| /*** |
| This file is part of systemd. |
| |
| Copyright 2010 Lennart Poettering |
| |
| systemd 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. |
| |
| systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <sys/resource.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #include "dirent-util.h" |
| #include "fd-util.h" |
| #include "fs-util.h" |
| #include "macro.h" |
| #include "missing.h" |
| #include "parse-util.h" |
| #include "path-util.h" |
| #include "socket-util.h" |
| #include "stdio-util.h" |
| #include "util.h" |
| |
| int close_nointr(int fd) { |
| assert(fd >= 0); |
| |
| if (close(fd) >= 0) |
| return 0; |
| |
| /* |
| * Just ignore EINTR; a retry loop is the wrong thing to do on |
| * Linux. |
| * |
| * http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html |
| * https://bugzilla.gnome.org/show_bug.cgi?id=682819 |
| * http://utcc.utoronto.ca/~cks/space/blog/unix/CloseEINTR |
| * https://sites.google.com/site/michaelsafyan/software-engineering/checkforeintrwheninvokingclosethinkagain |
| */ |
| if (errno == EINTR) |
| return 0; |
| |
| return -errno; |
| } |
| |
| int safe_close(int fd) { |
| |
| /* |
| * Like close_nointr() but cannot fail. Guarantees errno is |
| * unchanged. Is a NOP with negative fds passed, and returns |
| * -1, so that it can be used in this syntax: |
| * |
| * fd = safe_close(fd); |
| */ |
| |
| if (fd >= 0) { |
| PROTECT_ERRNO; |
| |
| /* The kernel might return pretty much any error code |
| * via close(), but the fd will be closed anyway. The |
| * only condition we want to check for here is whether |
| * the fd was invalid at all... */ |
| |
| assert_se(close_nointr(fd) != -EBADF); |
| } |
| |
| return -1; |
| } |
| |
| void safe_close_pair(int p[]) { |
| assert(p); |
| |
| if (p[0] == p[1]) { |
| /* Special case pairs which use the same fd in both |
| * directions... */ |
| p[0] = p[1] = safe_close(p[0]); |
| return; |
| } |
| |
| p[0] = safe_close(p[0]); |
| p[1] = safe_close(p[1]); |
| } |
| |
| void close_many(const int fds[], unsigned n_fd) { |
| unsigned i; |
| |
| assert(fds || n_fd <= 0); |
| |
| for (i = 0; i < n_fd; i++) |
| safe_close(fds[i]); |
| } |
| |
| int fclose_nointr(FILE *f) { |
| assert(f); |
| |
| /* Same as close_nointr(), but for fclose() */ |
| |
| if (fclose(f) == 0) |
| return 0; |
| |
| if (errno == EINTR) |
| return 0; |
| |
| return -errno; |
| } |
| |
| FILE* safe_fclose(FILE *f) { |
| |
| /* Same as safe_close(), but for fclose() */ |
| |
| if (f) { |
| PROTECT_ERRNO; |
| |
| assert_se(fclose_nointr(f) != EBADF); |
| } |
| |
| return NULL; |
| } |
| |
| DIR* safe_closedir(DIR *d) { |
| |
| if (d) { |
| PROTECT_ERRNO; |
| |
| assert_se(closedir(d) >= 0 || errno != EBADF); |
| } |
| |
| return NULL; |
| } |
| |
| int fd_nonblock(int fd, bool nonblock) { |
| int flags, nflags; |
| |
| assert(fd >= 0); |
| |
| flags = fcntl(fd, F_GETFL, 0); |
| if (flags < 0) |
| return -errno; |
| |
| if (nonblock) |
| nflags = flags | O_NONBLOCK; |
| else |
| nflags = flags & ~O_NONBLOCK; |
| |
| if (nflags == flags) |
| return 0; |
| |
| if (fcntl(fd, F_SETFL, nflags) < 0) |
| return -errno; |
| |
| return 0; |
| } |
| |
| int fd_cloexec(int fd, bool cloexec) { |
| int flags, nflags; |
| |
| assert(fd >= 0); |
| |
| flags = fcntl(fd, F_GETFD, 0); |
| if (flags < 0) |
| return -errno; |
| |
| if (cloexec) |
| nflags = flags | FD_CLOEXEC; |
| else |
| nflags = flags & ~FD_CLOEXEC; |
| |
| if (nflags == flags) |
| return 0; |
| |
| if (fcntl(fd, F_SETFD, nflags) < 0) |
| return -errno; |
| |
| return 0; |
| } |
| |
| void stdio_unset_cloexec(void) { |
| fd_cloexec(STDIN_FILENO, false); |
| fd_cloexec(STDOUT_FILENO, false); |
| fd_cloexec(STDERR_FILENO, false); |
| } |
| |
| _pure_ static bool fd_in_set(int fd, const int fdset[], unsigned n_fdset) { |
| unsigned i; |
| |
| assert(n_fdset == 0 || fdset); |
| |
| for (i = 0; i < n_fdset; i++) |
| if (fdset[i] == fd) |
| return true; |
| |
| return false; |
| } |
| |
| int close_all_fds(const int except[], unsigned n_except) { |
| _cleanup_closedir_ DIR *d = NULL; |
| struct dirent *de; |
| int r = 0; |
| |
| assert(n_except == 0 || except); |
