Re: [Qemu-devel] [PATCHv3 1/2] ui/curses: Do not assume wchar_t contains unicode

[Kamil Rytarowski]

On 27.04.2019 18:30, Samuel Thibault wrote:
> E.g. BSD and Solaris even use locale-specific encoding there.
> 
> We thus have to go through the native multibyte representation and use
> mbtowc/wctomb to make a proper conversion.
> 
> Signed-off-by: Samuel Thibault <address@hidden>

Both patches work for me on NetBSD/amd64 8.99.37 for qemu-system-x86_64.
Borders are printed correctly.

Regarding the patch I'm not sure whether to use MB_LEN_MAX or MB_CUR_MAX?

I'm also unsure whether to reset conversion state between a multibyte
character and wide character, with: `mbtowc(NULL, 0, 0);`. It's
recommended to use in code examples examples. I think it doesn't make
any harm to use it.


I'm not sure if this is related, but "qemu-system-hppa -curses" is
broken for me. I didn't use it in the past as it just recently acquired
NetBSD guest support.

(lldb) bt
* thread #1, stop reason = signal SIGSEGV
    frame #0: 0x00007f7ff6c1fb98
libcurses.so.7`wmove(win=0x0000000000000000, y=0, x=0) at move.c:71
    frame #1: 0x00007f7ff6c0ca9b
libcurses.so.7`mvwadd_wchnstr(win=0x0000000000000000, y=<unavailable>,
x=<unavailable>, wchstr=0x00007f7fffffe020, n=0) at add_wchstr.c:123
  * frame #2: 0x000000000078629e
qemu-system-hppa`curses_update(dcl=0x00007f7ff7bd8bc0, x=0, y=0, w=79,
h=24) at curses.c:86:9
    frame #3: 0x0000000000753dae
qemu-system-hppa`dpy_text_update(con=0x00007f7ff7bae580, x=0, y=0, w=79,
h=24) at console.c:1658:13
    frame #4: 0x0000000000758abe
qemu-system-hppa`text_console_update(opaque=0x00007f7ff7bae580,
chardata=0x000000000118e490) at console.c:1264:9
    frame #5: 0x0000000000751ef8
qemu-system-hppa`graphic_hw_text_update(con=0x00007f7ff7bae580,
chardata=0x000000000118c690) at console.c:389:9
    frame #6: 0x0000000000785bcb
qemu-system-hppa`curses_refresh(dcl=0x00007f7ff7bd8bc0) at curses.c:273:5
    frame #7: 0x0000000000758248
qemu-system-hppa`dpy_refresh(s=0x00007f7ff7bd8770) at console.c:1622:13
    frame #8: 0x000000000075809d
qemu-system-hppa`gui_update(opaque=0x00007f7ff7bd8770) at console.c:205:5
    frame #9: 0x00000000008d9f4d
qemu-system-hppa`timerlist_run_timers(timer_list=0x00007f7ff7e57d20) at
qemu-timer.c:574:9
    frame #10: 0x00000000008da01d
qemu-system-hppa`qemu_clock_run_timers(type=QEMU_CLOCK_REALTIME) at
qemu-timer.c:588:12
    frame #11: 0x00000000008da4ea
qemu-system-hppa`qemu_clock_run_all_timers at qemu-timer.c:708:25
    frame #12: 0x00000000008da962
qemu-system-hppa`main_loop_wait(nonblocking=0) at main-loop.c:519:5
    frame #13: 0x00000000005570a4 qemu-system-hppa`main_loop at vl.c:1970:9
    frame #14: 0x0000000000551fa4 qemu-system-hppa`main(argc=2,
argv=0x00007f7fffffe768, envp=0x00007f7fffffe780) at vl.c:4604:5
    frame #15: 0x000000000040e7ad qemu-system-hppa`___start + 280

(lldb) p screenpad
(WINDOW *) $2 = 0x0000000000000000

We pass NULL window argument to mvwadd_wchnstr(3) and crash. Can you
reproduce it locally?

I will try to investigate it.

