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1.1 root 1: /* Code for loading Linux executables. Mostly linux kenrel 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: void memcpy_to_target(target_ulong dest, const void *src,
17: unsigned long len)
18: {
19: void *host_ptr;
20:
21: host_ptr = lock_user(dest, len, 0);
22: memcpy(host_ptr, src, len);
23: unlock_user(host_ptr, dest, 1);
24: }
25:
26: static int in_group_p(gid_t g)
27: {
28: /* return TRUE if we're in the specified group, FALSE otherwise */
29: int ngroup;
30: int i;
31: gid_t grouplist[NGROUPS];
32:
33: ngroup = getgroups(NGROUPS, grouplist);
34: for(i = 0; i < ngroup; i++) {
35: if(grouplist[i] == g) {
36: return 1;
37: }
38: }
39: return 0;
40: }
41:
42: static int count(char ** vec)
43: {
44: int i;
45:
46: for(i = 0; *vec; i++) {
47: vec++;
48: }
49:
50: return(i);
51: }
52:
53: static int prepare_binprm(struct linux_binprm *bprm)
54: {
55: struct stat st;
56: int mode;
57: int retval, id_change;
58:
59: if(fstat(bprm->fd, &st) < 0) {
60: return(-errno);
61: }
62:
63: mode = st.st_mode;
64: if(!S_ISREG(mode)) { /* Must be regular file */
65: return(-EACCES);
66: }
67: if(!(mode & 0111)) { /* Must have at least one execute bit set */
68: return(-EACCES);
69: }
70:
71: bprm->e_uid = geteuid();
72: bprm->e_gid = getegid();
73: id_change = 0;
74:
75: /* Set-uid? */
76: if(mode & S_ISUID) {
77: bprm->e_uid = st.st_uid;
78: if(bprm->e_uid != geteuid()) {
79: id_change = 1;
80: }
81: }
82:
83: /* Set-gid? */
84: /*
85: * If setgid is set but no group execute bit then this
86: * is a candidate for mandatory locking, not a setgid
87: * executable.
88: */
89: if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
90: bprm->e_gid = st.st_gid;
91: if (!in_group_p(bprm->e_gid)) {
92: id_change = 1;
93: }
94: }
95:
96: memset(bprm->buf, 0, sizeof(bprm->buf));
97: retval = lseek(bprm->fd, 0L, SEEK_SET);
98: if(retval >= 0) {
99: retval = read(bprm->fd, bprm->buf, 128);
100: }
101: if(retval < 0) {
102: perror("prepare_binprm");
103: exit(-1);
104: /* return(-errno); */
105: }
106: else {
107: return(retval);
108: }
109: }
110:
111: /* Construct the envp and argv tables on the target stack. */
112: target_ulong loader_build_argptr(int envc, int argc, target_ulong sp,
113: target_ulong stringp, int push_ptr)
114: {
115: int n = sizeof(target_ulong);
116: target_ulong envp;
117: target_ulong argv;
118:
119: sp -= (envc + 1) * n;
120: envp = sp;
121: sp -= (argc + 1) * n;
122: argv = sp;
123: if (push_ptr) {
124: sp -= n; tputl(sp, envp);
125: sp -= n; tputl(sp, argv);
126: }
127: sp -= n; tputl(sp, argc);
128:
129: while (argc-- > 0) {
130: tputl(argv, stringp); argv += n;
131: stringp += target_strlen(stringp) + 1;
132: }
133: tputl(argv, 0);
134: while (envc-- > 0) {
135: tputl(envp, stringp); envp += n;
136: stringp += target_strlen(stringp) + 1;
137: }
138: tputl(envp, 0);
139:
140: return sp;
141: }
142:
143: int loader_exec(const char * filename, char ** argv, char ** envp,
144: struct target_pt_regs * regs, struct image_info *infop)
145: {
146: struct linux_binprm bprm;
147: int retval;
148: int i;
149:
150: bprm.p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int);
151: for (i=0 ; i<MAX_ARG_PAGES ; i++) /* clear page-table */
152: bprm.page[i] = 0;
153: retval = open(filename, O_RDONLY);
154: if (retval < 0)
155: return retval;
156: bprm.fd = retval;
157: bprm.filename = (char *)filename;
158: bprm.argc = count(argv);
159: bprm.argv = argv;
160: bprm.envc = count(envp);
161: bprm.envp = envp;
162:
163: retval = prepare_binprm(&bprm);
164:
165: if(retval>=0) {
166: if (bprm.buf[0] == 0x7f
167: && bprm.buf[1] == 'E'
168: && bprm.buf[2] == 'L'
169: && bprm.buf[3] == 'F') {
170: retval = load_elf_binary(&bprm,regs,infop);
171: #if defined(TARGET_HAS_BFLT)
172: } else if (bprm.buf[0] == 'b'
173: && bprm.buf[1] == 'F'
174: && bprm.buf[2] == 'L'
175: && bprm.buf[3] == 'T') {
176: retval = load_flt_binary(&bprm,regs,infop);
177: #endif
178: } else {
179: fprintf(stderr, "Unknown binary format\n");
180: return -1;
181: }
182: }
183:
184: if(retval>=0) {
185: /* success. Initialize important registers */
186: do_init_thread(regs, infop);
187: return retval;
188: }
189:
190: /* Something went wrong, return the inode and free the argument pages*/
191: for (i=0 ; i<MAX_ARG_PAGES ; i++) {
192: free(bprm.page[i]);
193: }
194: return(retval);
195: }
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