mirror of
https://github.com/ilyakooo0/nix-bundle.git
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If the content of the appimage contains $out/bin/sh, then /bin/sh exists and system() works.
281 lines
8.0 KiB
C
281 lines
8.0 KiB
C
/**************************************************************************
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Copyright (c) 2004-16 Simon Peter
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Portions Copyright (c) 2010 RazZziel
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All Rights Reserved.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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**************************************************************************/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <libgen.h>
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#include <dirent.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sched.h>
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#include <fcntl.h>
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#include <sys/mount.h>
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#include <errno.h>
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#define die(...) \
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do { \
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fprintf(stderr, "Error: " __VA_ARGS__); \
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exit(1); \
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} while (0);
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#define PATH_MAX 4096
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#define LINE_SIZE 255
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#define err_exit(format, ...) { fprintf(stderr, format ": %s\n", ##__VA_ARGS__, strerror(errno)); exit(EXIT_FAILURE); }
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int filter (const struct dirent *dir) {
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char *p = (char*) &dir->d_name;
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p = strrchr(p, '.');
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return p && !strcmp(p, ".desktop");
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}
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static void update_map(char *mapping, char *map_file) {
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int fd;
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fd = open(map_file, O_WRONLY);
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if (fd < 0) {
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err_exit("map open");
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}
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int map_len = strlen(mapping);
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if (write(fd, mapping, map_len) != map_len) {
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err_exit("map write");
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}
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close(fd);
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}
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static void add_path(const char* name, const char* rootdir) {
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char path_buf[PATH_MAX];
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snprintf(path_buf, sizeof(path_buf), "/%s", name);
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struct stat statbuf;
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if (stat(path_buf, &statbuf) < 0) {
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fprintf(stderr, "Cannot stat %s: %s\n", path_buf, strerror(errno));
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return;
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}
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char path_buf2[PATH_MAX];
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snprintf(path_buf2, sizeof(path_buf2), "%s/%s", rootdir, name);
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mkdir(path_buf2, statbuf.st_mode & ~S_IFMT);
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if (mount(path_buf, path_buf2, "none", MS_BIND | MS_REC, NULL) < 0) {
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fprintf(stderr, "Cannot bind mount %s to %s: %s\n", path_buf, path_buf2, strerror(errno));
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}
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}
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#define SAVE_ENV_VAR(x) char *x = getenv(#x)
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#define LOAD_ENV_VAR(x) do { if (x != NULL) setenv(#x, x, 1); } while(0)
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int main(int argc, char *argv[]) {
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char *appdir = dirname(realpath("/proc/self/exe", NULL));
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if (!appdir)
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die("Could not access /proc/self/exe\n");
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char *tmpdir = getenv("TMPDIR");
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if (!tmpdir) {
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tmpdir = "/tmp";
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}
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char template[PATH_MAX];
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int needed = snprintf(template, PATH_MAX, "%s/nixXXXXXX", tmpdir);
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if (needed < 0) {
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err_exit("TMPDIR too long: '%s'", tmpdir);
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}
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char *rootdir = mkdtemp(template);
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if (!rootdir) {
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err_exit("mkdtemp(%s)", template);
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}
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int ret;
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struct dirent **namelist;
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ret = scandir(appdir, &namelist, filter, NULL);
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if (ret == 0) {
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die("No .desktop files found\n");
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} else if(ret == -1) {
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die("Could not scan directory %s\n", appdir);
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}
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/* Extract executable from .desktop file */
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FILE *f;
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char *desktop_file = malloc(LINE_SIZE);
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snprintf(desktop_file, LINE_SIZE-1, "%s/%s", appdir, namelist[0]->d_name);
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f = fopen(desktop_file, "r");
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char *line = malloc(LINE_SIZE);
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size_t n = LINE_SIZE;
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int found = 0;
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while (getline(&line, &n, f) != -1)
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{
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if (!strncmp(line,"Exec=",5))
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{
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char *p = line+5;
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while (*++p && *p != ' ' && *p != '%' && *p != '\n');
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*p = 0;
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found = 1;
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break;
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}
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}
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fclose(f);
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if (!found)
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die("Executable not found, make sure there is a line starting with 'Exec='\n");
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/* Execution */
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char *executable = basename(line+5);
