xref: /openbmc/qemu/linux-user/linuxload.c (revision 1cf9412b)
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 count(char ** vec)
30 {
31     int		i;
32 
33     for(i = 0; *vec; i++) {
34         vec++;
35     }
36 
37     return(i);
38 }
39 
40 static int prepare_binprm(struct linux_binprm *bprm)
41 {
42     struct stat		st;
43     int mode;
44     int retval;
45 
46     if(fstat(bprm->fd, &st) < 0) {
47 	return(-errno);
48     }
49 
50     mode = st.st_mode;
51     if(!S_ISREG(mode)) {	/* Must be regular file */
52 	return(-EACCES);
53     }
54     if(!(mode & 0111)) {	/* Must have at least one execute bit set */
55 	return(-EACCES);
56     }
57 
58     bprm->e_uid = geteuid();
59     bprm->e_gid = getegid();
60 
61     /* Set-uid? */
62     if(mode & S_ISUID) {
63     	bprm->e_uid = st.st_uid;
64     }
65 
66     /* Set-gid? */
67     /*
68      * If setgid is set but no group execute bit then this
69      * is a candidate for mandatory locking, not a setgid
70      * executable.
71      */
72     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
73 	bprm->e_gid = st.st_gid;
74     }
75 
76     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
77     if (retval < 0) {
78 	perror("prepare_binprm");
79 	exit(-1);
80     }
81     if (retval < BPRM_BUF_SIZE) {
82         /* Make sure the rest of the loader won't read garbage.  */
83         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
84     }
85     return retval;
86 }
87 
88 /* Construct the envp and argv tables on the target stack.  */
89 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
90                               abi_ulong stringp, int push_ptr)
91 {
92     CPUArchState *env = thread_cpu->env_ptr;
93     TaskState *ts = (TaskState *)env->opaque;
94     int n = sizeof(abi_ulong);
95     abi_ulong envp;
96     abi_ulong argv;
97 
98     sp -= (envc + 1) * n;
99     envp = sp;
100     sp -= (argc + 1) * n;
101     argv = sp;
102     if (push_ptr) {
103         /* FIXME - handle put_user() failures */
104         sp -= n;
105         put_user_ual(envp, sp);
106         sp -= n;
107         put_user_ual(argv, sp);
108     }
109     sp -= n;
110     /* FIXME - handle put_user() failures */
111     put_user_ual(argc, sp);
112     ts->info->arg_start = stringp;
113     while (argc-- > 0) {
114         /* FIXME - handle put_user() failures */
115         put_user_ual(stringp, argv);
116         argv += n;
117         stringp += target_strlen(stringp) + 1;
118     }
119     ts->info->arg_end = stringp;
120     /* FIXME - handle put_user() failures */
121     put_user_ual(0, argv);
122     while (envc-- > 0) {
123         /* FIXME - handle put_user() failures */
124         put_user_ual(stringp, envp);
125         envp += n;
126         stringp += target_strlen(stringp) + 1;
127     }
128     /* FIXME - handle put_user() failures */
129     put_user_ual(0, envp);
130 
131     return sp;
132 }
133 
134 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
135              struct target_pt_regs * regs, struct image_info *infop,
136              struct linux_binprm *bprm)
137 {
138     int retval;
139     int i;
140 
141     bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
142     memset(bprm->page, 0, sizeof(bprm->page));
143     bprm->fd = fdexec;
144     bprm->filename = (char *)filename;
145     bprm->argc = count(argv);
146     bprm->argv = argv;
147     bprm->envc = count(envp);
148     bprm->envp = envp;
149 
150     retval = prepare_binprm(bprm);
151 
152     if(retval>=0) {
153         if (bprm->buf[0] == 0x7f
154                 && bprm->buf[1] == 'E'
155                 && bprm->buf[2] == 'L'
156                 && bprm->buf[3] == 'F') {
157             retval = load_elf_binary(bprm, regs, infop);
158 #if defined(TARGET_HAS_BFLT)
159         } else if (bprm->buf[0] == 'b'
160                 && bprm->buf[1] == 'F'
161                 && bprm->buf[2] == 'L'
162                 && bprm->buf[3] == 'T') {
163             retval = load_flt_binary(bprm,regs,infop);
164 #endif
165         } else {
166             return -ENOEXEC;
167         }
168     }
169 
170     if(retval>=0) {
171         /* success.  Initialize important registers */
172         do_init_thread(regs, infop);
173         return retval;
174     }
175 
176     /* Something went wrong, return the inode and free the argument pages*/
177     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
178         g_free(bprm->page[i]);
179     }
180     return(retval);
181 }
182