Re: [libvirt] [PATCH 3/4] util: introduce new helpers to manage shmem device

Signed-off-by: Luyao Huang <lhuang(a)redhat.com&gt; --- configure.ac | 10 + po/POTFILES.in | 3 +- src/Makefile.am | 5 +- src/libvirt_private.syms | 16 ++ src/util/virshm.c | 623 +++++++++++++++++++++++++++++++++++++++++++++++ src/util/virshm.h | 104 ++++++++ 6 files changed, 759 insertions(+), 2 deletions(-) create mode 100644 src/util/virshm.c create mode 100644 src/util/virshm.h

diff --git a/src/Makefile.am b/src/Makefile.am index 7338ab9..048a096 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -152,6 +152,7 @@ UTIL_SOURCES = \ noinst_LTLIBRARIES += libvirt_conf.la @@ -1284,6 +1285,7 @@ libvirt_driver_qemu_impl_la_LIBADD = $(CAPNG_LIBS) \ $(GNUTLS_LIBS) \ $(LIBNL_LIBS) \ $(LIBXML_LIBS) \ + $(LIBRT_LIBS) \ $(NULL) libvirt_driver_qemu_impl_la_SOURCES = $(QEMU_DRIVER_SOURCES) @@ -2264,6 +2266,7 @@ libvirt_setuid_rpc_client_la_LDFLAGS = \ $(AM_LDFLAGS) \ $(LIBXML_LIBS) \ $(SECDRIVER_LIBS) \ + $(LIBRT_LIBS) \ $(NULL) libvirt_setuid_rpc_client_la_CFLAGS = \ -DLIBVIRT_SETUID_RPC_CLIENT \

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index af73177..977fd34 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -2078,6 +2078,22 @@ sexpr_u64; string2sexpr; +# util/virshm.h +virShmBuildPath; +virShmCreate; +virShmObjectFree; +virShmObjectNew; +virShmObjectListAdd; +virShmObjectListDel; +virShmObjectFindByName; +virShmObjectListGetDefault; +virShmObjectRemoveStateFile; +virShmObjectSaveState; +virShmOpen; +virShmRemoveUsedDomain; +virShmSetUsedDomain; +virShmUnlink; +

diff --git a/src/util/virshm.c b/src/util/virshm.c new file mode 100644 index 0000000..7ab39be --- /dev/null +++ b/src/util/virshm.c +#include <config.h> + +#include <fcntl.h> +#include <sys/stat.h> +#include <sys/types.h> + +#ifdef HAVE_SHM_OPEN +# include <sys/mman.h> +#endif + +#include "virshm.h" +#include "virxml.h" +#include "virbuffer.h" +#include "virerror.h" +#include "virstring.h" +#include "virlog.h" +#include "virutil.h" +#include "viralloc.h" +#include "virfile.h" +#include "configmake.h" + +#define VIR_FROM_THIS VIR_FROM_NONE + +VIR_LOG_INIT("util.shm"); + +#define SHMEM_STATE_DIR LOCALSTATEDIR "/run/libvirt/shmem" + +VIR_ENUM_IMPL(virShmObject, VIR_SHM_TYPE_LAST, + "shm", + "server"); + +static virClassPtr virShmObjectListClass; + +static virShmObjectListPtr mainlist; /* global shm object list */ + +static void virShmObjectListDispose(void *obj);

+int +virShmSetUsedDomain(virShmObjectPtr shmobj, + const char *drvname, + const char *domname) +{ + char *tmpdomain = NULL; + + if (shmobj->drvname) { + if (STRNEQ(drvname, shmobj->drvname)) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("cannot use one shmem for different driver")); + goto error; + } + } else { + if (VIR_STRDUP(shmobj->drvname, drvname) < 0) + goto error; + } + + if (VIR_STRDUP(tmpdomain, domname) < 0) + goto error; + + if (VIR_APPEND_ELEMENT(shmobj->domains, shmobj->ndomains, tmpdomain) < 0) + goto error; + + return 0; + + error: + VIR_FREE(tmpdomain);

