[PATCH 3/3] genhomedircon: avoid use of non-standard `getpwent_r`

[Patrick Steinhardt]

The `getpwent_r` function is a non-standard but re-entrant version of
the sdardardized `getpwent` function. Next to the benefit of being
re-entrant, though, it avoids compilation with libc implementations that
do not provide this glibc-specific extension, for example musl libc.

As the code is usually not run in a threaded environment, it is save to
use the non-reentrant version, though. As such, convert code to use
`getpwent` instead to fix building with other libc implementations.

Signed-off-by: Patrick Steinhardt <p...@pks.im>
---
 libsemanage/src/genhomedircon.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/libsemanage/src/genhomedircon.c b/libsemanage/src/genhomedircon.c
index e8c95ee4..f58c17ce 100644
--- a/libsemanage/src/genhomedircon.c
+++ b/libsemanage/src/genhomedircon.c
@@ -295,9 +295,8 @@ static semanage_list_t 
*get_home_dirs(genhomedircon_settings_t * s)
        long rbuflen;
        uid_t temp, minuid = 500, maxuid = 60000;
        int minuid_set = 0;
-       struct passwd pwstorage, *pwbuf;
+       struct passwd *pwbuf;
        struct stat buf;
-       int retval;
 
        path = semanage_findval(PATH_ETC_USERADD, "HOME", "=");
        if (path && *path) {
@@ -369,7 +368,7 @@ static semanage_list_t 
*get_home_dirs(genhomedircon_settings_t * s)
        if (rbuf == NULL)
                goto fail;
        setpwent();
-       while ((retval = getpwent_r(&pwstorage, rbuf, rbuflen, &pwbuf)) == 0) {
+       while ((pwbuf = getpwent()) != NULL) {
                if (pwbuf->pw_uid < minuid || pwbuf->pw_uid > maxuid)
                        continue;
                if (!semanage_list_find(shells, pwbuf->pw_shell))
@@ -413,7 +412,7 @@ static semanage_list_t 
*get_home_dirs(genhomedircon_settings_t * s)
                path = NULL;
        }
 
-       if (retval && retval != ENOENT) {
+       if (errno && errno != ENOENT) {
                WARN(s->h_semanage, "Error while fetching users.  "
                     "Returning list so far.");
        }
@@ -1064,10 +1063,7 @@ static int get_group_users(genhomedircon_settings_t * s,
        long grbuflen;
        char *grbuf = NULL;
        struct group grstorage, *group = NULL;
-
-       long prbuflen;
-       char *pwbuf = NULL;
-       struct passwd pwstorage, *pw = NULL;
+       struct passwd *pw = NULL;
 
        grbuflen = sysconf(_SC_GETGR_R_SIZE_MAX);
        if (grbuflen <= 0)
@@ -1104,15 +1100,8 @@ static int get_group_users(genhomedircon_settings_t * s,
                }
        }
 
-       prbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
-       if (prbuflen <= 0)
-               goto cleanup;
-       pwbuf = malloc(prbuflen);
-       if (pwbuf == NULL)
-               goto cleanup;
-
        setpwent();
-       while ((retval = getpwent_r(&pwstorage, pwbuf, prbuflen, &pw)) == 0) {
+       while ((pw = getpwent()) != NULL) {
                // skip users who also have this group as their
                // primary group
                if (lfind(pw->pw_name, group->gr_mem, &nmembers,
@@ -1131,7 +1120,6 @@ static int get_group_users(genhomedircon_settings_t * s,
        retval = STATUS_SUCCESS;
 cleanup:
        endpwent();
-       free(pwbuf);
        free(grbuf);
 
        return retval;
-- 
2.13.1