From 999241f7aa459cfa20c6b122374eb4c62c10c5a9 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Mon, 13 Dec 2010 17:15:31 +0000 Subject: Adds an open xenstore connection function which tries to use the xenbus interface (xs_domain_open) when the socket interface (xs_daemon_opn) fails. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mihir Nanavati Acked-by: Ian Campbell Signed-off-by: Stefano Stabellini committer: Stefano Stabellini --- tools/xenstore/xs.c | 38 +++++++++++++++++++++++++++++++------- tools/xenstore/xs.h | 20 +++++++++++++++++++- 2 files changed, 50 insertions(+), 8 deletions(-) (limited to 'tools/xenstore') diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c index 112feec8a5..f3532b03c1 100644 --- a/tools/xenstore/xs.c +++ b/tools/xenstore/xs.c @@ -182,12 +182,15 @@ error: return -1; } -static int get_dev(const char *connect_to) +static int get_dev(const char *connect_to, unsigned long flags) { - return open(connect_to, O_RDWR); + if (flags & XS_OPEN_READONLY) + return open(connect_to, O_RDONLY); + else + return open(connect_to, O_RDWR); } -static struct xs_handle *get_handle(const char *connect_to) +static struct xs_handle *get_handle(const char *connect_to, unsigned long flags) { struct stat buf; struct xs_handle *h = NULL; @@ -199,7 +202,7 @@ static struct xs_handle *get_handle(const char *connect_to) if (S_ISSOCK(buf.st_mode)) fd = get_socket(connect_to); else - fd = get_dev(connect_to); + fd = get_dev(connect_to, flags); if (fd == -1) return NULL; @@ -237,17 +240,32 @@ static struct xs_handle *get_handle(const char *connect_to) struct xs_handle *xs_daemon_open(void) { - return get_handle(xs_daemon_socket()); + return xs_open(0); } struct xs_handle *xs_daemon_open_readonly(void) { - return get_handle(xs_daemon_socket_ro()); + return xs_open(XS_OPEN_READONLY); } struct xs_handle *xs_domain_open(void) { - return get_handle(xs_domain_dev()); + return xs_open(0); +} + +struct xs_handle *xs_open(unsigned long flags) +{ + struct xs_handle *xsh = NULL; + + if (flags & XS_OPEN_READONLY) + xsh = get_handle(xs_daemon_socket_ro(), flags); + else + xsh = get_handle(xs_daemon_socket(), flags); + + if (!xsh) + xsh = get_handle(xs_domain_dev(), flags); + + return xsh; } static void close_free_msgs(struct xs_handle *h) { @@ -303,6 +321,12 @@ void xs_daemon_close(struct xs_handle *h) close_fds_free(h); } +void xs_close(struct xs_handle* xsh) +{ + if (xsh) + xs_daemon_close(xsh); +} + static bool read_all(int fd, void *data, unsigned int len) { while (len) { diff --git a/tools/xenstore/xs.h b/tools/xenstore/xs.h index 4806f1e240..1e28849eac 100644 --- a/tools/xenstore/xs.h +++ b/tools/xenstore/xs.h @@ -24,6 +24,8 @@ #define XBT_NULL 0 +#define XS_OPEN_READONLY 1<<0 + struct xs_handle; typedef uint32_t xs_transaction_t; @@ -34,18 +36,34 @@ typedef uint32_t xs_transaction_t; /* On failure, these routines set errno. */ +/* Open a connection to the xs daemon. + * Attempts to make a connection over the socket interface, + * and if it fails, then over the xenbus interface. + * Mode 0 specifies read-write access, XS_OPEN_READONLY for + * read-only access. + * Returns a handle or NULL. + */ +struct xs_handle *xs_open(unsigned long flags); + +/* Close the connection to the xs daemon. */ +void xs_close(struct xs_handle *xsh); + /* Connect to the xs daemon. * Returns a handle or NULL. + * Deprecated, please use xs_open(0) instead */ struct xs_handle *xs_daemon_open(void); struct xs_handle *xs_domain_open(void); /* Connect to the xs daemon (readonly for non-root clients). * Returns a handle or NULL. + * Deprecated, please use xs_open(XS_OPEN_READONLY) instead */ struct xs_handle *xs_daemon_open_readonly(void); -/* Close the connection to the xs daemon. */ +/* Close the connection to the xs daemon. + * Deprecated, please use xs_close() instead + */ void xs_daemon_close(struct xs_handle *); /* Throw away the connection to the xs daemon, for use after fork(). */ -- cgit v1.2.3