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 count(char ** vec)
  30 {
  31     int         i;
  32
  33     for(i = 0; *vec; i++) {
  34         vec++;
  35     }
  36
  37     return(i);
  38 }
  39
  40 static int prepare_binprm(struct linux_binprm *bprm)
  41 {
  42     struct stat         st;
  43     int mode;
  44     int retval;
  45
  46     if(fstat(bprm->fd, &st) < 0) {
  47         return(-errno);
  48     }
  49
  50     mode = st.st_mode;
  51     if(!S_ISREG(mode)) {        /* Must be regular file */
  52         return(-EACCES);
  53     }
  54     if(!(mode & 0111)) {        /* Must have at least one execute bit set */
  55         return(-EACCES);
  56     }
  57
  58     bprm->e_uid = geteuid();
  59     bprm->e_gid = getegid();
  60
  61     /* Set-uid? */
  62     if(mode & S_ISUID) {
  63         bprm->e_uid = st.st_uid;
  64     }
  65
  66     /* Set-gid? */
  67     /*
  68      * If setgid is set but no group execute bit then this
  69      * is a candidate for mandatory locking, not a setgid
  70      * executable.
  71      */
  72     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
  73         bprm->e_gid = st.st_gid;
  74     }
  75
  76     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
  77     if (retval < 0) {
  78         perror("prepare_binprm");
  79         exit(-1);
  80     }
  81     if (retval < BPRM_BUF_SIZE) {
  82         /* Make sure the rest of the loader won't read garbage.  */
  83         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
  84     }
  85     return retval;
  86 }
  87
  88 /* Construct the envp and argv tables on the target stack.  */
  89 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
  90                               abi_ulong stringp, int push_ptr)
  91 {
  92     TaskState *ts = (TaskState *)thread_cpu->opaque;
  93     int n = sizeof(abi_ulong);
  94     abi_ulong envp;
  95     abi_ulong argv;
  96
  97     sp -= (envc + 1) * n;
  98     envp = sp;
  99     sp -= (argc + 1) * n;
 100     argv = sp;
 101     if (push_ptr) {
 102         /* FIXME - handle put_user() failures */
 103         sp -= n;
 104         put_user_ual(envp, sp);
 105         sp -= n;
 106         put_user_ual(argv, sp);
 107     }
 108     sp -= n;
 109     /* FIXME - handle put_user() failures */
 110     put_user_ual(argc, sp);
 111     ts->info->arg_start = stringp;
 112     while (argc-- > 0) {
 113         /* FIXME - handle put_user() failures */
 114         put_user_ual(stringp, argv);
 115         argv += n;
 116         stringp += target_strlen(stringp) + 1;
 117     }
 118     ts->info->arg_end = stringp;
 119     /* FIXME - handle put_user() failures */
 120     put_user_ual(0, argv);
 121     while (envc-- > 0) {
 122         /* FIXME - handle put_user() failures */
 123         put_user_ual(stringp, envp);
 124         envp += n;
 125         stringp += target_strlen(stringp) + 1;
 126     }
 127     /* FIXME - handle put_user() failures */
 128     put_user_ual(0, envp);
 129
 130     return sp;
 131 }
 132
 133 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
 134              struct target_pt_regs * regs, struct image_info *infop,
 135              struct linux_binprm *bprm)
 136 {
 137     int retval;
 138
 139     bprm->fd = fdexec;
 140     bprm->filename = (char *)filename;
 141     bprm->argc = count(argv);
 142     bprm->argv = argv;
 143     bprm->envc = count(envp);
 144     bprm->envp = envp;
 145
 146     retval = prepare_binprm(bprm);
 147
 148     if(retval>=0) {
 149         if (bprm->buf[0] == 0x7f
 150                 && bprm->buf[1] == 'E'
 151                 && bprm->buf[2] == 'L'
 152                 && bprm->buf[3] == 'F') {
 153             retval = load_elf_binary(bprm, infop);
 154 #if defined(TARGET_HAS_BFLT)
 155         } else if (bprm->buf[0] == 'b'
 156                 && bprm->buf[1] == 'F'
 157                 && bprm->buf[2] == 'L'
 158                 && bprm->buf[3] == 'T') {
 159             retval = load_flt_binary(bprm, infop);
 160 #endif
 161         } else {
 162             return -ENOEXEC;
 163         }
 164     }
 165
 166     if(retval>=0) {
 167         /* success.  Initialize important registers */
 168         do_init_thread(regs, infop);
 169         return retval;
 170     }
 171
 172     return(retval);
 173 }