minix/test/test43.c

/* Tests for MINIX3 realpath(3) - by Erik van der Kouwe */
#define _POSIX_SOURCE 1
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <libgen.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#define MAX_ERROR 3

int subtest;
static const char *executable;

#include "common.c"

#define ERR (e(__LINE__))

static char *remove_last_path_component(char *path)
{
	char *current, *last;

	assert(path);

	/* find last slash */
	last = NULL;
	for (current = path; *current; current++)
		if (*current == '/')
			last = current;

	/* check path component */
	if (last)
	{
		if (strcmp(last + 1, ".") == 0) ERR;
		if (strcmp(last + 1, "..") == 0) ERR;
	}

	/* if only root path slash, we are done */
	if (last <= path)
		return NULL;

	/* chop off last path component */
	*last = 0;
	return path;
}

static int check_path_components(const char *path)
{
	char buffer[PATH_MAX + 1], *bufferpos;
	struct stat statbuf;

	assert(strlen(path) < sizeof(buffer));

	bufferpos = buffer;
	while (*path)
	{
		/* copy next path segment */
		do 
		{
			*(bufferpos++) = *(path++);
		} while (*path && *path != '/');
		*bufferpos = 0;

		/* 
		 * is this a valid path segment? if not, return errno.
		 * one exception: the last path component need not exist
		 * - unless it is actually a dangling symlink
		 */
		if (stat(buffer, &statbuf) < 0 &&
			(*path || errno != ENOENT ||
			lstat(buffer, &statbuf) == 0))
			return errno;
	}

	return 0;
}

static void check_realpath(const char *path, int expected_errno)
{
	char buffer[PATH_MAX + 1], *resolved_path;
	int expected_errno2;
	struct stat statbuf[2];

	assert(path);

	/* any errors in the path that realpath should report? */
	expected_errno2 = check_path_components(path);
	
	/* run realpath */
	errno = 0;
	resolved_path = realpath(path, buffer);

	/* do we get errors when expected? */
	if (expected_errno || expected_errno2)
	{
		if (resolved_path) ERR;
		if (errno != expected_errno && errno != expected_errno2) ERR;
		return;
	}

	/* do we get success when expected? */
	if (!resolved_path)
	{
		ERR;
		return;
	}
	errno = 0;

	/* do the paths point to the same file? (only check if exists) */
	if (stat(path,          &statbuf[0]) < 0) 
	{
		if (errno != ENOENT) { ERR; return; }
	}
	else
	{
		if (stat(resolved_path, &statbuf[1]) < 0) { ERR; return; }
		if (statbuf[0].st_dev != statbuf[1].st_dev) ERR;
		if (statbuf[0].st_ino != statbuf[1].st_ino) ERR;
	}

	/* is the path absolute? */
	if (resolved_path[0] != '/') ERR;

	/* is each path element allowable? */
	while (remove_last_path_component(resolved_path))
	{
		/* not a symlink? */
		if (lstat(resolved_path, &statbuf[1]) < 0) { ERR; return; }
		if ((statbuf[1].st_mode & S_IFMT) != S_IFDIR) ERR;
	}
}

static void check_realpath_step_by_step(const char *path, int expected_errno)
{
	char buffer[PATH_MAX + 1];
	const char *path_current;

	assert(path);
	assert(strlen(path) < sizeof(buffer));

	/* check the absolute path */
	check_realpath(path, expected_errno);

	/* try with different CWDs */
	for (path_current = path; *path_current; path_current++)
		if (path_current[0] == '/' && path_current[1])
		{
			/* set CWD */
			memcpy(buffer, path, path_current - path + 1);
			buffer[path_current - path + 1] = 0;
			if (chdir(buffer) < 0) { ERR; continue; }

			/* perform test */
			check_realpath(path_current + 1, expected_errno);
		}
}

static char *pathncat(char *buffer, size_t size, const char *path1, const char *path2)
{
	size_t len1, len2, lenslash;

	assert(buffer);
	assert(path1);
	assert(path2);

	/* check whether it fits */
	len1 = strlen(path1);
	len2 = strlen(path2);
	lenslash = (len1 > 0 && path1[len1 - 1] == '/') ? 0 : 1;
	if (len1 >= size || /* check individual components to avoid overflow */
		len2 >= size || 
		len1 + len2 + lenslash >= size)
		return NULL;

	/* perform the copy */
	memcpy(buffer, path1, len1);
	if (lenslash)
		buffer[len1] = '/';

	memcpy(buffer + len1 + lenslash, path2, len2 + 1);
	return buffer;
}

static void check_realpath_recurse(const char *path, int depth)
{
	DIR *dir;
	struct dirent *dirent;
	char pathsub[PATH_MAX + 1];
	struct stat st;

	/* check with the path itself */
	check_realpath_step_by_step(path, 0);

	/* don't go too deep */
	if (depth < 1)
		return;

	/* don't bother with non-directories. Due to timeouts in drivers we
	 * might not get expected results and takes way too long */
	if (stat(path, &st) != 0) {
		/* dangling symlinks may cause legitimate failures here */
		if (lstat(path, &st) != 0) ERR;
		return;
	}
	if (!S_ISDIR(st.st_mode))
		return;

