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magic/utils/path.c

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/* path.c
*
* *********************************************************************
* * Copyright (C) 1985, 1990 Regents of the University of California. *
* * Permission to use, copy, modify, and distribute this *
* * software and its documentation for any purpose and without *
* * fee is hereby granted, provided that the above copyright *
* * notice appear in all copies. The University of California *
* * makes no representations about the suitability of this *
* * software for any purpose. It is provided "as is" without *
* * express or implied warranty. Export of this software outside *
* * of the United States of America may require an export license. *
* *********************************************************************
*
* This file contains routines that implement a path mechanism, whereby
* several places may be searched for files.
*/
#ifndef lint
static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/utils/path.c,v 1.3 2009/05/13 15:03:18 tim Exp $";
#endif /* not lint */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <pwd.h>
#include <ctype.h>
#include <sys/param.h>
#ifdef HAVE_ZLIB
#include <zlib.h>
#endif
#include "tcltk/tclmagic.h"
#include "utils/magic.h"
#include "utils/hash.h"
#include "utils/malloc.h"
#include "utils/utils.h"
/* Library routines: */
/* extern char *getenv(); */
/* extern char *strcmp(); */
/* A hash table is used to keep track of the logins and variable expansions we've
* already looked up.
*/
static HashTable expansionTable;
static bool noTable = TRUE;
#ifdef FILE_LOCKS
bool FileLocking = TRUE;
#endif
/* Limit on how long a single file name may be: */
#define MAXSIZE MAXPATHLEN
/*-------------------------------------------------------------------
* PaAppend --
* Add a string to the designated path variable.
*
* pathptr is a pointer to the path variable; srcptr is the
* newstring is the new string to append to the path.
*/
void
PaAppend(char **pathptr, char *newstring)
{
int oldlength, addlength;
char *new;
oldlength = strlen(*pathptr);
addlength = strlen(newstring);
new = (char *)mallocMagic((unsigned) (oldlength + addlength + 2));
(void) strcpy(new, *pathptr);
new[oldlength] = ' ';
(void) strcpy(new + oldlength + 1, newstring);
freeMagic(*pathptr);
*pathptr = new;
}
/*-------------------------------------------------------------------
* PaExpand --
* This routine converts tilde notation and environment variable
* notation into standard directory names.
*
* Results:
* If the conversion was done successfully, then the return value
* is the number of bytes of space left in the destination area.
* If a user name couldn't be found in the password file, then
* -1 is returned.
*
* Side Effects:
* If the first character of the string indicated by psource is a
* tilde ("~") then the subsequent user name is converted to a login
* directory name and stored in the string indicated by dest. Then
* remaining characters in the file name at psource are copied to
* pdest (the file name is terminated by white space, a null character,
* or a colon) and psource is updated. Upon return, psource points
* to the terminating character in the source file name, and pdest
* points to the null character terminating the expanded name.
* If a tilde cannot be converted because the user name cannot
* be found, psource is still advanced past the current entry, but
* nothing is stored at the destination. At most size characters
* (including the terminating null character) will be stored at pdest.
* Note: the name "~" with no user name expands to the home directory.
*
* If the first character of the string indicated by psource is a
* dollar sign ("$") then the subsequent name is converted to the
* expansion of the indicated environment variable. If the environment
* variable does not exist and the indicated name is "CAD_ROOT", then
* we substitute the value of CAD_DIR passed down from the Makefile.
* Otherwise, we return error status -1.
*
*-------------------------------------------------------------------
*/
int
PaExpand(psource, pdest, size)
char **psource; /* Pointer to a pointer to the source string */
char **pdest; /* Pointer to a ptr to dest string area. */
int size; /* Number of bytes available at pdest */
{
char *ps, *pd;
struct passwd *passwd, *getpwnam();
char expandName[512], *string, *newEntry;
HashEntry *h;
int i, length;
size -= 1;
ps = *psource;
if (*ps == '~')
{
/* Strip off the login name from the front of the file name. */
pd = expandName;
for (i=0; ; i++)
{
*pd = *++ps;
if (isspace(*pd) || (*pd=='\0') || (*pd=='/') || (*pd==':'))
break;
if (i < 511) pd++;
}
*pd = '\0';
/* Lookup the login name in the hash table. Create a hash
* table if we don't have one already.
*/
if (noTable)
{
HashInit(&expansionTable, 16, 0);
noTable = FALSE;
}
h = HashFind(&expansionTable, expandName);
string = HashGetValue(h);
if (string != 0) goto gotname;
/* We haven't seen this name before. Look it up in the
* password file. If the name is "~", then just use the
* home directory.
