bsd-user/bsdload.c

   1 /*
   2  *  Load BSD executables.
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 2 of the License, or
   7  *  (at your option) any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "qemu/osdep.h"
  19
  20 #include "qemu.h"
  21
  22 /* ??? This should really be somewhere else.  */
  23 abi_long memcpy_to_target(abi_ulong dest, const void *src,
  24                           unsigned long len)
  25 {
  26     void *host_ptr;
  27
  28     host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
  29     if (!host_ptr) {
  30         return -TARGET_EFAULT;
  31     }
  32     memcpy(host_ptr, src, len);
  33     unlock_user(host_ptr, dest, 1);
  34     return 0;
  35 }
  36
  37 static int count(char **vec)
  38 {
  39     int         i;
  40
  41     for (i = 0; *vec; i++) {
  42         vec++;
  43     }
  44
  45     return i;
  46 }
  47
  48 static int prepare_binprm(struct bsd_binprm *bprm)
  49 {
  50     struct stat         st;
  51     int mode;
  52     int retval;
  53
  54     if (fstat(bprm->fd, &st) < 0) {
  55         return -errno;
  56     }
  57
  58     mode = st.st_mode;
  59     if (!S_ISREG(mode)) {        /* Must be regular file */
  60         return -EACCES;
  61     }
  62     if (!(mode & 0111)) {        /* Must have at least one execute bit set */
  63         return -EACCES;
  64     }
  65
  66     bprm->e_uid = geteuid();
  67     bprm->e_gid = getegid();
  68
  69     /* Set-uid? */
  70     if (mode & S_ISUID) {
  71         bprm->e_uid = st.st_uid;
  72     }
  73
  74     /* Set-gid? */
  75     /*
  76      * If setgid is set but no group execute bit then this
  77      * is a candidate for mandatory locking, not a setgid
  78      * executable.
  79      */
  80     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
  81         bprm->e_gid = st.st_gid;
  82     }
  83
  84     memset(bprm->buf, 0, sizeof(bprm->buf));
  85     retval = lseek(bprm->fd, 0L, SEEK_SET);
  86     if (retval >= 0) {
  87         retval = read(bprm->fd, bprm->buf, 128);
  88     }
  89     if (retval < 0) {
  90         perror("prepare_binprm");
  91         exit(-1);
  92     } else {
  93         return retval;
  94     }
  95 }
  96
  97 /* Construct the envp and argv tables on the target stack.  */
  98 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
  99                               abi_ulong stringp)
 100 {
 101     int n = sizeof(abi_ulong);
 102     abi_ulong envp;
 103     abi_ulong argv;
 104
 105     sp -= (envc + 1) * n;
 106     envp = sp;
 107     sp -= (argc + 1) * n;
 108     argv = sp;
 109     sp -= n;
 110     /* FIXME - handle put_user() failures */
 111     put_user_ual(argc, sp);
 112
 113     while (argc-- > 0) {
 114         /* FIXME - handle put_user() failures */
 115         put_user_ual(stringp, argv);
 116         argv += n;
 117         stringp += target_strlen(stringp) + 1;
 118     }
 119     /* FIXME - handle put_user() failures */
 120     put_user_ual(0, argv);
 121     while (envc-- > 0) {
 122         /* FIXME - handle put_user() failures */
 123         put_user_ual(stringp, envp);
 124         envp += n;
 125         stringp += target_strlen(stringp) + 1;
 126     }
 127     /* FIXME - handle put_user() failures */
 128     put_user_ual(0, envp);
 129
 130     return sp;
 131 }
 132
 133 static bool is_there(const char *candidate)
 134 {
 135     struct stat fin;
 136
 137     /* XXX work around access(2) false positives for superuser */
 138     if (access(candidate, X_OK) == 0 && stat(candidate, &fin) == 0 &&
 139             S_ISREG(fin.st_mode) && (getuid() != 0 ||
 140                 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
 141         return true;
 142     }
 143
 144     return false;
 145 }
 146
 147 int loader_exec(const char *filename, char **argv, char **envp,
 148                 struct target_pt_regs *regs, struct image_info *infop,
 149                 struct bsd_binprm *bprm)
 150 {
 151     char *path, fullpath[PATH_MAX];
 152     int retval, i;
 153
 154     bprm->p = TARGET_PAGE_SIZE * MAX_ARG_PAGES;
 155     for (i = 0; i < MAX_ARG_PAGES; i++) {       /* clear page-table */
 156         bprm->page[i] = NULL;
 157     }
 158
 159     if (strchr(filename, '/') != NULL) {
 160         path = realpath(filename, fullpath);
 161         if (path == NULL) {
 162             /* Failed to resolve. */
 163             return -1;
 164         }
 165         if (!is_there(path)) {
 166             return -1;
 167         }
 168     } else {
 169         path = g_find_program_in_path(filename);
 170         if (path == NULL) {
 171             return -1;
 172         }
 173     }
 174
 175     retval = open(path, O_RDONLY);
 176     if (retval < 0) {
 177         g_free(path);
 178         return retval;
 179     }
 180
 181     bprm->fullpath = path;
 182     bprm->fd = retval;
 183     bprm->filename = (char *)filename;
 184     bprm->argc = count(argv);
 185     bprm->argv = argv;
 186     bprm->envc = count(envp);
 187     bprm->envp = envp;
 188
 189     retval = prepare_binprm(bprm);
 190
 191     if (retval >= 0) {
 192         if (bprm->buf[0] == 0x7f
 193                 && bprm->buf[1] == 'E'
 194                 && bprm->buf[2] == 'L'
 195                 && bprm->buf[3] == 'F') {
 196             retval = load_elf_binary(bprm, regs, infop);
 197         } else {
 198             fprintf(stderr, "Unknown binary format\n");
 199             return -1;
 200         }
 201     }
 202
 203     if (retval >= 0) {
 204         /* success.  Initialize important registers */
 205         do_init_thread(regs, infop);
 206         return retval;
 207     }
 208
 209     /* Something went wrong, return the inode and free the argument pages*/
 210     for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 211         g_free(bprm->page[i]);
 212     }
 213     return retval;
 214 }