On Mon, Mar 26, 2018 at 16:43:01 +0200, Michal Privoznik wrote: > This helper fetches dependencies for given device mapper target. > > At the same time, we need to provide a dummy log function because > by default libdevmapper prints out error messages to stderr which > we need to suppress. > > Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx> > --- > src/libvirt_private.syms | 4 ++ > src/util/Makefile.inc.am | 2 + > src/util/virdevmapper.c | 160 +++++++++++++++++++++++++++++++++++++++++++++++ > src/util/virdevmapper.h | 32 ++++++++++ > 4 files changed, 198 insertions(+) > create mode 100644 src/util/virdevmapper.c > create mode 100644 src/util/virdevmapper.h [...] > diff --git a/src/util/virdevmapper.c b/src/util/virdevmapper.c > new file mode 100644 > index 0000000000..9717482da8 > --- /dev/null > +++ b/src/util/virdevmapper.c > @@ -0,0 +1,160 @@ > +/* > + * virdevmapper.c: Functions for handling devmapper > + * > + * Copyright (C) 2018 Red Hat, Inc. > + * > + * This library is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * This library is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with this library. If not, see > + * <http://www.gnu.org/licenses/>. > + * > + * Authors: > + * Michal Privoznik <mprivozn@xxxxxxxxxx> > + */ > + > +#include <config.h> > + > +#ifdef MAJOR_IN_MKDEV > +# include <sys/mkdev.h> > +#elif MAJOR_IN_SYSMACROS > +# include <sys/sysmacros.h> > +#endif > + > +#ifdef WITH_DEVMAPPER > +# include <libdevmapper.h> > +#endif > + > +#include "virdevmapper.h" > +#include "internal.h" > +#include "virthread.h" > +#include "viralloc.h" > + > +#ifdef WITH_DEVMAPPER > +static void > +virDevMapperDummyLogger(int level ATTRIBUTE_UNUSED, > + const char *file ATTRIBUTE_UNUSED, > + int line ATTRIBUTE_UNUSED, > + int dm_errno ATTRIBUTE_UNUSED, > + const char *fmt ATTRIBUTE_UNUSED, > + ...) > +{ > + return; > +} > + > +static int > +virDevMapperOnceInit(void) > +{ > + /* Ideally, we would not need this. But libdevmapper prints > + * error messages to stderr by default. Sad but true. */ > + dm_log_with_errno_init(virDevMapperDummyLogger); > + return 0; > +} > + > + > +VIR_ONCE_GLOBAL_INIT(virDevMapper) > + > +/** > + * virDevMapperGetTargets: > + * @path: multipath device > + * @maj: returned array of MAJOR device numbers > + * @min: returner array of MINOR device numbers > + * @nmaj: number of items in @maj array > + * > + * For given @path figure out its targets, and store them in @maj > + * and @min arrays. Both arrays have the same number of items > + * upon return. > + * > + * If @path is not a multipath device, @ndevs is set to 0 and > + * success is returned. > + * > + * If we don't have permissions to talk to kernel, -1 is returned > + * and errno is set to EBADF. > + * > + * Returns 0 on success, > + * -1 otherwise (with errno set, no libvirt error is > + * reported) > + */ > +int > +virDevMapperGetTargets(const char *path, > + unsigned int **maj, > + unsigned int **min, > + size_t *nmaj) > +{ > + struct dm_task *dmt = NULL; > + struct dm_deps *deps; > + struct dm_info info; > + size_t i; > + int ret = -1; > + > + *nmaj = 0; > + > + if (virDevMapperInitialize() < 0) > + goto cleanup; [1] > + > + if (!(dmt = dm_task_create(DM_DEVICE_DEPS))) > + goto cleanup; [1] > + > + if (!dm_task_set_name(dmt, path)) { > + if (errno == ENOENT) { > + /* It's okay, @path is not managed by devmapper => > + * not a multipath device. */ > + ret = 0; > + } > + goto cleanup; > + } > + > + dm_task_no_open_count(dmt); > + > + if (!dm_task_run(dmt)) > + goto cleanup; > + > + if (!dm_task_get_info(dmt, &info)) > + goto cleanup; > + > + if (!info.exists) { > + ret = 0; > + goto cleanup; > + } > + > + if (!(deps = dm_task_get_deps(dmt))) > + goto cleanup; > + > + if (VIR_ALLOC_N_QUIET(*maj, deps->count) < 0 || > + VIR_ALLOC_N_QUIET(*min, deps->count) < 0) { > + VIR_FREE(*maj); > + goto cleanup; > + } > + *nmaj = deps->count; > + > + for (i = 0; i < deps->count; i++) { > + (*maj)[i] = major(deps->device[i]); > + (*min)[i] = minor(deps->device[i]); > + } > + > + ret = 0; > + cleanup: > + dm_task_destroy(dmt); [1] dm_task_destroy dereferences the argument without checking it for NULL first. Replace the two jumps above with direct returns. > + return ret; > +} > + > +#else /* ! WITH_DEVMAPPER */ > + > +int > +virDevMapperGetTargets(const char *path ATTRIBUTE_UNUSED, > + unsigned int **maj ATTRIBUTE_UNUSED, > + unsigned int **min ATTRIBUTE_UNUSED, > + size_t *nmaj ATTRIBUTE_UNUSED) > +{ > + errno = ENOSYS; > + return -1; > +} > +#endif /* ! WITH_DEVMAPPER */ > diff --git a/src/util/virdevmapper.h b/src/util/virdevmapper.h > new file mode 100644 > index 0000000000..e88ac0f8ce > --- /dev/null > +++ b/src/util/virdevmapper.h > @@ -0,0 +1,32 @@ > +/* > + * virdevmapper.h: Functions for handling devmapper > + * > + * Copyright (C) 2018 Red Hat, Inc. > + * > + * This library is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * This library is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with this library. If not, see > + * <http://www.gnu.org/licenses/>. > + * > + * Authors: > + * Michal Privoznik <mprivozn@xxxxxxxxxx> > + */ > + > +#ifndef __VIR_DEVMAPPER_H__ > +# define __VIR_DEVMAPPER_H__ > + > +int virDevMapperGetTargets(const char *path, > + unsigned int **maj, > + unsigned int **min, > + size_t *nmaj); Please adhere to the new coding style guidelines for new files. ACK with the two things above addressed.
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