| Message ID | 20170614171921.17475-4-wei.liu2@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 14, 2017 at 06:19:20PM +0100, Wei Liu wrote: > Signed-off-by: Wei Liu <wei.liu2@citrix.com> > --- > tools/xl/xl.h | 1 + > tools/xl/xl_utils.c | 19 +++++++++++++++++++ > tools/xl/xl_utils.h | 3 +++ > 3 files changed, 23 insertions(+) > > diff --git a/tools/xl/xl.h b/tools/xl/xl.h > index 93ec4d7e4c..8d667ff444 100644 > --- a/tools/xl/xl.h > +++ b/tools/xl/xl.h > @@ -292,6 +292,7 @@ extern void printf_info_sexp(int domid, libxl_domain_config *d_config, FILE *fh) > > #define XL_GLOBAL_CONFIG XEN_CONFIG_DIR "/xl.conf" > #define XL_LOCK_FILE XEN_LOCK_DIR "/xl" > +#define XL_DOMAIN_LOCK_FILE_FMT XEN_LOCK_DIR "/xl-%u" > > #endif /* XL_H */ > > diff --git a/tools/xl/xl_utils.c b/tools/xl/xl_utils.c > index e7038ec324..bb32ba0a1f 100644 > --- a/tools/xl/xl_utils.c > +++ b/tools/xl/xl_utils.c > @@ -27,6 +27,25 @@ > #include "xl.h" > #include "xl_utils.h" > > +int with_lock(uint32_t domid, domain_fn fn, void *arg) > +{ > + char filename[sizeof(XL_DOMAIN_LOCK_FILE_FMT)+15]; > + int fd_lock = -1; > + int rc; > + > + snprintf(filename, sizeof(filename), XL_DOMAIN_LOCK_FILE_FMT, domid); > + > + rc = acquire_lock(filename, &fd_lock); > + if (rc) goto out; > + It is necessary to check if the domain is still valid here. And we should probably accept a string instead of domid in this function and call find_domain, so that we can retry. Basically: retry: domid = find_domain(); snprintf(...) rc = acquire_lock() if (rc) goto out; if (domain is not valid anymore) { release_lock(); goto retry; } /* ... the rest ...*/
diff --git a/tools/xl/xl.h b/tools/xl/xl.h index 93ec4d7e4c..8d667ff444 100644 --- a/tools/xl/xl.h +++ b/tools/xl/xl.h @@ -292,6 +292,7 @@ extern void printf_info_sexp(int domid, libxl_domain_config *d_config, FILE *fh) #define XL_GLOBAL_CONFIG XEN_CONFIG_DIR "/xl.conf" #define XL_LOCK_FILE XEN_LOCK_DIR "/xl" +#define XL_DOMAIN_LOCK_FILE_FMT XEN_LOCK_DIR "/xl-%u" #endif /* XL_H */ diff --git a/tools/xl/xl_utils.c b/tools/xl/xl_utils.c index e7038ec324..bb32ba0a1f 100644 --- a/tools/xl/xl_utils.c +++ b/tools/xl/xl_utils.c @@ -27,6 +27,25 @@ #include "xl.h" #include "xl_utils.h" +int with_lock(uint32_t domid, domain_fn fn, void *arg) +{ + char filename[sizeof(XL_DOMAIN_LOCK_FILE_FMT)+15]; + int fd_lock = -1; + int rc; + + snprintf(filename, sizeof(filename), XL_DOMAIN_LOCK_FILE_FMT, domid); + + rc = acquire_lock(filename, &fd_lock); + if (rc) goto out; + + rc = fn(arg); + + release_lock(filename, &fd_lock); + +out: + return rc; +} + void dolog(const char *file, int line, const char *func, char *fmt, ...) { va_list ap; diff --git a/tools/xl/xl_utils.h b/tools/xl/xl_utils.h index 18280d7e84..5e0d502fa6 100644 --- a/tools/xl/xl_utils.h +++ b/tools/xl/xl_utils.h @@ -149,6 +149,9 @@ int do_daemonize(char *name, const char *pidfile); int acquire_lock(const char *lockfile, int *fd_lock); int release_lock(const char *lockfile, int *fd_lock); + +typedef int (*domain_fn)(void *arg); +int with_lock(uint32_t domid, domain_fn fn, void *arg); #endif /* XL_UTILS_H */ /*
Signed-off-by: Wei Liu <wei.liu2@citrix.com> --- tools/xl/xl.h | 1 + tools/xl/xl_utils.c | 19 +++++++++++++++++++ tools/xl/xl_utils.h | 3 +++ 3 files changed, 23 insertions(+)