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find.c
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find.c
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/*
* Copyright (c) 1999-2003 Smithsonian Astrophysical Observatory
*/
/*
*
* Find.c -- find files via the path environment variable
* (and related routines)
*
*/
#include <find.h>
/*
*
* private routines
*
*/
#define MAXBUFSIZE 8192
#ifndef HAVE_UNISTD_H
#define F_OK 0 /* does file exist */
#define X_OK 1 /* is it executable by caller */
#define W_OK 2 /* is it writable by caller */
#define R_OK 4 /* is it readable by caller */
#endif
/* not part of unistd.h but we need to differentiate directories */
#ifdef D_OK
#undef D_OK
#endif
#define D_OK 256 /* is it a directory */
#ifdef ANSI_FUNC
static int
amparse (char *mode)
#else
static int amparse(mode)
char *mode;
#endif
{
int xmode = 0;
xmode |= ( strpbrk(mode, "r") != NULL ? R_OK : 0 );
xmode |= ( strpbrk(mode, "w") != NULL ? W_OK : 0 );
xmode |= ( strpbrk(mode, "x") != NULL ? X_OK : 0 );
xmode |= ( strpbrk(mode, "f") != NULL ? F_OK : 0 );
xmode |= ( strpbrk(mode, "d") != NULL ? D_OK : 0 );
return xmode;
}
#ifdef ANSI_FUNC
static char *
findpath (char *name, char *mode, char *path)
#else
static char *findpath(name, mode, path)
char *name;
char *mode;
char *path;
#endif
{
char pathbuff[MAXBUFSIZE];
char namebuff[MAXBUFSIZE];
char tempbuff[MAXBUFSIZE];
char backmode[MAXBUFSIZE];
char *here, *found;
int len;
int mark = 0;
int skip = strpbrk(mode, ">") != NULL;
int pick = strpbrk(mode, "<") != NULL;
if ( skip && pick ) return NULL;
if ( (path==NULL) || ( name[0] == '.' && name[1] == '/' ) || name[0] == '/' )
return Access(name, mode);
strncpy(pathbuff, path, MAXBUFSIZE-1);
pathbuff[MAXBUFSIZE-1] = '\0';
path = pathbuff;
if ( (here = strpbrk(pathbuff, ":;")) ) {
mark = *here;
*here++ = '\0';
}
while ( path ) {
/* if there is an environment variable ... */
if ( strchr(path, '$') ) {
/* exand it */
ExpandEnv(path, tempbuff, MAXBUFSIZE);
/* make sure we could expand it (otherwise we get an infinite loop) */
if( !strchr(tempbuff, '$') ){
if ( (found = findpath(name, mode, tempbuff)) )
return found;
}
} else {
if ( !skip ) {
if ( !strcmp(".", path) ) path[0] = '\0';
strncpy(namebuff, path, MAXBUFSIZE-1);
namebuff[MAXBUFSIZE-1] = '\0';
len = strlen(namebuff);
if ( namebuff[0] && namebuff[len-1] != '/' ){
if( (len+1) <= (MAXBUFSIZE-1) ){
strcat(namebuff, "/");
len++;
}
/* filename is too large, so we can't find it */
else
return NULL;
}
if( len+strlen(name) <= MAXBUFSIZE-1 )
strcat(namebuff, name);
/* filename is too large, so we can't find it */
else
return NULL;
if ( (found = Access(namebuff, mode)) )
return found;
}
}
if ( mark == ';' ) {
if ( skip ) {
skip = 0;
/* Knock down the skip mode to select all
* directories in path after the first ";"
*/
strncpy(backmode, mode, MAXBUFSIZE-1);
backmode[MAXBUFSIZE-1] = '\0';
mode = backmode;
}
if ( pick ) return NULL;
}
path = here;
if ( here && (here = strpbrk(here, ":;")) ) {
mark = *here;
*here++ = '\0';
}
}
return NULL;
}
/*
*
* public routines
*
*/
/*
