src/runtime.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2004-18 Simon Peter
   4  * Portions Copyright (c) 2007 Alexander Larsson
   5  *
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #ident "AppImage by Simon Peter, http://appimage.org/"
  29
  30 #define _GNU_SOURCE
  31
  32 #include "squashfuse.h"
  33 #include <squashfs_fs.h>
  34 #include <nonstd.h>
  35
  36 #include <limits.h>
  37 #include <stdlib.h>
  38 #include <sys/types.h>
  39 #include <sys/stat.h>
  40 #include <fcntl.h>
  41 #include <stdio.h>
  42 #include <signal.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45 #include <pthread.h>
  46 #include <errno.h>
  47 #include <wait.h>
  48
  49 #include "elf.h"
  50 #include "getsection.h"
  51
  52 #ifndef ENABLE_DLOPEN
  53 #define ENABLE_DLOPEN
  54 #endif
  55 #include "squashfuse_dlopen.h"
  56
  57 #include <fnmatch.h>
  58
  59 //#include "notify.c"
  60 extern int notify(char *title, char *body, int timeout);
  61
  62 struct stat st;
  63
  64 static long unsigned int fs_offset; // The offset at which a filesystem image is expected = end of this ELF
  65
  66 static void die(const char *msg) {
  67     fprintf(stderr, "%s\n", msg);
  68     exit(1);
  69 }
  70
  71 /* Check whether directory is writable */
  72 bool is_writable_directory(char* str) {
  73     if(access(str, W_OK) == 0) {
  74         return true;
  75     } else {
  76         return false;
  77     }
  78 }
  79
  80 bool startsWith(const char *pre, const char *str)
  81 {
  82     size_t lenpre = strlen(pre),
  83     lenstr = strlen(str);
  84     return lenstr < lenpre ? false : strncmp(pre, str, lenpre) == 0;
  85 }
  86
  87 /* Fill in a stat structure. Does not set st_ino */
  88 sqfs_err private_sqfs_stat(sqfs *fs, sqfs_inode *inode, struct stat *st) {
  89         sqfs_err err = SQFS_OK;
  90         uid_t id;
  91
  92         memset(st, 0, sizeof(*st));
  93         st->st_mode = inode->base.mode;
  94         st->st_nlink = inode->nlink;
  95         st->st_mtime = st->st_ctime = st->st_atime = inode->base.mtime;
  96
  97         if (S_ISREG(st->st_mode)) {
  98                 /* FIXME: do symlinks, dirs, etc have a size? */
  99                 st->st_size = inode->xtra.reg.file_size;
 100                 st->st_blocks = st->st_size / 512;
 101         } else if (S_ISBLK(st->st_mode) || S_ISCHR(st->st_mode)) {
 102                 st->st_rdev = sqfs_makedev(inode->xtra.dev.major,
 103                         inode->xtra.dev.minor);
 104         } else if (S_ISLNK(st->st_mode)) {
 105                 st->st_size = inode->xtra.symlink_size;
 106         }
 107
 108         st->st_blksize = fs->sb.block_size; /* seriously? */
 109
 110         err = sqfs_id_get(fs, inode->base.uid, &id);
 111         if (err)
 112                 return err;
 113         st->st_uid = id;
 114         err = sqfs_id_get(fs, inode->base.guid, &id);
 115         st->st_gid = id;
 116         if (err)
 117                 return err;
 118
 119         return SQFS_OK;
 120 }
 121
 122 /* ================= End ELF parsing */
 123
 124 extern int fusefs_main(int argc, char *argv[], void (*mounted) (void));
 125 // extern void ext2_quit(void);
 126
 127 static pid_t fuse_pid;
 128 static int keepalive_pipe[2];
 129
 130 static void *
 131 write_pipe_thread (void *arg)
 132 {
 133     char c[32];
 134     int res;
 135     //  sprintf(stderr, "Called write_pipe_thread");
 136     memset (c, 'x', sizeof (c));
 137     while (1) {
 138         /* Write until we block, on broken pipe, exit */
 139         res = write (keepalive_pipe[1], c, sizeof (c));
 140         if (res == -1) {
 141             kill (fuse_pid, SIGHUP);
 142             break;
 143         }
 144     }
 145     return NULL;
