/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * * Copyright (C) 2017 Sebastian Leonhardt * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "plugin.h" /** * Follow Windows shortcuts (*.lnk files) in Rockbox. * If the destination is a file, it will be selected in the file browser, * a directory will be entered. * For now, only relative links are supported. */ /* a selection of link flags */ #define HAS_LINK_TARGET_ID_LIST 0x01 #define HAS_LINK_INFO 0x02 #define HAS_NAME 0x04 #define HAS_RELATIVE_PATH 0x08 #define HAS_WORKING_DIR 0x10 #define HAS_ARGUMENTS 0x20 #define HAS_ICON_LOCATION 0x40 #define IS_UNICODE 0x80 #define FORCE_NO_LINK_INFO 0x100 /* a selection of file attributes flags */ #define FILE_ATTRIBUTE_DIRECTORY 0x10 #define FILE_ATTRIBUTE_NORMAL 0x80 /** * Read one byte from file * \param fd file descriptor * \param *a where the data should go * \return false if an error occured, true on success */ static bool read_byte(const int fd, unsigned char *a) { if (!rb->read(fd, a, 1)) return false; return true; } /** * Read 16-bit word from file, respecting windows endianness (little endian) * \param fd file descriptor * \param *a where the data should go * \return false if an error occured, true on success */ static bool read_word(const int fd, int *a) { unsigned char a1,a2; int r; r = read_byte(fd, &a1); if (!r) return false; r = read_byte(fd, &a2); if (!r) return false; *a = (a2<<8) + a1; return true; } /** * Read 32-bit word from file, respecting windows endianness (little endian) * \param fd file descriptor * \param *a where the data should go * \return false if an error occured, true on success */ static bool read_lword(const int fd, uint32_t *a) { int a1,a2; int r; r = read_word(fd, &a1); if (!r) return false; r = read_word(fd, &a2); if (!r) return false; *a = (a2<<16) + a1; return true; } /** * Scan *.lnk file for relative link target * \param fd file descriptor * \param link_target the extracted link destination * \param target_size available space for the extracted link (in bytes) * \param link_flags the link flags are stored here * \param file_atts file attributes are stored here * \return returns false if extraction failed. */ static bool extract_link_destination(const int fd, char *link_target, const int target_size, uint32_t *link_flags, uint32_t *file_atts) { int r; /* Read ShellLinkHeader */ uint32_t size; r = read_lword(fd, &size); if (!r) return false; if (size!=0x4c) { /* header size MUST be 76 bytes */ DEBUGF("unexpected header size 0x%08x (must be 0x0000004c)\n", size); return false; } /* Skip LinkCLSID (class identifier) */ rb->lseek(fd, 0x10, SEEK_CUR); /* We need the LinkFlags and File attribute (to see if target is a directory) */ r = read_lword(fd, link_flags); if (!r) return false; r = read_lword(fd, file_atts); if (!r) return false; rb->lseek(fd, size, SEEK_SET); /* Skip to end of header */ /* For now we only support relative links, so we can exit right away if no relative link structure is present */ if (!(*link_flags & HAS_RELATIVE_PATH)) { DEBUGF("Link doesn't have relative path information\n"); return false; } /* Read (skip) LinkTargetIDList structure if present */ if (*link_flags & HAS_LINK_TARGET_ID_LIST) { int size; if (!read_word(fd, &size)) return false; rb->lseek(fd, size, SEEK_CUR); } /* Read (skip) LinkInfo structure if present */ if (*link_flags & HAS_LINK_INFO) { uint32_t size; r = read_lword(fd, &size); if (!r) return false; rb->lseek(fd, size-4, SEEK_CUR); } /* String Data section */ /* Read (skip) NAME_STRING StringData structure if present */ if (*link_flags & HAS_NAME) { int ccount; if (!read_word(fd, &ccount)) return false; if (*link_flags & IS_UNICODE) rb->lseek(fd, ccount*2, SEEK_CUR); else rb->lseek(fd, ccount, SEEK_CUR); } /* Read RELATIVE_PATH StringData structure if present */ /* This is finally the data we are searching for! */ if (*link_flags & HAS_RELATIVE_PATH) { int ccount; r = read_word(fd, &ccount); if (!r) return false; if (*link_flags & IS_UNICODE) { unsigned char utf16[4], utf8[10]; link_target[0] = '\0'; for (int i=0; i= 0xD8 && utf16[1] < 0xE0) { r = read_byte(fd, &utf16[2]); if (!r) return false; r = read_byte(fd, &utf16[3]); if (!r) return false; ++i; } char *ptr = rb->utf16LEdecode(utf16, utf8, 1); *ptr = '\0'; rb->strlcat(link_target, utf8, target_size); } } else { /* non-unicode */ if (ccount >= target_size) { DEBUGF("ERROR: link target filename exceeds size!"); return false; } rb->read(fd, link_target, ccount); link_target[ccount] = '\0'; } } /* convert from windows to unix subdir separators */ for (int i=0; link_target[i] != '\0'; ++i) { if (link_target[i]=='\\') link_target[i] = '/'; } return true; } /** * strip rightmost part of file/pathname to next '/', i.e. remove filename * or last subdirectory. Leaves a trailing '/' character. * \param pathname full path or filename */ static void strip_rightmost_part(char *pathname) { for (int i = rb->strlen(pathname)-2; i >= 0; --i) { if (pathname[i] == '/') { pathname[i+1] = '\0'; /* cut off */ return; } } pathname[0] = '\0'; } /** * Combine link file's absolute path with relative link target to form * (absolute) link destination * \param abs_path full shortcut filename (including path) * \param rel_path the extracted relative link target * \param max_len maximum lengt of combined filename */ static void assemble_link_dest(char *const abs_path, char const *rel_path, const size_t max_len) { strip_rightmost_part(abs_path); /* cut off link filename */ for (;;) { if (rb->strncmp(rel_path, "../", 3)==0) { rel_path += 3; strip_rightmost_part(abs_path); } else if (rb->strncmp(rel_path, "./", 2)==0) { rel_path += 2; } else break; } if (*rel_path=='/') ++rel_path; /* avoid double '/' chars when concatenating */ rb->strlcat(abs_path, rel_path, max_len); } /** * Select the chosen file in the file browser. A directory (filename ending * with '/') will be entered. * \param link_target link target to be selected in the browser * \return returns false if the target doesn't exist */ static bool goto_entry(char *link_target) { DEBUGF("Trying to go to '%s'...\n", link_target); if (!rb->file_exists(link_target)) return false; /* Set the browsers dirfilter to the global setting. * This is required in case the plugin was launched * from the plugins browser, in which case the * dirfilter is set to only display .rock files */ rb->set_dirfilter(rb->global_settings->dirfilter); /* Change directory to the entry selected by the user */ rb->set_current_file(link_target); return true; } enum plugin_status plugin_start(const void* void_parameter) { char *link_filename; char extracted_link[MAX_PATH]; char link_target[MAX_PATH]; uint32_t lnk_flags; uint32_t file_atts; /* This is a viewer, so a parameter must have been specified */ if (void_parameter == NULL) { rb->splash(HZ*3, "No *.lnk file selected"); return PLUGIN_OK; } link_filename = (char*)void_parameter; DEBUGF("Shortcut filename: \"%s\"\n", link_filename); int fd = rb->open(link_filename, O_RDONLY); if (fd < 0) { DEBUGF("Can't open link file\n"); rb->splashf(HZ*3, "Can't open link file!"); return PLUGIN_OK; } if (!extract_link_destination(fd, extracted_link, sizeof(extracted_link), &lnk_flags, &file_atts)) { rb->close(fd); DEBUGF("Error in extract_link_destination()\n"); rb->splashf(HZ*3, "Unsupported or erroneous link file format"); return PLUGIN_OK; } rb->close(fd); DEBUGF("Shortcut destination: \"%s\"\n", extracted_link); rb->strcpy(link_target, link_filename); assemble_link_dest(link_target, extracted_link, sizeof(link_target)); DEBUGF("Link absolute path: \"%s\"\n", link_target); /* if target is a directory, add '/' to the dir name, so that the directory gets entered instead of just highlighted */ if (file_atts & FILE_ATTRIBUTE_DIRECTORY) if (link_target[rb->strlen(link_target)-1] != '/') rb->strlcat(link_target, "/", sizeof(link_target)); if (!goto_entry(link_target)) { char *what; if (file_atts & FILE_ATTRIBUTE_DIRECTORY) what = "directory"; else what = "file"; rb->splashf(HZ*3, "Can't find %s %s", what, link_target); DEBUGF("Can't find %s %s", what, link_target); return PLUGIN_OK; } return PLUGIN_OK; }