xref: /illumos-kvm-cmd/linux-user/linuxload.c (revision 68396ea9)
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.  */
memcpy_to_target(abi_ulong dest,const void * src,unsigned long len)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 
in_group_p(gid_t g)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[NGROUPS];
35 
36     ngroup = getgroups(NGROUPS, grouplist);
37     for(i = 0; i < ngroup; i++) {
38 	if(grouplist[i] == g) {
39 	    return 1;
40 	}
41     }
42     return 0;
43 }
44 
count(char ** vec)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 
prepare_binprm(struct linux_binprm * bprm)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     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
100     if (retval < 0) {
101 	perror("prepare_binprm");
102 	exit(-1);
103     }
104     if (retval < BPRM_BUF_SIZE) {
105         /* Make sure the rest of the loader won't read garbage.  */
106         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
107     }
108     return retval;
109 }
110 
111 /* 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)112 abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
113                               abi_ulong stringp, int push_ptr)
114 {
115     TaskState *ts = (TaskState *)thread_env->opaque;
116     int n = sizeof(abi_ulong);
117     abi_ulong envp;
118     abi_ulong argv;
119 
120     sp -= (envc + 1) * n;
121     envp = sp;
122     sp -= (argc + 1) * n;
123     argv = sp;
124     if (push_ptr) {
125         /* FIXME - handle put_user() failures */
126         sp -= n;
127         put_user_ual(envp, sp);
128         sp -= n;
129         put_user_ual(argv, sp);
130     }
131     sp -= n;
132     /* FIXME - handle put_user() failures */
133     put_user_ual(argc, sp);
134     ts->info->arg_start = stringp;
135     while (argc-- > 0) {
136         /* FIXME - handle put_user() failures */
137         put_user_ual(stringp, argv);
138         argv += n;
139         stringp += target_strlen(stringp) + 1;
140     }
141     ts->info->arg_end = stringp;
142     /* FIXME - handle put_user() failures */
143     put_user_ual(0, argv);
144     while (envc-- > 0) {
145         /* FIXME - handle put_user() failures */
146         put_user_ual(stringp, envp);
147         envp += n;
148         stringp += target_strlen(stringp) + 1;
149     }
150     /* FIXME - handle put_user() failures */
151     put_user_ual(0, envp);
152 
153     return sp;
154 }
155 
loader_exec(const char * filename,char ** argv,char ** envp,struct target_pt_regs * regs,struct image_info * infop,struct linux_binprm * bprm)156 int loader_exec(const char * filename, char ** argv, char ** envp,
157              struct target_pt_regs * regs, struct image_info *infop,
158              struct linux_binprm *bprm)
159 {
160     int retval;
161     int i;
162 
163     bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
164     memset(bprm->page, 0, sizeof(bprm->page));
165     retval = open(filename, O_RDONLY);
166     if (retval < 0)
167         return retval;
168     bprm->fd = retval;
169     bprm->filename = (char *)filename;
170     bprm->argc = count(argv);
171     bprm->argv = argv;
172     bprm->envc = count(envp);
173     bprm->envp = envp;
174 
175     retval = prepare_binprm(bprm);
176 
177     if(retval>=0) {
178         if (bprm->buf[0] == 0x7f
179                 && bprm->buf[1] == 'E'
180                 && bprm->buf[2] == 'L'
181                 && bprm->buf[3] == 'F') {
182             retval = load_elf_binary(bprm, regs, infop);
183 #if defined(TARGET_HAS_BFLT)
184         } else if (bprm->buf[0] == 'b'
185                 && bprm->buf[1] == 'F'
186                 && bprm->buf[2] == 'L'
187                 && bprm->buf[3] == 'T') {
188             retval = load_flt_binary(bprm,regs,infop);
189 #endif
190         } else {
191             fprintf(stderr, "Unknown binary format\n");
192             return -1;
193         }
194     }
195 
196     if(retval>=0) {
197         /* success.  Initialize important registers */
198         do_init_thread(regs, infop);
199         return retval;
200     }
201 
202     /* Something went wrong, return the inode and free the argument pages*/
203     for (i=0 ; i<MAX_ARG_PAGES ; i++) {
204         free(bprm->page[i]);
205     }
206     return(retval);
207 }
208