l (dir, strlen (dir));
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if (dirlen < 0 || dirlen >= sizeof dir)
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return NULL;
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dir[dirlen] = '\0';
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# endif
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dirlen = strlen (dir);
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bufsize = dirlen + 1 + strlen (file) + 1; /* 1 for '/', 1 for null */
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if (OPENAT_BUFFER_SIZE < bufsize)
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{
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result = malloc (bufsize);
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if (! result)
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return NULL;
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}
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strcpy (result, dir);
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result[dirlen++] = '/';
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}
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#endif
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strcpy (result + dirlen, file);
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return result;
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}
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