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[50.124.247.140]) by smtp.gmail.com with ESMTPSA id i141sm53089ite.20.2019.05.28.13.33.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 28 May 2019 13:33:33 -0700 (PDT) From: Trond Myklebust X-Google-Original-From: Trond Myklebust To: SteveD@redhat.com Cc: linux-nfs@vger.kernel.org Subject: [PATCH v3 04/11] Add utilities for resolving nfsd paths and stat()ing them Date: Tue, 28 May 2019 16:31:15 -0400 Message-Id: <20190528203122.11401-5-trond.myklebust@hammerspace.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190528203122.11401-4-trond.myklebust@hammerspace.com> References: <20190528203122.11401-1-trond.myklebust@hammerspace.com> <20190528203122.11401-2-trond.myklebust@hammerspace.com> <20190528203122.11401-3-trond.myklebust@hammerspace.com> <20190528203122.11401-4-trond.myklebust@hammerspace.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 | 2 + support/include/nfsd_path.h | 16 ++++ support/include/xstat.h | 11 +++ support/misc/Makefile.am | 3 +- support/misc/nfsd_path.c | 168 ++++++++++++++++++++++++++++++++++++ support/misc/xstat.c | 33 +++++++ 7 files changed, 233 insertions(+), 2 deletions(-) create mode 100644 support/include/nfsd_path.h create mode 100644 support/include/xstat.h create mode 100644 support/misc/nfsd_path.c create mode 100644 support/misc/xstat.c diff --git a/configure.ac b/configure.ac index c6c2d73b06dd..e870862a8abb 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 fstatat], [] , []) AC_LIBPTHREAD([]) if test "$enable_nfsv4" = yes; then diff --git a/support/include/Makefile.am b/support/include/Makefile.am index df5e47836d29..1373891a7c76 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 \ @@ -24,6 +25,7 @@ noinst_HEADERS = \ xlog.h \ xmalloc.h \ xcommon.h \ + xstat.h \ conffile.h MAINTAINERCLEANFILES = Makefile.in diff --git a/support/include/nfsd_path.h b/support/include/nfsd_path.h new file mode 100644 index 000000000000..db9b41a179ad --- /dev/null +++ b/support/include/nfsd_path.h @@ -0,0 +1,16 @@ +/* + * Copyright (C) 2019 Trond Myklebust + */ +#ifndef NFSD_PATH_H +#define NFSD_PATH_H + +void nfsd_path_init(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/include/xstat.h b/support/include/xstat.h new file mode 100644 index 000000000000..f1241bbfdc0e --- /dev/null +++ b/support/include/xstat.h @@ -0,0 +1,11 @@ +/* + * Copyright (C) 2019 Trond Myklebust + */ +#ifndef XSTAT_H +#define XSTAT_H + +struct stat; + +int xlstat(const char *pathname, struct stat *statbuf); +int xstat(const char *pathname, struct stat *statbuf); +#endif diff --git a/support/misc/Makefile.am b/support/misc/Makefile.am index d0bff8feb6ae..f9993e3ac897 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 xstat.c MAINTAINERCLEANFILES = Makefile.in diff --git a/support/misc/nfsd_path.c b/support/misc/nfsd_path.c new file mode 100644 index 000000000000..fe2c011b1521 --- /dev/null +++ b/support/misc/nfsd_path.c @@ -0,0 +1,168 @@ +#include +#include +#include +#include + +#include "config.h" +#include "conffile.h" +#include "xmalloc.h" +#include "xlog.h" +#include "xstat.h" +#include "nfsd_path.h" +#include "workqueue.h" + +static struct xthread_workqueue *nfsd_wq; + +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("exports", "rootdir")); + 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; +} + +static void +nfsd_setup_workqueue(void) +{ + const char *rootdir = nfsd_path_nfsd_rootdir(); + + if (!rootdir) + return; + nfsd_wq = xthread_workqueue_alloc(); + if (!nfsd_wq) + return; + xthread_workqueue_chroot(nfsd_wq, rootdir); +} + +void +nfsd_path_init(void) +{ + nfsd_setup_workqueue(); +} + +struct nfsd_stat_data { + const char *pathname; + struct stat *statbuf; + int ret; + int err; +}; + +static void +nfsd_statfunc(void *data) +{ + struct nfsd_stat_data *d = data; + + d->ret = xstat(d->pathname, d->statbuf); + if (d->ret < 0) + d->err = errno; +} + +static void +nfsd_lstatfunc(void *data) +{ + struct nfsd_stat_data *d = data; + + d->ret = xlstat(d->pathname, d->statbuf); + if (d->ret < 0) + d->err = errno; +} + +static int +nfsd_run_stat(struct xthread_workqueue *wq, + void (*func)(void *), + const char *pathname, + struct stat *statbuf) +{ + struct nfsd_stat_data data = { + pathname, + statbuf, + 0, + 0 + }; + xthread_work_run_sync(wq, func, &data); + if (data.ret < 0) + errno = data.err; + return data.ret; +} + +int +nfsd_path_stat(const char *pathname, struct stat *statbuf) +{ + if (!nfsd_wq) + return xstat(pathname, statbuf); + return nfsd_run_stat(nfsd_wq, nfsd_statfunc, pathname, statbuf); +} + +int +nfsd_path_lstat(const char *pathname, struct stat *statbuf) +{ + if (!nfsd_wq) + return xlstat(pathname, statbuf); + return nfsd_run_stat(nfsd_wq, nfsd_lstatfunc, pathname, statbuf); +} diff --git a/support/misc/xstat.c b/support/misc/xstat.c new file mode 100644 index 000000000000..d092f73dfd65 --- /dev/null +++ b/support/misc/xstat.c @@ -0,0 +1,33 @@ +#include +#include +#include +#include + +#include "config.h" +#include "xstat.h" + +#ifdef HAVE_FSTATAT + +int xlstat(const char *pathname, struct stat *statbuf) +{ + return fstatat(AT_FDCWD, pathname, statbuf, AT_NO_AUTOMOUNT | + AT_SYMLINK_NOFOLLOW); +} + +int xstat(const char *pathname, struct stat *statbuf) +{ + return fstatat(AT_FDCWD, pathname, statbuf, AT_NO_AUTOMOUNT); +} + +#else + +int xlstat(const char *pathname, struct stat *statbuf) +{ + return lstat(pathname, statbuf); +} + +int xstat(const char *pathname, struct stat *statbuf) +{ + return stat(pathname, statbuf); +} +#endif