Re: [libvirt] [PATCH v2 02/18] util: Introduce xattr getter/setter/remover

Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/libvirt_private.syms | 3 + src/util/virfile.c | 121 +++++++++++++++++++++++++++++++++++++++ src/util/virfile.h | 11 ++++ 3 files changed, 135 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 5018a13e9c..8e5b610ab1 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1827,6 +1827,7 @@ virFileGetACLs; virFileGetHugepageSize; virFileGetMountReverseSubtree; virFileGetMountSubtree; +virFileGetXAtrr;

@@ -1873,6 +1875,7 @@ virFileRewriteStr; virFileSanitizePath; virFileSetACLs; virFileSetupDev; +virFileSetXAtrr;

+#if HAVE_LIBATTR +/** + * virFileGetXAtrr; + * @path: a filename + * @name: name of xattr + * @value: read value + * + * Reads xattr with @name for given @path and stores it into + * @value. Caller is responsible for freeing @value. + * + * Returns: 0 on success, + * -1 otherwise (with errno set). + */ +int +virFileGetXAtrr(const char *path, + const char *name, + char **value) +{ + char *buf = NULL; + int ret = -1; + + /* We might be racing with somebody who sets the same attribute. */ + do { + ssize_t need; + ssize_t got; + + /* The first call determines how many bytes we need to allocate. */ + if ((need = getxattr(path, name, NULL, 0)) < 0) + goto cleanup; + + if (VIR_REALLOC_N_QUIET(buf, need + 1) < 0) + goto cleanup; + + if ((got = getxattr(path, name, buf, need)) < 0) { + if (errno == ERANGE) + continue; + goto cleanup; + } + + buf[got] = '\0'; + break; + } while (1);

+ + VIR_STEAL_PTR(*value, buf); + ret = 0; + cleanup: + VIR_FREE(buf); + return ret; +}