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 = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
 100     if (retval < 0) {
 101         perror("prepare_binprm");
 102         exit(-1);
 103     }
 104     if (retval < BPRM_BUF_SIZE) {
 105         /* Make sure the rest of the loader won't read garbage.  */
 106         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
 107     }
 108     return retval;
 109 }
 110
 111 /* Construct the envp and argv tables on the target stack.  */
 112 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
 113                               abi_ulong stringp, int push_ptr)
 114 {
 115     TaskState *ts = (TaskState *)thread_env->opaque;
 116     int n = sizeof(abi_ulong);
 117     abi_ulong envp;
 118     abi_ulong argv;
 119
 120     sp -= (envc + 1) * n;
 121     envp = sp;
 122     sp -= (argc + 1) * n;
 123     argv = sp;
 124     if (push_ptr) {
 125         /* FIXME - handle put_user() failures */
 126         sp -= n;
 127         put_user_ual(envp, sp);
 128         sp -= n;
 129         put_user_ual(argv, sp);
 130     }
 131     sp -= n;
 132     /* FIXME - handle put_user() failures */
 133     put_user_ual(argc, sp);
 134     ts->info->arg_start = stringp;
 135     while (argc-- > 0) {
 136         /* FIXME - handle put_user() failures */
 137         put_user_ual(stringp, argv);
 138         argv += n;
 139         stringp += target_strlen(stringp) + 1;
 140     }
 141     ts->info->arg_end = stringp;
 142     /* FIXME - handle put_user() failures */
 143     put_user_ual(0, argv);
 144     while (envc-- > 0) {
 145         /* FIXME - handle put_user() failures */
 146         put_user_ual(stringp, envp);
 147         envp += n;
 148         stringp += target_strlen(stringp) + 1;
 149     }
 150     /* FIXME - handle put_user() failures */
 151     put_user_ual(0, envp);
 152
 153     return sp;
 154 }
 155
 156 int loader_exec(const char * filename, char ** argv, char ** envp,
 157              struct target_pt_regs * regs, struct image_info *infop,
 158              struct linux_binprm *bprm)
 159 {
 160     int retval;
 161     int i;
 162
 163     bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
 164     memset(bprm->page, 0, sizeof(bprm->page));
 165     retval = open(filename, O_RDONLY);
 166     if (retval < 0)
 167         return retval;
 168     bprm->fd = retval;
 169     bprm->filename = (char *)filename;
 170     bprm->argc = count(argv);
 171     bprm->argv = argv;
 172     bprm->envc = count(envp);
 173     bprm->envp = envp;
 174
 175     retval = prepare_binprm(bprm);
 176
 177     if(retval>=0) {
 178         if (bprm->buf[0] == 0x7f
 179                 && bprm->buf[1] == 'E'
 180                 && bprm->buf[2] == 'L'
 181                 && bprm->buf[3] == 'F') {
 182             retval = load_elf_binary(bprm, regs, infop);
 183 #if defined(TARGET_HAS_BFLT)
 184         } else if (bprm->buf[0] == 'b'
 185                 && bprm->buf[1] == 'F'
 186                 && bprm->buf[2] == 'L'
 187                 && bprm->buf[3] == 'T') {
 188             retval = load_flt_binary(bprm,regs,infop);
 189 #endif
 190         } else {
 191             fprintf(stderr, "Unknown binary format\n");
 192             return -1;
 193         }
 194     }
 195
 196     if(retval>=0) {
 197         /* success.  Initialize important registers */
 198         do_init_thread(regs, infop);
 199         return retval;
 200     }
 201
 202     /* Something went wrong, return the inode and free the argument pages*/
 203     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
 204         free(bprm->page[i]);
 205     }
 206     return(retval);
 207 }