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     memset(bprm->buf, 0, sizeof(bprm->buf));
 100     retval = lseek(bprm->fd, 0L, SEEK_SET);
 101     if(retval >= 0) {
 102         retval = read(bprm->fd, bprm->buf, 128);
 103     }
 104     if(retval < 0) {
 105         perror("prepare_binprm");
 106         exit(-1);
 107         /* return(-errno); */
 108     }
 109     else {
 110         return(retval);
 111     }
 112 }
 113
 114 /* Construct the envp and argv tables on the target stack.  */
 115 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
 116                               abi_ulong stringp, int push_ptr)
 117 {
 118     int n = sizeof(abi_ulong);
 119     abi_ulong envp;
 120     abi_ulong argv;
 121
 122     sp -= (envc + 1) * n;
 123     envp = sp;
 124     sp -= (argc + 1) * n;
 125     argv = sp;
 126     if (push_ptr) {
 127         /* FIXME - handle put_user() failures */
 128         sp -= n;
 129         put_user_ual(envp, sp);
 130         sp -= n;
 131         put_user_ual(argv, sp);
 132     }
 133     sp -= n;
 134     /* FIXME - handle put_user() failures */
 135     put_user_ual(argc, sp);
 136
 137     while (argc-- > 0) {
 138         /* FIXME - handle put_user() failures */
 139         put_user_ual(stringp, argv);
 140         argv += n;
 141         stringp += target_strlen(stringp) + 1;
 142     }
 143     /* FIXME - handle put_user() failures */
 144     put_user_ual(0, argv);
 145     while (envc-- > 0) {
 146         /* FIXME - handle put_user() failures */
 147         put_user_ual(stringp, envp);
 148         envp += n;
 149         stringp += target_strlen(stringp) + 1;
 150     }
 151     /* FIXME - handle put_user() failures */
 152     put_user_ual(0, envp);
 153
 154     return sp;
 155 }
 156
 157 int loader_exec(const char * filename, char ** argv, char ** envp,
 158              struct target_pt_regs * regs, struct image_info *infop)
 159 {
 160     struct linux_binprm bprm;
 161     int retval;
 162     int i;
 163
 164     bprm.p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
 165     for (i=0 ; i<MAX_ARG_PAGES ; i++)       /* clear page-table */
 166             bprm.page[i] = 0;
 167     retval = open(filename, O_RDONLY);
 168     if (retval < 0)
 169         return retval;
 170     bprm.fd = retval;
 171     bprm.filename = (char *)filename;
 172     bprm.argc = count(argv);
 173     bprm.argv = argv;
 174     bprm.envc = count(envp);
 175     bprm.envp = envp;
 176
 177     retval = prepare_binprm(&bprm);
 178
 179     infop->host_argv = argv;
 180
 181     if(retval>=0) {
 182         if (bprm.buf[0] == 0x7f
 183                 && bprm.buf[1] == 'E'
 184                 && bprm.buf[2] == 'L'
 185                 && bprm.buf[3] == 'F') {
 186 #ifndef TARGET_HAS_ELFLOAD32
 187             retval = load_elf_binary(&bprm,regs,infop);
 188 #else
 189             retval = load_elf_binary_multi(&bprm, regs, infop);
 190 #endif
 191 #if defined(TARGET_HAS_BFLT)
 192         } else if (bprm.buf[0] == 'b'
 193                 && bprm.buf[1] == 'F'
 194                 && bprm.buf[2] == 'L'
 195                 && bprm.buf[3] == 'T') {
 196             retval = load_flt_binary(&bprm,regs,infop);
 197 #endif
 198         } else {
 199             fprintf(stderr, "Unknown binary format\n");
 200             return -1;
 201         }
 202     }
 203
 204     if(retval>=0) {
 205         /* success.  Initialize important registers */
 206         do_init_thread(regs, infop);
 207         return retval;
 208     }
 209
 210     /* Something went wrong, return the inode and free the argument pages*/
 211     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
 212         free(bprm.page[i]);
 213     }
 214     return(retval);
 215 }