linux-user/linuxload.c

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