cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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path.c (2288B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * I'm tired of doing "vsnprintf()" etc just to open a
      4 * file, so here's a "return static buffer with printf"
      5 * interface for paths.
      6 *
      7 * It's obviously not thread-safe. Sue me. But it's quite
      8 * useful for doing things like
      9 *
     10 *   f = open(mkpath("%s/%s.perf", base, name), O_RDONLY);
     11 *
     12 * which is what it's designed for.
     13 */
     14#include "path.h"
     15#include "cache.h"
     16#include <linux/kernel.h>
     17#include <limits.h>
     18#include <stdio.h>
     19#include <string.h>
     20#include <sys/types.h>
     21#include <sys/stat.h>
     22#include <dirent.h>
     23#include <unistd.h>
     24
     25static char bad_path[] = "/bad-path/";
     26/*
     27 * One hack:
     28 */
     29static char *get_pathname(void)
     30{
     31	static char pathname_array[4][PATH_MAX];
     32	static int idx;
     33
     34	return pathname_array[3 & ++idx];
     35}
     36
     37static char *cleanup_path(char *path)
     38{
     39	/* Clean it up */
     40	if (!memcmp(path, "./", 2)) {
     41		path += 2;
     42		while (*path == '/')
     43			path++;
     44	}
     45	return path;
     46}
     47
     48char *mkpath(const char *fmt, ...)
     49{
     50	va_list args;
     51	unsigned len;
     52	char *pathname = get_pathname();
     53
     54	va_start(args, fmt);
     55	len = vsnprintf(pathname, PATH_MAX, fmt, args);
     56	va_end(args);
     57	if (len >= PATH_MAX)
     58		return bad_path;
     59	return cleanup_path(pathname);
     60}
     61
     62int path__join(char *bf, size_t size, const char *path1, const char *path2)
     63{
     64	return scnprintf(bf, size, "%s%s%s", path1, path1[0] ? "/" : "", path2);
     65}
     66
     67int path__join3(char *bf, size_t size, const char *path1, const char *path2, const char *path3)
     68{
     69	return scnprintf(bf, size, "%s%s%s%s%s", path1, path1[0] ? "/" : "",
     70			 path2, path2[0] ? "/" : "", path3);
     71}
     72
     73bool is_regular_file(const char *file)
     74{
     75	struct stat st;
     76
     77	if (stat(file, &st))
     78		return false;
     79
     80	return S_ISREG(st.st_mode);
     81}
     82
     83/* Helper function for filesystems that return a dent->d_type DT_UNKNOWN */
     84bool is_directory(const char *base_path, const struct dirent *dent)
     85{
     86	char path[PATH_MAX];
     87	struct stat st;
     88
     89	snprintf(path, sizeof(path), "%s/%s", base_path, dent->d_name);
     90	if (stat(path, &st))
     91		return false;
     92
     93	return S_ISDIR(st.st_mode);
     94}
     95
     96bool is_executable_file(const char *base_path, const struct dirent *dent)
     97{
     98	char path[PATH_MAX];
     99	struct stat st;
    100
    101	snprintf(path, sizeof(path), "%s/%s", base_path, dent->d_name);
    102	if (stat(path, &st))
    103		return false;
    104
    105	return !S_ISDIR(st.st_mode) && (st.st_mode & S_IXUSR);
    106}