snprintf/various.h

   1 /*
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (C) 1990 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  */
  10
  11 #ifndef UST_SNPRINTF_VARIOUS_H
  12 #define UST_SNPRINTF_VARIOUS_H
  13
  14 #include <stdarg.h>
  15 #include <stddef.h>
  16 #include <stdio.h>
  17 #include <wchar.h>
  18
  19 #include "ust-helper.h"
  20
  21 struct __lttng_ust_sbuf {
  22         unsigned char *_base;
  23         int     _size;
  24 };
  25
  26 /*
  27  * stdio state variables.
  28  *
  29  * The following always hold:
  30  *
  31  *      if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
  32  *              _lbfsize is -_bf._size, else _lbfsize is 0
  33  *      if _flags&__SRD, _w is 0
  34  *      if _flags&__SWR, _r is 0
  35  *
  36  * This ensures that the getc and putc macros (or inline functions) never
  37  * try to write or read from a file that is in `read' or `write' mode.
  38  * (Moreover, they can, and do, automatically switch from read mode to
  39  * write mode, and back, on "r+" and "w+" files.)
  40  *
  41  * _lbfsize is used only to make the inline line-buffered output stream
  42  * code as compact as possible.
  43  *
  44  * _ub, _up, and _ur are used when ungetc() pushes back more characters
  45  * than fit in the current _bf, or when ungetc() pushes back a character
  46  * that does not match the previous one in _bf.  When this happens,
  47  * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
  48  * _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
  49  */
  50 typedef struct __lttng_ust_sFILE {
  51         unsigned char *_p;      /* current position in (some) buffer */
  52         int     _r;             /* read space left for getc() */
  53         int     _w;             /* write space left for putc() */
  54         short   _flags;         /* flags, below; this FILE is free if 0 */
  55         short   _file;          /* fileno, if Unix descriptor, else -1 */
  56         struct  __lttng_ust_sbuf _bf;     /* the buffer (at least 1 byte, if !NULL) */
  57         int     _lbfsize;       /* 0 or -_bf._size, for inline putc */
  58
  59         /* operations */
  60         void    *_cookie;       /* cookie passed to io functions */
  61         int     (*_close)(void *);
  62         int     (*_read)(void *, char *, int);
  63         fpos_t  (*_seek)(void *, fpos_t, int);
  64         int     (*_write)(void *, const char *, int);
  65
  66         /* extension data, to avoid further ABI breakage */
  67         struct  __lttng_ust_sbuf _ext;
  68         /* data for long sequences of ungetc() */
  69         unsigned char *_up;     /* saved _p when _p is doing ungetc data */
  70         int     _ur;            /* saved _r when _r is counting ungetc data */
  71
  72         /* tricks to meet minimum requirements even when malloc() fails */
  73         unsigned char _ubuf[3]; /* guarantee an ungetc() buffer */
  74         unsigned char _nbuf[1]; /* guarantee a getc() buffer */
  75
  76         /* separate buffer for fgetln() when line crosses buffer boundary */
  77         struct  __lttng_ust_sbuf _lb;     /* buffer for fgetln() */
  78
  79         /* Unix stdio files get aligned to block boundaries on fseek() */
  80         int     _blksize;       /* stat.st_blksize (may be != _bf._size) */
  81         fpos_t  _offset;        /* current lseek offset */
  82 } LTTNG_UST_LFILE;
  83
  84 #define __SLBF  0x0001          /* line buffered */
  85 #define __SNBF  0x0002          /* unbuffered */
  86 #define __SRD   0x0004          /* OK to read */
  87 #define __SWR   0x0008          /* OK to write */
  88         /* RD and WR are never simultaneously asserted */
  89 #define __SRW   0x0010          /* open for reading & writing */
  90 #define __SEOF  0x0020          /* found EOF */
  91 #define __SERR  0x0040          /* found error */
  92 #define __SMBF  0x0080          /* _buf is from malloc */
  93 #define __SAPP  0x0100          /* fdopen()ed in append mode */
  94 #define __SSTR  0x0200          /* this is an sprintf/snprintf string */
  95 #define __SOPT  0x0400          /* do fseek() optimisation */
  96 #define __SNPT  0x0800          /* do not do fseek() optimisation */
  97 #define __SOFF  0x1000          /* set iff _offset is in fact correct */
  98 #define __SMOD  0x2000          /* true => fgetln modified _p text */
  99 #define __SALC  0x4000          /* allocate string space dynamically */
 100
 101 #define __sferror(p)    (((p)->_flags & __SERR) != 0)
 102
 103 LTTNG_HIDDEN
 104 extern int ust_safe_fflush(LTTNG_UST_LFILE *fp);
 105 LTTNG_HIDDEN
 106 extern int ust_safe_vfprintf(LTTNG_UST_LFILE *fp, const char *fmt0, va_list ap);
 107
 108 LTTNG_HIDDEN
 109 extern size_t ust_safe_mbrtowc(wchar_t *pwc, const char *s, size_t n, mbstate_t *ps);
 110
 111 #endif /* UST_SNPRINTF_VARIOUS_H */