1 /** @file 2 Implementation of the Posix access() function. 3 4 Copyright (c) 2011, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials are licensed and made available under 6 the terms and conditions of the BSD License that accompanies this distribution. 7 The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 **/ 13 #include <LibConfig.h> 14 #include <sys/EfiCdefs.h> 15 16 #include <ctype.h> 17 #include <errno.h> 18 #include <sys/stat.h> 19 #include <string.h> 20 #include <unistd.h> 21 #include <sys/syslimits.h> 22 23 /** Save some typing later on. */ 24 #define GOOD_MODE (F_OK | X_OK | W_OK | R_OK) 25 26 /** Determine accessibility of a file. 27 The access() function checks the file, named by the pathname pointed to by 28 the Path argument, for accessibility according to the bit pattern contained 29 in Mode. 30 31 The value of Mode is either the bitwise-inclusive OR of the access 32 permissions to be checked (R_OK, W_OK, X_OK) or the existence test (F_OK). 33 34 If Path ends in '/' or '\\', the target must be a directory, otherwise it doesn't matter. 35 A file is executable if it is NOT a directory and it ends in ".efi". 36 37 @param[in] Path Path or name of the file to be checked. 38 @param[in] Mode Access permissions to check for. 39 40 @retval 0 Successful completion. 41 @retval -1 File is not accessible with the given Mode. The error condition 42 is indicated by errno. Values of errno specific to the access 43 function include: EACCES, ENOENT, ENOTDIR, ENAMETOOLONG 44 **/ 45 int 46 access( 47 const char *Path, 48 int Mode 49 ) 50 { 51 struct stat FileStat; 52 int retval = -1; 53 size_t PLength; 54 uint32_t WantDir; 55 uint32_t DirMatch; 56 57 if((Path == NULL) || ((Mode & ~GOOD_MODE) != 0)) { 58 errno = EINVAL; 59 } 60 else { 61 PLength = strlen(Path); 62 if(PLength > PATH_MAX) { 63 errno = ENAMETOOLONG; 64 } 65 else { 66 retval = stat(Path, &FileStat); 67 if(retval == 0) { 68 /* Path exists. FileStat now holds valid information. */ 69 WantDir = isDirSep(Path[PLength - 1]); // Does Path end in '/' or '\\' ? 70 DirMatch = (! WantDir && (! S_ISDIR(FileStat.st_mode))); 71 72 /* Test each permission individually. */ 73 do { 74 if(Mode == F_OK) { /* Existence test. */ 75 if(DirMatch) { /* This is a directory or file as desired. */ 76 retval = 0; 77 } 78 else { 79 /* Indicate why we failed the test. */ 80 errno = (WantDir) ? ENOTDIR : EISDIR; 81 } 82 break; /* F_OK does not combine with any other tests. */ 83 } 84 if(Mode & R_OK) { 85 if((FileStat.st_mode & READ_PERMS) == 0) { 86 /* No read permissions. 87 For UEFI, everything should have READ permissions. 88 */ 89 errno = EDOOFUS; /* Programming Error. */ 90 break; 91 } 92 } 93 if(Mode & W_OK) { 94 if((FileStat.st_mode & WRITE_PERMS) == 0) { 95 /* No write permissions. */ 96 errno = EACCES; /* Writing is not OK. */ 97 break; 98 } 99 } 100 if(Mode & X_OK) { 101 /* In EDK II, executable files end in ".efi" */ 102 if(strcmp(&Path[PLength-4], ".efi") != 0) { 103 /* File is not an executable. */ 104 errno = EACCES; 105 break; 106 } 107 } 108 retval = 0; 109 } while(FALSE); 110 } 111 else { 112 /* File or path does not exist. */ 113 errno = ENOENT; 114 } 115 } 116 } 117 return retval; 118 } 119
