Re: [libvirt] [PATCH v3 2/4] util: Create virFileAccessibleAs function

This function checks if a given path is accessible under given uid and gid. --- src/util/util.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ src/util/util.h | 3 ++ 2 files changed, 79 insertions(+), 0 deletions(-) diff --git a/src/util/util.c b/src/util/util.c index dac616b..09d6281 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -671,6 +671,70 @@ virFileIsExecutable(const char *file) } #ifndef WIN32 +/* Check that a file is accessible under certain + * user & gid. + * @mode can be R_OK, W_OK, X_OK or F_OK. + * see 'man accesss' for more details. + * Returns 0 on success, -errno on fail, + * >0 on signaled child. + */ +int +virFileAccessibleAs(const char *path, int mode, + uid_t uid, gid_t gid) +{ + pid_t pid; + int waitret, status, ret = 0; + int forkRet; + + forkRet = virFork(&pid); + + if (pid < 0) { + return -errno; + }

+ + if (pid) { /* parent */ + do { + if ((waitret = waitpid(pid, &status, 0)) < 0) { + ret = -errno; + virKillProcess(pid, SIGKILL); + return ret; + } + } while (!WIFEXITED(status) && !WIFSIGNALED(status)); + + /* child actually returns positive value + * anded by 0xFF (see man waitpid @ WEXITSTATUS) + */ + + if (WIFSIGNALED(status)) + return WTERMSIG(status); + + return -WEXITSTATUS(status); + } + + /* child */ + + if (forkRet < 0) { + ret = errno; + goto childerror; + } + + if (virSetUIDGID(uid, gid) < 0) { + ret = errno; + goto childerror; + } + + if (access(path, mode) < 0) + ret = errno; + +childerror: + if ((ret & 0xFF) != ret) { + VIR_WARN("unable to pass desired return value %d", ret); + ret = 0xFF; + } + + _exit(ret); +} + /* return -errno on failure, or 0 on success */ static int virFileOpenAsNoFork(const char *path, int openflags, mode_t mode, @@ -993,6 +1057,18 @@ childerror: #else /* WIN32 */ +int +virFileAccessibleAs(const char *path ATTRIBUTE_UNUSED, + int mode ATTRIBUTE_UNUSED, + uid_t uid ATTRIBUTE_UNUSED, + git_t gid ATTRIBUTE_UNUSED) +{ + virUtilError(VIR_ERR_INTERNAL_ERROR, + "%s", _("virFileAccessibleAs is not implemented for WIN32")); + + return -ENOSYS; +}