[m25] Add quirk to support the Android L preview

* It calls restorecon_recursive /data in init.rc, which breaks multirom

multirom.c

@@ -1285,6 +1285,8 @@ int multirom_create_media_link(void)
         fclose(f);
         chmod(LAYOUT_VERSION, 0600);
     }
+
+    rom_quirks_on_android_media_link_created();
     return 0;
 }
 

rom_quirks.c

@@ -17,10 +17,15 @@
 
 #include <unistd.h>
 #include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <stdlib.h>
+#include <ctype.h>
 
 #include "multirom.h"
 #include "rom_quirks.h"
 #include "log.h"
+#include "util.h"
 
 void rom_quirks_on_android_mounted_fs(struct multirom_rom *rom)
 {
@@ -33,8 +38,140 @@ void rom_quirks_on_android_mounted_fs(struct multirom_rom *rom)
     // that file entirely.
     if(rom->type != ROM_ANDROID_USB_IMG && access("/system/etc/init.d/50selinuxrelabel", F_OK) >= 0)
     {
-        // run-parts won't run files which don't have +x
         INFO("Removing /system/etc/init.d/50selinuxrelabel.\n");
         remove("/system/etc/init.d/50selinuxrelabel");
     }
 }
+
+#define MULTIROM_DIR_ANDROID "/data/media/0/multirom"
+
+static void write_changed_restorecons(const char *path, FILE *rc)
+{
+    struct dirent *dt;
+    char *next_path = 0;
+    size_t new_len, allocd = 0;
+    const int path_len = strlen(path);
+    DIR *d = opendir(path);
+    if(!d)
+        return;
+
+    while((dt = readdir(d)))
+    {
+        if(strcmp(dt->d_name, ".") == 0 || strcmp(dt->d_name, "..") == 0)
+            continue;
+
+        if(dt->d_type == DT_DIR)
+        {
+            new_len = imax((size_t)(path_len + strlen(dt->d_name) + 2), allocd);
+            if(new_len > allocd)
+            {
+                next_path = realloc(next_path, new_len);
+                allocd = new_len;
+            }
+
+            snprintf(next_path, allocd, "%s/%s", path, dt->d_name);
+
+            if(strncmp(next_path, MULTIROM_DIR_ANDROID, strlen(next_path)) == 0)
+            {
+                if(strlen(next_path) != strlen(MULTIROM_DIR_ANDROID))
+                {
+                    fprintf(rc, "    restorecon %s/%s\n", path, dt->d_name);
+                    write_changed_restorecons(next_path, rc);
+                }
+            }
+            else
+                fprintf(rc, "    restorecon_recursive %s/%s\n", path, dt->d_name);
+        }
+        else
+            fprintf(rc, "    restorecon %s/%s\n", path, dt->d_name);
+    }
+
+    closedir(d);
+    free(next_path);
+}
+
+static void workaround_rc_restorecon(const char *rc_file_name)
+{
+    FILE *f_in, *f_out;
+    char *name_out = NULL;
+    char line[512];
+    char *r;
+    int changed = 0;
+
+    f_in = fopen(rc_file_name, "r");
+    if(!f_in)
+    {
+        ERROR("Failed to open input file %s\n", rc_file_name);
+        return;
+    }
+
+    name_out = malloc(strlen(rc_file_name)+5);
+    snprintf(name_out, strlen(rc_file_name)+5, "%s.new", rc_file_name);
+
+    f_out = fopen(name_out, "w");
+    if(!f_out)
+    {
+        ERROR("Failed to open output file %s\n", name_out);
+        fclose(f_in);
+        free(name_out);
+        return;
+    }
+
+    while(fgets(line, sizeof(line), f_in))
+    {
+        r = strstr(line, "restorecon_recursive");
+        if(r)
+        {
+            r += strlen("restorecon_recursive");
+            while(*r && isspace(*r)) ++r;
+            if(strncmp(r, "/data", 5) == 0)
+            {
+                changed = 1;
+                write_changed_restorecons("/data", f_out);
+            }
+            else
+                fputs(line, f_out);
+        }
+        else
+            fputs(line, f_out);
+    }
+
+    fclose(f_out);
+    fclose(f_in);
+
+    if(changed)
+    {
+        rename(name_out, rc_file_name);
+        chmod(rc_file_name, 0750);
+    }
+    else
+        unlink(name_out);
+    free(name_out);
+}
+
+void rom_quirks_on_android_media_link_created(void)
+{
+    // The Android L preview (and presumably later releases) have SELinux
+    // set to "enforcing" and "restorecon_recursive /data" line in init.rc.
+    // Restorecon on /data goes into /data/media/0/multirom/roms/ and changes
+    // context of all secondary ROMs files to that of /data, including the files
+    // in secondary ROMs /system dirs. We need to prevent that.
+    DIR *d = opendir("/");
+    if(d)
+    {
+        struct dirent *dt;
+        char buff[128];
+        while((dt = readdir(d)))
+        {
+            if(dt->d_type != DT_REG)
+                continue;
+
+            if(strstr(dt->d_name, ".rc"))
+            {
+                snprintf(buff, sizeof(buff), "/%s", dt->d_name);
+                workaround_rc_restorecon(buff);
+            }
+        }
+        closedir(d);
+    }
+}

rom_quirks.h

@@ -20,5 +20,6 @@
 struct multirom_rom;
 
 void rom_quirks_on_android_mounted_fs(struct multirom_rom *rom);
+void rom_quirks_on_android_media_link_created(void);
 
 #endif

version.h

@@ -17,7 +17,7 @@
 
 #ifndef VERSION_H
 #define VERSION_H
-    #define VERSION_MULTIROM 24
+    #define VERSION_MULTIROM 25
     #define VERSION_TRAMPOLINE 14
 
     // For device-specific fixes. Use letters, the version will then be like "12a"