 146 }
 147
 148 void
 149 fuse_mounted (void)
 150 {
 151     pthread_t thread;
 152     fuse_pid = getpid();
 153     pthread_create(&thread, NULL, write_pipe_thread, keepalive_pipe);
 154 }
 155
 156 char* getArg(int argc, char *argv[],char chr)
 157 {
 158     int i;
 159     for (i=1; i<argc; ++i)
 160         if ((argv[i][0]=='-') && (argv[i][1]==chr))
 161             return &(argv[i][2]);
 162         return NULL;
 163 }
 164
 165 /* mkdir -p implemented in C, needed for https://github.com/AppImage/AppImageKit/issues/333
 166  * https://gist.github.com/JonathonReinhart/8c0d90191c38af2dcadb102c4e202950 */
 167 int
 168 mkdir_p(const char *path)
 169 {
 170     /* Adapted from http://stackoverflow.com/a/2336245/119527 */
 171     const size_t len = strlen(path);
 172     char _path[PATH_MAX];
 173     char *p;
 174
 175     errno = 0;
 176
 177     /* Copy string so its mutable */
 178     if (len > sizeof(_path)-1) {
 179         errno = ENAMETOOLONG;
 180         return -1;
 181     }
 182     strcpy(_path, path);
 183
 184     /* Iterate the string */
 185     for (p = _path + 1; *p; p++) {
 186         if (*p == '/') {
 187             /* Temporarily truncate */
 188             *p = '\0';
 189
 190             if (mkdir(_path, S_IRWXU) != 0) {
 191                 if (errno != EEXIST)
 192                     return -1;
 193             }
 194
 195             *p = '/';
 196         }
 197     }
 198
 199     if (mkdir(_path, S_IRWXU) != 0) {
 200         if (errno != EEXIST)
 201             return -1;
 202     }
 203
 204     return 0;
 205 }
 206
 207 void
 208 print_help(const char *appimage_path)
 209 {
 210     // TODO: "--appimage-list                 List content from embedded filesystem image\n"
 211     printf(
 212         "AppImage options:\n\n"
 213         "  --appimage-extract              Extract content from embedded filesystem image\n"
 214         "  --appimage-help                 Print this help\n"
 215         "  --appimage-mount                Mount embedded filesystem image and print\n"
 216         "                                  mount point and wait for kill with Ctrl-C\n"
 217         "  --appimage-offset               Print byte offset to start of embedded\n"
 218         "                                  filesystem image\n"
 219         "  --appimage-portable-home        Create a portable home folder to use as $HOME\n"
 220         "  --appimage-portable-config      Create a portable config folder to use as\n"
 221         "                                  $XDG_CONFIG_HOME\n"
 222         "  --appimage-signature            Print digital signature embedded in AppImage\n"
 223         "  --appimage-updateinfo[rmation]  Print update info embedded in AppImage\n"
 224         "  --appimage-version              Print version of AppImageKit\n"
 225         "\n"
 226         "Portable home:\n"
 227         "\n"
 228         "  If you would like the application contained inside this AppImage to store its\n"
 229         "  data alongside this AppImage rather than in your home directory, then you can\n"
 230         "  place a directory named\n"
 231         "\n"
 232         "  %s.home\n"
 233         "\n"
 234         "  Or you can invoke this AppImage with the --appimage-portable-home option,\n"
 235         "  which will create this directory for you. As long as the directory exists\n"
 236         "  and is neither moved nor renamed, the application contained inside this\n"
 237         "  AppImage to store its data in this directory rather than in your home\n"
 238         "  directory\n"
 239     , appimage_path);
 240 }
 241
 242 void
 243 portable_option(const char *arg, const char *appimage_path, const char *name)
 244 {
 245     char option[32];
