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build: tolerate unlimited group size

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POSIX allows sysconf(_SC_GETPW_R_SIZE_MAX) to return -1 if there
is no fixed limit, and requires ERANGE errors to track real size.
Model our behavior after the example in POSIX itself:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html

Also, on error for get*_r functions, errno is undefined, and the
real error was the return value.

* src/util/util.c (virGetUserEnt, virGetUserID, virGetGroupID)
(virSetUIDGID):  Cope with sysconf failure or too small buffer.
Reported by Matthias Bolte.
This commit is contained in:
Eric Blake 2011-05-16 15:37:15 -06:00
parent 00fa155578
commit b3918fabda
1 changed files with 51 additions and 23 deletions
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74
src/util/util.c
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@ -603,7 +603,7 @@ virExecWithHook(const char *const*argv,
goto fork_error;
}
openmax = sysconf (_SC_OPEN_MAX);
openmax = sysconf(_SC_OPEN_MAX);
for (i = 3; i < openmax; i++)
if (i != infd &&
i != null &&
@ -2732,11 +2732,11 @@ static char *virGetUserEnt(uid_t uid,
struct passwd *pw = NULL;
long val = sysconf(_SC_GETPW_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
if (val < 0) {
virReportSystemError(errno, "%s", _("sysconf failed"));
return NULL;
}
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
strbuflen = 1024;
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
@ -2750,8 +2750,15 @@ static char *virGetUserEnt(uid_t uid,
* 0 or ENOENT or ESRCH or EBADF or EPERM or ...
* The given name or uid was not found.
*/
if (getpwuid_r(uid, &pwbuf, strbuf, strbuflen, &pw) != 0 || pw == NULL) {
virReportSystemError(errno,
while ((rc = getpwuid_r(uid, &pwbuf, strbuf, strbuflen, &pw)) == ERANGE) {
if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) {
virReportOOMError();
VIR_FREE(strbuf);
return NULL;
}
}
if (rc != 0 || pw == NULL) {
virReportSystemError(rc,
_("Failed to find user record for uid '%u'"),
(unsigned int) uid);
VIR_FREE(strbuf);
@ -2789,11 +2796,11 @@ int virGetUserID(const char *name,
struct passwd *pw = NULL;
long val = sysconf(_SC_GETPW_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
if (val < 0) {
virReportSystemError(errno, "%s", _("sysconf failed"));
return -1;
}
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
strbuflen = 1024;
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
@ -2807,8 +2814,15 @@ int virGetUserID(const char *name,
* 0 or ENOENT or ESRCH or EBADF or EPERM or ...
* The given name or uid was not found.
*/
if (getpwnam_r(name, &pwbuf, strbuf, strbuflen, &pw) != 0 || pw == NULL) {
virReportSystemError(errno,
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;
}
}
if (rc != 0 || pw == NULL) {
virReportSystemError(rc,
_("Failed to find user record for name '%s'"),
name);
VIR_FREE(strbuf);
@ -2831,11 +2845,11 @@ int virGetGroupID(const char *name,
struct group *gr = NULL;
long val = sysconf(_SC_GETGR_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
if (val < 0) {
virReportSystemError(errno, "%s", _("sysconf failed"));
return -1;
}
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
strbuflen = 1024;
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
@ -2849,8 +2863,15 @@ int virGetGroupID(const char *name,
* 0 or ENOENT or ESRCH or EBADF or EPERM or ...
* The given name or uid was not found.
*/
if (getgrnam_r(name, &grbuf, strbuf, strbuflen, &gr) != 0 || gr == NULL) {
virReportSystemError(errno,
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;
}
}
if (rc != 0 || gr == NULL) {
virReportSystemError(rc,
_("Failed to find group record for name '%s'"),
name);
VIR_FREE(strbuf);
@ -2886,6 +2907,7 @@ virSetUIDGID(uid_t uid, gid_t gid)
struct passwd pwd, *pwd_result;
char *buf = NULL;
size_t bufsize;
int rc;
bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
if (bufsize == -1)
@ -2895,10 +2917,16 @@ virSetUIDGID(uid_t uid, gid_t gid)
virReportOOMError();
return -1;
}
getpwuid_r(uid, &pwd, buf, bufsize, &pwd_result);
if (!pwd_result) {
virReportSystemError(errno,
_("cannot getpwuid_r(%d)"),
while ((rc = getpwuid_r(uid, &pwd, buf, bufsize,
&pwd_result)) == ERANGE) {
if (VIR_RESIZE_N(buf, bufsize, bufsize, bufsize) < 0) {
virReportOOMError();
VIR_FREE(buf);
return -1;
}
}
if (rc || !pwd_result) {
virReportSystemError(rc, _("cannot getpwuid_r(%d)"),
(unsigned int) uid);
VIR_FREE(buf);
return -1;