	/* loop through subdirectories (including . and ..) */
	if (!(dir = opendir(path))) 
	{
		/* Opening some special files might result in errors when the
		 * corresponding hardware is not present, or simply when access
		 * rights prohibit access (e.g., /dev/log).
		 */
		if (errno != ENOTDIR
		    && errno != ENXIO && errno != EIO && errno != EACCES) {
			ERR;
		}
		return;
	}
	while ((dirent = readdir(dir)) != NULL)
	{
		/* build path */
		if (!pathncat(pathsub, sizeof(pathsub), path, dirent->d_name))
		{
			ERR;
			continue;
		}

		/* check path */
		check_realpath_recurse(pathsub, depth - 1);
	}
	if (closedir(dir) < 0) ERR;
}

#define PATH_DEPTH 4
#define PATH_BASE "/."
#define L(x) PATH_BASE "/link_" #x ".tmp"

static char basepath[PATH_MAX + 1];

static char *addbasepath(char *buffer, const char *path)
{
	size_t basepathlen, pathlen;
	
	/* assumption: both start with slash and neither end with it */
	assert(basepath[0] == '/');
	assert(basepath[strlen(basepath) - 1] != '/');
	assert(buffer);
	assert(path);
	assert(path[0] == '/');
	
	/* check result length */
	basepathlen = strlen(basepath);
	pathlen = strlen(path);
	if (basepathlen + pathlen > PATH_MAX)
	{
		printf("path too long\n");
		exit(-1);
	}

	/* concatenate base path and path */
	memcpy(buffer, basepath, basepathlen);
	memcpy(buffer + basepathlen, path, pathlen + 1);
	return buffer;
}

static void test_dirname(const char *path, const char *exp)
{
	char buffer[PATH_MAX];
	int i, j;
	size_t pathlen = strlen(path);
	char *pathout;

	assert(pathlen + 3 < PATH_MAX);

	/* try with no, one or two trailing slashes */
	for (i = 0; i < 3; i++)
	{
		/* no trailing slashes for empty string */
		if (pathlen < 1 && i > 0)
			continue;
			
		/* prepare buffer */
		strcpy(buffer, path);
		for (j = 0; j < i; j++)
			buffer[pathlen + j] = '/';
	
		buffer[pathlen + i] = 0;
	
		/* perform test */
		pathout = dirname(buffer);
		if (strcmp(pathout, exp) != 0)
			ERR;
	}
}

int main(int argc, char **argv)
{
	char buffer1[PATH_MAX + 1], buffer2[PATH_MAX + 1];
	subtest = 1;

	/* initialize */
	start(43);
	executable = argv[0];
	getcwd(basepath, sizeof(basepath));

	/* prepare some symlinks to make it more difficult */
	if (symlink("/",      addbasepath(buffer1, L(1))) < 0) ERR;
	if (symlink(basepath, addbasepath(buffer1, L(2))) < 0) ERR;

	/* perform some tests */
	check_realpath_recurse(basepath, PATH_DEPTH);

	/* now try with recursive symlinks */
	if (symlink(addbasepath(buffer1, L(3)), addbasepath(buffer2, L(3))) < 0) ERR;
	if (symlink(addbasepath(buffer1, L(5)), addbasepath(buffer2, L(4))) < 0) ERR;
	if (symlink(addbasepath(buffer1, L(4)), addbasepath(buffer2, L(5))) < 0) ERR;
	check_realpath_step_by_step(addbasepath(buffer1, L(3)), ELOOP);
	check_realpath_step_by_step(addbasepath(buffer1, L(4)), ELOOP);
	check_realpath_step_by_step(addbasepath(buffer1, L(5)), ELOOP);

	/* delete the symlinks */
	cleanup();

	/* also test dirname */
	test_dirname("", ".");	
	test_dirname(".", ".");	
	test_dirname("..", ".");	
	test_dirname("x", ".");	
	test_dirname("xy", ".");	
	test_dirname("x/y", "x");	
	test_dirname("xy/z", "xy");	
	test_dirname("x/yz", "x");	
	test_dirname("ab/cd", "ab");	
	test_dirname("x//y", "x");	
	test_dirname("xy//z", "xy");	
	test_dirname("x//yz", "x");	
	test_dirname("ab//cd", "ab");	
	test_dirname("/", "/");	
	test_dirname("/x", "/");	
	test_dirname("/xy", "/");	
	test_dirname("/x/y", "/x");	
	test_dirname("/xy/z", "/xy");	
	test_dirname("/x/yz", "/x");	
	test_dirname("/ab/cd", "/ab");	
	test_dirname("/x//y", "/x");	
	test_dirname("/xy//z", "/xy");	
	test_dirname("/x//yz", "/x");	
	test_dirname("/ab//cd", "/ab");	
	test_dirname("/usr/src", "/usr");	
	test_dirname("/usr/src/test", "/usr/src");	
	test_dirname("usr/src", "usr");	
	test_dirname("usr/src/test", "usr/src");	

	/* done */
	quit();
	return(-1);	/* impossible */
}