Re: [libvirt] [PATCHv2 1/2] util: Don't fail virGetUserIDByName when user not found

virGetUserIDByName is documented as returning 1 if the username cannot be found. getpwnam_r is documented as returning: « 0 or ENOENT or ESRCH or EBADF or EPERM or ... The given name or uid was not found. » and that: « The formulation given above under "RETURN VALUE" is from POSIX.1-2001. It does not call "not found" an error, hence does not specify what value errno might have in this situation. But that makes it impossible to recognize errors. One might argue that according to POSIX errno should be left unchanged if an entry is not found. Experiments on various UNIX-like systems shows that lots of different values occur in this situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others. » virGetUserIDByName returns an error when the return value of getpwnam_r is non-0. However on my RHEL system, getpwnam_r returns ENOENT when the requested user cannot be found, which then causes virGetUserID not to behave as documented (it returns an error instead of falling back to parsing the passed-in value as an uid). This commit makes virGetUserIDByName only report an error when errno is set to one of the values in the posix description of getpwnam_r (which are the same as the ones described in the manpage on my system). --- src/util/util.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/src/util/util.c b/src/util/util.c index 2fd0f2c..b50563b 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -2531,9 +2531,18 @@ virGetUserIDByName(const char *name, uid_t *uid) } if (rc != 0) { - virReportSystemError(rc, _("Failed to get user record for name '%s'"), - name); - goto cleanup; + /* We explicitly test for the known error values returned by + * getpwnam_r as the manpage says: + * ERRORS + * 0 or ENOENT or ESRCH or EBADF or EPERM or ... + * The given name or uid was not found. + */ + if ((rc == EINTR) || (rc == EIO) || (rc == EMFILE) + || (rc == ENFILE) || (rc == ENOMEM)) {

+ virReportSystemError(rc, _("Failed to get user record for name '%s'"), + name); + goto cleanup; + } } if (!pw) {