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      1 /*
      2  * Copyright  2018 Alexey Dobriyan <adobriyan (at) gmail.com>
      3  *
      4  * Permission to use, copy, modify, and distribute this software for any
      5  * purpose with or without fee is hereby granted, provided that the above
      6  * copyright notice and this permission notice appear in all copies.
      7  *
      8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     15  */
     16 /* Test readlink /proc/self/map_files/... with minimum address. */
     17 #include <errno.h>
     18 #include <sys/types.h>
     19 #include <sys/stat.h>
     20 #include <fcntl.h>
     21 #include <stdio.h>
     22 #include <unistd.h>
     23 #include <sys/mman.h>
     24 #include <stdlib.h>
     25 
     26 static void pass(const char *fmt, unsigned long a, unsigned long b)
     27 {
     28 	char name[64];
     29 	char buf[64];
     30 
     31 	snprintf(name, sizeof(name), fmt, a, b);
     32 	if (readlink(name, buf, sizeof(buf)) == -1)
     33 		exit(1);
     34 }
     35 
     36 static void fail(const char *fmt, unsigned long a, unsigned long b)
     37 {
     38 	char name[64];
     39 	char buf[64];
     40 
     41 	snprintf(name, sizeof(name), fmt, a, b);
     42 	if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
     43 		return;
     44 	exit(1);
     45 }
     46 
     47 int main(void)
     48 {
     49 	const unsigned int PAGE_SIZE = sysconf(_SC_PAGESIZE);
     50 #ifdef __arm__
     51 	unsigned long va = 2 * PAGE_SIZE;
     52 #else
     53 	unsigned long va = 0;
     54 #endif
     55 	void *p;
     56 	int fd;
     57 	unsigned long a, b;
     58 
     59 	fd = open("/dev/zero", O_RDONLY);
     60 	if (fd == -1)
     61 		return 1;
     62 
     63 	p = mmap((void *)va, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0);
     64 	if (p == MAP_FAILED) {
     65 		if (errno == EPERM)
     66 			return 2;
     67 		return 1;
     68 	}
     69 
     70 	a = (unsigned long)p;
     71 	b = (unsigned long)p + PAGE_SIZE;
     72 
     73 	pass("/proc/self/map_files/%lx-%lx", a, b);
     74 	fail("/proc/self/map_files/ %lx-%lx", a, b);
     75 	fail("/proc/self/map_files/%lx -%lx", a, b);
     76 	fail("/proc/self/map_files/%lx- %lx", a, b);
     77 	fail("/proc/self/map_files/%lx-%lx ", a, b);
     78 	fail("/proc/self/map_files/0%lx-%lx", a, b);
     79 	fail("/proc/self/map_files/%lx-0%lx", a, b);
     80 	if (sizeof(long) == 4) {
     81 		fail("/proc/self/map_files/100000000%lx-%lx", a, b);
     82 		fail("/proc/self/map_files/%lx-100000000%lx", a, b);
     83 	} else if (sizeof(long) == 8) {
     84 		fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
     85 		fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
     86 	} else
     87 		return 1;
     88 
     89 	return 0;
     90 }
     91