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