linux-user/linuxload.c

   1 /* Code for loading Linux executables.  Mostly linux kernel code.  */
   2
   3 #include "qemu/osdep.h"
   4
   5 #include "qemu.h"
   6
   7 #if !defined(O_BINARY)
   8 # define O_BINARY 0
   9 #endif
  10
  11 #define NGROUPS 32
  12
  13 /* ??? This should really be somewhere else.  */
  14 abi_long memcpy_to_target(abi_ulong dest, const void *src,
  15                           unsigned long len)
  16 {
  17     void *host_ptr;
  18
  19     host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
  20     if (!host_ptr)
  21         return -TARGET_EFAULT;
  22     memcpy(host_ptr, src, len);
  23     unlock_user(host_ptr, dest, 1);
  24     return 0;
  25 }
  26
  27 static int count(char ** vec)
  28 {
  29     int         i;
  30
  31     for(i = 0; *vec; i++) {
  32         vec++;
  33     }
  34
  35     return(i);
  36 }
  37
  38 static int prepare_binprm(struct linux_binprm *bprm)
  39 {
  40     struct stat         st;
  41     int mode;
  42     int retval;
  43
  44     if(fstat(bprm->fd, &st) < 0) {
  45         return(-errno);
  46     }
  47
  48     mode = st.st_mode;
  49     if(!S_ISREG(mode)) {        /* Must be regular file */
  50         return(-EACCES);
  51     }
  52     if(!(mode & 0111)) {        /* Must have at least one execute bit set */
  53         return(-EACCES);
  54     }
  55
  56     bprm->e_uid = geteuid();
  57     bprm->e_gid = getegid();
  58
  59     /* Set-uid? */
  60     if(mode & S_ISUID) {
  61         bprm->e_uid = st.st_uid;
  62     }
  63
  64     /* Set-gid? */
  65     /*
  66      * If setgid is set but no group execute bit then this
  67      * is a candidate for mandatory locking, not a setgid
  68      * executable.
  69      */
  70     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
  71         bprm->e_gid = st.st_gid;
  72     }
  73
  74     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
  75     if (retval < 0) {
  76         perror("prepare_binprm");
  77         exit(-1);
  78     }
  79     if (retval < BPRM_BUF_SIZE) {
  80         /* Make sure the rest of the loader won't read garbage.  */
  81         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
  82     }
  83     return retval;
  84 }
  85
  86 /* Construct the envp and argv tables on the target stack.  */
  87 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
  88                               abi_ulong stringp, int push_ptr)
  89 {
  90     TaskState *ts = (TaskState *)thread_cpu->opaque;
  91     int n = sizeof(abi_ulong);
  92     abi_ulong envp;
  93     abi_ulong argv;
  94
  95     sp -= (envc + 1) * n;
  96     envp = sp;
  97     sp -= (argc + 1) * n;
  98     argv = sp;
  99     if (push_ptr) {
 100         /* FIXME - handle put_user() failures */
 101         sp -= n;
 102         put_user_ual(envp, sp);
 103         sp -= n;
 104         put_user_ual(argv, sp);
 105     }
 106     sp -= n;
 107     /* FIXME - handle put_user() failures */
 108     put_user_ual(argc, sp);
 109     ts->info->arg_start = stringp;
 110     while (argc-- > 0) {
 111         /* FIXME - handle put_user() failures */
 112         put_user_ual(stringp, argv);
 113         argv += n;
 114         stringp += target_strlen(stringp) + 1;
 115     }
 116     ts->info->arg_end = stringp;
 117     /* FIXME - handle put_user() failures */
 118     put_user_ual(0, argv);
 119     while (envc-- > 0) {
 120         /* FIXME - handle put_user() failures */
 121         put_user_ual(stringp, envp);
 122         envp += n;
 123         stringp += target_strlen(stringp) + 1;
 124     }
 125     /* FIXME - handle put_user() failures */
 126     put_user_ual(0, envp);
 127
 128     return sp;
 129 }
 130
 131 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
 132              struct target_pt_regs * regs, struct image_info *infop,
 133              struct linux_binprm *bprm)
 134 {
 135     int retval;
 136
 137     bprm->fd = fdexec;
 138     bprm->filename = (char *)filename;
 139     bprm->argc = count(argv);
 140     bprm->argv = argv;
 141     bprm->envc = count(envp);
 142     bprm->envp = envp;
 143
 144     retval = prepare_binprm(bprm);
 145
 146     if(retval>=0) {
 147         if (bprm->buf[0] == 0x7f
 148                 && bprm->buf[1] == 'E'
 149                 && bprm->buf[2] == 'L'
 150                 && bprm->buf[3] == 'F') {
 151             retval = load_elf_binary(bprm, infop);
 152 #if defined(TARGET_HAS_BFLT)
 153         } else if (bprm->buf[0] == 'b'
 154                 && bprm->buf[1] == 'F'
 155                 && bprm->buf[2] == 'L'
 156                 && bprm->buf[3] == 'T') {
 157             retval = load_flt_binary(bprm, infop);
 158 #endif
 159         } else {
 160             return -ENOEXEC;
 161         }
 162     }
 163
 164     if(retval>=0) {
 165         /* success.  Initialize important registers */
 166         do_init_thread(regs, infop);
 167         return retval;
 168     }
 169
 170     return(retval);
 171 }