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Fix the printf issue for 64 bits. The following case:
authorAlexander Ivchenko <alexander.ivchenko@intel.com>
Tue, 1 Apr 2014 13:01:39 +0000 (17:01 +0400)
committerAlexander Ivchenko <alexander.ivchenko@intel.com>
Wed, 2 Apr 2014 14:30:55 +0000 (18:30 +0400)
printf("%1$s %1$s\n", "test");

would print garbage instead of the second "test". The problem is __find_arguments
and the patch is a backport of two patches from OpenBSD that fix the issue:

Author: tedu <tedu@cvs.openbsd.org>
Date:   Sat Apr 29 23:00:24 2006 +0000

    check mmap for failure.  the helper functions using it return -1, but
    callers do not yet check since printf() for example is not documented
    to return an error.
    some formatting cleanups.
    mostly ok deraadt millert

Author: millert <millert@cvs.openbsd.org>
Date:   Fri May 16 14:28:54 2008 +0000

    C99 says that for each va_copy() there must be a matching va_end().
    Replace the non-portable hackery in __find_arguments() with a union.
    From FreeBSD.

Change-Id: I6ea392ce6fcf4a319ae6a67ec58cc52fe7cbe534
Signed-off-by: Alexander Ivchenko <alexander.ivchenko@intel.com>
libc/stdio/vfprintf.c
tests/stdio_test.cpp

index b101145..efc8fd0 100644 (file)
 #include "local.h"
 #include "fvwrite.h"
 
-static void __find_arguments(const char *fmt0, va_list ap, va_list **argtable,
+union arg {
+       int                     intarg;
+       unsigned int            uintarg;
+       long                    longarg;
+       unsigned long           ulongarg;
+       long long               longlongarg;
+       unsigned long long      ulonglongarg;
+       ptrdiff_t               ptrdiffarg;
+       size_t                  sizearg;
+       size_t                  ssizearg;
+       intmax_t                intmaxarg;
+       uintmax_t               uintmaxarg;
+       void                    *pvoidarg;
+       char                    *pchararg;
+       signed char             *pschararg;
+       short                   *pshortarg;
+       int                     *pintarg;
+       long                    *plongarg;
+       long long               *plonglongarg;
+       ptrdiff_t               *pptrdiffarg;
+       size_t                  *pssizearg;
+       intmax_t                *pintmaxarg;
+#ifdef FLOATING_POINT
+       double                  doublearg;
+       long double             longdoublearg;
+#endif
+};
+
+static int __find_arguments(const char *fmt0, va_list ap, union arg **argtable,
     size_t *argtablesiz);
 static int __grow_type_table(unsigned char **typetable, int *tablesize);
 
@@ -169,13 +197,13 @@ vfprintf(FILE *fp, const char *fmt0, __va_list ap)
 int
 __vfprintf(FILE *fp, const char *fmt0, __va_list ap)
 {
-       char *fmt;      /* format string */
-       int ch; /* character from fmt */
-       int n, m, n2;   /* handy integers (short term usage) */
-       char *cp;       /* handy char pointer (short term usage) */
-       char *cp_free = NULL;  /* BIONIC: copy of cp to be freed after usage */
-       struct __siov *iovp;/* for PRINT macro */
-       int flags;      /* flags as above */
+       char *fmt;              /* format string */
+       int ch;                 /* character from fmt */
+       int n, m, n2;           /* handy integers (short term usage) */
+       char *cp;               /* handy char pointer (short term usage) */
+       char *cp_free = NULL;   /* BIONIC: copy of cp to be freed after usage */
+       struct __siov *iovp;    /* for PRINT macro */
+       int flags;              /* flags as above */
        int ret;                /* return value accumulator */
        int width;              /* width from format (%8d), or 0 */
        int prec;               /* precision from format (%.3d), or -1 */
@@ -203,8 +231,8 @@ __vfprintf(FILE *fp, const char *fmt0, __va_list ap)
        struct __siov iov[NIOV];/* ... and individual io vectors */
        char buf[BUF];          /* space for %c, %[diouxX], %[eEfgG] */
        char ox[2];             /* space for 0x hex-prefix */
-       va_list *argtable;      /* args, built due to positional arg */
-       va_list statargtable[STATIC_ARG_TBL_SIZE];
+       union arg *argtable;    /* args, built due to positional arg */
+       union arg statargtable[STATIC_ARG_TBL_SIZE];
        size_t argtablesiz;
        int nextarg;            /* 1-based argument index */
        va_list orgap;          /* original argument pointer */
@@ -303,8 +331,8 @@ __vfprintf(FILE *fp, const char *fmt0, __va_list ap)
 * argument (and arguments must be gotten sequentially).
 */
 #define GETARG(type) \
-       (((argtable != NULL) ? (void)(ap = argtable[nextarg]) : (void)0), \
-        nextarg++, va_arg(ap, type))
+       ((argtable != NULL) ? *((type*)(&argtable[nextarg++])) : \
+               (nextarg++, va_arg(ap, type)))
 
