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 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 infop->host_argv = argv; 166 167 if(retval>=0) { 168 if (bprm.buf[0] == 0x7f 169 && bprm.buf[1] == 'E' 170 && bprm.buf[2] == 'L' 171 && bprm.buf[3] == 'F') { 172 retval = load_elf_binary(&bprm,regs,infop); 173 #if defined(TARGET_HAS_BFLT) 174 } else if (bprm.buf[0] == 'b' 175 && bprm.buf[1] == 'F' 176 && bprm.buf[2] == 'L' 177 && bprm.buf[3] == 'T') { 178 retval = load_flt_binary(&bprm,regs,infop); 179 #endif 180 } else { 181 fprintf(stderr, "Unknown binary format\n"); 182 return -1; 183 } 184 } 185 186 if(retval>=0) { 187 /* success. Initialize important registers */ 188 do_init_thread(regs, infop); 189 return retval; 190 } 191 192 /* Something went wrong, return the inode and free the argument pages*/ 193 for (i=0 ; i<MAX_ARG_PAGES ; i++) { 194 free(bprm.page[i]); 195 } 196 return(retval); 197 } 198