diff --git a/ports/linux/guts/fopen64.c b/ports/linux/guts/fopen64.c index e76da69..a6efd18 100644 --- a/ports/linux/guts/fopen64.c +++ b/ports/linux/guts/fopen64.c @@ -22,8 +22,11 @@ pseudo_debug(PDBGF_FILE, "fopen64 '%s': fd %d \n", path, fd, (void *) rc); if (real___fxstat64(_STAT_VER, fd, &buf) != -1) { if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(fd, PSEUDO_FS_MODE(0666 & ~pseudo_umask, 0)); - pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + if (pseudo_client_path_matches_fd(path, fd, 0)) + pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, pseudo_access_fopen(mode), fd, -1, path, &buf); } else { diff --git a/ports/linux/guts/freopen64.c b/ports/linux/guts/freopen64.c index 5fc9073..6057eda 100644 --- a/ports/linux/guts/freopen64.c +++ b/ports/linux/guts/freopen64.c @@ -21,8 +21,11 @@ pseudo_debug(PDBGF_FILE, "freopen64 '%s': fd %d\n", path, fd); if (real___fxstat64(_STAT_VER, fd, &buf) != -1) { if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(fd, PSEUDO_FS_MODE(0666 & ~pseudo_umask, 0)); - pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + if (pseudo_client_path_matches_fd(path, fd, 0)) + pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, pseudo_access_fopen(mode), fd, -1, path, &buf); } else { diff --git a/ports/linux/guts/openat.c b/ports/linux/guts/openat.c index 0a44063..4fd83dd 100644 --- a/ports/linux/guts/openat.c +++ b/ports/linux/guts/openat.c @@ -147,9 +147,15 @@ if (stat_rc != -1) { buf.st_mode = PSEUDO_DB_MODE(buf.st_mode, mode); if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(rc, PSEUDO_FS_MODE(mode, 0)); // file has no path, but has been created - pseudo_client_op(OP_CREAT, 0, -1, dirfd, path, &buf); + if (pseudo_client_path_matches_fd(path, rc, flags & O_NOFOLLOW) && + real___fxstat64(_STAT_VER, rc, &buf) != -1) { + buf.st_mode = PSEUDO_DB_MODE(buf.st_mode, mode); + pseudo_client_op(OP_CREAT, 0, -1, dirfd, path, &buf); + } + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, PSEUDO_ACCESS(flags), rc, dirfd, path, &buf); } else { diff --git a/ports/linux/openat2/guts/openat2.c b/ports/linux/openat2/guts/openat2.c index f1c523e..06fcec8 100644 --- a/ports/linux/openat2/guts/openat2.c +++ b/ports/linux/openat2/guts/openat2.c @@ -182,9 +182,15 @@ if (stat_rc != -1) { buf.st_mode = PSEUDO_DB_MODE(buf.st_mode, my_how.mode); if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(rc, PSEUDO_FS_MODE(my_how.mode, 0)); // file has no path, but has been created - pseudo_client_op(OP_CREAT, 0, -1, dirfd, pseudo_path, &buf); + if (pseudo_client_path_matches_fd(pseudo_path, rc, my_how.flags & O_NOFOLLOW) && + real___fxstat64(_STAT_VER, rc, &buf) != -1) { + buf.st_mode = PSEUDO_DB_MODE(buf.st_mode, my_how.mode); + pseudo_client_op(OP_CREAT, 0, -1, dirfd, pseudo_path, &buf); + } + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, PSEUDO_ACCESS(my_how.flags), rc, dirfd, pseudo_path, &buf); } else { diff --git a/ports/unix/guts/fopen.c b/ports/unix/guts/fopen.c index 26a6abc..78388f7 100644 --- a/ports/unix/guts/fopen.c +++ b/ports/unix/guts/fopen.c @@ -21,8 +21,11 @@ pseudo_debug(PDBGF_OP, "fopen '%s': fd %d \n", path, fd, (void *) rc); if (base_fstat(fd, &buf) != -1) { if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(fd, PSEUDO_FS_MODE(0666 & ~pseudo_umask, 0)); - pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + if (pseudo_client_path_matches_fd(path, fd, 0)) + pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, pseudo_access_fopen(mode), fd, -1, path, &buf); } else { diff --git a/ports/unix/guts/freopen.c b/ports/unix/guts/freopen.c index 703b6aa..5d63c9f 100644 --- a/ports/unix/guts/freopen.c +++ b/ports/unix/guts/freopen.c @@ -21,8 +21,11 @@ pseudo_debug(PDBGF_OP, "freopen '%s': fd %d\n", path, fd); if (base_fstat(fd, &buf) != -1) { if (!existed) { + int path_lock_fd = pseudo_client_path_lock(0); real_fchmod(fd, PSEUDO_FS_MODE(0666 & ~pseudo_umask, 0)); - pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + if (pseudo_client_path_matches_fd(path, fd, 0)) + pseudo_client_op(OP_CREAT, 0, -1, -1, path, &buf); + pseudo_client_path_unlock(path_lock_fd); } pseudo_client_op(OP_OPEN, pseudo_access_fopen(mode), fd, -1, path, &buf); } else { diff --git a/pseudo_client.c b/pseudo_client.c index ffd3450..a3d461e 100644 --- a/pseudo_client.c +++ b/pseudo_client.c @@ -1225,6 +1225,31 @@ pseudo_client_path_unlock(int fd) { errno = save_errno; } +/* Operations that can block, such as open() on a FIFO, can't hold the path + * lock across the real call. Instead they take the lock afterwards and + * check that the path still names the file they opened before recording + * it. With the lock held, no other client is part way through changing the + * path, so if it now names a different file, that client has already + * recorded the change, and recording ours would be wrong. + */ +int +pseudo_client_path_matches_fd(const char *path, int fd, int nofollow) { + PSEUDO_STATBUF pbuf, fbuf; + int save_errno = errno; + int rc; + + if (!path || fd < 0 || !pseudo_real_fstat || !pseudo_real_lstat || !pseudo_real_stat) + return 1; + rc = pseudo_real_fstat(fd, &fbuf) == 0 && + (nofollow ? pseudo_real_lstat(path, &pbuf) : pseudo_real_stat(path, &pbuf)) == 0 && + pbuf.st_dev == fbuf.st_dev && pbuf.st_ino == fbuf.st_ino; + if (!rc) + pseudo_debug(PDBGF_FILE, "'%s' no longer names fd %d, not recording it.\n", + path, fd); + errno = save_errno; + return rc; +} + static int client_connect(void) { /* we have a server pid, is it responsive? */ diff --git a/pseudo_client.h b/pseudo_client.h index 3958f6d..716c441 100644 --- a/pseudo_client.h +++ b/pseudo_client.h @@ -29,6 +29,7 @@ extern int pseudo_client_shutdown(int); extern int pseudo_fd(int fd, int how); extern int pseudo_client_path_lock(int shared); extern void pseudo_client_path_unlock(int fd); +extern int pseudo_client_path_matches_fd(const char *path, int fd, int nofollow); #define MOVE_FD 0 #define COPY_FD 1 #define PSEUDO_MIN_FD 20