 246     sprintf(option, "appimage-portable-%s", name);
 247
 248     if (arg && strcmp(arg, option)==0) {
 249         char portable_dir[PATH_MAX];
 250         char fullpath[PATH_MAX];
 251
 252         ssize_t length = readlink(appimage_path, fullpath, sizeof(fullpath));
 253         if (length < 0) {
 254             printf("Error getting realpath for %s\n", appimage_path);
 255             exit(EXIT_FAILURE);
 256         }
 257         fullpath[length] = '\0';
 258
 259         sprintf(portable_dir, "%s.%s", fullpath, name);
 260         if (!mkdir(portable_dir, S_IRWXU))
 261             printf("Portable %s directory created at %s\n", name, portable_dir);
 262         else
 263             printf("Error creating portable %s directory at %s: %s\n", name, portable_dir, strerror(errno));
 264
 265         exit(0);
 266     }
 267 }
 268
 269 int
 270 main (int argc, char *argv[])
 271 {
 272     char appimage_path[PATH_MAX];
 273     char argv0_path[PATH_MAX];
 274     char * arg;
 275
 276     /* We might want to operate on a target appimage rather than this file itself,
 277      * e.g., for appimaged which must not run untrusted code from random AppImages.
 278      * This variable is intended for use by e.g., appimaged and is subject to
 279      * change any time. Do not rely on it being present. We might even limit this
 280      * functionality specifically for builds used by appimaged.
 281      */
 282     if(getenv("TARGET_APPIMAGE") == NULL){
 283         sprintf(appimage_path, "/proc/self/exe");
 284     } else {
 285         sprintf(appimage_path, "%s", getenv("TARGET_APPIMAGE"));
 286         fprintf(stderr, "Using TARGET_APPIMAGE %s\n", appimage_path);
 287     }
 288
 289     sprintf(argv0_path, argv[0]);
 290
 291     fs_offset = get_elf_size(appimage_path);
 292
 293     arg=getArg(argc,argv,'-');
 294
 295     /* Print the help and then exit */
 296     if(arg && strcmp(arg,"appimage-help")==0) {
 297         char fullpath[PATH_MAX];
 298
 299         ssize_t length = readlink(appimage_path, fullpath, sizeof(fullpath));
 300         if (length < 0) {
 301             printf("Error getting realpath for %s\n", appimage_path);
 302             exit(EXIT_FAILURE);
 303         }
 304         fullpath[length] = '\0';
 305
 306         print_help(fullpath);
 307         exit(0);
 308     }
 309
 310     /* Just print the offset and then exit */
 311     if(arg && strcmp(arg,"appimage-offset")==0) {
 312         printf("%lu\n", fs_offset);
 313         exit(0);
 314     }
 315
 316     /* Exract the AppImage */
 317     arg=getArg(argc,argv,'-');
 318     if(arg && strcmp(arg,"appimage-extract")==0) {
 319         sqfs_err err = SQFS_OK;
 320         sqfs_traverse trv;
 321         sqfs fs;
 322         char *pattern;
 323         char *prefix;
 324         char prefixed_path_to_extract[1024];
 325
 326         prefix = "squashfs-root/";
 327
 328         if(access(prefix, F_OK ) == -1 ) {
 329             if (mkdir_p(prefix) == -1) {
 330                 perror("mkdir_p error");
 331                 exit(EXIT_FAILURE);
 332             }
 333         }
 334
 335         if(argc == 3){
 336             pattern = argv[2];
 337             if (pattern[0] == '/') pattern++; // Remove leading '/'
 338         }
 339
 340         if ((err = sqfs_open_image(&fs, appimage_path, fs_offset)))
 341             exit(1);
 342
 343         if ((err = sqfs_traverse_open(&trv, &fs, sqfs_inode_root(&fs))))
 344             die("sqfs_traverse_open error");
 345         while (sqfs_traverse_next(&trv, &err)) {
 346             if (!trv.dir_end) {
 347                 if((argc != 3) || (fnmatch (pattern, trv.path, FNM_FILE_NAME) == 0)){
 348                     // fprintf(stderr, "trv.path: %s\n", trv.path);
