Magisk/native/jni/utils/missing.cpp
2021-10-20 03:17:42 -07:00

137 lines
3.9 KiB
C++

// This file implements all missing symbols that should exist in normal API 21
// libc.a but missing in our extremely lean libc.a replacements.
#include <cstdlib>
#include <cstring>
#include <cerrno>
#include <mntent.h>
#include <unistd.h>
#include <sys/syscall.h>
extern "C" {
/* Original source: https://github.com/freebsd/freebsd/blob/master/contrib/file/src/getline.c
* License: BSD, full copyright notice please check original source */
ssize_t getdelim(char **buf, size_t *bufsiz, int delimiter, FILE *fp) {
char *ptr, *eptr;
if (*buf == nullptr || *bufsiz == 0) {
*bufsiz = BUFSIZ;
if ((*buf = (char *) malloc(*bufsiz)) == nullptr)
return -1;
}
for (ptr = *buf, eptr = *buf + *bufsiz;;) {
int c = fgetc(fp);
if (c == -1) {
if (feof(fp))
return ptr == *buf ? -1 : ptr - *buf;
else
return -1;
}
*ptr++ = c;
if (c == delimiter) {
*ptr = '\0';
return ptr - *buf;
}
if (ptr + 2 >= eptr) {
char *nbuf;
size_t nbufsiz = *bufsiz * 2;
ssize_t d = ptr - *buf;
if ((nbuf = (char *) realloc(*buf, nbufsiz)) == nullptr)
return -1;
*buf = nbuf;
*bufsiz = nbufsiz;
eptr = nbuf + nbufsiz;
ptr = nbuf + d;
}
}
}
ssize_t getline(char **buf, size_t *bufsiz, FILE *fp) {
return getdelim(buf, bufsiz, '\n', fp);
}
/* Original source: https://android.googlesource.com/platform/bionic/+/master/libc/bionic/mntent.cpp
* License: AOSP, full copyright notice please check original source */
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;
}
// Missing system call wrappers
int setns(int fd, int nstype) {
return syscall(__NR_setns, fd, nstype);
}
int unshare(int flags) {
return syscall(__NR_unshare, flags);
}
int accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags) {
return syscall(__NR_accept4, sockfd, addr, addrlen, flags);
}
int dup3(int oldfd, int newfd, int flags) {
return syscall(__NR_dup3, oldfd, newfd, flags);
}
ssize_t readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz) {
return syscall(__NR_readlinkat, dirfd, pathname, buf, bufsiz);
}
int symlinkat(const char *target, int newdirfd, const char *linkpath) {
return syscall(__NR_symlinkat, target, newdirfd, linkpath);
}
int linkat(int olddirfd, const char *oldpath,
int newdirfd, const char *newpath, int flags) {
return syscall(__NR_linkat, olddirfd, oldpath, newdirfd, newpath, flags);
}
int inotify_init1(int flags) {
return syscall(__NR_inotify_init1, flags);
}
int faccessat(int dirfd, const char *pathname, int mode, int flags) {
return syscall(__NR_faccessat, dirfd, pathname, mode, flags);
}
#if !defined(__LP64__)
void android_set_abort_message(const char *msg) {}
#endif
} // extern "C"