*/
if (strcmp(expandName, "") == 0)
string = getenv("HOME");
else
{
string = NULL;
passwd = getpwnam(expandName);
if (passwd != NULL) string = passwd->pw_dir;
}
if (string != NULL)
{
newEntry = (char *) mallocMagic((unsigned) (strlen(string) + 1));
(void) strcpy(newEntry, string);
HashSetValue(h, newEntry);
}
else
{
/* No login entry. Skip the rest of the file name. */
while ((*ps != '\0') && !isspace(*ps) && (*ps != ':')) ps++;
*psource = ps;
return -1;
}
gotname: length = strlen(string);
if (length > size) length = size;
(void) strncpy(*pdest, string, length+1);
size -= length;
pd = *pdest+length;
}
else if (*ps == '$') /* (Possible) environment variable expansion */
{
char saveChar;
pd = expandName;
for (i=0; ; i++)
{
*pd = *++ps;
if (isspace(*pd) || (*pd=='\0') || (*pd=='/') || (*pd==':'))
break;
if ((i < 511) && (*pd != '{') && (*pd != '}')) pd++;
}
saveChar = *pd;
*pd = '\0';
/* Lookup the environment variable in the hash table. Make a new
* table if we don't have one already.
*/
if (noTable)
{
HashInit(&expansionTable, 16, 0);
noTable = FALSE;
}
h = HashFind(&expansionTable, expandName);
string = HashGetValue(h);
if (string != 0) goto gotvar;
/* We haven't seen this name before. Get it with "getenv".
*/
#ifdef MAGIC_WRAPPER
string = (char *)Tcl_GetVar(magicinterp, expandName, TCL_GLOBAL_ONLY);
#else
string = getenv(expandName);
#endif
if (string == NULL)
{
/* Check for CAD_ROOT = CAD_DIR, the only internal variable */
/* recognized (this is passed down from the Makefile). */
/* Note that in the MAGIC_WRAPPER version, CAD_ROOT was set */
/* as a Tcl variable in tcltk/tclmagic.c, such that if */
/* expandName == "CAD_ROOT", then string should not be NULL */
/* here. */
if (!strcmp(expandName, "CAD_ROOT"))
string = CAD_DIR;
else
{
*pd = saveChar;
ps = *psource;
goto noexpand;
}
}
newEntry = (char *) mallocMagic((unsigned) (strlen(string) + 1));
(void) strcpy(newEntry, string);
HashSetValue(h, newEntry);
gotvar: length = strlen(string);
if (length > size) length = size;
(void) strncpy(*pdest, string, length+1);
size -= length;
pd = *pdest+length;
}
else
{
/* No tilde or variable to expand. As a minor convenience, check
* to see if the first two characters of the name are "./". If so,
* then just skip over them.
*/
noexpand:
while (ps[0] == '.')
{
if (ps[1] == '/') ps += 2;
else
{
if ((ps[1] == 0) || (ps[1] == ':') || isspace(ps[1]))
ps += 1;
break;
}
}
pd = *pdest;
}
/* Copy the rest of the directory name from the source to the dest. */
while ((*ps != '\0') && !isspace(*ps) && (*ps != ':'))
if (size > 0)
{
*pd++ = *ps++;
size--;
}
else ps++;
*pd = 0;
*psource = ps;
*pdest = pd;
return size;
}
/* ----------------------------------------------------------------------------
* nextName --
* This local procedure is used to step through a path, adding a
* directory name from the path to a file name.
*
* Results:
* The return value is a pointer to a path-extended name, or
* NULL if the end of the path has been reached. If a tilde
* couldn't be expanded, then a zero-length string is returned.
*
* Side effects:
* The pointer at *ppath is updated to refer to the terminating
* character of the path entry used this time.
* ----------------------------------------------------------------------------
*/
char *
nextName(ppath, file, dest, size)
char **ppath; /* Pointer to a pointer to the next
* entry in the path.
*/
char *file; /* Pointer to a file name. */
char *dest; /* Place to build result name. */
int size; /* Size of result area. */
{
char *p;
/* Don't bother with NULL paths */
if (*ppath == 0) return NULL;
/* Skip leading blanks and colons. Then make sure that there's
* another entry in the path.
*/
while (isspace(**ppath) || (**ppath == ':')) *ppath += 1;
if (**ppath == 0) return NULL;
/* Grab the next directory name and terminate it with a slash if
* there isn't one there already.
