LXR qemu/bsd-user/bsdload.c

   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.  */
  16abi_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
  29static 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
  45static int count(char ** vec)
  46{
  47    int         i;
  48
  49    for(i = 0; *vec; i++) {
  50        vec++;
  51    }
  52
  53    return(i);
  54}
  55
  56static 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.  */
 115abi_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
 157int 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        g_free(bprm.page[i]);
 200    }
 201    return(retval);
 202}
 203