qemu

bsdload.c (5435B)

---

 /*
  *  Load BSD executables.
  *
  *  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 program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #include "qemu/osdep.h"
 
 #include "qemu.h"
 
 /* ??? This should really be somewhere else.  */
 abi_long memcpy_to_target(abi_ulong dest, const void *src,
                           unsigned long len)
 {
     void *host_ptr;
 
     host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
     if (!host_ptr) {
         return -TARGET_EFAULT;
     }
     memcpy(host_ptr, src, len);
     unlock_user(host_ptr, dest, 1);
     return 0;
 }
 
 static int count(char **vec)
 {
     int         i;
 
     for (i = 0; *vec; i++) {
         vec++;
     }
 
     return i;
 }
 
 static int prepare_binprm(struct bsd_binprm *bprm)
 {
     struct stat         st;
     int mode;
     int retval;
 
     if (fstat(bprm->fd, &st) < 0) {
         return -errno;
     }
 
     mode = st.st_mode;
     if (!S_ISREG(mode)) {        /* Must be regular file */
         return -EACCES;
     }
     if (!(mode & 0111)) {        /* Must have at least one execute bit set */
         return -EACCES;
     }
 
     bprm->e_uid = geteuid();
     bprm->e_gid = getegid();
 
     /* Set-uid? */
     if (mode & S_ISUID) {
         bprm->e_uid = st.st_uid;
     }
 
     /* Set-gid? */
     /*
      * If setgid is set but no group execute bit then this
      * is a candidate for mandatory locking, not a setgid
      * executable.
      */
     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
         bprm->e_gid = st.st_gid;
     }
 
     memset(bprm->buf, 0, sizeof(bprm->buf));
     retval = lseek(bprm->fd, 0L, SEEK_SET);
     if (retval >= 0) {
         retval = read(bprm->fd, bprm->buf, 128);
     }
     if (retval < 0) {
         perror("prepare_binprm");
         exit(-1);
     } else {
         return retval;
     }
 }
 
 /* Construct the envp and argv tables on the target stack.  */
 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
                               abi_ulong stringp)
 {
     int n = sizeof(abi_ulong);
     abi_ulong envp;
     abi_ulong argv;
 
     sp -= (envc + 1) * n;
     envp = sp;
     sp -= (argc + 1) * n;
     argv = sp;
     sp -= n;
     /* FIXME - handle put_user() failures */
     put_user_ual(argc, sp);
 
     while (argc-- > 0) {
         /* FIXME - handle put_user() failures */
         put_user_ual(stringp, argv);
         argv += n;
         stringp += target_strlen(stringp) + 1;
     }
     /* FIXME - handle put_user() failures */
     put_user_ual(0, argv);
     while (envc-- > 0) {
         /* FIXME - handle put_user() failures */
         put_user_ual(stringp, envp);
         envp += n;
         stringp += target_strlen(stringp) + 1;
     }
     /* FIXME - handle put_user() failures */
     put_user_ual(0, envp);
 
     return sp;
 }
 
 static bool is_there(const char *candidate)
 {
     struct stat fin;
 
     /* XXX work around access(2) false positives for superuser */
     if (access(candidate, X_OK) == 0 && stat(candidate, &fin) == 0 &&
             S_ISREG(fin.st_mode) && (getuid() != 0 ||
                 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
         return true;
     }
 
     return false;
 }
 
 int loader_exec(const char *filename, char **argv, char **envp,
                 struct target_pt_regs *regs, struct image_info *infop,
                 struct bsd_binprm *bprm)
 {
     char *path, fullpath[PATH_MAX];
     int retval, i;
 
     bprm->p = TARGET_PAGE_SIZE * MAX_ARG_PAGES;
     for (i = 0; i < MAX_ARG_PAGES; i++) {       /* clear page-table */
         bprm->page[i] = NULL;
     }
 
     if (strchr(filename, '/') != NULL) {
         path = realpath(filename, fullpath);
         if (path == NULL) {
             /* Failed to resolve. */
             return -1;
         }
         if (!is_there(path)) {
             return -1;
         }
     } else {
         path = g_find_program_in_path(filename);
         if (path == NULL) {
             return -1;
         }
     }
 
     retval = open(path, O_RDONLY);
     if (retval < 0) {
         g_free(path);
         return retval;
     }
 
     bprm->fullpath = path;
     bprm->fd = retval;
     bprm->filename = (char *)filename;
     bprm->argc = count(argv);
     bprm->argv = argv;
     bprm->envc = count(envp);
     bprm->envp = envp;
 
     retval = prepare_binprm(bprm);
 
     if (retval >= 0) {
         if (bprm->buf[0] == 0x7f
                 && bprm->buf[1] == 'E'
                 && bprm->buf[2] == 'L'
                 && bprm->buf[3] == 'F') {
             retval = load_elf_binary(bprm, regs, infop);
         } else {
             fprintf(stderr, "Unknown binary format\n");
             return -1;
         }
     }
 
     if (retval >= 0) {
         /* success.  Initialize important registers */
         do_init_thread(regs, infop);
         return retval;
     }
 
     /* Something went wrong, return the inode and free the argument pages*/
     for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
         g_free(bprm->page[i]);
     }
     return retval;
 }