 349                     // fprintf(stderr, "sqfs_inode_id: %lu\n", trv.entry.inode);
 350                     sqfs_inode inode;
 351                     if (sqfs_inode_get(&fs, &inode, trv.entry.inode))
 352                         die("sqfs_inode_get error");
 353                     // fprintf(stderr, "inode.base.inode_type: %i\n", inode.base.inode_type);
 354                     // fprintf(stderr, "inode.xtra.reg.file_size: %lu\n", inode.xtra.reg.file_size);
 355                     strcpy(prefixed_path_to_extract, "");
 356                     strcat(strcat(prefixed_path_to_extract, prefix), trv.path);
 357                     fprintf(stderr, "%s\n", prefixed_path_to_extract);
 358                     if(inode.base.inode_type == SQUASHFS_DIR_TYPE || inode.base.inode_type == SQUASHFS_LDIR_TYPE){
 359                         // fprintf(stderr, "inode.xtra.dir.parent_inode: %ui\n", inode.xtra.dir.parent_inode);
 360                         // fprintf(stderr, "mkdir_p: %s/\n", prefixed_path_to_extract);
 361                         if(access(prefixed_path_to_extract, F_OK ) == -1 ) {
 362                             if (mkdir_p(prefixed_path_to_extract) == -1) {
 363                                 perror("mkdir_p error");
 364                                 exit(EXIT_FAILURE);
 365                             }
 366                         }
 367                     } else if(inode.base.inode_type == SQUASHFS_REG_TYPE || inode.base.inode_type == SQUASHFS_LREG_TYPE){
 368                         // fprintf(stderr, "Extract to: %s\n", prefixed_path_to_extract);
 369                         if(private_sqfs_stat(&fs, &inode, &st) != 0)
 370                             die("private_sqfs_stat error");
 371                         // Read the file in chunks
 372                         off_t bytes_already_read = 0;
 373                         sqfs_off_t bytes_at_a_time = 64*1024;
 374                         FILE * f;
 375                         f = fopen (prefixed_path_to_extract, "w+");
 376                         if (f == NULL)
 377                             die("fopen error");
 378                         while (bytes_already_read < inode.xtra.reg.file_size)
 379                         {
 380                             char buf[bytes_at_a_time];
 381                             if (sqfs_read_range(&fs, &inode, (sqfs_off_t) bytes_already_read, &bytes_at_a_time, buf))
 382                                 die("sqfs_read_range error");
 383                             // fwrite(buf, 1, bytes_at_a_time, stdout);
 384                             fwrite(buf, 1, bytes_at_a_time, f);
 385                             bytes_already_read = bytes_already_read + bytes_at_a_time;
 386                         }
 387                         fclose(f);
 388                         chmod (prefixed_path_to_extract, st.st_mode);
 389                     } else if(inode.base.inode_type == SQUASHFS_SYMLINK_TYPE){
 390                         size_t size;
 391                         sqfs_readlink(&fs, &inode, NULL, &size);
 392                         char buf[size];
 393                         int ret = sqfs_readlink(&fs, &inode, buf, &size);
 394                         if (ret != 0)
 395                             die("symlink error");
 396                         // fprintf(stderr, "Symlink: %s to %s \n", prefixed_path_to_extract, buf);
 397                         unlink(prefixed_path_to_extract);
 398                         ret = symlink(buf, prefixed_path_to_extract);
 399                         if (ret != 0)
 400                             die("symlink error");
 401                     } else {
 402                         fprintf(stderr, "TODO: Implement inode.base.inode_type %i\n", inode.base.inode_type);