*/
p = dest;
dest[size-1] = 0;
size = PaExpand(ppath, &p, size);
if (**ppath) *ppath += 1; /* Skip the terminating character. */
if (size < 0)
{
dest[0] = 0;
return dest;
}
if ((p != dest) && (*(p-1) != '/'))
{
*p++ = '/';
size -= 1;
}
if (size < strlen(file)) strncpy(p, file, size);
else strcpy(p, file);
return dest;
}
/*-------------------------------------------------------------------
* PaLockOpen --
* This routine does a file lookup using the current path and
* supplying a default extension.
*
* Results:
* A pointer to a FILE, or NULL if the file couldn't be found.
*
* Side Effects:
* If ext is specified, then it is tacked onto the end of
* the given file name. If the first character of the
* file name is "~" or "/" or if nosearch is TRUE, then we try
* to look up the file with the original name, doing tilde
* expansion of course and returning that result. If none of
* these conditions is met, we go through the path trying to
* look up the file once for each path entry by prepending the
* path entry to the original file name. This concatenated name
* is stored in a static string and made available to the caller
* through prealName if the open succeeds. If the entire path is
* tried, and still nothing works, then we try each entry in the
* library path next.
* Note: the static string will be trashed on the next call to this
* routine. Also, note that no individual file name is allowed to
* be more than MAXSIZE characters long. Excess characters are lost.
*
* Path Format:
* A path is a string containing directory names separated by
* colons or white space. Tilde notation may be used within paths.
*-------------------------------------------------------------------
*/
FILE *
PaLockOpen(file, mode, ext, path, library, pRealName, is_locked)
char *file; /* Name of the file to be opened. */
char *mode; /* The file mode, as given to fopen. */
char *ext; /* The extension to be added to the file name,
* or NULL. Note: this string must include
* the dot (or whatever separator you use).
*/
char *path; /* A search path: a list of directory names
* separated by colons or blanks. To use
* only the working directory, use "." for
* the path.
*/
char *library; /* A 2nd path containing library names. Can be
* NULL to indicate no library.
*/
char **pRealName; /* Pointer to a location that will be filled
* in with the address of the real name of
* the file that was successfully opened.
* If NULL, then nothing is stored.
*/
bool *is_locked; /* Pointer to a location to store the result
* of the attempt to grab an advisory lock
* on the file. If NULL, then nothing is
* stored.
*/
{
char extendedName[MAXSIZE], *p1, *p2;
static char realName[MAXSIZE];
int length, extLength, i;
FILE *f;
if (file == NULL) return (FILE *) NULL;
if (file[0] == '\0') return (FILE *) NULL;
if (pRealName != NULL) (*pRealName) = realName;
/* See if we must supply an extension. */
length = strlen(file);
if (length >= MAXSIZE) length = MAXSIZE - 1;
if (ext != NULL)
{
(void) strncpy(extendedName, file, length + 1);
i = MAXSIZE - 1 - length;
extLength = strlen(ext);
if (extLength > i) extLength = i;
/* (Modified by Tim, 1/13/2015; assume that "file" has */
/* the extension already stripped, therefore always add */
/* the extension if one is specified. This allows the */
/* code to distinguish between, say, "a.mag" and */
/* "a.mag.mag".) */
/* If the extension is already on the name, don't add it */
// if ((length < extLength) || ((extLength > 0)
// && (strcmp(ext, file + length - extLength))))
(void) strncpy(&(extendedName[length]), ext, extLength + 1);
extendedName[MAXSIZE-1] = '\0';
file = extendedName;
}
/* If the first character of the file name is a tilde or dollar sign,
* do tilde or environment variable expansion but don't touch a search
* path.
*/
if (file[0] == '~' || file[0] == '$')
{
p1 = realName;
p2 = file;
if (PaExpand(&p2, &p1, MAXSIZE) < 0) return NULL;
#ifdef FILE_LOCKS
if (FileLocking)
return flock_open(realName, mode, is_locked);
else
#endif
return fopen(realName, mode);
}
/* If we were already given a full rooted file name,
* or a relative pathname, just use it.
