linux-user/linuxload.c

   1 /* Code for loading Linux executables.  Mostly linux kernel code.  */
   2
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <fcntl.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 #include "qemu.h"
  12
  13 #define NGROUPS 32
  14
  15 /* ??? This should really be somewhere else.  */
  16 abi_long memcpy_to_target(abi_ulong dest, const void *src,
  17                           unsigned long len)
  18 {
  19     void *host_ptr;
  20
  21     host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
  22     if (!host_ptr)
  23         return -TARGET_EFAULT;
  24     memcpy(host_ptr, src, len);
  25     unlock_user(host_ptr, dest, 1);
  26     return 0;
  27 }
  28
  29 static int in_group_p(gid_t g)
  30 {
  31     /* return TRUE if we're in the specified group, FALSE otherwise */
  32     int         ngroup;
  33     int         i;
  34     gid_t       grouplist[NGROUPS];
  35
  36     ngroup = getgroups(NGROUPS, grouplist);
  37     for(i = 0; i < ngroup; i++) {
  38         if(grouplist[i] == g) {
  39             return 1;
  40         }
  41     }
  42     return 0;
  43 }
  44
  45 static int count(char ** vec)
  46 {
  47     int         i;
  48
  49     for(i = 0; *vec; i++) {
  50         vec++;
  51     }
  52
  53     return(i);
  54 }
  55
  56 static int prepare_binprm(struct linux_binprm *bprm)
  57 {
  58     struct stat         st;
  59     int mode;
  60     int retval, id_change;
  61
  62     if(fstat(bprm->fd, &st) < 0) {
  63         return(-errno);
  64     }
  65
  66     mode = st.st_mode;
  67     if(!S_ISREG(mode)) {        /* Must be regular file */
  68         return(-EACCES);
  69     }
  70     if(!(mode & 0111)) {        /* Must have at least one execute bit set */
  71         return(-EACCES);
  72     }
  73
  74     bprm->e_uid = geteuid();
  75     bprm->e_gid = getegid();
  76     id_change = 0;
  77
  78     /* Set-uid? */
  79     if(mode & S_ISUID) {
  80         bprm->e_uid = st.st_uid;
  81         if(bprm->e_uid != geteuid()) {
  82             id_change = 1;
  83         }
  84     }
  85
  86     /* Set-gid? */
  87     /*
  88      * If setgid is set but no group execute bit then this
  89      * is a candidate for mandatory locking, not a setgid
  90      * executable.
  91      */
  92     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
  93         bprm->e_gid = st.st_gid;
  94         if (!in_group_p(bprm->e_gid)) {
  95                 id_change = 1;
  96         }
  97     }
  98
  99     retval = lseek(bprm->fd, 0L, SEEK_SET);
 100     if(retval >= 0) {
 101         retval = read(bprm->fd, bprm->buf, 128);
 102     }
 103     if(retval < 0) {
 104         perror("prepare_binprm");
 105         exit(-1);
 106         /* return(-errno); */
 107     }
 108     else {
 109         return(retval);
 110     }
 111 }
 112
 113 /* Construct the envp and argv tables on the target stack.  */
 114 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
 115                               abi_ulong stringp, int push_ptr)
 116 {
 117     TaskState *ts = (TaskState *)thread_env->opaque;
 118     int n = sizeof(abi_ulong);
 119     abi_ulong envp;
 120     abi_ulong argv;
 121
 122     sp -= (envc + 1) * n;
 123     envp = sp;
 124     sp -= (argc + 1) * n;
 125     argv = sp;
 126     if (push_ptr) {
 127         /* FIXME - handle put_user() failures */
 128         sp -= n;
 129         put_user_ual(envp, sp);
 130         sp -= n;
 131         put_user_ual(argv, sp);
 132     }
 133     sp -= n;
 134     /* FIXME - handle put_user() failures */
 135     put_user_ual(argc, sp);
 136     ts->info->arg_start = stringp;
 137     while (argc-- > 0) {
 138         /* FIXME - handle put_user() failures */
 139         put_user_ual(stringp, argv);
 140         argv += n;
 141         stringp += target_strlen(stringp) + 1;
 142     }
 143     ts->info->arg_end = stringp;
 144     /* FIXME - handle put_user() failures */
 145     put_user_ual(0, argv);
 146     while (envc-- > 0) {
 147         /* FIXME - handle put_user() failures */
 148         put_user_ual(stringp, envp);
 149         envp += n;
 150         stringp += target_strlen(stringp) + 1;
 151     }
 152     /* FIXME - handle put_user() failures */
 153     put_user_ual(0, envp);
 154
 155     return sp;
 156 }
 157
 158 int loader_exec(const char * filename, char ** argv, char ** envp,
 159              struct target_pt_regs * regs, struct image_info *infop,
 160              struct linux_binprm *bprm)
 161 {
 162     int retval;
 163     int i;
 164
 165     bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
 166     for (i=0 ; i<MAX_ARG_PAGES ; i++)       /* clear page-table */
 167             bprm->page[i] = NULL;
 168     retval = open(filename, O_RDONLY);
 169     if (retval < 0)
 170         return retval;
 171     bprm->fd = retval;
 172     bprm->filename = (char *)filename;
 173     bprm->argc = count(argv);
 174     bprm->argv = argv;
 175     bprm->envc = count(envp);
 176     bprm->envp = envp;
 177
 178     retval = prepare_binprm(bprm);
 179
 180     infop->host_argv = argv;
 181
 182     if(retval>=0) {
 183         if (bprm->buf[0] == 0x7f
 184                 && bprm->buf[1] == 'E'
 185                 && bprm->buf[2] == 'L'
 186                 && bprm->buf[3] == 'F') {
 187             retval = load_elf_binary(bprm, regs, infop);
 188 #if defined(TARGET_HAS_BFLT)
 189         } else if (bprm->buf[0] == 'b'
 190                 && bprm->buf[1] == 'F'
 191                 && bprm->buf[2] == 'L'
 192                 && bprm->buf[3] == 'T') {
 193             retval = load_flt_binary(bprm,regs,infop);
 194 #endif
 195         } else {
 196             fprintf(stderr, "Unknown binary format\n");
 197             return -1;
 198         }
 199     }
 200
 201     if(retval>=0) {
 202         /* success.  Initialize important registers */
 203         do_init_thread(regs, infop);
 204         return retval;
 205     }
 206
 207     /* Something went wrong, return the inode and free the argument pages*/
 208     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
 209         free(bprm->page[i]);
 210     }
 211     return(retval);
 212 }