Rewrite libpackagelistparser.

I was happy to ignore this as long as it wasn't being touched, but it's
been modified twice in the last year. Time to just throw it out and
rewrite it.

Also add some basic tests and put them in presubmit.

Bug: http://b/127686429
Test: new tests
Change-Id: Ie7e9406521291de0eab3138f55068cee6aaf365a

1 files changed, 143 insertions, 0 deletions

diff --git a/libpackagelistparser/packagelistparser.cpp b/libpackagelistparser/packagelistparser.cpp
new file mode 100644
index 000000000..ddf558b5b
--- /dev/null
+++ b/libpackagelistparser/packagelistparser.cpp
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "packagelistparser"
+
+#include <packagelistparser/packagelistparser.h>
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/limits.h>
+
+#include <memory>
+
+#include <log/log.h>
+
+static bool parse_gids(const char* path, size_t line_number, const char* gids, pkg_info* info) {
+  // Nothing to do?
+  if (!gids || !strcmp(gids, "none")) return true;
+
+  // How much space do we need?
+  info->gids.cnt = 1;
+  for (const char* p = gids; *p; ++p) {
+    if (*p == ',') ++info->gids.cnt;
+  }
+
+  // Allocate the space.
+  info->gids.gids = new gid_t[info->gids.cnt];
+  if (!info->gids.gids) return false;
+
+  // And parse the individual gids.
+  size_t i = 0;
+  while (true) {
+    char* end;
+    unsigned long gid = strtoul(gids, &end, 10);
+    if (gid > GID_MAX) {
+      ALOGE("%s:%zu: gid %lu > GID_MAX", path, line_number, gid);
+      return false;
+    }
+
+    if (i >= info->gids.cnt) return false;
+    info->gids.gids[i++] = gid;
+
+    if (*end == '\0') return true;
+    if (*end != ',') return false;
+    gids = end + 1;
+  }
+  return true;
+}
+
+static bool parse_line(const char* path, size_t line_number, const char* line, pkg_info* info) {
+  unsigned long uid;
+  int debuggable;
+  char* gid_list;
+  int profileable_from_shell = 0;
+
+  int fields =
+      sscanf(line, "%ms %lu %d %ms %ms %ms %d %ld", &info->name, &uid, &debuggable, &info->data_dir,
+             &info->seinfo, &gid_list, &profileable_from_shell, &info->version_code);
+
+  // Handle the more complicated gids field and free the temporary string.
+  bool gids_okay = parse_gids(path, line_number, gid_list, info);
+  free(gid_list);
+  if (!gids_okay) return false;
+
+  // Did we see enough fields to be getting on with?
+  // The final fields are optional (and not usually present).
+  if (fields < 6) {
+    ALOGE("%s:%zu: too few fields in line", path, line_number);
+    return false;
+  }
+
+  // Extra validation.
+  if (uid > UID_MAX) {
+    ALOGE("%s:%zu: uid %lu > UID_MAX", path, line_number, uid);
+    return false;
+  }
+  info->uid = uid;
+
+  // Integer to bool conversions.
+  if (debuggable != 0 && debuggable != 1) return false;
+  info->debuggable = debuggable;
+
+  if (profileable_from_shell != 0 && profileable_from_shell != 1) return false;
+  info->profileable_from_shell = profileable_from_shell;
+
+  return true;
+}
+
+bool packagelist_parse_file(const char* path, bool (*callback)(pkg_info*, void*), void* user_data) {
+  std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(path, "re"), &fclose);
+  if (!fp) {
+    ALOGE("couldn't open '%s': %s", path, strerror(errno));
+    return false;
+  }
+
+  size_t line_number = 0;
+  char* line = nullptr;
+  size_t allocated_length = 0;
+  while (getline(&line, &allocated_length, fp.get()) > 0) {
+    ++line_number;
+    std::unique_ptr<pkg_info, decltype(&packagelist_free)> info(
+        static_cast<pkg_info*>(calloc(1, sizeof(pkg_info))), &packagelist_free);
+    if (!info) {
+      ALOGE("%s:%zu: couldn't allocate pkg_info", path, line_number);
+      return false;
+    }
+
+    if (!parse_line(path, line_number, line, info.get())) return false;
+
+    if (!callback(info.release(), user_data)) break;
+  }
+  free(line);
+  return true;
+}
+
+bool packagelist_parse(bool (*callback)(pkg_info*, void*), void* user_data) {
+  return packagelist_parse_file("/data/system/packages.list", callback, user_data);
+}
+
+void packagelist_free(pkg_info* info) {
+  if (!info) return;
+
+  free(info->name);
+  free(info->data_dir);
+  free(info->seinfo);
+  delete[] info->gids.gids;
+  free(info);
+}