[libvirt] [PATCH 1/7] util: improve user lookup helper
https://bugzilla.redhat.com/show_bug.cgi?id=964358
A future patch needs to look up pw_gid; but it is wasteful
to crawl through getpwuid_r twice for two separate pieces
of information, and annoying to copy that much boilerplate
code for doing the crawl. The current internal-only
virGetUserEnt is also a rather awkward interface; it's easier
to just design it to let callers request multiple pieces of
data as needed from one traversal.
And while at it, I noticed that virGetXDGDirectory could deref
NULL if the getpwuid_r lookup fails.
* src/util/virutil.c (virGetUserEnt): Alter signature.
(virGetUserDirectory, virGetXDGDirectory, virGetUserName): Adjust
callers.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
(cherry picked from commit c1983ba4e3902308054e961fcae75cece73ef4ba)
Conflicts:
src/util/virutil.c - oom reporting/strdup changes not backported
---
src/util/util.c | 60 ++++++++++++++++++++++++++++++++++-----------------------
1 file changed, 36 insertions(+), 24 deletions(-)
diff --git a/src/util/util.c b/src/util/util.c
index 8315515..dd4e4ea 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -2290,21 +2290,23 @@ check_and_return:
}
#ifdef HAVE_GETPWUID_R
-enum {
- VIR_USER_ENT_DIRECTORY,
- VIR_USER_ENT_NAME,
-};
-
-static char *virGetUserEnt(uid_t uid,
- int field)
+/* Look up fields from the user database for the given user. On
+ * error, set errno, report the error, and return -1. */
+static int
+virGetUserEnt(uid_t uid, char **name, gid_t *group, char **dir)
{
char *strbuf;
- char *ret;
struct passwd pwbuf;
struct passwd *pw = NULL;
long val = sysconf(_SC_GETPW_R_SIZE_MAX);
size_t strbuflen = val;
int rc;
+ int ret = -1;
+
+ if (name)
+ *name = NULL;
+ if (dir)
+ *dir = NULL;
/* sysconf is a hint; if it fails, fall back to a reasonable size */
if (val < 0)
@@ -2312,7 +2314,7 @@ static char *virGetUserEnt(uid_t uid,
if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
virReportOOMError();
- return NULL;
+ return -1;
}
/*
@@ -2325,28 +2327,33 @@ static char *virGetUserEnt(uid_t uid,
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;
+ goto cleanup;
}
}
if (rc != 0 || pw == NULL) {
virReportSystemError(rc,
_("Failed to find user record for uid
'%u'"),
(unsigned int) uid);
- VIR_FREE(strbuf);
- return NULL;
+ goto cleanup;
}
- if (field == VIR_USER_ENT_DIRECTORY)
- ret = strdup(pw->pw_dir);
- else
- ret = strdup(pw->pw_name);
+ if (name && !(*name = strdup(pw->pw_name)))
+ goto no_memory;
+ if (group)
+ *group = pw->pw_gid;
+ if (dir && !(*dir = strdup(pw->pw_dir))) {
+ if (name)
+ VIR_FREE(*name);
+ goto no_memory;
+ }
+ ret = 0;
+cleanup:
VIR_FREE(strbuf);
- if (!ret)
- virReportOOMError();
-
return ret;
+no_memory:
+ virReportOOMError();
+ goto cleanup;
}
static char *virGetGroupEnt(gid_t gid)
@@ -2401,20 +2408,23 @@ static char *virGetGroupEnt(gid_t gid)
char *virGetUserDirectory(void)
{
- return virGetUserEnt(geteuid(), VIR_USER_ENT_DIRECTORY);
+ char *ret;
+ virGetUserEnt(geteuid(), NULL, NULL, &ret);
+ return ret;
}
static char *virGetXDGDirectory(const char *xdgenvname, const char *xdgdefdir)
{
const char *path = getenv(xdgenvname);
char *ret = NULL;
- char *home = virGetUserEnt(geteuid(), VIR_USER_ENT_DIRECTORY);
+ char *home = virGetUserDirectory();
if (path && path[0]) {
if (virAsprintf(&ret, "%s/libvirt", path) < 0)
goto no_memory;
} else {
- if (virAsprintf(&ret, "%s/%s/libvirt", home, xdgdefdir) < 0)
+ if (home &&
+ virAsprintf(&ret, "%s/%s/libvirt", home, xdgdefdir) < 0)
goto no_memory;
}
@@ -2456,7 +2466,9 @@ char *virGetUserRuntimeDirectory(void)
char *virGetUserName(uid_t uid)
{
- return virGetUserEnt(uid, VIR_USER_ENT_NAME);
+ char *ret;
+ virGetUserEnt(uid, &ret, NULL, NULL);
+ return ret;
}
char *virGetGroupName(gid_t gid)
--
1.8.3.1