*/
if (file[0] == '/'
|| (file[0] == '.' && (strcmp(file, ".") == 0
|| strncmp(file, "./", 2) == 0
|| strcmp(file, "..") == 0
|| strncmp(file, "../", 3) == 0)))
{
(void) strncpy(realName, file, MAXSIZE-1);
realName[MAXSIZE-1] = '\0';
#ifdef FILE_LOCKS
if (FileLocking)
return flock_open(realName, mode, is_locked);
else
#endif
return fopen(realName, mode);
}
/* Now try going through the path, one entry at a time. */
while (nextName(&path, file, realName, MAXSIZE) != NULL)
{
if (*realName == 0) continue;
#ifdef FILE_LOCKS
if (FileLocking)
f = flock_open(realName, mode, is_locked);
else
#endif
f = fopen(realName, mode);
if (f != NULL) return f;
// If any error other than "file not found" occurred,
// then halt immediately.
if (errno != ENOENT) return NULL;
}
/* We've tried the path and that didn't work. Now go through
* the library area, one entry at a time.
*/
if (library == NULL) return NULL;
while (nextName(&library, file, realName, MAXSIZE) != NULL)
{
#ifdef FILE_LOCKS
if (FileLocking)
f = flock_open(realName, mode, is_locked);
else
#endif
f = fopen(realName, mode);
if (f != NULL) return f;
// If any error other than "file not found" occurred,
// then halt immediately.
if (errno != ENOENT) return NULL;
}
return NULL;
}
#ifdef HAVE_ZLIB
/*-------------------------------------------------------------------
* PaZOpen --
* This routine does a file lookup using the current path and
* supplying a default extension. The return type is a Zlib-
* type compressed stream.
*
* Results:
* A gzFile type, or NULL if the file couldn't be found.
*
* Side Effects:
* See notes for PaLockOpen() for handling of extensions.
*
* Path Format:
* A path is a string containing directory names separated by
* colons or white space. Tilde notation may be used within paths.
*-------------------------------------------------------------------
*/
gzFile
PaZOpen(file, mode, ext, path, library, pRealName)
char *file; /* Name of the file to be opened. */
char *mode; /* The file mode, as given to gzopen. */
char *ext; /* The extension to be added to the file name,
* or NULL. Note: this string must include
* the dot (or whatever separator you use).
*/
char *path; /* A search path: a list of directory names
* separated by colons or blanks. To use
* only the working directory, use "." for
* the path.
*/
char *library; /* A 2nd path containing library names. Can be
* NULL to indicate no library.
*/
char **pRealName; /* Pointer to a location that will be filled
* in with the address of the real name of
* the file that was successfully opened.
* If NULL, then nothing is stored.
*/
{
char extendedName[MAXSIZE], *p1, *p2;
static char realName[MAXSIZE];
int length, extLength, i;
gzFile f;
if (file == NULL) return (gzFile) NULL;
if (file[0] == '\0') return (gzFile) NULL;
if (pRealName != NULL) (*pRealName) = realName;
/* See if we must supply an extension. */
length = strlen(file);
if (length >= MAXSIZE) length = MAXSIZE - 1;
if (ext != NULL)
{
(void) strncpy(extendedName, file, length + 1);
i = MAXSIZE - 1 - length;
extLength = strlen(ext);
if (extLength > i) extLength = i;
(void) strncpy(&(extendedName[length]), ext, extLength + 1);
extendedName[MAXSIZE-1] = '\0';
file = extendedName;
}
/* If the first character of the file name is a tilde or dollar sign,
* do tilde or environment variable expansion but don't touch a search
* path.
*/
if (file[0] == '~' || file[0] == '$')
{
p1 = realName;
p2 = file;
if (PaExpand(&p2, &p1, MAXSIZE) < 0) return NULL;
return gzopen(realName, mode);
}
/* If we were already given a full rooted file name,
* or a relative pathname, just use it.
*/
if (file[0] == '/'
|| (file[0] == '.' && (strcmp(file, ".") == 0
|| strncmp(file, "./", 2) == 0
|| strcmp(file, "..") == 0
|| strncmp(file, "../", 3) == 0)))
{
(void) strncpy(realName, file, MAXSIZE-1);
realName[MAXSIZE-1] = '\0';
return gzopen(realName, mode);
}
/* Now try going through the path, one entry at a time. */
while (nextName(&path, file, realName, MAXSIZE) != NULL)
{
if (*realName == 0) continue;
f = gzopen(realName, mode);
if (f != NULL) return f;
// If any error other than "file not found" occurred,
// then halt immediately.
if (errno != ENOENT) return NULL;
}
/* We've tried the path and that didn't work. Now go through
* the library area, one entry at a time.