> ---
>  ui/curses.c | 151 ++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 94 insertions(+), 57 deletions(-)
> 
> diff --git a/ui/curses.c b/ui/curses.c
> index fb63945188..395f9545e9 100644
> --- a/ui/curses.c
> +++ b/ui/curses.c
> @@ -400,65 +400,102 @@ static void curses_atexit(void)
>      endwin();
>  }
>  
> +/*
> + * In the following:
> + * - fch is the font glyph number
> + * - uch is the unicode value
> + * - wch is the wchar_t value (may not be unicode, e.g. on BSD/solaris)
> + * - mbch is the native local-dependent multibyte representation
> + */
> +
>  /* Setup wchar glyph for one UCS-2 char */
> -static void convert_ucs(int glyph, uint16_t ch, iconv_t conv)
> +static void convert_ucs(unsigned char fch, uint16_t uch, iconv_t conv)
>  {
> +    char mbch[MB_CUR_MAX];
>      wchar_t wch;
> -    char *pch, *pwch;
> -    size_t sch, swch;
> -
> -    pch = (char *) &ch;
> -    pwch = (char *) &wch;
> -    sch = sizeof(ch);
> -    swch = sizeof(wch);
> +    char *puch, *pmbch;
> +    size_t such, smbch;
> +
> +    puch = (char *) &uch;
> +    pmbch = (char *) mbch;
> +    such = sizeof(uch);
> +    smbch = sizeof(mbch);
> +
> +    if (iconv(conv, &puch, &such, &pmbch, &smbch) == (size_t) -1) {
> +        fprintf(stderr, "Could not convert 0x%04x "
> +                        "from UCS-2 to a multibyte character: %s\n",
> +                        uch, strerror(errno));
> +        return;
> +    }
>  
> -    if (iconv(conv, &pch, &sch, &pwch, &swch) == (size_t) -1) {
> -        fprintf(stderr, "Could not convert 0x%04x from UCS-2 to WCHAR_T: 
> %s\n",
> -                        ch, strerror(errno));
> -    } else {
> -        vga_to_curses[glyph].chars[0] = wch;
> +    if (mbtowc(&wch, mbch, sizeof(mbch) - smbch) == -1) {
> +        fprintf(stderr, "Could not convert 0x%04x "
> +                        "from a multibyte character to wchar_t: %s\n",
> +                        uch, strerror(errno));
> +        return;
>      }
> +    vga_to_curses[fch].chars[0] = wch;
>  }
>  
>  /* Setup wchar glyph for one font character */
> -static void convert_font(unsigned char ch, iconv_t conv)
> +static void convert_font(unsigned char fch, iconv_t conv)
>  {
> +    char mbch[MB_CUR_MAX];
>      wchar_t wch;
> -    char *pch, *pwch;
> -    size_t sch, swch;
> -
> -    pch = (char *) &ch;
> -    pwch = (char *) &wch;
> -    sch = sizeof(ch);
> -    swch = sizeof(wch);
> +    char *pfch, *pmbch;
> +    size_t sfch, smbch;
> +
> +    pfch = (char *) &fch;
> +    pmbch = (char *) &mbch;
> +    sfch = sizeof(fch);
> +    smbch = sizeof(mbch);
> +
> +    if (iconv(conv, &pfch, &sfch, &pmbch, &smbch) == (size_t) -1) {
> +        fprintf(stderr, "Could not convert font glyph 0x%02x "
> +                        "from %s to a multibyte character: %s\n",
> +                        fch, font_charset, strerror(errno));
> +        return;
> +    }
>  
> -    if (iconv(conv, &pch, &sch, &pwch, &swch) == (size_t) -1) {
> -        fprintf(stderr, "Could not convert 0x%02x from %s to WCHAR_T: %s\n",
> -                        ch, font_charset, strerror(errno));
> -    } else {
> -        vga_to_curses[ch].chars[0] = wch;
> +    if (mbtowc(&wch, mbch, sizeof(mbch) - smbch) == -1) {
> +        fprintf(stderr, "Could not convert font glyph 0x%02x "
> +                        "from a multibyte character to wchar_t: %s\n",
> +                        fch, strerror(errno));
> +        return;
>      }
> +    vga_to_curses[fch].chars[0] = wch;
>  }
>  
>  /* Convert one wchar to UCS-2 */
>  static uint16_t get_ucs(wchar_t wch, iconv_t conv)
>  {
> -    uint16_t ch;
> -    char *pch, *pwch;
> -    size_t sch, swch;
> -
> -    pch = (char *) &ch;
> -    pwch = (char *) &wch;
> -    sch = sizeof(ch);
> -    swch = sizeof(wch);
> -
> -    if (iconv(conv, &pwch, &swch, &pch, &sch) == (size_t) -1) {
> -        fprintf(stderr, "Could not convert 0x%02lx from WCHAR_T to UCS-2: 
> %s\n",
> -                (unsigned long)wch, strerror(errno));
> +    char mbch[MB_CUR_MAX];
> +    uint16_t uch;
