1 /* This file contains a few general purpose utility routines. 2 * 3 * The entry points into this file are 4 * clock_timespec: ask the clock task for the real time 5 * copy_path: copy a path name from a path request from userland 6 * fetch_name: go get a path name from user space 7 * panic: something awful has occurred; MINIX cannot continue 8 * in_group: determines if group 'grp' is in rfp->fp_sgroups[] 9 */ 10 11 #include "fs.h" 12 #include <minix/callnr.h> 13 #include <minix/endpoint.h> 14 #include <unistd.h> 15 #include <stdlib.h> 16 #include <string.h> 17 #include <assert.h> 18 #include <time.h> 19 #include "file.h" 20 #include "vmnt.h" 21 22 /*===========================================================================* 23 * copy_path * 24 *===========================================================================*/ 25 int copy_path(char *dest, size_t size) 26 { 27 /* Go get the path for a path request. Put the result in in 'dest', which 28 * should be at least PATH_MAX in size. 29 */ 30 vir_bytes name; 31 size_t len; 32 33 assert(size >= PATH_MAX); 34 35 name = job_m_in.m_lc_vfs_path.name; 36 len = job_m_in.m_lc_vfs_path.len; 37 38 if (len > size) { /* 'len' includes terminating-nul */ 39 err_code = ENAMETOOLONG; 40 return(EGENERIC); 41 } 42 43 /* Is the string contained in the message? If not, perform a normal copy. */ 44 if (len > M_PATH_STRING_MAX) 45 return fetch_name(name, len, dest); 46 47 /* Just copy the path from the message */ 48 strncpy(dest, job_m_in.m_lc_vfs_path.buf, len); 49 50 if (dest[len - 1] != '\0') { 51 err_code = ENAMETOOLONG; 52 return(EGENERIC); 53 } 54 55 return(OK); 56 } 57 58 /*===========================================================================* 59 * fetch_name * 60 *===========================================================================*/ 61 int fetch_name(vir_bytes path, size_t len, char *dest) 62 { 63 /* Go get path and put it in 'dest'. */ 64 int r; 65 66 if (len > PATH_MAX) { /* 'len' includes terminating-nul */ 67 err_code = ENAMETOOLONG; 68 return(EGENERIC); 69 } 70 71 /* Check name length for validity. */ 72 if (len > SSIZE_MAX) { 73 err_code = EINVAL; 74 return(EGENERIC); 75 } 76 77 /* String is not contained in the message. Get it from user space. */ 78 r = sys_datacopy_wrapper(who_e, path, VFS_PROC_NR, (vir_bytes) dest, len); 79 if (r != OK) { 80 err_code = EINVAL; 81 return(r); 82 } 83 84 if (dest[len - 1] != '\0') { 85 err_code = ENAMETOOLONG; 86 return(EGENERIC); 87 } 88 89 return(OK); 90 } 91 92 /*===========================================================================* 93 * isokendpt_f * 94 *===========================================================================*/ 95 int isokendpt_f(const char *file, int line, endpoint_t endpoint, int *proc, 96 int fatal) 97 { 98 int failed = 0; 99 endpoint_t ke; 100 *proc = _ENDPOINT_P(endpoint); 101 if (endpoint == NONE) { 102 printf("VFS %s:%d: endpoint is NONE\n", file, line); 103 failed = 1; 104 } else if (*proc < 0 || *proc >= NR_PROCS) { 105 printf("VFS %s:%d: proc (%d) from endpoint (%d) out of range\n", 106 file, line, *proc, endpoint); 107 failed = 1; 108 } else if ((ke = fproc[*proc].fp_endpoint) != endpoint) { 109 if(ke == NONE) { 110 assert(fproc[*proc].fp_pid == PID_FREE); 111 } else { 112 printf("VFS %s:%d: proc (%d) from endpoint (%d) doesn't match " 113 "known endpoint (%d)\n", file, line, *proc, endpoint, 114 fproc[*proc].fp_endpoint); 115 assert(fproc[*proc].fp_pid != PID_FREE); 116 } 117 failed = 1; 118 } 119 120 if(failed && fatal) 121 panic("isokendpt_f failed"); 122 123 return(failed ? EDEADEPT : OK); 124 } 125 126 127 /*===========================================================================* 128 * clock_timespec * 129 *===========================================================================*/ 130 struct timespec clock_timespec(void) 131 { 132 /* This routine returns the time in seconds since 1.1.1970. MINIX is an 133 * astrophysically naive system that assumes the earth rotates at a constant 134 * rate and that such things as leap seconds do not exist. 135 */ 136 137 register int r; 138 struct timespec tv; 139 clock_t uptime; 140 clock_t realtime; 141 time_t boottime; 142 143 r = getuptime(&uptime, &realtime, &boottime); 144 if (r != OK) 145 panic("clock_timespec err: %d", r); 146 147 tv.tv_sec = boottime + (realtime/system_hz); 148 /* We do not want to overflow, and system_hz can be as high as 50kHz */ 149 assert(system_hz < LONG_MAX/40000); 150 tv.tv_nsec = (realtime%system_hz) * 40000 / system_hz * 25000; 151 return tv; 152 } 153 154 /*===========================================================================* 155 * in_group * 156 *===========================================================================*/ 157 int in_group(struct fproc *rfp, gid_t grp) 158 { 159 int i; 160 161 for (i = 0; i < rfp->fp_ngroups; i++) 162 if (rfp->fp_sgroups[i] == grp) 163 return(OK); 164 165 return(EINVAL); 166 } 167 168 /*===========================================================================* 169 * sys_datacopy_wrapper * 170 *===========================================================================*/ 171 int sys_datacopy_wrapper(endpoint_t src, vir_bytes srcv, 172 endpoint_t dst, vir_bytes dstv, size_t len) 173 { 174 /* Safe function to copy data from or to a user buffer. 175 * VFS has to be a bit more careful as a regular copy 176 * might trigger VFS action needed by VM while it's 177 * blocked on the kernel call. This wrapper tries the 178 * copy, invokes VM itself asynchronously if necessary, 179 * then tries the copy again. 180 * 181 * This function assumes it's between VFS and a user process, 182 * and therefore one of the endpoints is SELF (VFS). 183 */ 184 int r; 185 endpoint_t them = NONE; 186 vir_bytes themv = -1; 187 int writable = -1; 188 189 r = sys_datacopy_try(src, srcv, dst, dstv, len); 190 191 if(src == VFS_PROC_NR) src = SELF; 192 if(dst == VFS_PROC_NR) dst = SELF; 193 194 assert(src == SELF || dst == SELF); 195 196 if(src == SELF) { them = dst; themv = dstv; writable = 1; } 197 if(dst == SELF) { them = src; themv = srcv; writable = 0; } 198 199 assert(writable >= 0); 200 assert(them != SELF); 201 202 if(r == EFAULT) { 203 /* The copy has failed with EFAULT, this means the kernel has 204 * given up but it might not be a legitimate error. Ask VM. 205 */ 206 if((r=vm_vfs_procctl_handlemem(them, themv, len, writable)) != OK) { 207 return r; 208 } 209 210 r = sys_datacopy_try(src, srcv, dst, dstv, len); 211 } 212 213 return r; 214 } 215 216