File:  [Qemu by Fabrice Bellard] / qemu / bsd-user / bsdload.c
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 18:42:42 2018 UTC (3 years, 3 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, qemu1000, qemu0151, qemu0150, qemu0141, qemu0140, HEAD
qemu 0.14.0

    1: /* Code for loading BSD 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 TARGET_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[TARGET_NGROUPS];
   35: 
   36:     ngroup = getgroups(TARGET_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] = NULL;
  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:     if(retval>=0) {
  180:         if (bprm.buf[0] == 0x7f
  181:                 && bprm.buf[1] == 'E'
  182:                 && bprm.buf[2] == 'L'
  183:                 && bprm.buf[3] == 'F') {
  184:             retval = load_elf_binary(&bprm,regs,infop);
  185:         } else {
  186:             fprintf(stderr, "Unknown binary format\n");
  187:             return -1;
  188:         }
  189:     }
  190: 
  191:     if(retval>=0) {
  192:         /* success.  Initialize important registers */
  193:         do_init_thread(regs, infop);
  194:         return retval;
  195:     }
  196: 
  197:     /* Something went wrong, return the inode and free the argument pages*/
  198:     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
  199:         free(bprm.page[i]);
  200:     }
  201:     return(retval);
  202: }

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