Eliminate variable length arrays in grub_vsnprintf_real.
A bit tricky because this function has to continue to work without heap for short strings. Fixing prealloc to 32 arguments is reasonable but make all stack references use 32-bit offset rather than 8-bit one. So split va_args preparsing to separate function and put the prealloc into the caller.
This commit is contained in:
Vladimir Serbinenko
parent
4f9541226c
commit
2d76b4d81e
2 changed files with 180 additions and 128 deletions
10
ChangeLog
10
ChangeLog
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@ -1,3 +1,13 @@
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2013-11-27 Vladimir Serbinenko <phcoder@gmail.com>
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Eliminate variable length arrays in grub_vsnprintf_real.
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A bit tricky because this function has to continue to work without
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heap for short strings. Fixing prealloc to 32 arguments is reasonable
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but make all stack references use 32-bit offset rather than 8-bit one.
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So split va_args preparsing to separate function and put the prealloc
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into the caller.
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2013-11-27 Vladimir Serbinenko <phcoder@gmail.com>
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Introduce grub_util_file_sync and use it instead of fsync(fileno(f)).
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@ -25,8 +25,39 @@
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#include <grub/env.h>
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#include <grub/i18n.h>
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union printf_arg
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{
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/* Yes, type is also part of union as the moment we fill the value
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we don't need to store its type anymore (when we'll need it, we'll
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have format spec again. So save some space. */
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enum
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{
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INT, LONG, LONGLONG,
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UNSIGNED_INT = 3, UNSIGNED_LONG, UNSIGNED_LONGLONG
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} type;
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long long ll;
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};
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struct printf_args
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{
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union printf_arg prealloc[32];
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union printf_arg *ptr;
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grub_size_t count;
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};
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static void
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parse_printf_args (const char *fmt0, struct printf_args *args,
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va_list args_in);
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static int
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grub_vsnprintf_real (char *str, grub_size_t n, const char *fmt, va_list args);
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grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0,
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struct printf_args *args);
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static void
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free_printf_args (struct printf_args *args)
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{
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if (args->ptr != args->prealloc)
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grub_free (args->ptr);
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}
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static int
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grub_iswordseparator (int c)
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@ -169,15 +200,16 @@ grub_real_dprintf (const char *file, const int line, const char *condition,
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#define PREALLOC_SIZE 255
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int
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grub_vprintf (const char *fmt, va_list args)
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grub_vprintf (const char *fmt, va_list ap)
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{
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grub_size_t s;
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static char buf[PREALLOC_SIZE + 1];
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char *curbuf = buf;
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va_list ap2;
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va_copy (ap2, args);
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struct printf_args args;
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s = grub_vsnprintf_real (buf, PREALLOC_SIZE, fmt, args);
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parse_printf_args (fmt, &args, ap);
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s = grub_vsnprintf_real (buf, PREALLOC_SIZE, fmt, &args);
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if (s > PREALLOC_SIZE)
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{
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curbuf = grub_malloc (s + 1);
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@ -191,16 +223,16 @@ grub_vprintf (const char *fmt, va_list args)
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curbuf = buf;
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}
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else
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s = grub_vsnprintf_real (curbuf, s, fmt, ap2);
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s = grub_vsnprintf_real (curbuf, s, fmt, &args);
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}
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va_end (ap2);
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free_printf_args (&args);
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grub_xputs (curbuf);
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if (curbuf != buf)
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grub_free (curbuf);
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return s;
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}
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@ -724,7 +756,7 @@ __umoddi3 (grub_uint64_t a, grub_uint64_t b)
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/* Convert a long long value to a string. This function avoids 64-bit
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modular arithmetic or divisions. */
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static char *
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static inline char *
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grub_lltoa (char *str, int c, unsigned long long n)
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{
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unsigned base = (c == 'x') ? 16 : 10;
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@ -762,39 +794,21 @@ grub_lltoa (char *str, int c, unsigned long long n)
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return p;
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}
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static inline void
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write_char (char *str, grub_size_t *count, grub_size_t max_len, unsigned char ch)
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{
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if (*count < max_len)
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str[*count] = ch;
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(*count)++;
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}
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static inline void
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write_str (char *str, grub_size_t *count, grub_size_t max_len, const char *s)
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{
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while (*s)
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write_char (str, count, max_len, *s++);
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}
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static inline void
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write_fill (char *str, grub_size_t *count, grub_size_t max_len, const char ch, int count_fill)
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{
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int i;
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for (i = 0; i < count_fill; i++)
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write_char (str, count, max_len, ch);
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}
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static int
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grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list args_in)
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static void
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parse_printf_args (const char *fmt0, struct printf_args *args,
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va_list args_in)
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{
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const char *fmt;
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char c;
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grub_size_t n = 0;
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grub_size_t count = 0;
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grub_size_t count_args = 0;
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const char *fmt;
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args->count = 0;
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COMPILE_TIME_ASSERT (sizeof (int) == sizeof (grub_uint32_t));
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COMPILE_TIME_ASSERT (sizeof (int) <= sizeof (long long));
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COMPILE_TIME_ASSERT (sizeof (long) <= sizeof (long long));
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COMPILE_TIME_ASSERT (sizeof (long long) == sizeof (void *)
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|| sizeof (int) == sizeof (void *));
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fmt = fmt0;
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while ((c = *fmt++) != 0)
