Magisk/native/jni/utils/missing.cpp

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2019-06-23 23:54:48 +02:00
/*
* Host all missing/incomplete implementation in bionic
* Copied from various sources
* */
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <mntent.h>
#include "missing.h"
/* Original source: https://opensource.apple.com/source/cvs/cvs-19/cvs/lib/getline.c
* License: GPL 2 or later
* Adjusted to match POSIX */
#define MIN_CHUNK 64
ssize_t __getdelim(char **lineptr, size_t *n, int delim, FILE *stream) {
size_t nchars_avail;
char *read_pos;
if (!lineptr || !n || !stream) {
errno = EINVAL;
return -1;
}
if (!*lineptr) {
*n = MIN_CHUNK;
*lineptr = (char *) malloc(*n);
if (!*lineptr) {
errno = ENOMEM;
return -1;
}
}
nchars_avail = *n;
read_pos = *lineptr;
for (;;) {
int save_errno;
int c = getc(stream);
save_errno = errno;
if (nchars_avail < 2) {
if (*n > MIN_CHUNK)
*n *= 2;
else
*n += MIN_CHUNK;
nchars_avail = *n + *lineptr - read_pos;
*lineptr = (char *) realloc(*lineptr, *n);
if (!*lineptr) {
errno = ENOMEM;
return -1;
}
read_pos = *n - nchars_avail + *lineptr;
}
if (ferror(stream)) {
errno = save_errno;
return -1;
}
if (c == EOF) {
if (read_pos == *lineptr)
return -1;
else
break;
}
*read_pos++ = c;
nchars_avail--;
if (c == delim)
break;
}
*read_pos = '\0';
return read_pos - *lineptr;
}
ssize_t __getline(char **lineptr, size_t *n, FILE *stream) {
return getdelim(lineptr, n, '\n', stream);
}
/* mntent functions are copied from AOSP libc/bionic/mntent.cpp */
struct mntent *__getmntent_r(FILE* fp, struct mntent* e, char* buf, int buf_len) {
memset(e, 0, sizeof(*e));
while (fgets(buf, buf_len, fp) != nullptr) {
// Entries look like "proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0".
// That is: mnt_fsname mnt_dir mnt_type mnt_opts 0 0.
int fsname0, fsname1, dir0, dir1, type0, type1, opts0, opts1;
if (sscanf(buf, " %n%*s%n %n%*s%n %n%*s%n %n%*s%n %d %d",
&fsname0, &fsname1, &dir0, &dir1, &type0, &type1, &opts0, &opts1,
&e->mnt_freq, &e->mnt_passno) == 2) {
e->mnt_fsname = &buf[fsname0];
buf[fsname1] = '\0';
e->mnt_dir = &buf[dir0];
buf[dir1] = '\0';
e->mnt_type = &buf[type0];
buf[type1] = '\0';
e->mnt_opts = &buf[opts0];
buf[opts1] = '\0';
return e;
}
}
return nullptr;
}
FILE *__setmntent(const char* path, const char* mode) {
return fopen(path, mode);
}
int __endmntent(FILE* fp) {
if (fp != nullptr) {
fclose(fp);
}
return 1;
}
char *__hasmntopt(const struct mntent* mnt, const char* opt) {
char* token = mnt->mnt_opts;
char* const end = mnt->mnt_opts + strlen(mnt->mnt_opts);
const size_t optLen = strlen(opt);
while (token) {
char* const tokenEnd = token + optLen;
if (tokenEnd > end) break;
if (memcmp(token, opt, optLen) == 0 &&
(*tokenEnd == '\0' || *tokenEnd == ',' || *tokenEnd == '=')) {
return token;
}
token = strchr(token, ',');
if (token) token++;
}
return nullptr;
}