*/
if (library == NULL) return NULL;
while (nextName(&library, file, realName, MAXSIZE) != NULL)
{
f = gzopen(realName, mode);
if (f != NULL) return f;
// If any error other than "file not found" occurred,
// then halt immediately.
if (errno != ENOENT) return NULL;
}
return NULL;
}
#endif /* HAVE_ZLIB */
/*
*-------------------------------------------------------------------
* PaOpen --
* This is a wrapper for PaLockOpen() that is backwardly-
* compatible with the original (non-file-locking) PaOpen(),
* and is here because it's a pain to add an extra argument
* to every call to PaOpen() when only .mag files are locked.
*
* Results:
* See PaLockOpen()
*
* Side Effects:
* See PaLockOpen()
*
*-------------------------------------------------------------------
*/
FILE *
PaOpen(file, mode, ext, path, library, pRealName)
char *file; /* Name of the file to be opened. */
char *mode; /* The file mode, as given to fopen. */
char *ext; /* The extension to be added to the file name,
* or NULL. Note: this string must include
* the dot (or whatever separator you use).
*/
char *path; /* A search path: a list of directory names
* separated by colons or blanks. To use
* only the working directory, use "." for
* the path.
*/
char *library; /* A 2nd path containing library names. Can be
* NULL to indicate no library.
*/
char **pRealName; /* Pointer to a location that will be filled
* in with the address of the real name of
* the file that was successfully opened.
* If NULL, then nothing is stored.
*/
{
return PaLockOpen(file, mode, ext, path, library, pRealName, NULL);
}
/*
* ----------------------------------------------------------------------------
* PaSubsWD --
*
* Replaces all uses of the working directory in a path
* by some fixed directory.
*
* Results:
* The return result is a path that is just like the path
* argument except that every implicit or explicit use of
* the working directory is replaced by the newWD argument.
* The result is a static array, which will be trashed on
* the next call to this procedure.
*
* Side effects:
* None.
* ----------------------------------------------------------------------------
*/
char *
PaSubsWD(path, newWD)
char *path; /* Path in which to substitute. */
char *newWD; /* New working directory to be used. Must
* end in a slash.
*/
{
#define NEWPATHSIZE 1000
static char newPath[NEWPATHSIZE];
char *pOld, *pNew, *pWD;
int spaceLeft;
pOld = path;
pNew = newPath;
spaceLeft = NEWPATHSIZE;
while (TRUE)
{
/* Scan through the old path, copying separators to the new
* path until getting the first character of the directory.
*/
while (isspace(*pOld) || (*pOld == ':'))
{
if (spaceLeft <= 0) goto subsDone;
spaceLeft -= 1;
*pNew++ = *pOld++;
}
/* If the first character of the directory isn't a "/", "$", or "~",
* then add in the new directory name in front of it in newPath.
*/
if ((*pOld != '/') && (*pOld != '~') && (*pOld != '$') && (*pOld != 0))
{
pWD = newWD;
while (*pWD != 0)
{
if (spaceLeft <= 0) goto subsDone;
spaceLeft -= 1;
*pNew++ = *pWD++;
}
}
/* Add in the rest of the path entry from the old path to the new. */
while ((!isspace(*pOld)) && (*pOld != ':') && (*pOld != 0))
{
if (spaceLeft <= 0) goto subsDone;
spaceLeft -= 1;
*pNew++ = *pOld++;
}
/* See if we're done. */
if (*pOld == 0) break;
}
subsDone: if (spaceLeft > 0) *pNew = 0;
else newPath[NEWPATHSIZE-1] = 0;
return newPath;
}
/*
* ----------------------------------------------------------------------------
* PaEnum --
*
* Call a client procedure with each directory in a path
* prepended to a filename. The client procedure is as
* follows:
*
* int
* (*proc)(name, cdata)
* char *name; /# A directory in the path prepended to
* # a file name.
* #/
* ClientData *cdata; /# Provided by caller #/
* {
* }
*
* The client procedure should return 0 normally, or 1 to abort
* the path enumeration. If a directory in the search path
* refers to a non-existent user name (using the ~user syntax),
* we skip that component.
*
* Results:
* Returns 0 if all the clients returned 0, or 1 if
* some client returned 1. When a client returns 1
* we abort the enumeration.
*
* Side effects:
* Calls the client procedure.
*
* ----------------------------------------------------------------------------
*/
int
PaEnum(path, file, proc, cdata)
char *path; /* Search path */
char *file; /* Each element of the search path is prepended to
* this file name and passed to the client.
*/
int (*proc)(); /* Client procedure */
ClientData cdata; /* Passed to (*proc)() */
{
char component[MAXSIZE], *next;
while (next = nextName(&path, file, component, sizeof component))
if (next[0] && (*proc)(next, cdata))
return (1);
return (0);
}
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