The Tor Browser: config/pathsub.c@97036ab72558 (annotated)

config/pathsub.c@97036ab72558 (annotated)

config/pathsub.c

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
 ** Pathname subroutines.
 **
 ** Brendan Eich, 8/29/95
 */
 #include <assert.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/stat.h>
 #include "pathsub.h"
 #ifdef USE_REENTRANT_LIBC
 #include <libc_r.h>
 #endif
 #ifdef SUNOS4
 #include "sunos4.h"
 #endif
 #ifndef D_INO
 #define D_INO	d_ino
 #endif
 char *program;
 void
 fail(char *format, ...)
 {
     int error;
     va_list ap;
 #ifdef USE_REENTRANT_LIBC
     R_STRERROR_INIT_R();
 #endif
     error = errno;
     fprintf(stderr, "%s: ", program);
     va_start(ap, format);
     vfprintf(stderr, format, ap);
     va_end(ap);
     if (error) {
 #ifdef USE_REENTRANT_LIBC
     R_STRERROR_R(errno);
 	fprintf(stderr, ": %s", r_strerror_r);
 #else
 	fprintf(stderr, ": %s", strerror(errno));
 #endif
     }
     putc('\n', stderr);
     exit(1);
 }
 char *
 getcomponent(char *path, char *name)
 {
     if (*path == '\0')
 	return 0;
     if (*path == '/') {
 	*name++ = '/';
     } else {
 	do {
 	    *name++ = *path++;
 	} while (*path != '/' && *path != '\0');
     }
     *name = '\0';
     while (*path == '/')
 	path++;
     return path;
 }
 #ifdef LAME_READDIR
 #include <sys/param.h>
 /*
 ** The static buffer in Unixware's readdir is too small.
 */
 struct dirent *readdir(DIR *d)
 {
         static struct dirent *buf = NULL;
         if(buf == NULL)
                 buf = (struct dirent *) malloc(sizeof(struct dirent) + MAXPATHLEN);
         return(readdir_r(d, buf));
 }
 #endif
 char *
 ino2name(ino_t ino)
 {
     DIR *dp;
     struct dirent *ep;
     char *name;
     dp = opendir("..");
     if (!dp)
 	fail("cannot read parent directory");
     for (;;) {
 	if (!(ep = readdir(dp)))
 	    fail("cannot find current directory");
 	if (ep->D_INO == ino)
 	    break;
     }
     name = xstrdup(ep->d_name);
     closedir(dp);
     return name;
 }
 void *
 xmalloc(size_t size)
 {
     void *p = malloc(size);
     if (!p)
 	fail("cannot allocate %u bytes", size);
     return p;
 }
 char *
 xstrdup(char *s)
 {
     return strcpy(xmalloc(strlen(s) + 1), s);
 }
 char *
 xbasename(char *path)
 {
     char *cp;
     while ((cp = strrchr(path, '/')) && cp[1] == '\0')
 	*cp = '\0';
     if (!cp) return path;
     return cp + 1;
 }
 void
 xchdir(char *dir)
 {
     if (chdir(dir) < 0)
 	fail("cannot change directory to %s", dir);
 }
 int
 relatepaths(char *from, char *to, char *outpath)
 {
     char *cp, *cp2;
     int len;
     char buf[NAME_MAX];
     assert(*from == '/' && *to == '/');
     for (cp = to, cp2 = from; *cp == *cp2; cp++, cp2++)
 	if (*cp == '\0')
 	    break;
     while (cp[-1] != '/')
 	cp--, cp2--;
     if (cp - 1 == to) {
 	/* closest common ancestor is /, so use full pathname */
 	len = strlen(strcpy(outpath, to));
 	if (outpath[len] != '/') {
 	    outpath[len++] = '/';
 	    outpath[len] = '\0';
 	}
     } else {
 	len = 0;
 	while ((cp2 = getcomponent(cp2, buf)) != 0) {
 	    strcpy(outpath + len, "../");
 	    len += 3;
 	}
 	while ((cp = getcomponent(cp, buf)) != 0) {
 	    sprintf(outpath + len, "%s/", buf);
 	    len += strlen(outpath + len);
 	}
     }
     return len;
 }
 void
 reversepath(char *inpath, char *name, int len, char *outpath)
 {
     char *cp, *cp2;
     char buf[NAME_MAX];
     struct stat sb;
     cp = strcpy(outpath + PATH_MAX - (len + 1), name);
     cp2 = inpath;
     while ((cp2 = getcomponent(cp2, buf)) != 0) {
 	if (strcmp(buf, ".") == 0)
 	    continue;
 	if (strcmp(buf, "..") == 0) {
 	    if (stat(".", &sb) < 0)
 		fail("cannot stat current directory");
 	    name = ino2name(sb.st_ino);
 	    len = strlen(name);
 	    cp -= len + 1;
 	    strcpy(cp, name);
 	    cp[len] = '/';
 	    free(name);
 	    xchdir("..");
 	} else {
 	    cp -= 3;
 	    strncpy(cp, "../", 3);
 	    xchdir(buf);
 	}
     }
     strcpy(outpath, cp);
 }

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config/pathsub.c@97036ab72558 (annotated)

config/pathsub.c