        _SET_ORIENTATION(fp, -1);
        /* sorry, fprintf(read_only_file, "") returns EOF, not 0 */
@@ -548,15 +576,16 @@ reswitch: switch (ch) {
                                        size = expt;
                                        if (prec || flags & ALT)
                                                size += prec + 1;
-                               } else  /* "0.X" */
+                               } else { /* "0.X" */
                                        size = prec + 2;
+                               }
                        } else if (expt >= ndig) {      /* fixed g fmt */
                                size = expt;
                                if (flags & ALT)
                                        ++size;
-                       } else
-                               size = ndig + (expt > 0 ?
-                                       1 : 2 - expt);
+                       } else {
+                               size = ndig + (expt > 0 ?  1 : 2 - expt);
+                       }
 
                        if (softsign)
                                sign = '-';
@@ -624,10 +653,12 @@ reswitch: switch (ch) {
                                        size = p - cp;
                                        if (size > prec)
                                                size = prec;
-                               } else
+                               } else {
                                        size = prec;
-                       } else
+                               }
+                       } else {
                                size = strlen(cp);
+                       }
                        sign = '\0';
                        break;
                case 'U':
@@ -793,11 +824,13 @@ number:                   if ((dprec = prec) >= 0)
                                        PRINT(ox, 2);
                                        if (_double) {
                                                PRINT(cp, ndig-1);
-                                       } else  /* 0.[0..] */
+                                       } else {/* 0.[0..] */
                                                /* __dtoa irregularity */
                                                PAD(ndig - 1, zeroes);
-                               } else  /* XeYYY */
+                                       }
+                               } else { /* XeYYY */
                                        PRINT(cp, 1);
+                               }
                                PRINT(expstr, expsize);
                        }
                }
@@ -874,15 +907,15 @@ error:
  * used since we are attempting to make snprintf thread safe, and alloca is
  * problematic since we have nested functions..)
  */
-static void
-__find_arguments(const char *fmt0, va_list ap, va_list **argtable,
+static int
+__find_arguments(const char *fmt0, va_list ap, union arg **argtable,
     size_t *argtablesiz)
 {
-       char *fmt;      /* format string */
-       int ch; /* character from fmt */
-       int n, n2;      /* handy integer (short term usage) */
-       char *cp;       /* handy char pointer (short term usage) */
-       int flags;      /* flags as above */
+       char *fmt;              /* format string */
+       int ch;                 /* character from fmt */
+       int n, n2;              /* handy integer (short term usage) */
+       char *cp;               /* handy char pointer (short term usage) */
+       int flags;              /* flags as above */
        unsigned char *typetable; /* table of types */
        unsigned char stattypetable[STATIC_ARG_TBL_SIZE];
        int tablesize;          /* current size of type table */
@@ -1105,86 +1138,89 @@ done:
         * Build the argument table.
         */
        if (tablemax >= STATIC_ARG_TBL_SIZE) {
-               *argtablesiz = sizeof (va_list) * (tablemax + 1);
-               *argtable = (va_list *)mmap(NULL, *argtablesiz,
+               *argtablesiz = sizeof(union arg) * (tablemax + 1);
+               *argtable = mmap(NULL, *argtablesiz,
                    PROT_WRITE|PROT_READ, MAP_ANON|MAP_PRIVATE, -1, 0);
+               if (*argtable == MAP_FAILED)
+                       return (-1);
        }
 