> +    char *pmbch, *puch;
> +    size_t smbch, such;
> +    int ret;
> +
> +    ret = wctomb(mbch, wch);
> +    if (ret == -1) {
> +        fprintf(stderr, "Could not convert 0x%04x "
> +                        "from wchar_t to a multibyte character: %s\n",
> +                        wch, strerror(errno));
> +        return 0xFFFD;
> +    }
> +
> +    pmbch = (char *) mbch;
> +    puch = (char *) &uch;
> +    smbch = ret;
> +    such = sizeof(uch);
> +
> +    if (iconv(conv, &pmbch, &smbch, &puch, &such) == (size_t) -1) {
> +        fprintf(stderr, "Could not convert 0x%04x "
> +                        "from a multibyte character to UCS-2 : %s\n",
> +                        wch, strerror(errno));
>          return 0xFFFD;
>      }
>  
> -    return ch;
> +    return uch;
>  }
>  
>  /*
> @@ -466,6 +503,11 @@ static uint16_t get_ucs(wchar_t wch, iconv_t conv)
>   */
>  static void font_setup(void)
>  {
> +    iconv_t ucs2_to_nativecharset;
> +    iconv_t nativecharset_to_ucs2;
> +    iconv_t font_conv;
> +    int i;
> +
>      /*
>       * Control characters are normally non-printable, but VGA does have
>       * well-known glyphs for them.
> @@ -505,30 +547,25 @@ static void font_setup(void)
>        0x25bc
>      };
>  
> -    iconv_t ucs_to_wchar_conv;
> -    iconv_t wchar_to_ucs_conv;
> -    iconv_t font_conv;
> -    int i;
> -
> -    ucs_to_wchar_conv = iconv_open("WCHAR_T", "UCS-2");
> -    if (ucs_to_wchar_conv == (iconv_t) -1) {
> +    ucs2_to_nativecharset = iconv_open(nl_langinfo(CODESET), "UCS-2");
> +    if (ucs2_to_nativecharset == (iconv_t) -1) {
>          fprintf(stderr, "Could not convert font glyphs from UCS-2: '%s'\n",
>                          strerror(errno));
>          exit(1);
>      }
>  
> -    wchar_to_ucs_conv = iconv_open("UCS-2", "WCHAR_T");
> -    if (wchar_to_ucs_conv == (iconv_t) -1) {
> -        iconv_close(ucs_to_wchar_conv);
> +    nativecharset_to_ucs2 = iconv_open("UCS-2", nl_langinfo(CODESET));
> +    if (nativecharset_to_ucs2 == (iconv_t) -1) {
> +        iconv_close(ucs2_to_nativecharset);
>          fprintf(stderr, "Could not convert font glyphs to UCS-2: '%s'\n",
>                          strerror(errno));
>          exit(1);
>      }
>  
> -    font_conv = iconv_open("WCHAR_T", font_charset);
> +    font_conv = iconv_open(nl_langinfo(CODESET), font_charset);
>      if (font_conv == (iconv_t) -1) {
> -        iconv_close(ucs_to_wchar_conv);
> -        iconv_close(wchar_to_ucs_conv);
> +        iconv_close(ucs2_to_nativecharset);
> +        iconv_close(nativecharset_to_ucs2);
>          fprintf(stderr, "Could not convert font glyphs from %s: '%s'\n",
>                          font_charset, strerror(errno));
>          exit(1);
> @@ -536,7 +573,7 @@ static void font_setup(void)
>  
>      /* Control characters */
>      for (i = 0; i <= 0x1F; i++) {
> -        convert_ucs(i, control_characters[i], ucs_to_wchar_conv);
> +        convert_ucs(i, control_characters[i], ucs2_to_nativecharset);
>      }
>  
>      for (i = 0x20; i <= 0xFF; i++) {
> @@ -544,12 +581,12 @@ static void font_setup(void)
>      }
>  
>      /* DEL */
> -    convert_ucs(0x7F, 0x2302, ucs_to_wchar_conv);
> +    convert_ucs(0x7F, 0x2302, ucs2_to_nativecharset);
>  
>      if (strcmp(nl_langinfo(CODESET), "UTF-8")) {
>          /* Non-Unicode capable, use termcap equivalents for those available 
> */
>          for (i = 0; i <= 0xFF; i++) {
> -            switch (get_ucs(vga_to_curses[i].chars[0], wchar_to_ucs_conv)) {
> +            switch (get_ucs(vga_to_curses[i].chars[0], 
> nativecharset_to_ucs2)) {
>              case 0x00a3:
>                  vga_to_curses[i] = *WACS_STERLING;
>                  break;
> @@ -649,8 +686,8 @@ static void font_setup(void)
>              }
>          }
>      }
> -    iconv_close(ucs_to_wchar_conv);
> -    iconv_close(wchar_to_ucs_conv);
> +    iconv_close(ucs2_to_nativecharset);
> +    iconv_close(nativecharset_to_ucs2);
>      iconv_close(font_conv);
>  }
>  
>

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