summaryrefslogtreecommitdiff
path: root/linux-user/linuxload.c
blob: 9ee27c3558d3da1928f80afad455caeff9096b5f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
/* Code for loading Linux executables.  Mostly linux kernel code.  */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

#include "qemu.h"

#define NGROUPS 32

/* ??? This should really be somewhere else.  */
abi_long memcpy_to_target(abi_ulong dest, const void *src,
                          unsigned long len)
{
    void *host_ptr;

    host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
    if (!host_ptr)
        return -TARGET_EFAULT;
    memcpy(host_ptr, src, len);
    unlock_user(host_ptr, dest, 1);
    return 0;
}

static int in_group_p(gid_t g)
{
    /* return TRUE if we're in the specified group, FALSE otherwise */
    int		ngroup;
    int		i;
    gid_t	grouplist[NGROUPS];

    ngroup = getgroups(NGROUPS, grouplist);
    for(i = 0; i < ngroup; i++) {
	if(grouplist[i] == g) {
	    return 1;
	}
    }
    return 0;
}

static int count(char ** vec)
{
    int		i;

    for(i = 0; *vec; i++) {
        vec++;
    }

    return(i);
}

static int prepare_binprm(struct linux_binprm *bprm)
{
    struct stat		st;
    int mode;
    int retval, id_change;

    if(fstat(bprm->fd, &st) < 0) {
	return(-errno);
    }

    mode = st.st_mode;
    if(!S_ISREG(mode)) {	/* Must be regular file */
	return(-EACCES);
    }
    if(!(mode & 0111)) {	/* Must have at least one execute bit set */
	return(-EACCES);
    }

    bprm->e_uid = geteuid();
    bprm->e_gid = getegid();
    id_change = 0;

    /* Set-uid? */
    if(mode & S_ISUID) {
    	bprm->e_uid = st.st_uid;
	if(bprm->e_uid != geteuid()) {
	    id_change = 1;
	}
    }

    /* Set-gid? */
    /*
     * If setgid is set but no group execute bit then this
     * is a candidate for mandatory locking, not a setgid
     * executable.
     */
    if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
	bprm->e_gid = st.st_gid;
	if (!in_group_p(bprm->e_gid)) {
		id_change = 1;
	}
    }

    retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
    if (retval < 0) {
	perror("prepare_binprm");
	exit(-1);
    }
    if (retval < BPRM_BUF_SIZE) {
        /* Make sure the rest of the loader won't read garbage.  */
        memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
    }
    return retval;
}

/* Construct the envp and argv tables on the target stack.  */
abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
                              abi_ulong stringp, int push_ptr)
{
    TaskState *ts = (TaskState *)thread_env->opaque;
    int n = sizeof(abi_ulong);
    abi_ulong envp;
    abi_ulong argv;

    sp -= (envc + 1) * n;
    envp = sp;
    sp -= (argc + 1) * n;
    argv = sp;
    if (push_ptr) {
        /* FIXME - handle put_user() failures */
        sp -= n;
        put_user_ual(envp, sp);
        sp -= n;
        put_user_ual(argv, sp);
    }
    sp -= n;
    /* FIXME - handle put_user() failures */
    put_user_ual(argc, sp);
    ts->info->arg_start = stringp;
    while (argc-- > 0) {
        /* FIXME - handle put_user() failures */
        put_user_ual(stringp, argv);
        argv += n;
        stringp += target_strlen(stringp) + 1;
    }
    ts->info->arg_end = stringp;
    /* FIXME - handle put_user() failures */
    put_user_ual(0, argv);
    while (envc-- > 0) {
        /* FIXME - handle put_user() failures */
        put_user_ual(stringp, envp);
        envp += n;
        stringp += target_strlen(stringp) + 1;
    }
    /* FIXME - handle put_user() failures */
    put_user_ual(0, envp);

    return sp;
}

int loader_exec(const char * filename, char ** argv, char ** envp,
             struct target_pt_regs * regs, struct image_info *infop,
             struct linux_binprm *bprm)
{
    int retval;
    int i;

    bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
    memset(bprm->page, 0, sizeof(bprm->page));
    retval = open(filename, O_RDONLY);
    if (retval < 0)
        return retval;
    bprm->fd = retval;
    bprm->filename = (char *)filename;
    bprm->argc = count(argv);
    bprm->argv = argv;
    bprm->envc = count(envp);
    bprm->envp = envp;

    retval = prepare_binprm(bprm);

    infop->host_argv = argv;

    if(retval>=0) {
        if (bprm->buf[0] == 0x7f
                && bprm->buf[1] == 'E'
                && bprm->buf[2] == 'L'
                && bprm->buf[3] == 'F') {
            retval = load_elf_binary(bprm, regs, infop);
#if defined(TARGET_HAS_BFLT)
        } else if (bprm->buf[0] == 'b'
                && bprm->buf[1] == 'F'
                && bprm->buf[2] == 'L'
                && bprm->buf[3] == 'T') {
            retval = load_flt_binary(bprm,regs,infop);
#endif
        } else {
            fprintf(stderr, "Unknown binary format\n");
            return -1;
        }
    }

    if(retval>=0) {
        /* success.  Initialize important registers */
        do_init_thread(regs, infop);
        return retval;
    }

    /* Something went wrong, return the inode and free the argument pages*/
    for (i=0 ; i<MAX_ARG_PAGES ; i++) {
        free(bprm->page[i]);
    }
    return(retval);
}