1 /* This file contains a few general purpose utility routines. 2 * 3 * The entry points into this file are 4 * copy_path: copy a path name from a path request from userland 5 * fetch_name: go get a path name from user space 6 * panic: something awful has occurred; MINIX cannot continue 7 * in_group: determines if group 'grp' is in rfp->fp_sgroups[] 8 */ 9 10 #include "fs.h" 11 #include <minix/callnr.h> 12 #include <minix/endpoint.h> 13 #include <unistd.h> 14 #include <stdlib.h> 15 #include <string.h> 16 #include <assert.h> 17 #include <time.h> 18 #include "file.h" 19 #include "vmnt.h" 20 21 /*===========================================================================* 22 * copy_path * 23 *===========================================================================*/ 24 int copy_path(char *dest, size_t size) 25 { 26 /* Go get the path for a path request. Put the result in in 'dest', which 27 * should be at least PATH_MAX in size. 28 */ 29 vir_bytes name; 30 size_t len; 31 32 assert(size >= PATH_MAX); 33 34 name = job_m_in.m_lc_vfs_path.name; 35 len = job_m_in.m_lc_vfs_path.len; 36 37 if (len > size) { /* 'len' includes terminating-nul */ 38 err_code = ENAMETOOLONG; 39 return(EGENERIC); 40 } 41 42 /* Is the string contained in the message? If not, perform a normal copy. */ 43 if (len > M_PATH_STRING_MAX) 44 return fetch_name(name, len, dest); 45 46 /* Just copy the path from the message */ 47 strncpy(dest, job_m_in.m_lc_vfs_path.buf, len); 48 49 if (dest[len - 1] != '\0') { 50 err_code = ENAMETOOLONG; 51 return(EGENERIC); 52 } 53 54 return(OK); 55 } 56 57 /*===========================================================================* 58 * fetch_name * 59 *===========================================================================*/ 60 int fetch_name(vir_bytes path, size_t len, char *dest) 61 { 62 /* Go get path and put it in 'dest'. */ 63 int r; 64 65 if (len > PATH_MAX) { /* 'len' includes terminating-nul */ 66 err_code = ENAMETOOLONG; 67 return(EGENERIC); 68 } 69 70 /* Check name length for validity. */ 71 if (len > SSIZE_MAX) { 72 err_code = EINVAL; 73 return(EGENERIC); 74 } 75 76 /* String is not contained in the message. Get it from user space. */ 77 r = sys_datacopy_wrapper(who_e, path, VFS_PROC_NR, (vir_bytes) dest, len); 78 if (r != OK) { 79 err_code = EINVAL; 80 return(r); 81 } 82 83 if (dest[len - 1] != '\0') { 84 err_code = ENAMETOOLONG; 85 return(EGENERIC); 86 } 87 88 return(OK); 89 } 90 91 /*===========================================================================* 92 * isokendpt_f * 93 *===========================================================================*/ 94 int isokendpt_f(const char *file, int line, endpoint_t endpoint, int *proc, 95 int fatal) 96 { 97 int failed = 0; 98 endpoint_t ke; 99 *proc = _ENDPOINT_P(endpoint); 100 if (endpoint == NONE) { 101 printf("VFS %s:%d: endpoint is NONE\n", file, line); 102 failed = 1; 103 } else if (*proc < 0 || *proc >= NR_PROCS) { 104 printf("VFS %s:%d: proc (%d) from endpoint (%d) out of range\n", 105 file, line, *proc, endpoint); 106 failed = 1; 107 } else if ((ke = fproc[*proc].fp_endpoint) != endpoint) { 108 if(ke == NONE) { 109 assert(fproc[*proc].fp_pid == PID_FREE); 110 } else { 111 printf("VFS %s:%d: proc (%d) from endpoint (%d) doesn't match " 112 "known endpoint (%d)\n", file, line, *proc, endpoint, 113 fproc[*proc].fp_endpoint); 114 assert(fproc[*proc].fp_pid != PID_FREE); 115 } 116 failed = 1; 117 } 118 119 if(failed && fatal) 120 panic("isokendpt_f failed"); 121 122 return(failed ? EDEADEPT : OK); 123 } 124 125 /*===========================================================================* 126 * in_group * 127 *===========================================================================*/ 128 int in_group(struct fproc *rfp, gid_t grp) 129 { 130 int i; 131 132 for (i = 0; i < rfp->fp_ngroups; i++) 133 if (rfp->fp_sgroups[i] == grp) 134 return(OK); 135 136 return(EINVAL); 137 } 138 139 /*===========================================================================* 140 * sys_datacopy_wrapper * 141 *===========================================================================*/ 142 int sys_datacopy_wrapper(endpoint_t src, vir_bytes srcv, 143 endpoint_t dst, vir_bytes dstv, size_t len) 144 { 145 /* Safe function to copy data from or to a user buffer. 146 * VFS has to be a bit more careful as a regular copy 147 * might trigger VFS action needed by VM while it's 148 * blocked on the kernel call. This wrapper tries the 149 * copy, invokes VM itself asynchronously if necessary, 150 * then tries the copy again. 151 * 152 * This function assumes it's between VFS and a user process, 153 * and therefore one of the endpoints is SELF (VFS). 154 */ 155 int r; 156 endpoint_t them = NONE; 157 vir_bytes themv = -1; 158 int writable = -1; 159 160 r = sys_datacopy_try(src, srcv, dst, dstv, len); 161 162 if(src == VFS_PROC_NR) src = SELF; 163 if(dst == VFS_PROC_NR) dst = SELF; 164 165 assert(src == SELF || dst == SELF); 166 167 if(src == SELF) { them = dst; themv = dstv; writable = 1; } 168 if(dst == SELF) { them = src; themv = srcv; writable = 0; } 169 170 assert(writable >= 0); 171 assert(them != SELF); 172 173 if(r == EFAULT) { 174 /* The copy has failed with EFAULT, this means the kernel has 175 * given up but it might not be a legitimate error. Ask VM. 176 */ 177 if((r=vm_vfs_procctl_handlemem(them, themv, len, writable)) != OK) { 178 return r; 179 } 180 181 r = sys_datacopy_try(src, srcv, dst, dstv, len); 182 } 183 184 return r; 185 } 186 187