From patchwork Sat Aug 11 13:14:37 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Corey Bryant X-Patchwork-Id: 176681 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C38022C00C5 for ; Sat, 11 Aug 2012 23:15:19 +1000 (EST) Received: from localhost ([::1]:60210 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T0BXB-00051s-PD for incoming@patchwork.ozlabs.org; Sat, 11 Aug 2012 09:15:17 -0400 Received: from eggs.gnu.org ([208.118.235.92]:38991) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T0BWo-0004ku-FK for qemu-devel@nongnu.org; Sat, 11 Aug 2012 09:14:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T0BWm-0002i0-JE for qemu-devel@nongnu.org; Sat, 11 Aug 2012 09:14:54 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:50507) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T0BWm-0002hq-BY for qemu-devel@nongnu.org; Sat, 11 Aug 2012 09:14:52 -0400 Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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X-Received-From: 32.97.182.137 Cc: kwolf@redhat.com, aliguori@us.ibm.com, stefanha@linux.vnet.ibm.com, libvir-list@redhat.com, Corey Bryant , lcapitulino@redhat.com, pbonzini@redhat.com, eblake@redhat.com Subject: [Qemu-devel] [PATCH v9 6/7] block: Enable qemu_open/close to work with fd sets X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org When qemu_open is passed a filename of the "/dev/fdset/nnn" format (where nnn is the fdset ID), an fd with matching access mode flags will be searched for within the specified monitor fd set. If the fd is found, a dup of the fd will be returned from qemu_open. Signed-off-by: Corey Bryant --- v2: -Get rid of file_open and move dup code to qemu_open (kwolf@redhat.com) -Use strtol wrapper instead of atoi (kwolf@redhat.com) v3: -Add note about fd leakage (eblake@redhat.com) v4 -Moved patch to be later in series (lcapitulino@redhat.com) -Update qemu_open to check access mode flags and set flags that can be set (eblake@redhat.com, kwolf@redhat.com) v5: -This patch was overhauled quite a bit in this version, with the addition of fd set and refcount support. -Use qemu_set_cloexec() on dup'd fd (eblake@redhat.com) -Modify flags set by fcntl on dup'd fd (eblake@redhat.com) -Reduce syscalls when setting flags for dup'd fd (eblake@redhat.com) -Fix O_RDWR, O_RDONLY, O_WRONLY checks (eblake@redhat.com) v6: -Pass only the fd to qemu_close() and keep track of dup fds per fd set. (kwolf@redhat.com, eblake@redhat.com) -Handle refcount incr/decr in new dup_fd_add/remove fd functions. -Use qemu_set_cloexec() appropriately in qemu_dup() (kwolf@redhat.com) -Simplify setting of setfl_flags in qemu_dup() (kwolf@redhat.com) -Add preprocessor checks for F_DUPFD_CLOEXEC (eblake@redhat.com) -Simplify flag checking in monitor_fdset_get_fd() (kwolf@redhat.com) v7: -Minor updates to reference global mon_fdsets, and to remove default_mon usage in osdep.c. (kwolf@redhat.com) v8: -Use camel case for structures. (stefanha@linux.vnet.ibm.com) v9: -Drop fdset refcount and check dup_fds instead. (eblake@redhat.com) -Fix dupfd leak in qemu_dup(). (eblake@redhat.com) -Always set O_CLOEXEC in qemu_dup(). (kwolf@redhat.com) -Change name of qemu_dup() to qemu_dup_flags(). (kwolf@redhat.com) cutils.c | 5 +++ monitor.c | 83 +++++++++++++++++++++++++++++++++++++++++++- monitor.h | 5 +++ osdep.