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@ -838,30 +852,31 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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case 'c':
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case 'C':
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case 's':
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count_args++;
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args->count++;
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break;
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}
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}
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enum { INT, LONG, LONGLONG, POINTER } types[count_args];
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union
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{
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int i;
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long l;
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long long ll;
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void *p;
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} args[count_args];
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if (args->count <= ARRAY_SIZE (args->prealloc))
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args->ptr = args->prealloc;
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else
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{
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args->ptr = grub_malloc (args->count * sizeof (args->ptr[0]));
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if (!args->ptr)
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{
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grub_errno = GRUB_ERR_NONE;
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args->ptr = args->prealloc;
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args->count = ARRAY_SIZE (args->prealloc);
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}
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}
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COMPILE_TIME_ASSERT (sizeof (int) == sizeof (grub_uint32_t));
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grub_memset (types, 0, sizeof (types));
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grub_memset (args->ptr, 0, args->count * sizeof (args->ptr[0]));
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fmt = fmt0;
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n = 0;
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while ((c = *fmt++) != 0)
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{
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int longfmt = 0;
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int longlongfmt = 0;
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grub_size_t curn;
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const char *p;
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@ -901,69 +916,87 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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{
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c = *fmt++;
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longfmt = 1;
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if (c == 'l')
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{
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c = *fmt++;
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longlongfmt = 1;
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}
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}
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if (curn >= count_args)
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if (c == 'l')
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{
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c = *fmt++;
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longfmt = 2;
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}
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if (curn >= args->count)
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continue;
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switch (c)
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{
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case 'x':
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case 'u':
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args->ptr[curn].type = UNSIGNED_INT + longfmt;
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break;
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case 'd':
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if (longlongfmt)
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types[curn] = LONGLONG;
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else if (longfmt)
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types[curn] = LONG;
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else
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types[curn] = INT;
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args->ptr[curn].type = INT + longfmt;
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break;
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case 'p':
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case 's':
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types[curn] = POINTER;
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if (sizeof (void *) == sizeof (long long))
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args->ptr[curn].type = UNSIGNED_LONGLONG;
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else
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args->ptr[curn].type = UNSIGNED_INT;
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break;
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case 'C':
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case 'c':
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types[curn] = INT;
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args->ptr[curn].type = INT;
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break;
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}
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}
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for (n = 0; n < count_args; n++)
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switch (types[n])
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for (n = 0; n < args->count; n++)
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switch (args->ptr[n].type)
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{
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case POINTER:
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args[n].p = va_arg (args_in, void *);
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break;
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case INT:
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args[n].i = va_arg (args_in, int);
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args->ptr[n].ll = va_arg (args_in, int);
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break;
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case LONG:
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args[n].l = va_arg (args_in, long);
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args->ptr[n].ll = va_arg (args_in, long);
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break;
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case UNSIGNED_INT:
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args->ptr[n].ll = va_arg (args_in, unsigned int);
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break;
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case UNSIGNED_LONG:
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args->ptr[n].ll = va_arg (args_in, unsigned long);
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break;
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case LONGLONG:
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args[n].ll = va_arg (args_in, long long);
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case UNSIGNED_LONGLONG:
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args->ptr[n].ll = va_arg (args_in, long long);
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break;
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}
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}
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static inline void __attribute__ ((always_inline))
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write_char (char *str, grub_size_t *count, grub_size_t max_len, unsigned char ch)
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{
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if (*count < max_len)
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str[*count] = ch;
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(*count)++;
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}
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static int
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grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0,
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struct printf_args *args)
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{
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char c;
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grub_size_t n = 0;
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grub_size_t count = 0;
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const char *fmt;
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fmt = fmt0;
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n = 0;
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while ((c = *fmt++) != 0)
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{
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char tmp[32];
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unsigned int format1 = 0;
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unsigned int format2 = ~ 0U;
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char zerofill = ' ';
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int rightfill = 0;
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int longfmt = 0;
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int longlongfmt = 0;
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int unsig = 0;
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char rightfill = 0;
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grub_size_t curn;
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if (c != '%')
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{
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write_char (str, &count, max_len,c);
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@ -1008,15 +1041,9 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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c = *fmt++;
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if (c == 'l')
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{
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longfmt = 1;
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c = *fmt++;
