libbrillo: handle EINTR on getpwnam_r() and getgrnam_r() calls

CL:1311594 incorrectly uses the HANDLE_EINTR() macro on getpwnam_r() and
getgrnam_r() to handle EINTR as the two functions actually return the
error number instead of setting errno. This CL fixes the EINTR handling
as well as the error message.

Reported-by: fdegros@chromium.org

BUG=None
TEST=Run unit tests.

Change-Id: I0f388b84a7cc38a0c7db1c67d9628024e87285b5
Reviewed-on: https://chromium-review.googlesource.com/1762631
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: François Degros <fdegros@chromium.org>
Cr-Mirrored-From: https://chromium.googlesource.com/chromiumos/platform2
Cr-Mirrored-Commit: 61a4b73ae52dcfdc44783d4a13ae2aff39f57840

1 files changed, 22 insertions, 9 deletions

diff --git a/brillo/userdb_utils.cc b/brillo/userdb_utils.cc
index a204094..1308fb7 100644
--- a/brillo/userdb_utils.cc
+++ b/brillo/userdb_utils.cc
@@ -4,6 +4,7 @@
 
 #include "brillo/userdb_utils.h"
 
+#include <errno.h>
 #include <grp.h>
 #include <pwd.h>
 #include <sys/types.h>
@@ -12,7 +13,7 @@
 #include <vector>
 
 #include <base/logging.h>
-#include <base/posix/eintr_wrapper.h>
+#include <base/posix/safe_strerror.h>
 
 namespace brillo {
 namespace userdb {
@@ -24,10 +25,16 @@ bool GetUserInfo(const std::string& user, uid_t* uid, gid_t* gid) {
   passwd pwd_buf;
   passwd* pwd = nullptr;
   std::vector<char> buf(buf_len);
-  if (HANDLE_EINTR(
-          getpwnam_r(user.c_str(), &pwd_buf, buf.data(), buf_len, &pwd)) ||
-      !pwd) {
-    PLOG(ERROR) << "Unable to find user " << user;
+
+  int err_num;
+  do {
+    err_num = getpwnam_r(user.c_str(), &pwd_buf, buf.data(), buf_len, &pwd);
+  } while (err_num == EINTR);
+
+  if (!pwd) {
+    LOG(ERROR) << "Unable to find user " << user << ": "
+               << (err_num ? base::safe_strerror(err_num)
+                           : "No matching record");
     return false;
   }
 
@@ -45,10 +52,16 @@ bool GetGroupInfo(const std::string& group, gid_t* gid) {
   struct group grp_buf;
   struct group* grp = nullptr;
   std::vector<char> buf(buf_len);
-  if (HANDLE_EINTR(
-          getgrnam_r(group.c_str(), &grp_buf, buf.data(), buf_len, &grp)) ||
-      !grp) {
-    PLOG(ERROR) << "Unable to find group " << group;
+
+  int err_num;
+  do {
+    err_num = getgrnam_r(group.c_str(), &grp_buf, buf.data(), buf_len, &grp);
+  } while (err_num == EINTR);
+
+  if (!grp) {
+    LOG(ERROR) << "Unable to find group " << group << ": "
+               << (err_num ? base::safe_strerror(err_num)
+                           : "No matching record");
     return false;
   }