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Fix safezero()

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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@redhat.com>
This commit is contained in:
Jiri Denemark 2010-03-02 16:11:24 +01:00
parent cf1045338e
commit a64e3b3e68
2 changed files with 11 additions and 9 deletions
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4
src/storage/storage_backend.c
View File

@ -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;
}

16
src/util/util.c
View File

@ -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 */