*
* ResolvePath -- resolve the path to remove . and .. entries
*
*/
#ifdef ANSI_FUNC
char *
ResolvePath (char *ibuf, char *obuf, int maxlen)
#else
char *ResolvePath(ibuf, obuf, maxlen)
char *ibuf;
char *obuf;
int maxlen;
#endif
{
char path[MAXBUFSIZE];
char *part[MAXBUFSIZE];
char *tbuf;
int i, j;
int len;
int npart=0;
/* if we have no path separators, we really don't have much to do! */
if( strchr(ibuf, '/') == NULL ){
strncpy(obuf, ibuf, maxlen-1);
obuf[maxlen-1] = '\0';
return(obuf);
}
/* if its just "/" or "/.", its easy */
if( !strcmp(ibuf, "/") || !strcmp(ibuf, "/.") ){
strncpy(obuf, "/", maxlen-1);
obuf[maxlen-1] = '\0';
return(obuf);
}
/* if we have a relative path to deal with, get current directory */
if( (*ibuf == '.') || ( (strchr(ibuf, '/') != NULL) && (*ibuf != '/') ) ){
if( !getcwd(path, MAXBUFSIZE) ){
*path = '\0';
}
}
else{
*path = '\0';
}
/* construct the total string we have to deal with */
len = strlen(path) + strlen(ibuf) + 1;
tbuf = (char *)xmalloc(len+1);
if( *path ){
strcpy(tbuf, path);
strcat(tbuf, "/");
strcat(tbuf, ibuf);
}
else{
strcpy(tbuf, ibuf);
}
/* construct the parts array from this string, removing / characters
and null-terminating each part */
for(i=0; i<len; i++){
if( tbuf[i] == '/' ){
tbuf[i] = '\0';
/* skip adjacent slashes */
if( tbuf[i+1] == '/' ) continue;
part[npart] = &tbuf[i+1];
npart++;
}
}
/* loop through the parts array and resolve the . and .. entries */
for(i=0; i<npart; i++){
/* for ".", just remove it */
if( !strcmp(part[i], ".") ){
part[i] = NULL;
}
/* for "..", also remove the previous part -- if possible */
else if( !strcmp(part[i], "..") ){
part[i] = NULL;
for(j=i-1; j>=0; j--){
if( part[j] ){
part[j] = NULL;
break;
}
}
}
}
/* construct a new string from the remaining parts */
*obuf = '\0';
len = 0;
for(i=0; i<npart; i++){
if( part[i] != NULL ){
if( len+(int)strlen(part[i])+1 <= maxlen-1 ){
strcat(obuf, "/");
strcat(obuf, part[i]);
len += strlen(part[i])+1;
}
else{
break;
}
}
}
/* free up buffer space */
if( tbuf ) free(tbuf);
/* return the string */
return(obuf);
}
#ifdef ANSI_FUNC
void
ExpandEnv (char *name, char *envname, int maxlen)
#else
void ExpandEnv(name, envname, maxlen)
char *name;
char *envname;
int maxlen;
#endif
{
char brace[2];
char tbuf[MAXBUFSIZE];
char *fullname=NULL;
char *mip;
char *ip;
char *s;
int len;
int i=0, j=0;
/* allocate temp working buffer (so dest can be same as source) */
if( !(fullname=(char *)xcalloc(maxlen, sizeof(char))) ) return;
/* process each character */
for(ip=name; *ip; ip++){
/* if its not beginning of an env, just store and loop */
if( *ip != '$' ){
fullname[i++] = *ip;
fullname[i] = '\0';
}
else{
mip = ip;
/* skip past '$' */
ip++;
/* skip past brace, if necessary */
if( *ip == '{' ){
brace[0] = '{';
ip++;
}
else if( *ip == '(' ){
brace[0] = '(';
ip++;
}
else
brace[0] = '\0';
/* get variable up to next white space */
for(*tbuf='\0', j=0;
(!isspace((int)*ip)) && (*ip != '"') && (*ip != '\'') && (*ip);
ip++){
/* look for trailing brace, if necessary */
if( *brace && *ip == (*brace == '(' ? ')' : '}') ){
ip++;