+ return -1; +}

+#ifdef HAVE_SHM_OPEN +int +virShmOpen(const char *name, + unsigned long long size, + mode_t mode) +{ + int fd = -1; + struct stat sb; + + if ((fd = shm_open(name, O_RDWR, mode)) < 0) { + virReportSystemError(errno, + _("Unable to open shared memory" + " objects '%s'"), + name); + return -1; + } + + if (fstat(fd, &sb) < 0) { + virReportSystemError(errno, + _("cannot stat file '%s'"), name); + goto error; + } + + if (sb.st_size < size) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("already exist shared memory object" + " size %ju is smaller than required size %llu"), + (uintmax_t)sb.st_size, size); + goto error;

+int +virShmCreate(const char *name, + unsigned long long size, + bool outerr, + bool *othercreate, + mode_t mode) +{ + int fd = -1; + + fd = shm_open(name, O_RDWR|O_CREAT|O_EXCL, mode); + + if (fd > 0) { + if (ftruncate(fd, size) != 0) { + virReportSystemError(errno, + _("Unable to truncate" + " file descriptor to %llu"), + size); + ignore_value(shm_unlink(name)); + VIR_FORCE_CLOSE(fd); + return -1; + } + } else if (errno == EEXIST) { + if (outerr) { + virReportSystemError(errno, + _("shared memory objects" + " '%s' is already exist"), + name); + return -1; + } + + VIR_WARN("shared memory objects '%s' is already exist", name); + *othercreate = true; +

+ return virShmOpen(name, size, mode); + } else { + virReportSystemError(errno, + _("Unable to create shared memory" + " objects '%s'"), + name); + return -1; + } + + return fd; +} + +int +virShmUnlink(const char *name) +{ + int ret; + + if ((ret = shm_unlink(name)) < 0) { + virReportSystemError(errno, + _("Unable to delete shared memory" + " objects '%s'"), + name); + } + return ret; +} + +# if defined(__linux__) +# define SHM_DEFAULT_PATH "/dev/shm" + +int +virShmBuildPath(const char *name, char **path) +{ + + if (virAsprintf(path, "%s/%s", SHM_DEFAULT_PATH, name) < 0) + return -1; + + if (!virFileExists(*path)) { + virReportSystemError(errno, + _("could not access %s"), + *path); + VIR_FREE(*path); + return -1; + } + return 0; +} + +# else + +int +virShmBuildPath(const char *name ATTRIBUTE_UNUSED, + char **path ATTRIBUTE_UNUSED) +{ + virReportSystemError(ENOSYS, "%s", + _("Cannot get share memory object path on this platform")); + return -2; +}

diff --git a/src/util/virshm.h b/src/util/virshm.h new file mode 100644 index 0000000..945a541 --- /dev/null +++ b/src/util/virshm.h

+# include "internal.h" +# include "virutil.h" +# include "virobject.h" + +typedef enum { + VIR_SHM_TYPE_SHM = 0, + VIR_SHM_TYPE_SERVER, + + VIR_SHM_TYPE_LAST +} virShmObjectType;

+ +typedef struct _virShmObject virShmObject; +typedef virShmObject *virShmObjectPtr; +struct _virShmObject { + char *name; /* shmem object name */ + int type; /* shmem object type */ + unsigned long long size; /* size of shmem object */ + char *path; /* shmem path */ + bool othercreate; /* a bool parameter record if the shm is created by libvirt */ + + char *drvname; /* which driver */ + char **domains; /* domain(s) using this shm */ + size_t ndomains; /* number of useds */ +}; + +VIR_ENUM_DECL(virShmObject); + +typedef struct _virShmObjectList virShmObjectList; +typedef virShmObjectList *virShmObjectListPtr; +struct _virShmObjectList { + virObjectLockable parent; + char *stateDir; + size_t nshmobjs; + virShmObjectPtr *shmobjs; +};

+# ifdef HAVE_SHM_OPEN +int virShmCreate(const char *name, unsigned long long size, + bool outerr, bool *othercreate, mode_t mode) + ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(4); +int virShmOpen(const char *name, + unsigned long long size, + mode_t mode) + ATTRIBUTE_NONNULL(1); +int virShmUnlink(const char *name) + ATTRIBUTE_NONNULL(1); +int virShmBuildPath(const char *name, char **path) + ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2); +# else /* HAVE_SHM_OPEN */ +# define virShmCreate(name, size, outerr, othercreate, mode) -2 +# define virShmOpen(name, size, mode) -2 +# define virShmUnlink(name) -2 +# define virShmBuildPath(name, path) -2 + +# endif /* HAVE_SHM_OPEN */