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ qemu-common.h | 1 + qemu-tool.c | 20 +++++++++++ 6 files changed, 221 insertions(+), 1 deletion(-) diff --git a/cutils.c b/cutils.c index 9d4c570..8b0d2bb 100644 --- a/cutils.c +++ b/cutils.c @@ -382,3 +382,8 @@ int qemu_parse_fd(const char *param) } return fd; } + +int qemu_parse_fdset(const char *param) +{ + return qemu_parse_fd(param); +} diff --git a/monitor.c b/monitor.c index c1851f0..4f6d2ce 100644 --- a/monitor.c +++ b/monitor.c @@ -154,6 +154,7 @@ typedef struct MonFdset MonFdset; struct MonFdset { int64_t id; QLIST_HEAD(, MonFdsetFd) fds; + QLIST_HEAD(, MonFdsetFd) dup_fds; QLIST_ENTRY(MonFdset) next; }; @@ -2421,7 +2422,7 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset) } } - if (QLIST_EMPTY(&mon_fdset->fds)) { + if (QLIST_EMPTY(&mon_fdset->fds) && QLIST_EMPTY(&mon_fdset->dup_fds)) { QLIST_REMOVE(mon_fdset, next); g_free(mon_fdset); } @@ -2574,6 +2575,86 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) return fdset_list; } +int monitor_fdset_get_fd(int64_t fdset_id, int flags) +{ + MonFdset *mon_fdset; + MonFdsetFd *mon_fdset_fd; + int mon_fd_flags; + + QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { + if (mon_fdset->id != fdset_id) { + continue; + } + QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) { + mon_fd_flags = fcntl(mon_fdset_fd->fd, F_GETFL); + if (mon_fd_flags == -1) { + return -1; + } + + if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) { + return mon_fdset_fd->fd; + } + } + errno = EACCES; + return -1; + } + errno = ENOENT; + return -1; +} + +int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd) +{ + MonFdset *mon_fdset; + MonFdsetFd *mon_fdset_fd_dup; + + QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { + if (mon_fdset->id != fdset_id) { + continue; + } + QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) { + if (mon_fdset_fd_dup->fd == dup_fd) { + return -1; + } + } + mon_fdset_fd_dup = g_malloc0(sizeof(*mon_fdset_fd_dup)); + mon_fdset_fd_dup->fd = dup_fd; + QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next); + return 0; + } + return -1; +} + +static int _monitor_fdset_dup_fd_find(int dup_fd, bool remove) +{ + MonFdset *mon_fdset; + MonFdsetFd *mon_fdset_fd_dup; + + QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { + QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) { + if (mon_fdset_fd_dup->fd == dup_fd) { + if (remove) { + QLIST_REMOVE(mon_fdset_fd_dup, next); + if (QLIST_EMPTY(&mon_fdset->dup_fds)) { + monitor_fdset_cleanup(mon_fdset); + } + } + return mon_fdset->id; + } + } + } + return -1; +} + +int monitor_fdset_dup_fd_find(int dup_fd) +{ + return _monitor_fdset_dup_fd_find(dup_fd, false); +} + +int monitor_fdset_dup_fd_remove(int dup_fd) +{ + return _monitor_fdset_dup_fd_find(dup_fd, true); +} + /* mon_cmds and info_cmds would be sorted at runtime */ static mon_cmd_t mon_cmds[] = { #include "hmp-commands.h" diff --git a/monitor.h b/monitor.h index 5f4de1b..30b660f 100644 --- a/monitor.h +++ b/monitor.h @@ -86,4 +86,9 @@ int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret); int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret); +int monitor_fdset_get_fd(int64_t fdset_id, int flags); +int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd); +int monitor_fdset_dup_fd_remove(int dup_fd); +int monitor_fdset_dup_fd_find(int dup_fd); + #endif /* !MONITOR_H */ diff --git a/osdep.c b/osdep.c index 7f876ae..a326639 