break;
}
/* a "/" will end the environment variable as well */
if( *ip == '/' ){
break;
}
tbuf[j++] = *ip;
tbuf[j] = '\0';
}
/* back up so we can process the white space in the outer loop */
ip--;
if( (s = (char *)getenv(tbuf)) != NULL ){
i += strlen(s);
if( i <= maxlen )
strcat(fullname, s);
}
/* if we don't recognize this macro, put it back onto the string */
else{
len = ip - mip + 1;
i += len;
if( i <= maxlen )
strncat(fullname, mip, len);
}
}
}
/* transfer to output buffer */
strncpy(envname, fullname, maxlen);
/* free up temp space */
if( fullname ) xfree(fullname);
}
#ifdef ANSI_FUNC
char *
Access (char *name, char *mode)
#else
char *Access (name, mode)
char *name;
char *mode;
#endif
{
struct stat info;
char fullname[MAXBUFSIZE];
char AccessName[MAXBUFSIZE];
ExpandEnv(name, fullname, MAXBUFSIZE);
if ( stat(fullname, &info) !=0 ) return NULL;
#if HAVE_MINGW32==0 && HAVE_CYGWIN==0
if ( mode ) {
int m = amparse(mode);
/* distinguish between directories and files */
if ( (m & D_OK) && !(info.st_mode & S_IFDIR) ) return NULL;
if ( !(m & D_OK) && (info.st_mode & S_IFDIR) ) return NULL;
if ( getuid() == info.st_uid ) {
if ( m & R_OK && !(info.st_mode & S_IRUSR) ) return NULL;
if ( m & W_OK && !(info.st_mode & S_IWUSR) ) return NULL;
if ( m & X_OK && !(info.st_mode & S_IXUSR) ) return NULL;
} else
if ( getgid() == info.st_gid ) {
if ( m & R_OK && !(info.st_mode & S_IRGRP) ) return NULL;
if ( m & W_OK && !(info.st_mode & S_IWGRP) ) return NULL;
if ( m & X_OK && !(info.st_mode & S_IXGRP) ) return NULL;
} else {
if ( m & R_OK && !(info.st_mode & S_IROTH) ) return NULL;
if ( m & W_OK && !(info.st_mode & S_IWOTH) ) return NULL;
if ( m & X_OK && !(info.st_mode & S_IXOTH) ) return NULL;
}
}
#endif
ResolvePath(fullname, AccessName, MAXBUFSIZE);
return(xstrdup(AccessName));
}
#ifdef ANSI_FUNC
char *
Find (char *name, char *mode, char *exten, char *path)
#else
char *Find (name, mode, exten, path)
char *name;
char *mode;
char *exten;
char *path;
#endif
{
char extenbuff[MAXBUFSIZE];
char namebuff[MAXBUFSIZE];
char *here, *found;
int len;
/* sanity check */
if( !name || !*name )
return NULL;
/* if its a WWW file, we just say 'yes' */
if( !strncmp(name, "ftp://", 6) ||
!strncmp(name, "http://", 7) ){
return(xstrdup(name));
}
if ( exten == NULL )
return findpath(name, mode, path);
strncpy(extenbuff, exten, MAXBUFSIZE-1);
extenbuff[MAXBUFSIZE-1] = '\0';
exten = extenbuff;
if ( (here = strpbrk(extenbuff, ":;")) ) *here++ = '\0';
while ( exten ) {
if ( exten[0] == '$' ) {
if ( (exten = (char *)getenv(&exten[1])) )
if ( (found = Find(name, mode, exten, path)) )
return found;
} else {
char *e = strstr(name, exten);
strncpy(namebuff, name, MAXBUFSIZE-1);
namebuff[MAXBUFSIZE-1] = '\0';
len = strlen(namebuff);
if ( (e==NULL) || ( e && *(e + len)) ){
if( len+strlen(exten) <= MAXBUFSIZE-1 )
strcat(namebuff, exten);
/* filename is too large, so we can't find it */
else
return NULL;
}
if ( (found = findpath(namebuff, mode, path)) )
return found;
}
exten = here;
if ( here && (here = strpbrk(here, ":;")) ) *here++ = '\0';
}
return NULL;
}