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char full_exec[PATH_MAX];
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snprintf(full_exec, sizeof(full_exec), "/usr/bin/%s", executable);
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// get uid, gid before going to new namespace
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uid_t uid = getuid();
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gid_t gid = getgid();
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// "unshare" into new namespace
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if (unshare(CLONE_NEWNS | CLONE_NEWUSER) < 0) {
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err_exit("unshare()");
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}
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// add necessary system stuff to rootdir namespace
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add_path("dev", rootdir);
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add_path("proc", rootdir);
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add_path("sys", rootdir);
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add_path("run", rootdir);
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add_path("etc", rootdir);
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add_path("home", rootdir);
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// setup skeleton
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char path_buf[PATH_MAX];
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snprintf(path_buf, sizeof(path_buf), "%s/tmp", rootdir);
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mkdir(path_buf, ~0);
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snprintf(path_buf, sizeof(path_buf), "%s/var", rootdir);
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mkdir(path_buf, ~0);
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// make sure nixdir exists
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struct stat statbuf2;
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if (stat(appdir, &statbuf2) < 0) {
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err_exit("stat(%s)", appdir);
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}
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char nixdir[PATH_MAX];
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snprintf(nixdir, sizeof(nixdir), "%s/nix", appdir);
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snprintf(path_buf, sizeof(path_buf), "%s/nix", rootdir);
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mkdir(path_buf, statbuf2.st_mode & ~S_IFMT);
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if (mount(nixdir, path_buf, "none", MS_BIND | MS_REC, NULL) < 0) {
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err_exit("mount(%s, %s)", nixdir, path_buf);
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}
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char usrdir[PATH_MAX];
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snprintf(usrdir, sizeof(usrdir), "%s/usr", appdir);
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snprintf(path_buf, sizeof(path_buf), "%s/usr", rootdir);
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mkdir(path_buf, statbuf2.st_mode & ~S_IFMT);
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if (mount(usrdir, path_buf, "none", MS_BIND | MS_REC, NULL) < 0) {
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err_exit("mount(%s, %s)", usrdir, path_buf);
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}
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snprintf(path_buf, sizeof(path_buf), "%s/bin", rootdir);
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if (symlink("/usr/bin", path_buf) < 0) {
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err_exit("symlink(/usr/bin, %s)", path_buf);
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}
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// fixes issue #1 where writing to /proc/self/gid_map fails
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// see user_namespaces(7) for more documentation
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int fd_setgroups = open("/proc/self/setgroups", O_WRONLY);
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if (fd_setgroups > 0) {
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write(fd_setgroups, "deny", 4);
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}
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// map the original uid/gid in the new ns
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char map_buf[1024];
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snprintf(map_buf, sizeof(map_buf), "%d %d 1", uid, uid);
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update_map(map_buf, "/proc/self/uid_map");
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snprintf(map_buf, sizeof(map_buf), "%d %d 1", gid, gid);
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update_map(map_buf, "/proc/self/gid_map");
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// chroot to rootdir
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if (chroot(rootdir) < 0) {
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err_exit("chroot(%s)", rootdir);
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}
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char *pwddir = getenv("PWD");
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chdir(pwddir);
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SAVE_ENV_VAR(PWD);
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SAVE_ENV_VAR(DBUS_SESSION_BUS_ADDRESS);
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SAVE_ENV_VAR(USER);
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SAVE_ENV_VAR(HOSTNAME);
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SAVE_ENV_VAR(LANG);
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SAVE_ENV_VAR(LC_ALL);
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SAVE_ENV_VAR(TERM);
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SAVE_ENV_VAR(DISPLAY);
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SAVE_ENV_VAR(XDG_RUNTIME_DIR);
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SAVE_ENV_VAR(XAUTHORITY);
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SAVE_ENV_VAR(XDG_SESSION_ID);
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SAVE_ENV_VAR(XDG_SEAT);
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SAVE_ENV_VAR(HOME);
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clearenv();
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LOAD_ENV_VAR(PWD);
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LOAD_ENV_VAR(DBUS_SESSION_BUS_ADDRESS);
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LOAD_ENV_VAR(USER);
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LOAD_ENV_VAR(HOSTNAME);
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LOAD_ENV_VAR(LANG);
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LOAD_ENV_VAR(LC_ALL);
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LOAD_ENV_VAR(TERM);
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LOAD_ENV_VAR(DISPLAY);
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LOAD_ENV_VAR(XDG_RUNTIME_DIR);
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LOAD_ENV_VAR(XAUTHORITY);
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LOAD_ENV_VAR(XDG_SESSION_ID);
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LOAD_ENV_VAR(XDG_SEAT);
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LOAD_ENV_VAR(HOME);
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setenv("PATH", ENV_PATH, 1);
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setenv("TMPDIR", "/tmp", 1);
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/* Run */
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// FIXME: What about arguments in the Exec= line of the desktop file?
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ret = execvp(full_exec, argv);
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if (ret == -1)
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die("Error executing '%s'; return code: %d\n", full_exec, ret);
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free(line);
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free(desktop_file);
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return 0;
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}
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