100644 --- a/osdep.c +++ b/osdep.c @@ -48,6 +48,7 @@ extern int madvise(caddr_t, size_t, int); #include "qemu-common.h" #include "trace.h" #include "qemu_socket.h" +#include "monitor.h" static bool fips_enabled = false; @@ -78,6 +79,64 @@ int qemu_madvise(void *addr, size_t len, int advice) #endif } +/* + * Dups an fd and sets the flags + */ +static int qemu_dup_flags(int fd, int flags) +{ + int ret; + int serrno; + int dup_flags; + int setfl_flags; + +#ifdef F_DUPFD_CLOEXEC + ret = fcntl(fd, F_DUPFD_CLOEXEC, 0); +#else + ret = dup(fd); + if (ret != -1) { + qemu_set_cloexec(ret); + } +#endif + if (ret == -1) { + goto fail; + } + + dup_flags = fcntl(ret, F_GETFL); + if (dup_flags == -1) { + goto fail; + } + + if ((flags & O_SYNC) != (dup_flags & O_SYNC)) { + errno = EINVAL; + goto fail; + } + + /* Set/unset flags that we can with fcntl */ + setfl_flags = O_APPEND | O_ASYNC | O_DIRECT | O_NOATIME | O_NONBLOCK; + dup_flags &= ~setfl_flags; + dup_flags |= (flags & setfl_flags); + if (fcntl(ret, F_SETFL, dup_flags) == -1) { + goto fail; + } + + /* Truncate the file in the cases that open() would truncate it */ + if (flags & O_TRUNC || + ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) { + if (ftruncate(ret, 0) == -1) { + goto fail; + } + } + + return ret; + +fail: + serrno = errno; + if (ret != -1) { + close(ret); + } + errno = serrno; + return -1; +} /* * Opens a file with FD_CLOEXEC set @@ -87,6 +146,40 @@ int qemu_open(const char *name, int flags, ...) int ret; int mode = 0; +#ifndef _WIN32 + const char *fdset_id_str; + + /* Attempt dup of fd from fd set */ + if (strstart(name, "/dev/fdset/", &fdset_id_str)) { + int64_t fdset_id; + int fd, dupfd; + + fdset_id = qemu_parse_fdset(fdset_id_str); + if (fdset_id == -1) { + errno = EINVAL; + return -1; + } + + fd = monitor_fdset_get_fd(fdset_id, flags); + if (fd == -1) { + return -1; + } + + dupfd = qemu_dup_flags(fd, flags); + if (fd == -1) { + return -1; + } + + ret = monitor_fdset_dup_fd_add(fdset_id, dupfd); + if (ret == -1) { + close(dupfd); + return -1; + } + + return dupfd; + } +#endif + if (flags & O_CREAT) { va_list ap; @@ -109,6 +202,21 @@ int qemu_open(const char *name, int flags, ...) int qemu_close(int fd) { + int64_t fdset_id; + + /* Close fd that was dup'd from an fdset */ + fdset_id = monitor_fdset_dup_fd_find(fd); + if (fdset_id != -1) { + int ret; + + ret = close(fd); + if (ret == 0) { + monitor_fdset_dup_fd_remove(fd); + } + + return ret; + } + return close(fd); } diff --git a/qemu-common.h b/qemu-common.h index e53126d..9becb32 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -166,6 +166,7 @@ int qemu_fls(int i); int qemu_fdatasync(int fd); int fcntl_setfl(int fd, int flag); int qemu_parse_fd(const char *param); +int qemu_parse_fdset(const char *param); /* * strtosz() suffixes used to specify the default treatment of an diff --git a/qemu-tool.c b/qemu-tool.c index 318c5fc..b7622f5 100644 --- a/qemu-tool.c +++ b/qemu-tool.c @@ -57,6 +57,26 @@ void monitor_protocol_event(MonitorEvent event, QObject *data) { } +int monitor_fdset_get_fd(int64_t fdset_id, int flags) +{ + return -1; +} + +int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd) +{ + return -1; +} + +int monitor_fdset_dup_fd_remove(int dup_fd) +{ + return -1; +} + +int monitor_fdset_dup_fd_find(int dup_fd) +{ + return -1; +} + int64_t cpu_get_clock(void) { return qemu_get_clock_ns(rt_clock);