 403                     }
 404                     // fprintf(stderr, "\n");
 405                 }
 406             }
 407         }
 408         if (err)
 409             die("sqfs_traverse_next error");
 410         sqfs_traverse_close(&trv);
 411         sqfs_fd_close(fs.fd);
 412         exit(0);
 413     }
 414
 415     if(arg && strcmp(arg,"appimage-version")==0) {
 416         fprintf(stderr,"Version: %s\n", GIT_COMMIT);
 417         exit(0);
 418     }
 419
 420     if(arg && (strcmp(arg,"appimage-updateinformation")==0 || strcmp(arg,"appimage-updateinfo")==0)) {
 421         unsigned long offset = 0;
 422         unsigned long length = 0;
 423         get_elf_section_offset_and_length(appimage_path, ".upd_info", &offset, &length);
 424         // printf("offset: %lu\n", offset);
 425         // printf("length: %lu\n", length);
 426         // print_hex(appimage_path, offset, length);
 427         print_binary(appimage_path, offset, length);
 428         exit(0);
 429     }
 430
 431     if(arg && strcmp(arg,"appimage-signature")==0) {
 432         unsigned long offset = 0;
 433         unsigned long length = 0;
 434         get_elf_section_offset_and_length(appimage_path, ".sha256_sig", &offset, &length);
 435         // printf("offset: %lu\n", offset);
 436         // printf("length: %lu\n", length);
 437         // print_hex(appimage_path, offset, length);
 438         print_binary(appimage_path, offset, length);
 439         exit(0);
 440     }
 441
 442     portable_option(arg, appimage_path, "home");
 443     portable_option(arg, appimage_path, "config");
 444
 445     // If there is an argument starting with appimage- (but not appimage-mount which is handled further down)
 446     // then stop here and print an error message
 447     if((arg && strncmp(arg, "appimage-", 8) == 0) && (arg && strcmp(arg,"appimage-mount")!=0)) {
 448         fprintf(stderr,"--%s is not yet implemented in version %s\n", arg, GIT_COMMIT);
 449         exit(1);
 450     }
 451
 452     LOAD_LIBRARY; /* exit if libfuse is missing */
 453
 454     int dir_fd, res;
 455
 456     char mount_dir[64];
 457     int namelen = strlen(basename(argv[0]));
 458     if(namelen>6){
 459         namelen=6;
 460     }
 461     strncpy(mount_dir, "/tmp/.mount_", 12);
 462     strncpy(mount_dir+12, basename(argv[0]), namelen);
 463     strncpy(mount_dir+12+namelen, "XXXXXX", 6);
 464     mount_dir[12+namelen+6] = 0; // null terminate destination
 465
 466     char filename[100]; /* enough for mount_dir + "/AppRun" */
 467     pid_t pid;
 468     char **real_argv;
 469     int i;
 470
 471     if (mkdtemp(mount_dir) == NULL) {
 472         exit (1);
 473     }
 474
 475     if (pipe (keepalive_pipe) == -1) {
 476         perror ("pipe error");
 477         exit (1);
 478     }
 479
 480     pid = fork ();
 481     if (pid == -1) {
 482         perror ("fork error");
 483         exit (1);
 484     }
 485
 486     if (pid == 0) {
 487         /* in child */
 488
 489         char *child_argv[5];
 490
 491         /* close read pipe */
 492         close (keepalive_pipe[0]);
 493
 494         char *dir = realpath(appimage_path, NULL );
 495
 496         char options[100];
 497         sprintf(options, "ro,offset=%lu", fs_offset);
 498
 499         child_argv[0] = dir;
 500         child_argv[1] = "-o";
 501         child_argv[2] = options;
 502         child_argv[3] = dir;
 503         child_argv[4] = mount_dir;
 504
 505         if(0 != fusefs_main (5, child_argv, fuse_mounted)){
 506             char *title;
 507             char *body;
 508             title = "Cannot mount AppImage, please check your FUSE setup.";
 509             body = "You might still be able to extract the contents of this AppImage \n"