 #if 0
        /* XXX is this required? */
-       (*argtable) [0] = NULL;
+       (*argtable)[0].intarg = 0;
 #endif
        for (n = 1; n <= tablemax; n++) {
-               va_copy((*argtable)[n], ap);
                switch (typetable[n]) {
                case T_UNUSED:
-                       (void) va_arg(ap, int);
+                       (*argtable)[n].intarg = va_arg(ap, int);
                        break;
                case T_SHORT:
-                       (void) va_arg(ap, int);
+                       (*argtable)[n].intarg = va_arg(ap, int);
                        break;
                case T_U_SHORT:
-                       (void) va_arg(ap, int);
+                       (*argtable)[n].intarg = va_arg(ap, int);
                        break;
                case TP_SHORT:
-                       (void) va_arg(ap, short *);
+                       (*argtable)[n].pshortarg = va_arg(ap, short *);
                        break;
                case T_INT:
-                       (void) va_arg(ap, int);
+                       (*argtable)[n].intarg = va_arg(ap, int);
                        break;
                case T_U_INT:
-                       (void) va_arg(ap, unsigned int);
+                       (*argtable)[n].uintarg = va_arg(ap, unsigned int);
                        break;
                case TP_INT:
-                       (void) va_arg(ap, int *);
+                       (*argtable)[n].pintarg = va_arg(ap, int *);
                        break;
                case T_LONG:
-                       (void) va_arg(ap, long);
+                       (*argtable)[n].longarg = va_arg(ap, long);
                        break;
                case T_U_LONG:
-                       (void) va_arg(ap, unsigned long);
+                       (*argtable)[n].ulongarg = va_arg(ap, unsigned long);
                        break;
                case TP_LONG:
-                       (void) va_arg(ap, long *);
+                       (*argtable)[n].plongarg = va_arg(ap, long *);
                        break;
                case T_LLONG:
-                       (void) va_arg(ap, long long);
+                       (*argtable)[n].longlongarg = va_arg(ap, long long);
                        break;
                case T_U_LLONG:
-                       (void) va_arg(ap, unsigned long long);
+                       (*argtable)[n].ulonglongarg = va_arg(ap, unsigned long long);
                        break;
                case TP_LLONG:
-                       (void) va_arg(ap, long long *);
+                       (*argtable)[n].plonglongarg = va_arg(ap, long long *);
                        break;
+#ifdef FLOATING_POINT
                case T_DOUBLE:
-                       (void) va_arg(ap, double);
+                       (*argtable)[n].doublearg = va_arg(ap, double);
                        break;
                case T_LONG_DOUBLE:
-                       (void) va_arg(ap, long double);
+                       (*argtable)[n].longdoublearg = va_arg(ap, long double);
                        break;
+#endif
                case TP_CHAR:
-                       (void) va_arg(ap, char *);
+                       (*argtable)[n].pchararg = va_arg(ap, char *);
                        break;
                case TP_VOID:
-                       (void) va_arg(ap, void *);
+                       (*argtable)[n].pvoidarg = va_arg(ap, void *);
                        break;
                case T_PTRINT:
-                       (void) va_arg(ap, ptrdiff_t);
+                       (*argtable)[n].ptrdiffarg = va_arg(ap, ptrdiff_t);
                        break;
                case TP_PTRINT:
-                       (void) va_arg(ap, ptrdiff_t *);
+                       (*argtable)[n].pptrdiffarg = va_arg(ap, ptrdiff_t *);
                        break;
                case T_SIZEINT:
-                       (void) va_arg(ap, size_t);
+                       (*argtable)[n].sizearg = va_arg(ap, size_t);
                        break;
                case T_SSIZEINT:
-                       (void) va_arg(ap, ssize_t);
+                       (*argtable)[n].ssizearg = va_arg(ap, ssize_t);
                        break;
                case TP_SSIZEINT:
-                       (void) va_arg(ap, ssize_t *);
+                       (*argtable)[n].pssizearg = va_arg(ap, ssize_t *);
                        break;
                case TP_MAXINT:
-                       (void) va_arg(ap, intmax_t *);
+                       (*argtable)[n].intmaxarg = va_arg(ap, intmax_t);
                        break;
                }
        }
@@ -1193,6 +1229,7 @@ done:
                munmap(typetable, *argtablesiz);
                typetable = NULL;
        }
+       return (0);
 }
 
