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[68.40.189.247]) by smtp.gmail.com with ESMTPSA id v139sm1693180itb.25.2019.05.21.05.49.13 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 21 May 2019 05:49:14 -0700 (PDT) From: Trond Myklebust X-Google-Original-From: Trond Myklebust To: SteveD@redhat.com Cc: linux-nfs@vger.kernel.org Subject: [RFC PATCH v2 3/7] Add utilities for resolving nfsd paths and stat()ing them Date: Tue, 21 May 2019 08:46:57 -0400 Message-Id: <20190521124701.61849-4-trond.myklebust@hammerspace.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190521124701.61849-3-trond.myklebust@hammerspace.com> References: <20190521124701.61849-1-trond.myklebust@hammerspace.com> <20190521124701.61849-2-trond.myklebust@hammerspace.com> <20190521124701.61849-3-trond.myklebust@hammerspace.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Add helper functions that can resolve nfsd paths by prepending the necessary prefix if the admin has specified a root path in the nfs.conf file. Signed-off-by: Trond Myklebust --- configure.ac | 2 +- support/include/Makefile.am | 1 + support/include/nfsd_path.h | 17 ++++ support/misc/Makefile.am | 3 +- support/misc/nfsd_path.c | 173 ++++++++++++++++++++++++++++++++++++ 5 files changed, 194 insertions(+), 2 deletions(-) create mode 100644 support/include/nfsd_path.h create mode 100644 support/misc/nfsd_path.c diff --git a/configure.ac b/configure.ac index c6c2d73b06dd..4793daeb2716 100644 --- a/configure.ac +++ b/configure.ac @@ -321,7 +321,7 @@ AC_CHECK_FUNC([getservbyname], , AC_CHECK_LIB([crypt], [crypt], [LIBCRYPT="-lcrypt"]) AC_CHECK_HEADERS([sched.h], [], []) -AC_CHECK_FUNCS([unshare], [] , []) +AC_CHECK_FUNCS([unshare openat fstatat], [] , []) AC_LIBPTHREAD([]) if test "$enable_nfsv4" = yes; then diff --git a/support/include/Makefile.am b/support/include/Makefile.am index df5e47836d29..fbf487eee0e2 100644 --- a/support/include/Makefile.am +++ b/support/include/Makefile.am @@ -10,6 +10,7 @@ noinst_HEADERS = \ misc.h \ nfs_mntent.h \ nfs_paths.h \ + nfsd_path.h \ nfslib.h \ nfsrpc.h \ nls.h \ diff --git a/support/include/nfsd_path.h b/support/include/nfsd_path.h new file mode 100644 index 000000000000..5936cd5ed666 --- /dev/null +++ b/support/include/nfsd_path.h @@ -0,0 +1,17 @@ +/* + * Copyright (C) 2019 Trond Myklebust + */ +#ifndef XPATH_H +#define XPATH_H + +void nfsd_path_init(void); +void nfsd_path_nfsd_rootfs_close(void); + +const char * nfsd_path_nfsd_rootdir(void); +char * nfsd_path_strip_root(char *pathname); +char * nfsd_path_prepend_dir(const char *dir, const char *pathname); + +int nfsd_path_stat(const char *pathname, struct stat *statbuf); +int nfsd_path_lstat(const char *pathname, struct stat *statbuf); + +#endif diff --git a/support/misc/Makefile.am b/support/misc/Makefile.am index d0bff8feb6ae..ff1e8ab79ae3 100644 --- a/support/misc/Makefile.am +++ b/support/misc/Makefile.am @@ -1,6 +1,7 @@ ## Process this file with automake to produce Makefile.in noinst_LIBRARIES = libmisc.a -libmisc_a_SOURCES = tcpwrapper.c from_local.c mountpoint.c file.c workqueue.c +libmisc_a_SOURCES = tcpwrapper.c from_local.c mountpoint.c file.c \ + nfsd_path.c workqueue.c MAINTAINERCLEANFILES = Makefile.in diff --git a/support/misc/nfsd_path.c b/support/misc/nfsd_path.c new file mode 100644 index 000000000000..481ba49a38fd --- /dev/null +++ b/support/misc/nfsd_path.c @@ -0,0 +1,173 @@ +#include +#include +#include +#include + +#include "config.h" +#include "conffile.h" +#include "xmalloc.h" +#include "xlog.h" +#include "nfsd_path.h" + +static int +nfsd_path_isslash(const char *path) +{ + return path[0] == '/' && path[1] == '/'; +} + +static int +nfsd_path_isdot(const char *path) +{ + return path[0] == '.' && path[1] == '/'; +} + +static const char * +nfsd_path_strip(const char *path) +{ + if (!path || *path == '\0') + goto out; + for (;;) { + if (nfsd_path_isslash(path)) { + path++; + continue; + } + if (nfsd_path_isdot(path)) { + path += 2; + continue; + } + break; + } +out: + return path; +} + +const char * +nfsd_path_nfsd_rootdir(void) +{ + const char *rootdir; + + rootdir = nfsd_path_strip(conf_get_str("nfsd", "root_dir")); + if (!rootdir || rootdir[0] == '\0') + return NULL; + if (rootdir[0] == '/' && rootdir[1] == '\0') + return NULL; + return rootdir; +} + +char * +nfsd_path_strip_root(char *pathname) +{ + const char *dir = nfsd_path_nfsd_rootdir(); + char *ret; + + ret = strstr(pathname, dir); + if (!ret || ret != pathname) + return pathname; + return pathname + strlen(dir); +} + +char * +nfsd_path_prepend_dir(const char *dir, const char *pathname) +{ + size_t len, dirlen; + char *ret; + + dirlen = strlen(dir); + while (dirlen > 0 && dir[dirlen - 1] == '/') + dirlen--; + if (!dirlen) + return NULL; + len = dirlen + strlen(pathname) + 1; + ret = xmalloc(len + 1); + snprintf(ret, len, "%.*s/%s", (int)dirlen, dir, pathname); + return ret; +} + +#if defined(HAVE_FSTATAT) && defined(HAVE_OPENAT) +static int nfsd_rootfs = AT_FDCWD; + +void nfsd_path_nfsd_rootfs_close(void) +{ + if (nfsd_rootfs != AT_FDCWD) { + close(nfsd_rootfs); + nfsd_rootfs = AT_FDCWD; + } +} + +void nfsd_path_init(void) +{ + const char *rootdir = nfsd_path_nfsd_rootdir(); + + nfsd_path_nfsd_rootfs_close(); + if (rootdir) { + nfsd_rootfs = openat(AT_FDCWD, rootdir, O_PATH); + if (nfsd_rootfs == -1) + xlog_err("Could not open directory %s: %m", rootdir); + } +} + +int nfsd_path_stat(const char *pathname, struct stat *statbuf) +{ + if (nfsd_rootfs != AT_FDCWD) { + while (pathname[0] == '/') + pathname++; + } + return fstatat(nfsd_rootfs, pathname, statbuf, AT_EMPTY_PATH | + AT_NO_AUTOMOUNT); +} + +int nfsd_path_lstat(const char *pathname, struct stat *statbuf) +{ + if (nfsd_rootfs != AT_FDCWD) { + while (pathname[0] == '/') + pathname++; + } + return fstatat(nfsd_rootfs, pathname, statbuf, AT_EMPTY_PATH | + AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW); +} + +#else /* defined(HAVE_FSTATAT) && defined(HAVE_OPENAT) */ +void nfsd_path_init(void) +{ +} + +void nfsd_path_nfsd_rootfs_close(void) +{ +} + +int nfsd_path_stat(const char *pathname, struct stat *statbuf) +{ + const char *rootdir = nfsd_path_nfsd_rootdir(); + char *str; + int ret; + + if (!rootdir) + goto out_stat; + str = nfsd_path_prepend_dir(rootdir, nfsd_path_strip(pathname)); + if (!str) + goto out_stat; + ret = stat(str, statbuf); + xfree(str); + return ret; +out_stat: + return stat(pathname, statbuf); +} + +int nfsd_path_lstat(const char *pathname, struct stat *statbuf) +{ + const char *rootdir = nfsd_path_nfsd_rootdir(); + char *str; + int ret; + + if (!rootdir) + goto out_lstat; + str = nfsd_path_prepend_dir(rootdir, nfsd_path_strip(pathname)); + if (!str) + goto out_lstat; + ret = lstat(str, statbuf); + xfree(str); + return ret; +out_lstat: + return lstat(pathname, statbuf); +} +#endif -- 2.21.0