1 /* Code for loading Linux executables.  Mostly linux kernel code.  */
2 
3 #include "qemu/osdep.h"
4 
5 #include "qemu.h"
6 
7 #define NGROUPS 32
8 
9 /* ??? This should really be somewhere else.  */
memcpy_to_target(abi_ulong dest,const void * src,unsigned long len)10 abi_long memcpy_to_target(abi_ulong dest, const void *src,
11                           unsigned long len)
12 {
13     void *host_ptr;
14 
15     host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
16     if (!host_ptr)
17         return -TARGET_EFAULT;
18     memcpy(host_ptr, src, len);
19     unlock_user(host_ptr, dest, 1);
20     return 0;
21 }
22 
count(char ** vec)23 static int count(char ** vec)
24 {
25     int		i;
26 
27     for(i = 0; *vec; i++) {
28         vec++;
29     }
30 
31     return(i);
32 }
33 
prepare_binprm(struct linux_binprm * bprm)34 static int prepare_binprm(struct linux_binprm *bprm)
35 {
36     struct stat		st;
37     int mode;
38     int retval;
39 
40     if(fstat(bprm->fd, &st) < 0) {
41         return(-errno);
42     }
43 
44     mode = st.st_mode;
45     if(!S_ISREG(mode)) {	/* Must be regular file */
46         return(-EACCES);
47     }
48     if(!(mode & 0111)) {	/* Must have at least one execute bit set */
49         return(-EACCES);
50     }
51 
52     bprm->e_uid = geteuid();
53     bprm->e_gid = getegid();
54 
55     /* Set-uid? */
56     if(mode & S_ISUID) {
57         bprm->e_uid = st.st_uid;
58     }
59 
60     /* Set-gid? */
61     /*
62      * If setgid is set but no group execute bit then this
63      * is a candidate for mandatory locking, not a setgid
64      * executable.
65      */
66     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
67         bprm->e_gid = st.st_gid;
68     }
69 
70     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
71     if (retval < 0) {
72         perror("prepare_binprm");
73         exit(-1);
74     }
75     if (retval < BPRM_BUF_SIZE) {
76         /* Make sure the rest of the loader won't read garbage.  */
77         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
78     }
79     return retval;
80 }
81 
82 /* Construct the envp and argv tables on the target stack.  */
loader_build_argptr(int envc,int argc,abi_ulong sp,abi_ulong stringp,int push_ptr)83 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
84                               abi_ulong stringp, int push_ptr)
85 {
86     TaskState *ts = (TaskState *)thread_cpu->opaque;
87     int n = sizeof(abi_ulong);
88     abi_ulong envp;
89     abi_ulong argv;
90 
91     sp -= (envc + 1) * n;
92     envp = sp;
93     sp -= (argc + 1) * n;
94     argv = sp;
95     if (push_ptr) {
96         /* FIXME - handle put_user() failures */
97         sp -= n;
98         put_user_ual(envp, sp);
99         sp -= n;
100         put_user_ual(argv, sp);
101     }
102     sp -= n;
103     /* FIXME - handle put_user() failures */
104     put_user_ual(argc, sp);
105     ts->info->arg_start = stringp;
106     while (argc-- > 0) {
107         /* FIXME - handle put_user() failures */
108         put_user_ual(stringp, argv);
109         argv += n;
110         stringp += target_strlen(stringp) + 1;
111     }
112     ts->info->arg_end = stringp;
113     /* FIXME - handle put_user() failures */
114     put_user_ual(0, argv);
115     while (envc-- > 0) {
116         /* FIXME - handle put_user() failures */
117         put_user_ual(stringp, envp);
118         envp += n;
119         stringp += target_strlen(stringp) + 1;
120     }
121     /* FIXME - handle put_user() failures */
122     put_user_ual(0, envp);
123 
124     return sp;
125 }
126 
loader_exec(int fdexec,const char * filename,char ** argv,char ** envp,struct target_pt_regs * regs,struct image_info * infop,struct linux_binprm * bprm)127 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
128              struct target_pt_regs * regs, struct image_info *infop,
129              struct linux_binprm *bprm)
130 {
131     int retval;
132 
133     bprm->fd = fdexec;
134     bprm->filename = (char *)filename;
135     bprm->argc = count(argv);
136     bprm->argv = argv;
137     bprm->envc = count(envp);
138     bprm->envp = envp;
139 
140     retval = prepare_binprm(bprm);
141 
142     if(retval>=0) {
143         if (bprm->buf[0] == 0x7f
144                 && bprm->buf[1] == 'E'
145                 && bprm->buf[2] == 'L'
146                 && bprm->buf[3] == 'F') {
147             retval = load_elf_binary(bprm, infop);
148 #if defined(TARGET_HAS_BFLT)
149         } else if (bprm->buf[0] == 'b'
150                 && bprm->buf[1] == 'F'
151                 && bprm->buf[2] == 'L'
152                 && bprm->buf[3] == 'T') {
153             retval = load_flt_binary(bprm, infop);
154 #endif
155         } else {
156             return -ENOEXEC;
157         }
158     }
159 
160     if(retval>=0) {
161         /* success.  Initialize important registers */
162         do_init_thread(regs, infop);
163         return retval;
164     }
165 
166     return(retval);
167 }
168