 /*
@@ -1205,24 +1242,24 @@ __grow_type_table(unsigned char **typetable, int *tablesize)
        int newsize = *tablesize * 2;
 
        if (*tablesize == STATIC_ARG_TBL_SIZE) {
-               *typetable = (unsigned char *)mmap(NULL,
-                   sizeof (unsigned char) * newsize, PROT_WRITE|PROT_READ,
+               *typetable = mmap(NULL, newsize, PROT_WRITE|PROT_READ,
                    MAP_ANON|MAP_PRIVATE, -1, 0);
-               /* XXX unchecked */
+               if (*typetable == MAP_FAILED)
+                       return (-1);
                memcpy( *typetable, oldtable, *tablesize);
        } else {
-               unsigned char *new = (unsigned char *)mmap(NULL,
-                   sizeof (unsigned char) * newsize, PROT_WRITE|PROT_READ,
+               unsigned char *new = mmap(NULL, newsize, PROT_WRITE|PROT_READ,
                    MAP_ANON|MAP_PRIVATE, -1, 0);
+               if (new == MAP_FAILED)
+                       return (-1);
                memmove(new, *typetable, *tablesize);
                munmap(*typetable, *tablesize);
                *typetable = new;
-               /* XXX unchecked */
        }
        memset(*typetable + *tablesize, T_UNUSED, (newsize - *tablesize));
 
        *tablesize = newsize;
-       return(0);
+       return (0);
 }
 
 
@@ -1256,7 +1293,7 @@ cvt(double value, int ndigits, int flags, char *sign, int *decpt, int ch,
        } else
                *sign = '\000';
        digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
-       if ((ch != 'g' && ch != 'G') || flags & ALT) {  /* Print trailing zeros */
+       if ((ch != 'g' && ch != 'G') || flags & ALT) {/* Print trailing zeros */
                bp = digits + ndigits;
                if (ch == 'f') {
                        if (*digits == '0' && value)
@@ -1283,8 +1320,7 @@ exponent(char *p0, int exp, int fmtch)
        if (exp < 0) {
                exp = -exp;
                *p++ = '-';
-       }
-       else
+       } else
                *p++ = '+';
        t = expbuf + MAXEXP;
        if (exp > 9) {
@@ -1292,9 +1328,9 @@ exponent(char *p0, int exp, int fmtch)
                        *--t = to_char(exp % 10);
                } while ((exp /= 10) > 9);
                *--t = to_char(exp);
-               for (; t < expbuf + MAXEXP; *p++ = *t++);
-       }
-       else {
+               for (; t < expbuf + MAXEXP; *p++ = *t++)
+                       /* nothing */;
+       else {
                *p++ = '0';
                *p++ = to_char(exp);
        }
index 8c1cef9..cc1fd85 100644 (file)
@@ -297,6 +297,9 @@ TEST(stdio, snprintf_smoke) {
 
   snprintf(buf, sizeof(buf), "a_%g_b", 3.14);
   EXPECT_STREQ("a_3.14_b", buf);
+
+  snprintf(buf, sizeof(buf), "%1$s %1$s", "print_me_twice");
+  EXPECT_STREQ("print_me_twice print_me_twice", buf);
 }
 
 TEST(stdio, snprintf_d_INT_MAX) {