/*

* MIT License

*

* Copyright (c) 2019 Jianhui Zhao <zhaojh329@gmail.com>

*

* Permission is hereby granted, free of charge, to any person obtaining a copy

* of this software and associated documentation files (the "Software"), to deal

* in the Software without restriction, including without limitation the rights

* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

* copies of the Software, and to permit persons to whom the Software is

* furnished to do so, subject to the following conditions:

*

* The above copyright notice and this permission notice shall be included in all

* copies or substantial portions of the Software.

*

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

* SOFTWARE.

*/

#include <sys/stat.h>

#include <mntent.h>

#include <stdio.h>

#include <stdint.h>

#include <string.h>

#include <ctype.h>

#include <unistd.h>

#include "utils.h"

int find_login(char *buf, int len)

{

FILE *fp = popen("which login", "r");

if (fp) {

if (fgets(buf, len, fp))

buf[strlen(buf) - 1] = 0;

pclose(fp);

if (!buf[0])

return -1;

return 0;

}

return -1;

}

bool valid_id(const char *id)

{

while (*id) {

if (!isalnum(*id) && *id != '-' && *id != '_')

return false;

id++;

}

return true;

}

/* reference from https://tools.ietf.org/html/rfc4648#section-4 */

int b64_encode(const void *src, size_t srclen, void *dest, size_t destsize)

{

char *Base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

const uint8_t *input = src;

char *output = dest;

while (srclen > 0) {

int skip = 1;

int i0 = input[0] >> 2;

int i1 = (input[0] & 0x3) << 4;

int i2 = 64;

int i3 = 64;

if (destsize < 5)

return -1;

if (srclen > 1) {

skip++;

i1 += input[1] >> 4;

i2 = (input[1] & 0xF) << 2;

if (srclen > 2) {

i2 += input[2] >> 6;

i3 = input[2] & 0x3F;

skip++;

}

}

*output++ = Base64[i0];

*output++ = Base64[i1];

*output++ = Base64[i2];

*output++ = Base64[i3];

input += skip;

srclen -= skip;

destsize -= 4;

}

*output++ = 0;

return output - (char *) dest - 1;

}

const char *format_size(size_t size)

{

static char str[64];

if (size < 1024)

sprintf(str, "%zu B", size);

else if (size < 1024 * 1024)

sprintf(str, "%.2f KB", size / 1024.0);

else

sprintf(str, "%.2f MB", size / 1024.0 / 1024.0);

return str;

}

/*

* Given any file (or directory), find the mount table entry for its

* filesystem.

*/

struct mntent *find_mount_point(const char *name)

{

struct mntent *ment;

dev_t devno_of_name;

struct stat s;

FILE *mtab_fp;

if (stat(name, &s) < 0)

return NULL;

devno_of_name = s.st_dev;

if (S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode))

return NULL;

mtab_fp = setmntent("/etc/mtab", "r");

if (!mtab_fp)

return NULL;

while ((ment = getmntent(mtab_fp))) {

if (!strcmp(ment->mnt_fsname, "rootfs"))

continue;

/* string match */

if (!strcmp(name, ment->mnt_dir))

break;

/* match the directory's mount point. */

if (stat(ment->mnt_dir, &s) == 0 && s.st_dev == devno_of_name)

break;

}

endmntent(mtab_fp);

return ment;

}

/*

* getcwd_pid does not append a null byte to buf. It will (silently) truncate the contents (to

* a length of bufsiz characters), in case the buffer is too small to hold all the contents.

*/

ssize_t getcwd_by_pid(pid_t pid, char *buf, size_t bufsiz)

{

char link[128];

sprintf(link, "/proc/%d/cwd", pid);

return readlink(link, buf, bufsiz);

}

bool getuid_by_pid(pid_t pid, uid_t *uid)

{

char status[128];

char line[128];

int i = 9;

FILE *fp;

sprintf(status, "/proc/%d/status", pid);

fp = fopen(status, "r");

if (!fp)

return false;

while (i-- > 0) {

if (!fgets(line, sizeof(line), fp)) {

fclose(fp);

return false;

}

}

fclose(fp);

sscanf(line, "Uid:\t%u", uid);

return true;

}

bool getgid_by_pid(pid_t pid, gid_t *gid)

{

char status[128];

char line[128];

int i = 10;

FILE *fp;

sprintf(status, "/proc/%d/status", pid);

fp = fopen(status, "r");

if (!fp)

return false;

while (i-- > 0) {

if (!fgets(line, sizeof(line), fp)) {

fclose(fp);

return false;

}

}

fclose(fp);

sscanf(line, "Gid:\t%u", gid);

return true;

}