Dynamic implementation of Linux related library functions and system calls

Library functions

void Memset (void *mem, unsigned char byte, unsigned int len), void _memcpy (void *, void *, unsigned int), int _printf (char * , ...); char * itoa (Long, char *), char * ITOX (Long, char *), int _puts (char *), int _puts_nl (char *); size_t _strlen (char *); int _str NCMP (const char *, const char *, size_t), int _strcmp (const char *, const char *), int _memcmp (const void *, const void *, U nsigned int); Char _toupper (char c); void Memset (void *mem, unsigned char byte, unsigned int len) {unsigned char *p = (UN    Signed char *) mem;    int i = len;        while (i--) {*p = byte;    p++;    }}void _memcpy (void *dst, void *src, unsigned int len) {int i;    unsigned char *s = (unsigned char *) src;    unsigned char *d = (unsigned char *) DST;        for (i = 0; i < len; i++) {*d = *s;    s++, d++; }}int _printf (char *fmt, ...)    {int in_p;    unsigned long DWORD;    unsigned int word;    Char numbuf[26] = {0};    __builtin_va_list alist;    In_p;    __builtin_va_start ((alist), (FMT)); In_p = 0;            while (*FMT) {if (*fmt!= '% ' &&!in_p) {_write (1, FMT, 1);        in_p = 0; } else if (*fmt!= '% ') {switch (*FMT) {case ' s ': DWORD = (Unsigned lon                    g) __builtin_va_arg (alist, long);                    _puts ((char *) DWORD);                Break                    Case ' u ': Word = (unsigned int) __builtin_va_arg (alist, int);                    _puts (itoa (Word, numbuf));                Break                    Case ' d ': Word = (unsigned int) __builtin_va_arg (alist, int);                    _puts (itoa (Word, numbuf));                Break                    Case ' X ': DWORD = (unsigned long) __builtin_va_arg (alist, long);                    _puts (Itox (DWORD, numbuf));                Break                    Default: _write (1, FMT, 1);            Break        } in_p = 0; } else {            In_p = 1;    } fmt++; } return 1;}    char * ITOA (long x, char *t) {int i;    Int J;    i = 0;        do {T[i] = (x% 10) + ' 0 ';        x/= 10;    i++;    } while (x!=0);    T[i] = 0;        for (J=0; J < I/2; J + +) {T[j] ^= t[i-j-1];        T[i-j-1] ^= t[j];    T[J] ^= t[i-j-1]; } return t;}    char * ITOX (long x, char *t) {int i;    Int J;    i = 0;        do {T[i] = (x% 16);        /* Char Conversion */if (T[i] > 9) t[i] = (T[i]-ten) + ' a ';        else T[i] + = ' 0 ';        x/= 16;    i++;    } while (x! = 0);    T[i] = 0;        for (J=0; J < I/2; J + +) {T[j] ^= t[i-j-1];        T[i-j-1] ^= t[j];    T[J] ^= t[i-j-1]; } return t;}    int _puts (char *str) {_write (1, str, _strlen (str));    _fsync (1); return 1;}    int _puts_nl (char *str) {_write (1, str, _strlen (str));    _write (1, "\ n", 1);    _fsync (1); return 1;} size_t _strlen (char *s) {   size_t sz;    for (sz=0;s[sz];sz++); return sz;}            int _strncmp (const char *S1, const char *S2, size_t N) {for (; n > 0; s1++, s2++,--n) if (*s1! = *s2)        Return ((* (* (unsigned char *) S1 < * (unsigned char *) s2)-1: + 1);    else if (*s1 = = ') ' return 0; return 0;} int _strcmp (const char *S1, const char *s2) {for (; *s1 = = *s2; s1++, s2++) if (*s1 = = ') ' Return    0; Return ((* (* (unsigned char *) S1 < * (unsigned char *) s2)-1: + 1);}    int _memcmp (const void *S1, const void *S2, unsigned int n) {unsigned char U1, U2;        for (; n--; s1++, s2++) {u1 = * (unsigned char *) s1;        U2 = * (unsigned char *) s2;        if (u1! = U2) {return (U1-U2);    }}}char _toupper (char c) {if (C >= ' a ' && c <= ' z ') return (c = C + ' A '-' a '); return c;}

