1 files changed, 124 insertions, 0 deletions

diff --git a/src/jailtest/utils.c b/src/jailtest/utils.c
new file mode 100644
index 000000000..b24783355
--- /dev/null
+++ b/src/jailtest/utils.c
@@ -0,0 +1,124 @@
+#include "jailtest.h"
+#include <errno.h>
+#include <pwd.h>
+#include <dirent.h>
+
+#define BUFLEN 4096
+
+char *get_sudo_user(void) {
+        char *user = getenv("SUDO_USER");
+        if (!user) {
+                user = getpwuid(getuid())->pw_name;
+                if (!user) {
+                        fprintf(stderr, "Error: cannot detect login user\n");
+                        exit(1);
+                }
+        }
+
+        return user;
+}
+
+char *get_homedir(const char *user, uid_t *uid, gid_t *gid) {
+        // find home directory
+        struct passwd *pw = getpwnam(user);
+        if (!pw)
+                goto errexit;
+
+        char *home = pw->pw_dir;
+        if (!home)
+                goto errexit;
+
+        *uid = pw->pw_uid;
+        *gid = pw->pw_gid;
+
+        return home;
+
+errexit:
+        fprintf(stderr, "Error: cannot find home directory for user %s\n", user);
+        exit(1);
+}
+
+int find_child(pid_t parent, pid_t *child) {
+        *child = 0;                               // use it to flag a found child
+
+        DIR *dir;
+        if (!(dir = opendir("/proc"))) {
+                // sleep 2 seconds and try again
+                sleep(2);
+                if (!(dir = opendir("/proc"))) {
+                        fprintf(stderr, "Error: cannot open /proc directory\n");
+                        exit(1);
+                }
+        }
+
+        struct dirent *entry;
+        char *end;
+        while (*child == 0 && (entry = readdir(dir))) {
+                pid_t pid = strtol(entry->d_name, &end, 10);
+                if (end == entry->d_name || *end)
+                        continue;
+                if (pid == parent)
+                        continue;
+
+                // open stat file
+                char *file;
+                if (asprintf(&file, "/proc/%u/status", pid) == -1) {
+                        perror("asprintf");
+                        exit(1);
+                }
+                FILE *fp = fopen(file, "r");
+                if (!fp) {
+                        free(file);
+                        continue;
+                }
+
+                // look for firejail executable name
+                char buf[BUFLEN];
+                while (fgets(buf, BUFLEN - 1, fp)) {
+                        if (strncmp(buf, "PPid:", 5) == 0) {
+                                char *ptr = buf + 5;
+                                while (*ptr != '\0' && (*ptr == ' ' || *ptr == '\t')) {
+                                        ptr++;
+                                }
+                                if (*ptr == '\0') {
+                                        fprintf(stderr, "Error: cannot read /proc file\n");
+                                        exit(1);
+                                }
+                                if (parent == atoi(ptr)) {
+                                        // we don't want /usr/bin/xdg-dbus-proxy!
+                                        char *cmdline = pid_proc_cmdline(pid);
+                                        if (strncmp(cmdline, XDG_DBUS_PROXY_PATH, strlen(XDG_DBUS_PROXY_PATH)) != 0)
+                                                *child = pid;
+                                        free(cmdline);
+                                }
+                                break;            // stop reading the file
+                        }
+                }
+                fclose(fp);
+                free(file);
+        }
+        closedir(dir);
+        return (*child)? 0:1;                     // 0 = found, 1 = not found
+}
+
+pid_t switch_to_child(pid_t pid) {
+        pid_t rv = pid;
+        errno = 0;
+        char *comm = pid_proc_comm(pid);
+        if (!comm) {
+                if (errno == ENOENT)
+                        fprintf(stderr, "Error: cannot find process with pid %d\n", pid);
+                else
+                        fprintf(stderr, "Error: cannot read /proc file\n");
+                exit(1);
+        }
+
+        if (strcmp(comm, "firejail") == 0) {
+                if (find_child(pid, &rv) == 1) {
+                        fprintf(stderr, "Error: no valid sandbox\n");
+                        exit(1);
+                }
+        }
+        free(comm);
+        return rv;
+}