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if (c == 'l')
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{
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longlongfmt = 1;
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c = *fmt++;
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}
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}
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c = *fmt++;
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if (c == 'l')
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c = *fmt++;
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if (c == '%')
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{
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@ -1024,45 +1051,47 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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continue;
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}
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if (curn >= count_args)
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if (curn >= args->count)
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continue;
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long long curarg = args->ptr[curn].ll;
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switch (c)
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{
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case 'p':
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write_str (str, &count, max_len, "0x");
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write_char (str, &count, max_len, '0');
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write_char (str, &count, max_len, 'x');
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c = 'x';
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longlongfmt |= (sizeof (void *) == sizeof (long long));
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/* Fall through. */
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case 'x':
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case 'u':
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unsig = 1;
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/* Fall through. */
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case 'd':
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if (longlongfmt)
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grub_lltoa (tmp, c, args[curn].ll);
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else if (longfmt && unsig)
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grub_lltoa (tmp, c, (unsigned long) args[curn].l);
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else if (longfmt)
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grub_lltoa (tmp, c, args[curn].l);
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else if (unsig)
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grub_lltoa (tmp, c, (unsigned) args[curn].i);
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else
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grub_lltoa (tmp, c, args[curn].i);
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if (! rightfill && grub_strlen (tmp) < format1)
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write_fill (str, &count, max_len, zerofill, format1 - grub_strlen (tmp));
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write_str (str, &count, max_len, tmp);
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if (rightfill && grub_strlen (tmp) < format1)
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write_fill (str, &count, max_len, zerofill, format1 - grub_strlen (tmp));
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{
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char tmp[32];
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const char *p = tmp;
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grub_size_t len;
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grub_size_t fill;
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len = grub_lltoa (tmp, c, curarg) - tmp;
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fill = len < format1 ? format1 - len : 0;
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if (! rightfill)
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while (fill--)
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write_char (str, &count, max_len, zerofill);
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while (*p)
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write_char (str, &count, max_len, *p++);
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if (rightfill)
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while (fill--)
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write_char (str, &count, max_len, zerofill);
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}
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break;
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case 'c':
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write_char (str, &count, max_len,args[curn].i & 0xff);
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write_char (str, &count, max_len,curarg & 0xff);
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break;
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case 'C':
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{
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grub_uint32_t code = args[curn].i;
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grub_uint32_t code = curarg;
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int shift;
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unsigned mask;
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|
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@ -1103,20 +1132,25 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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case 's':
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{
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grub_size_t len = 0;
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const char *p = args[curn].p ? : "(null)";
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grub_size_t fill;
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const char *p = ((char *) (grub_addr_t) curarg) ? : "(null)";
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grub_size_t i;
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while (len < format2 && p[len])
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len++;
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if (!rightfill && len < format1)
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write_fill (str, &count, max_len, zerofill, format1 - len);
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fill = len < format1 ? format1 - len : 0;
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if (!rightfill)
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while (fill--)
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write_char (str, &count, max_len, zerofill);
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grub_size_t i;
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for (i = 0; i < len; i++)
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write_char (str, &count, max_len,*p++);
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if (rightfill && len < format1)
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write_fill (str, &count, max_len, zerofill, format1 - len);
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if (rightfill)
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while (fill--)
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write_char (str, &count, max_len, zerofill);
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}
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|
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break;
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@ -1131,7 +1165,6 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0, va_list a
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str[count] = '\0';
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else
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str[max_len] = '\0';
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return count;
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}
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|
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@ -1139,13 +1172,18 @@ int
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grub_vsnprintf (char *str, grub_size_t n, const char *fmt, va_list ap)
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{
|
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grub_size_t ret;
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struct printf_args args;
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if (!n)
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return 0;
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n--;
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ret = grub_vsnprintf_real (str, n, fmt, ap);
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parse_printf_args (fmt, &args, ap);
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|
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ret = grub_vsnprintf_real (str, n, fmt, &args);
|
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free_printf_args (&args);
|
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|
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return ret < n ? ret : n;
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}
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|
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@ -1168,22 +1206,26 @@ grub_xvasprintf (const char *fmt, va_list ap)
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{
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grub_size_t s, as = PREALLOC_SIZE;
|
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char *ret;
|
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struct printf_args args;
|
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|
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parse_printf_args (fmt, &args, ap);
|
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|
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while (1)
|
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{
|
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va_list ap2;
|
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ret = grub_malloc (as + 1);
|
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if (!ret)
|
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return NULL;
|
||||
{
|
||||
free_printf_args (&args);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
va_copy (ap2, ap);
|
||||
|
||||
s = grub_vsnprintf_real (ret, as, fmt, ap2);
|
||||
|
||||
va_end (ap2);
|
||||
s = grub_vsnprintf_real (ret, as, fmt, &args);
|
||||
|
||||
if (s <= as)
|
||||
return ret;
|
||||
{
|
||||
free_printf_args (&args);
|
||||
return ret;
|
||||
}
|
||||
|
||||
grub_free (ret);
|
||||
as = s;
|
||||
|
|
|
|||
Loading…
Reference in a new issue