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shared/offline-passwd: look at /usr/lib/{passwd,group} too

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This changes the code to allow looking at multiple files with different
prefixes, but uses "/etc" and "/usr/lib". rpm-ostree uses
/usr/lib/{passwd,group} with nss-altfiles. I see no harm in simply trying both
paths on all systems.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1857530.

A minor memory leak is fixed: hashmap_put() returns -EEXIST is the key is
present *and* and the value is different. It return 0 if the value is the
same. Thus, we would leak the user/group name if it was specified multiple
times with the same uid/gid. I opted to remove the warning message completely:
with multiple files it is reasonable to have the same name defined more than
once. But even with one file the warning is dubious: all tools that read those
files deal correctly with duplicate entries and we are not writing a linter.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2020-07-18 14:06:19 +02:00
parent 3e5d2264b5
commit 241947d1b4
1 changed files with 102 additions and 66 deletions
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168
src/shared/offline-passwd.c
View file

@ -7,6 +7,102 @@
DEFINE_PRIVATE_HASH_OPS_WITH_KEY_DESTRUCTOR(uid_gid_hash_ops, char, string_hash_func, string_compare_func, free);
static int open_passwd_file(const char *root, const char *fname, FILE **ret_file) {
const char *p = prefix_roota(root, fname);
if (!p)
return -ENOMEM;
FILE *f = fopen(p, "re");
if (!f)
return -errno;
log_debug("Reading %s entries from %s...", basename(fname), p);
*ret_file = f;
return 0;
}
static int populate_uid_cache(const char *root, Hashmap **ret) {
_cleanup_(hashmap_freep) Hashmap *cache = NULL;
int r;
cache = hashmap_new(&uid_gid_hash_ops);
if (!cache)
return -ENOMEM;
/* The directory list is harcoded here: /etc is the standard, and rpm-ostree uses /usr/lib. This
* could be made configurable, but I don't see the point right now. */
const char *fname;
FOREACH_STRING(fname, "/etc/passwd", "/usr/lib/passwd") {
_cleanup_fclose_ FILE *f = NULL;
r = open_passwd_file(root, fname, &f);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
struct passwd *pw;
while ((r = fgetpwent_sane(f, &pw)) > 0) {
_cleanup_free_ char *n = NULL;
n = strdup(pw->pw_name);
if (!n)
return -ENOMEM;
r = hashmap_put(cache, n, UID_TO_PTR(pw->pw_uid));
if (IN_SET(r, 0 -EEXIST))
continue;
if (r < 0)
return r;
TAKE_PTR(n);
}
}
*ret = TAKE_PTR(cache);
return 0;
}
static int populate_gid_cache(const char *root, Hashmap **ret) {
_cleanup_(hashmap_freep) Hashmap *cache = NULL;
int r;
cache = hashmap_new(&uid_gid_hash_ops);
if (!cache)
return -ENOMEM;
const char *fname;
FOREACH_STRING(fname, "/etc/group", "/usr/lib/group") {
_cleanup_fclose_ FILE *f = NULL;
r = open_passwd_file(root, fname, &f);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
struct group *gr;
while ((r = fgetgrent_sane(f, &gr)) > 0) {
_cleanup_free_ char *n = NULL;
n = strdup(gr->gr_name);
if (!n)
return -ENOMEM;
r = hashmap_put(cache, n, GID_TO_PTR(gr->gr_gid));
if (IN_SET(r, 0, -EEXIST))
continue;
if (r < 0)
return r;
TAKE_PTR(n);
}
}
*ret = TAKE_PTR(cache);
return 0;
}
int name_to_uid_offline(
const char *root,
const char *user,
@ -21,39 +117,9 @@ int name_to_uid_offline(
assert(cache);
if (!*cache) {
_cleanup_(hashmap_freep) Hashmap *uid_by_name = NULL;
_cleanup_fclose_ FILE *f = NULL;
struct passwd *pw;
const char *passwd_path;
passwd_path = prefix_roota(root, "/etc/passwd");
f = fopen(passwd_path, "re");
if (!f)
return errno == ENOENT ? -ESRCH : -errno;
uid_by_name = hashmap_new(&uid_gid_hash_ops);
if (!uid_by_name)
return -ENOMEM;
while ((r = fgetpwent_sane(f, &pw)) > 0) {
_cleanup_free_ char *n = NULL;
n = strdup(pw->pw_name);
if (!n)
return -ENOMEM;
r = hashmap_put(uid_by_name, n, UID_TO_PTR(pw->pw_uid));
if (r == -EEXIST) {
log_warning_errno(r, "Duplicate entry in %s for %s: %m", passwd_path, pw->pw_name);
continue;
}
if (r < 0)
return r;
TAKE_PTR(n);
}
*cache = TAKE_PTR(uid_by_name);
r = populate_uid_cache(root, cache);
if (r < 0)
return r;
}
found = hashmap_get(*cache, user);
@ -78,39 +144,9 @@ int name_to_gid_offline(
assert(cache);
if (!*cache) {
_cleanup_(hashmap_freep) Hashmap *gid_by_name = NULL;
_cleanup_fclose_ FILE *f = NULL;
struct group *gr;
const char *group_path;
group_path = prefix_roota(root, "/etc/group");
f = fopen(group_path, "re");
if (!f)
return errno == ENOENT ? -ESRCH : -errno;
gid_by_name = hashmap_new(&uid_gid_hash_ops);
if (!gid_by_name)
return -ENOMEM;
while ((r = fgetgrent_sane(f, &gr)) > 0) {
_cleanup_free_ char *n = NULL;
n = strdup(gr->gr_name);
if (!n)
return -ENOMEM;
r = hashmap_put(gid_by_name, n, GID_TO_PTR(gr->gr_gid));
if (r == -EEXIST) {
log_warning_errno(r, "Duplicate entry in %s for %s: %m", group_path, gr->gr_name);
continue;
}
if (r < 0)
return r;
TAKE_PTR(n);
}
*cache = TAKE_PTR(gid_by_name);
r = populate_gid_cache(root, cache);
if (r < 0)
return r;
}
found = hashmap_get(*cache, group);