55cdd057b9
In standard linux parlance, "hidden" usually means that the file name starts with ".", and nothing else. Rename the function to convey what the function does better to casual readers. Stop exposing hidden_file_allow_backup which is rather ugly and rewrite hidden_file to extract the suffix first. Note that hidden_file_allow_backup excluded files with "~" at the end, which is quite confusing. Let's get rid of it before it gets used in the wrong place.
369 lines
9.7 KiB
C
369 lines
9.7 KiB
C
/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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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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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/resource.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include "fd-util.h"
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#include "fs-util.h"
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#include "macro.h"
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#include "missing.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "socket-util.h"
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#include "stdio-util.h"
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#include "util.h"
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int close_nointr(int fd) {
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assert(fd >= 0);
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if (close(fd) >= 0)
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return 0;
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/*
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* Just ignore EINTR; a retry loop is the wrong thing to do on
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* Linux.
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*
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* http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html
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* https://bugzilla.gnome.org/show_bug.cgi?id=682819
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* http://utcc.utoronto.ca/~cks/space/blog/unix/CloseEINTR
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* https://sites.google.com/site/michaelsafyan/software-engineering/checkforeintrwheninvokingclosethinkagain
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*/
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if (errno == EINTR)
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return 0;
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return -errno;
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}
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int safe_close(int fd) {
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/*
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* Like close_nointr() but cannot fail. Guarantees errno is
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* unchanged. Is a NOP with negative fds passed, and returns
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* -1, so that it can be used in this syntax:
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*
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* fd = safe_close(fd);
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*/
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if (fd >= 0) {
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PROTECT_ERRNO;
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/* The kernel might return pretty much any error code
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* via close(), but the fd will be closed anyway. The
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* only condition we want to check for here is whether
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* the fd was invalid at all... */
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assert_se(close_nointr(fd) != -EBADF);
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}
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return -1;
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}
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void safe_close_pair(int p[]) {
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assert(p);
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if (p[0] == p[1]) {
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/* Special case pairs which use the same fd in both
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* directions... */
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p[0] = p[1] = safe_close(p[0]);
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return;
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}
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p[0] = safe_close(p[0]);
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p[1] = safe_close(p[1]);
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}
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void close_many(const int fds[], unsigned n_fd) {
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unsigned i;
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assert(fds || n_fd <= 0);
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for (i = 0; i < n_fd; i++)
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safe_close(fds[i]);
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}
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int fclose_nointr(FILE *f) {
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assert(f);
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/* Same as close_nointr(), but for fclose() */
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if (fclose(f) == 0)
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return 0;
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if (errno == EINTR)
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return 0;
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return -errno;
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}
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FILE* safe_fclose(FILE *f) {
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/* Same as safe_close(), but for fclose() */
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if (f) {
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PROTECT_ERRNO;
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assert_se(fclose_nointr(f) != EBADF);
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}
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return NULL;
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}
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DIR* safe_closedir(DIR *d) {
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if (d) {
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PROTECT_ERRNO;
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assert_se(closedir(d) >= 0 || errno != EBADF);
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}
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return NULL;
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}
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int fd_nonblock(int fd, bool nonblock) {
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int flags, nflags;
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assert(fd >= 0);
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flags = fcntl(fd, F_GETFL, 0);
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if (flags < 0)
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return -errno;
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if (nonblock)
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nflags = flags | O_NONBLOCK;
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else
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nflags = flags & ~O_NONBLOCK;
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if (nflags == flags)
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return 0;
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if (fcntl(fd, F_SETFL, nflags) < 0)
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return -errno;
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return 0;
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}
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int fd_cloexec(int fd, bool cloexec) {
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int flags, nflags;
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assert(fd >= 0);
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flags = fcntl(fd, F_GETFD, 0);
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if (flags < 0)
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return -errno;
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if (cloexec)
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nflags = flags | FD_CLOEXEC;
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else
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nflags = flags & ~FD_CLOEXEC;
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if (nflags == flags)
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return 0;
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if (fcntl(fd, F_SETFD, nflags) < 0)
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return -errno;
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return 0;
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}
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_pure_ static bool fd_in_set(int fd, const int fdset[], unsigned n_fdset) {
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unsigned i;
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assert(n_fdset == 0 || fdset);
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for (i = 0; i < n_fdset; i++)
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if (fdset[i] == fd)
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return true;
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return false;
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}
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int close_all_fds(const int except[], unsigned n_except) {
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_cleanup_closedir_ DIR *d = NULL;