//System call

int _getuid (void), int _unlink (const char *path), int _mprotect (void * addr, unsigned long len, int prot); int _puts (char *st  r); int _puts_nl (char *str); int _fsync (int fd); Long _ptrace (long request, long pid, void *addr, void *data); int _prctl (Long option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5); int _fstat (long, void *); long _ls Eek (long, long, unsigned int), void Exit (long), void *_mmap (void *, unsigned long, unsigned long, unsigned long, long, unsi gned long); int _munmap (void *, size_t); Long _open (const char *, unsigned long, long); Long _write (Long, char *, unsigned lo                    NG); int _read (Long, char *, unsigned long), int _getdents64 (unsigned int fd, struct Linux_dirent64 *dirp,  unsigned int count), int _rename (const char *, const char *), int _close (unsigned int), int _gettimeofday (struct timeval *,        struct timezone *); int _getuid (void) {unsigned long ret;   __asm__ volatile ("mov $102,%rax\n" "Syscall");      ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;        int _unlink (const char *path) {long ret; __asm__ volatile ("mov%0,%%rdi\n" "Mov $87,%%rax\n" "Syscall":: "G" (    path));        ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;        int _mprotect (void * addr, unsigned long len, int prot) {unsigned long ret;                        __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "mov%2,%%rdx\n" "mov $ $,%%rax\n" "Syscall":: "G" (addr), "G" (Len), "G"        (prot));        ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;        int _puts (char *str) {_write (1, str, _strlen (str));        _fsync (1); return 1;}    int _puts_nl (char *str) {_write (1, str, _strlen (str));    _write (1, "\ n", 1);        _fsync (1); return 1;}        int _fsync (int fd) {long ret;        __asm__ volatile (                "Mov%0,%%rdi\n" "Mov $74,%%rax\n" "Syscall":: "G" (FD));        ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    Long _ptrace (long request, long pid, void *addr, void *data) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2, %%rdx\n "" mov%3,%%r10\n "" Mov $101,%%rax\n "" Syscall "::    "G" (Request), "G" (PID), "G" (addr), "G" (data);    ASM ("mov%%rax,%0": "=r" (ret)); return ret;}    int _prctl (long option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,  %%rdx\n "" mov%3,%%r10\n "" Mov $157,%%rax\n "" syscall\n ":: "G" (option), "G" (ARG2),"G" (Arg3), "G" (ARG4), "G" (ARG5));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    int _fstat (long fd, void *buf) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov $ $,    %%rax\n "" Syscall "::" G "(FD)," G "(BUF));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    Long _lseek (long fd, long offset, unsigned int whence) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,    %%rdx\n "" Mov $8,%%rax\n "" Syscall "::" G "(FD)," G "(offset)," G "(whence));    ASM ("mov%%rax,%0": "=r" (ret)); return ret;} void Exit (Long status) {__asm__ volatile ("mov%0,%%rdi\n" "Mov $,%%rax\n" " Syscall "::" R "(status));} void *_mmap (void *addr, unsigned long len, unsigned long prot, unsigned long flags, long FD, unsigned lonG off) {long mmap_fd = FD;    unsigned long mmap_off = off;    unsigned long mmap_flags = flags;    unsigned long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,                     %%rdx\n "" mov%3,%%r10\n "" Mov%4,%%r8\n "" mov%5,%%r9\n " "Mov $9,%%rax\n" "syscall\n":: "G" (addr), "G" (Len), "G" (Prot), "G" (Flags), "G" (    MMAP_FD), "G" (Mmap_off));    ASM ("mov%%rax,%0": "=r" (ret)); return (void *) ret;    int _munmap (void *addr, size_t len) {long ret; __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov $11    ,%%rax\n "Syscall":: "G" (addr), "G" (Len));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    Long _open (const char *path, unsigned long, long) {long ret; __asm__ volatile ("mov%0,%%rdi\n "" mov%1,%%rsi\n "" mov%2,%%rdx\n "" Mov $%%rax\    N "" Syscall "::" G "(Path)," G "(Flags)," G "(mode));    ASM ("mov%%rax,%0": "=r" (ret)); return ret;}    Long _write (Long fd, char *buf, unsigned long len) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,    %%rdx\n "" mov $ $,%%rax\n "" Syscall "::" G "(FD)," G "(BUF)," G "(Len));    ASM ("mov%%rax,%0": "=r" (ret)); return ret;}    int _read (long fd, char *buf, unsigned long len) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,    %%rdx\n "" Mov $,%%rax\n "" Syscall "::" G "(FD)," G "(BUF)," G "(Len));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret; int _getdents64 (unsigned int fd, struct LINux_dirent64 *dirp, unsigned int count) {long ret;  __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov% 2,    %%rdx\n "" Mov $217,%%rax\n "" Syscall "::" G "(FD)," G "(DIRP)," G "(count));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    int _rename (const char *old, const char *new) {long ret; __asm__ volatile ("mov%0,%%rdi\n" "mov%1,%%rsi\n" "Mov $82    ,%%rax\n "Syscall":: "G" (old), "G" (new));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;    int _close (unsigned int fd) {long ret; __asm__ volatile ("mov%0,%%rdi\n" "mov $ $,%%rax\n" "Syscall    "::" G "(FD)); return (int) ret;    int _gettimeofday (struct timeval *tv, struct timezone *tz) {long ret; __asm__ volatile ("mov% 0,%%rdi\n "" mov%1,%%rsi\n "" Mov $96,%%rax\n "" Syscall "::" G "(    TV), "G" (TZ));    ASM ("mov%%rax,%0": "=r" (ret)); return (int) ret;

Linux related library functions and system calls dynamically implemented