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util: extend virGetUserID and virGetGroupID to support names and IDs

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This patch updates virGetUserID and virGetGroupID to be able to parse a
user or group name in a similar way to coreutils' chown. This means that
a numeric value with a leading plus sign is always parsed as an ID,
otherwise the functions try to parse the input first as a user or group
name and if this fails they try to parse it as an ID.

This patch includes Peter Krempa's changes to correctly handle errors
returned by getpwnam_r and getgrnam_r.
This commit is contained in:
Marcelo Cerri 2012-10-08 17:37:01 -03:00 committed by Eric Blake
parent 458c499841
commit 0b237296ef
1 changed files with 104 additions and 39 deletions
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143
src/util/util.c
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@ -2495,16 +2495,19 @@ char *virGetGroupName(gid_t gid)
return virGetGroupEnt(gid);
}
int virGetUserID(const char *name,
uid_t *uid)
/* Search in the password database for a user id that matches the user name
* `name`. Returns 0 on success, -1 on failure or 1 if name cannot be found.
*/
static int
virGetUserIDByName(const char *name, uid_t *uid)
{
char *strbuf;
char *strbuf = NULL;
struct passwd pwbuf;
struct passwd *pw = NULL;
long val = sysconf(_SC_GETPW_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
int ret = -1;
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
@ -2512,48 +2515,81 @@ int virGetUserID(const char *name,
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
return -1;
goto cleanup;
}
/*
* From the manpage (terrifying but true):
*
* ERRORS
* 0 or ENOENT or ESRCH or EBADF or EPERM or ...
* The given name or uid was not found.
*/
while ((rc = getpwnam_r(name, &pwbuf, strbuf, strbuflen, &pw)) == ERANGE) {
if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) {
virReportOOMError();
VIR_FREE(strbuf);
return -1;
goto cleanup;
}
}
if (rc != 0 || pw == NULL) {
virReportSystemError(rc,
_("Failed to find user record for name '%s'"),
if (rc != 0) {
virReportSystemError(rc, _("Failed to get user record for name '%s'"),
name);
VIR_FREE(strbuf);
return -1;
goto cleanup;
}
if (!pw) {
VIR_DEBUG("User record for user '%s' does not exist", name);
ret = 1;
goto cleanup;
}
*uid = pw->pw_uid;
ret = 0;
cleanup:
VIR_FREE(strbuf);
return ret;
}
/* Try to match a user id based on `user`. The default behavior is to parse
* `user` first as a user name and then as a user id. However if `user`
* contains a leading '+', the rest of the string is always parsed as a uid.
*
* Returns 0 on success and -1 otherwise.
*/
int
virGetUserID(const char *user, uid_t *uid)
{
unsigned int uint_uid;
if (*user == '+') {
user++;
} else {
int rc = virGetUserIDByName(user, uid);
if (rc <= 0)
return rc;
}
if (virStrToLong_ui(user, NULL, 10, &uint_uid) < 0 ||
((uid_t) uint_uid) != uint_uid) {
virReportError(VIR_ERR_INVALID_ARG, _("Failed to parse user '%s'"),
user);
return -1;
}
*uid = uint_uid;
return 0;
}
int virGetGroupID(const char *name,
gid_t *gid)
/* Search in the group database for a group id that matches the group name
* `name`. Returns 0 on success, -1 on failure or 1 if name cannot be found.
*/
static int
virGetGroupIDByName(const char *name, gid_t *gid)
{
char *strbuf;
char *strbuf = NULL;
struct group grbuf;
struct group *gr = NULL;
long val = sysconf(_SC_GETGR_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
int ret = -1;
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
@ -2561,39 +2597,68 @@ int virGetGroupID(const char *name,
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
return -1;
goto cleanup;
}
/*
* From the manpage (terrifying but true):
*
* ERRORS
* 0 or ENOENT or ESRCH or EBADF or EPERM or ...
* The given name or uid was not found.
*/
while ((rc = getgrnam_r(name, &grbuf, strbuf, strbuflen, &gr)) == ERANGE) {
if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) {
virReportOOMError();
VIR_FREE(strbuf);
return -1;
goto cleanup;
}
}
if (rc != 0 || gr == NULL) {
virReportSystemError(rc,
_("Failed to find group record for name '%s'"),
if (rc != 0) {
virReportSystemError(rc, _("Failed to get group record for name '%s'"),
name);
VIR_FREE(strbuf);
return -1;
goto cleanup;
}
if (!gr) {
VIR_DEBUG("Group record for group '%s' does not exist", name);
ret = 1;
goto cleanup;
}
*gid = gr->gr_gid;
ret = 0;
cleanup:
VIR_FREE(strbuf);
return ret;
}
/* Try to match a group id based on `group`. The default behavior is to parse
* `group` first as a group name and then as a group id. However if `group`
* contains a leading '+', the rest of the string is always parsed as a guid.
*
* Returns 0 on success and -1 otherwise.
*/
int
virGetGroupID(const char *group, gid_t *gid)
{
unsigned int uint_gid;
if (*group == '+') {
group++;
} else {
int rc = virGetGroupIDByName(group, gid);
if (rc <= 0)
return rc;
}
if (virStrToLong_ui(group, NULL, 10, &uint_gid) < 0 ||
((gid_t) uint_gid) != uint_gid) {
virReportError(VIR_ERR_INVALID_ARG, _("Failed to parse group '%s'"),
group);
return -1;
}
*gid = uint_gid;
return 0;
}
/* Set the real and effective uid and gid to the given values, and call
* initgroups so that the process has all the assumed group membership of
* that uid. return 0 on success, -1 on failure (the original system error