 510             "if you run it with the --appimage-extract option. \n"
 511             "See https://github.com/AppImage/AppImageKit/wiki/FUSE \n"
 512             "for more information";
 513             notify(title, body, 0); // 3 seconds timeout
 514         };
 515     } else {
 516         /* in parent, child is $pid */
 517         int c;
 518
 519         /* close write pipe */
 520         close (keepalive_pipe[1]);
 521
 522         /* Pause until mounted */
 523         read (keepalive_pipe[0], &c, 1);
 524
 525
 526         dir_fd = open (mount_dir, O_RDONLY);
 527         if (dir_fd == -1) {
 528             perror ("open dir error");
 529             exit (1);
 530         }
 531
 532         res = dup2 (dir_fd, 1023);
 533         if (res == -1) {
 534             perror ("dup2 error");
 535             exit (1);
 536         }
 537         close (dir_fd);
 538
 539         strcpy (filename, mount_dir);
 540         strcat (filename, "/AppRun");
 541
 542         real_argv = malloc (sizeof (char *) * (argc + 1));
 543         for (i = 0; i < argc; i++) {
 544             real_argv[i] = argv[i];
 545         }
 546         real_argv[i] = NULL;
 547
 548         if(arg && strcmp(arg,"appimage-mount")==0) {
 549             printf("%s\n", mount_dir);
 550             for (;;) pause();
 551         }
 552
 553         int length;
 554         char fullpath[PATH_MAX];
 555
 556         if(getenv("TARGET_APPIMAGE") == NULL){
 557             // If we are operating on this file itself
 558             length = readlink(appimage_path, fullpath, sizeof(fullpath));
 559             fullpath[length] = '\0';
 560         } else {
 561             // If we are operating on a different AppImage than this file
 562             sprintf(fullpath, "%s", appimage_path); // TODO: Make absolute
 563         }
 564
 565         /* Setting some environment variables that the app "inside" might use */
 566         setenv( "APPIMAGE", fullpath, 1 );
 567         setenv( "ARGV0", argv0_path, 1 );
 568         setenv( "APPDIR", mount_dir, 1 );
 569
 570         char portable_home_dir[PATH_MAX];
 571         char portable_config_dir[PATH_MAX];
 572
 573         /* If there is a directory with the same name as the AppImage plus ".home", then export $HOME */
 574         strcpy (portable_home_dir, fullpath);
 575         strcat (portable_home_dir, ".home");
 576         if(is_writable_directory(portable_home_dir)){
 577             printf("Setting $HOME to %s\n", portable_home_dir);
 578             setenv("HOME",portable_home_dir,1);
 579         }
 580
 581         /* If there is a directory with the same name as the AppImage plus ".config", then export $XDG_CONFIG_HOME */
 582         strcpy (portable_config_dir, fullpath);
 583         strcat (portable_config_dir, ".config");
 584         if(is_writable_directory(portable_config_dir)){
 585             printf("Setting $XDG_CONFIG_HOME to %s\n", portable_config_dir);
 586             setenv("XDG_CONFIG_HOME",portable_config_dir,1);
 587         }
 588
 589         /* Original working directory */
 590         char cwd[1024];
 591         if (getcwd(cwd, sizeof(cwd)) != NULL) {
 592             setenv( "OWD", cwd, 1 );
 593         }
 594
 595         /* If we are operating on an AppImage different from this file,
 596          * then we do not execute the payload */
 597         if(getenv("TARGET_APPIMAGE") == NULL){
 598             /* TODO: Find a way to get the exit status and/or output of this */
 599             execv (filename, real_argv);
 600             /* Error if we continue here */
 601             perror ("execv error");
 602             exit (1);
 603         }
 604     }
 605
 606     return 0;
 607 }