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#if !defined(lint) && !defined(DOS)
static char rcsid[] = "$Id: canaccess.c 769 2007-10-24 00:15:40Z hubert@u.washington.edu $";
#endif
/*
* ========================================================================
* Copyright 2013-2020 Eduardo Chappa
* Copyright 2006-2007 University of Washington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* ========================================================================
*/
#include <system.h>
#include "bldpath.h"
#include "fnexpand.h"
#include "../charconv/utf8.h"
#include "../charconv/filesys.h"
#include "canaccess.h"
/*
* Useful definitions
*/
#ifdef _WINDOWS
#define ACCESS_IN_CWD(F,M) (can_access((F), (M)))
#define PATH_SEP ';'
#define FILE_SEP '\\'
#else /* UNIX */
#define ACCESS_IN_CWD(F,M) (-1)
#define PATH_SEP ':'
#define FILE_SEP '/'
#endif /* UNIX */
/*
* Check if we can access a file in a given way
*
* Args: file -- The file to check
* mode -- The mode ala the access() system call, see ACCESS_EXISTS
* and friends in alpine.h.
*
* Result: returns 0 if the user can access the file according to the mode,
* -1 if he can't (and errno is set).
*
*
*/
int
can_access(char *file, int mode)
{
#ifdef _WINDOWS
struct stat buf;
/*
* NOTE: The WinNT access call returns that every directory is readable and
* writable. We actually want to know if the write is going to fail, so we
* try it. We don't read directories in Windows so we skip implementing that.
*/
if(mode & WRITE_ACCESS && file && !our_stat(file, &buf) && (buf.st_mode & S_IFMT) == S_IFDIR){
char *testname;
int fd;
size_t l = 0;
/*
* We'd like to just call temp_nam here, since it creates a file
* and does what we want. However, temp_nam calls us!
*/
if((testname = malloc(MAXPATH * sizeof(char)))){
strncpy(testname, file, MAXPATH-1);
testname[MAXPATH-1] = '\0';
if(testname[0] && testname[(l=strlen(testname))-1] != '\\' &&
l+1 < MAXPATH){
l++;
strncat(testname, "\\", MAXPATH-strlen(testname)-1);
testname[MAXPATH-1] = '\0';
}
if(l+8 < MAXPATH &&
strncat(testname, "caXXXXXX", MAXPATH-strlen(testname)-1) && mktemp(testname)){
if((fd = our_open(testname, O_CREAT|O_EXCL|O_WRONLY|O_BINARY, 0600)) >= 0){
(void)close(fd);
our_unlink(testname);
free(testname);
/* success, drop through to access call */
}
else{
free(testname);
/* can't write in the directory */
return(-1);
}
}
else{
free(testname);
return(-1);
}
}
}
if(mode & EXECUTE_ACCESS) /* Windows access has no execute mode */
mode &= ~EXECUTE_ACCESS; /* and crashes because of it */
#endif /* WINDOWS */
return(our_access(file, mode));
}
/*----------------------------------------------------------------------
Check if we can access a file in a given way in the given path
Args: path -- The path to look for "file" in
file -- The file to check
mode -- The mode ala the access() system call, see ACCESS_EXISTS
and friends in alpine.h.
Result: returns 0 if the user can access the file according to the mode,
-1 if he can't (and errno is set).
----*/
int
can_access_in_path(char *path, char *file, int mode)
{
char tmp[MAXPATH];
int rv = -1;
if(!path || !*path || is_rooted_path(file)){
rv = can_access(file, mode);
}
else if(is_homedir_path(file)){
strncpy(tmp, file, sizeof(tmp));
tmp[sizeof(tmp)-1] = '\0';
rv = fnexpand(tmp, sizeof(tmp)) ? can_access(tmp, mode) : -1;
}
else if((rv = ACCESS_IN_CWD(file,mode)) < 0){
char path_copy[MAXPATH + 1], *p, *t;
if(strlen(path) < MAXPATH){
strncpy(path_copy, path, sizeof(path_copy));
path_copy[sizeof(path_copy)-1] = '\0';
for(p = path_copy; p && *p; p = t){
if((t = strchr(p, PATH_SEP)) != NULL)
*t++ = '\0';
snprintf(tmp, sizeof(tmp), "%s%c%s", p, FILE_SEP, file);
if((rv = can_access(tmp, mode)) == 0)
break;
}
}
}
return(rv);
}
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