| |
| d = opendir("/proc/self/fd"); |
| if (!d) { |
| int fd; |
| struct rlimit rl; |
| |
| /* When /proc isn't available (for example in chroots) |
| * the fallback is brute forcing through the fd |
| * table */ |
| |
| assert_se(getrlimit(RLIMIT_NOFILE, &rl) >= 0); |
| for (fd = 3; fd < (int) rl.rlim_max; fd ++) { |
| |
| if (fd_in_set(fd, except, n_except)) |
| continue; |
| |
| if (close_nointr(fd) < 0) |
| if (errno != EBADF && r == 0) |
| r = -errno; |
| } |
| |
| return r; |
| } |
| |
| FOREACH_DIRENT(de, d, return -errno) { |
| int fd = -1; |
| |
| if (safe_atoi(de->d_name, &fd) < 0) |
| /* Let's better ignore this, just in case */ |
| continue; |
| |
| if (fd < 3) |
| continue; |
| |
| if (fd == dirfd(d)) |
| continue; |
| |
| if (fd_in_set(fd, except, n_except)) |
| continue; |
| |
| if (close_nointr(fd) < 0) { |
| /* Valgrind has its own FD and doesn't want to have it closed */ |
| if (errno != EBADF && r == 0) |
| r = -errno; |
| } |
| } |
| |
| return r; |
| } |
| |
| int same_fd(int a, int b) { |
| struct stat sta, stb; |
| pid_t pid; |
| int r, fa, fb; |
| |
| assert(a >= 0); |
| assert(b >= 0); |
| |
| /* Compares two file descriptors. Note that semantics are |
| * quite different depending on whether we have kcmp() or we |
| * don't. If we have kcmp() this will only return true for |
| * dup()ed file descriptors, but not otherwise. If we don't |
| * have kcmp() this will also return true for two fds of the same |
| * file, created by separate open() calls. Since we use this |
| * call mostly for filtering out duplicates in the fd store |
| * this difference hopefully doesn't matter too much. */ |
| |
| if (a == b) |
| return true; |
| |
| /* Try to use kcmp() if we have it. */ |
| pid = getpid(); |
| r = kcmp(pid, pid, KCMP_FILE, a, b); |
| if (r == 0) |
| return true; |
| if (r > 0) |
| return false; |
| if (errno != ENOSYS) |
| return -errno; |
| |
| /* We don't have kcmp(), use fstat() instead. */ |
| if (fstat(a, &sta) < 0) |
| return -errno; |
| |
| if (fstat(b, &stb) < 0) |
| return -errno; |
| |
| if ((sta.st_mode & S_IFMT) != (stb.st_mode & S_IFMT)) |
| return false; |
| |
| /* We consider all device fds different, since two device fds |
| * might refer to quite different device contexts even though |
| * they share the same inode and backing dev_t. */ |
| |
| if (S_ISCHR(sta.st_mode) || S_ISBLK(sta.st_mode)) |
| return false; |
| |
| if (sta.st_dev != stb.st_dev || sta.st_ino != stb.st_ino) |
| return false; |
| |
| /* The fds refer to the same inode on disk, let's also check |
| * if they have the same fd flags. This is useful to |
| * distinguish the read and write side of a pipe created with |
| * pipe(). */ |
| fa = fcntl(a, F_GETFL); |
| if (fa < 0) |
| return -errno; |
| |
| fb = fcntl(b, F_GETFL); |
| if (fb < 0) |
| return -errno; |
| |
| return fa == fb; |
| } |
| |
| void cmsg_close_all(struct msghdr *mh) { |
| struct cmsghdr *cmsg; |
| |
| assert(mh); |
| |
| CMSG_FOREACH(cmsg, mh) |
| if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) |
| close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int)); |
| } |
| |
| bool fdname_is_valid(const char *s) { |
| const char *p; |
| |
| /* Validates a name for $LISTEN_FDNAMES. We basically allow |
| * everything ASCII that's not a control character. Also, as |
| * special exception the ":" character is not allowed, as we |
| * use that as field separator in $LISTEN_FDNAMES. |
| * |
| * Note that the empty string is explicitly allowed |
| * here. However, we limit the length of the names to 255 |
| * characters. */ |
| |
| if (!s) |
| return false; |
| |
| for (p = s; *p; p++) { |
| if (*p < ' ') |
| return false; |
| if (*p >= 127) |
| return false; |
| if (*p == ':') |
| return false; |
| } |
| |
| return p - s < 256; |
| } |
| |
| int fd_get_path(int fd, char **ret) { |
| char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; |
| int r; |
| |
| xsprintf(procfs_path, "/proc/self/fd/%i", fd); |
| |
| r = readlink_malloc(procfs_path, ret); |
| |
| if (r == -ENOENT) /* If the file doesn't exist the fd is invalid */ |
| return -EBADF; |
| |
| return r; |
| } |