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struct dirent *de;
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int r = 0;
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assert(n_except == 0 || except);
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d = opendir("/proc/self/fd");
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if (!d) {
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int fd;
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struct rlimit rl;
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/* When /proc isn't available (for example in chroots)
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* the fallback is brute forcing through the fd
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* table */
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assert_se(getrlimit(RLIMIT_NOFILE, &rl) >= 0);
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for (fd = 3; fd < (int) rl.rlim_max; fd ++) {
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if (fd_in_set(fd, except, n_except))
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continue;
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if (close_nointr(fd) < 0)
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if (errno != EBADF && r == 0)
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r = -errno;
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}
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return r;
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}
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while ((de = readdir(d))) {
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int fd = -1;
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if (hidden_or_backup_file(de->d_name))
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continue;
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if (safe_atoi(de->d_name, &fd) < 0)
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/* Let's better ignore this, just in case */
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continue;
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if (fd < 3)
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continue;
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if (fd == dirfd(d))
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continue;
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if (fd_in_set(fd, except, n_except))
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continue;
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if (close_nointr(fd) < 0) {
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/* Valgrind has its own FD and doesn't want to have it closed */
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if (errno != EBADF && r == 0)
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r = -errno;
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}
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}
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return r;
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}
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int same_fd(int a, int b) {
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struct stat sta, stb;
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pid_t pid;
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int r, fa, fb;
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assert(a >= 0);
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assert(b >= 0);
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/* Compares two file descriptors. Note that semantics are
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* quite different depending on whether we have kcmp() or we
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* don't. If we have kcmp() this will only return true for
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* dup()ed file descriptors, but not otherwise. If we don't
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* have kcmp() this will also return true for two fds of the same
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* file, created by separate open() calls. Since we use this
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* call mostly for filtering out duplicates in the fd store
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* this difference hopefully doesn't matter too much. */
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if (a == b)
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return true;
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/* Try to use kcmp() if we have it. */
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pid = getpid();
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r = kcmp(pid, pid, KCMP_FILE, a, b);
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if (r == 0)
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return true;
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if (r > 0)
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return false;
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if (errno != ENOSYS)
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return -errno;
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/* We don't have kcmp(), use fstat() instead. */
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if (fstat(a, &sta) < 0)
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return -errno;
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if (fstat(b, &stb) < 0)
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return -errno;
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if ((sta.st_mode & S_IFMT) != (stb.st_mode & S_IFMT))
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return false;
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/* We consider all device fds different, since two device fds
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* might refer to quite different device contexts even though
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* they share the same inode and backing dev_t. */
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if (S_ISCHR(sta.st_mode) || S_ISBLK(sta.st_mode))
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return false;
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if (sta.st_dev != stb.st_dev || sta.st_ino != stb.st_ino)
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return false;
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/* The fds refer to the same inode on disk, let's also check
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* if they have the same fd flags. This is useful to
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* distinguish the read and write side of a pipe created with
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* pipe(). */
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fa = fcntl(a, F_GETFL);
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if (fa < 0)
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return -errno;
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fb = fcntl(b, F_GETFL);
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if (fb < 0)
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return -errno;
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return fa == fb;
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}
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void cmsg_close_all(struct msghdr *mh) {
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struct cmsghdr *cmsg;
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assert(mh);
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CMSG_FOREACH(cmsg, mh)
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if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
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close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));
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}
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bool fdname_is_valid(const char *s) {
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const char *p;
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/* Validates a name for $LISTEN_FDNAMES. We basically allow
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* everything ASCII that's not a control character. Also, as
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* special exception the ":" character is not allowed, as we
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* use that as field separator in $LISTEN_FDNAMES.
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*
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* Note that the empty string is explicitly allowed
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* here. However, we limit the length of the names to 255
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* characters. */
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if (!s)
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return false;
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for (p = s; *p; p++) {
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if (*p < ' ')
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return false;
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if (*p >= 127)
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return false;
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if (*p == ':')
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return false;
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}
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return p - s < 256;
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}
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int fd_get_path(int fd, char **ret) {
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char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
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xsprintf(procfs_path, "/proc/self/fd/%i", fd);
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return readlink_malloc(procfs_path, ret);
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}
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