Re: [libvirt] [PATCH] Fix safezero()

Various safezero() implementations used either -1, errno or -errno return values. This patch fixes them all to return -1 and set errno appropriately. There was also a bug in size parameter passed to safewrite() which could result in an attempt to write gigabytes out of a megabyte buffer. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/storage/storage_backend.c | 4 ++-- src/util/util.c | 16 +++++++++------- 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 3742493..849f01b 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -316,7 +316,7 @@ static int createRawFileOpHook(int fd, void *data) { if ((r = safezero(fd, 0, hdata->vol->allocation - remain, bytes)) != 0) { ret = errno; - virReportSystemError(r, _("cannot fill file '%s'"), + virReportSystemError(errno, _("cannot fill file '%s'"), hdata->vol->target.path); goto cleanup; } @@ -327,7 +327,7 @@ static int createRawFileOpHook(int fd, void *data) { if ((r = safezero(fd, 0, 0, remain)) != 0) { ret = errno; - virReportSystemError(r, _("cannot fill file '%s'"), + virReportSystemError(errno, _("cannot fill file '%s'"), hdata->vol->target.path); goto cleanup; } diff --git a/src/util/util.c b/src/util/util.c index cf7bba5..34c585d 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -146,11 +146,11 @@ int safezero(int fd, int flags ATTRIBUTE_UNUSED, off_t offset, off_t len) */ r = ftruncate(fd, offset + len); if (r < 0) - return -errno; + return -1; buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset); if (buf == MAP_FAILED) - return -errno; + return -1; memset(buf, 0, len); munmap(buf, len); @@ -167,24 +167,26 @@ int safezero(int fd, int flags ATTRIBUTE_UNUSED, off_t offset, off_t len) unsigned long long remain, bytes; if (lseek(fd, offset, SEEK_SET) < 0) - return errno; + return -1; /* Split up the write in small chunks so as not to allocate lots of RAM */ remain = len; bytes = 1024 * 1024; r = VIR_ALLOC_N(buf, bytes); - if (r < 0) - return -ENOMEM; + if (r < 0) { + errno = ENOMEM; + return -1; + } while (remain) { if (bytes > remain) bytes = remain; - r = safewrite(fd, buf, len); + r = safewrite(fd, buf, bytes); if (r < 0) { VIR_FREE(buf); - return r; + return -1; } /* safewrite() guarantees all data will be written */