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Diffstat (limited to 'src/util/vbuf_print.c')
| -rw-r--r-- | src/util/vbuf_print.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/src/util/vbuf_print.c b/src/util/vbuf_print.c new file mode 100644 index 0000000..bdb6fe9 --- /dev/null +++ b/src/util/vbuf_print.c @@ -0,0 +1,384 @@ +/*++ +/* NAME +/* vbuf_print 3 +/* SUMMARY +/* formatted print to generic buffer +/* SYNOPSIS +/* #include <stdarg.h> +/* #include <vbuf_print.h> +/* +/* VBUF *vbuf_print(bp, format, ap) +/* VBUF *bp; +/* const char *format; +/* va_list ap; +/* DESCRIPTION +/* vbuf_print() appends data to the named buffer according to its +/* \fIformat\fR argument. It understands the s, c, d, u, o, x, X, p, e, +/* f and g format types, the l modifier, field width and precision, +/* sign, and padding with zeros or spaces. +/* +/* In addition, vbuf_print() recognizes the %m format specifier +/* and expands it to the error message corresponding to the current +/* value of the global \fIerrno\fR variable. +/* REENTRANCY +/* .ad +/* .fi +/* vbuf_print() allocates a static buffer. After completion +/* of the first vbuf_print() call, this buffer is safe for +/* reentrant vbuf_print() calls by (asynchronous) terminating +/* signal handlers or by (synchronous) terminating error +/* handlers. vbuf_print() initialization typically happens +/* upon the first formatted output to a VSTRING or VSTREAM. +/* +/* However, it is up to the caller to ensure that the destination +/* VSTREAM or VSTRING buffer is protected against reentrant usage. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/* +/* Wietse Venema +/* Google, Inc. +/* 111 8th Avenue +/* New York, NY 10011, USA +/*--*/ + +/* System library. */ + +#include "sys_defs.h" +#include <stdlib.h> /* 44BSD stdarg.h uses abort() */ +#include <stdarg.h> +#include <string.h> +#include <ctype.h> +#include <stdlib.h> /* 44bsd stdarg.h uses abort() */ +#include <stdio.h> /* sprintf() prototype */ +#include <float.h> /* range of doubles */ +#include <errno.h> +#include <limits.h> /* CHAR_BIT, INT_MAX */ + +/* Application-specific. */ + +#include "msg.h" +#include "mymalloc.h" +#include "vbuf.h" +#include "vstring.h" +#include "vbuf_print.h" + + /* + * What we need here is a *sprintf() routine that can ask for more room (as + * in 4.4 BSD). However, that functionality is not widely available, and I + * have no plans to maintain a complete 4.4 BSD *sprintf() alternative. + * + * Postfix vbuf_print() was implemented when many mainstream systems had no + * usable snprintf() implementation (usable means: return the length, + * excluding terminator, that the output would have if the buffer were large + * enough). For example, GLIBC before 2.1 (1999) snprintf() did not + * distinguish between formatting error and buffer size error, while SUN had + * no snprintf() implementation before Solaris 2.6 (1997). + * + * For the above reasons, vbuf_print() was implemented with sprintf() and a + * generously-sized output buffer. Current vbuf_print() implementations use + * snprintf(), and report an error if the output does not fit (in that case, + * the old sprintf()-based implementation would have had a buffer overflow + * vulnerability). The old implementation is still available for building + * Postfix on ancient systems. + * + * Guessing the output size of a string (%s) conversion is not hard. The + * problem is with numerical results. Instead of making an accurate guess we + * take a wide margin when reserving space. The INT_SPACE margin should be + * large enough to hold the result from any (octal, hex, decimal) integer + * conversion that has no explicit width or precision specifiers. With + * floating-point numbers, use a similar estimate, and add DBL_MAX_10_EXP + * just to be sure. + */ +#define INT_SPACE ((CHAR_BIT * sizeof(long)) / 2) +#define DBL_SPACE ((CHAR_BIT * sizeof(double)) / 2 + DBL_MAX_10_EXP) +#define PTR_SPACE ((CHAR_BIT * sizeof(char *)) / 2) + + /* + * Helper macros... Note that there is no need to check the result from + * VSTRING_SPACE() because that always succeeds or never returns. + */ +#ifndef NO_SNPRINTF +#define VBUF_SNPRINTF(bp, sz, fmt, arg) do { \ + ssize_t _ret; \ + if (VBUF_SPACE((bp), (sz)) != 0) \ + return (bp); \ + _ret = snprintf((char *) (bp)->ptr, (bp)->cnt, (fmt), (arg)); \ + if (_ret < 0) \ + msg_panic("%s: output error for '%s'", myname, mystrdup(fmt)); \ + if (_ret >= (bp)->cnt) \ + msg_panic("%s: output for '%s' exceeds space %ld", \ + myname, mystrdup(fmt), (long) (bp)->cnt); \ + VBUF_SKIP(bp); \ + } while (0) +#else +#define VBUF_SNPRINTF(bp, sz, fmt, arg) do { \ + if (VBUF_SPACE((bp), (sz)) != 0) \ + return (bp); \ + sprintf((char *) (bp)->ptr, (fmt), (arg)); \ + VBUF_SKIP(bp); \ + } while (0) +#endif + +#define VBUF_SKIP(bp) do { \ + while ((bp)->cnt > 0 && *(bp)->ptr) \ + (bp)->ptr++, (bp)->cnt--; \ + } while (0) + +#define VSTRING_ADDNUM(vp, n) do { \ + VBUF_SNPRINTF(&(vp)->vbuf, INT_SPACE, "%d", n); \ + } while (0) + +#define VBUF_STRCAT(bp, s) do { \ + unsigned char *_cp = (unsigned char *) (s); \ + int _ch; \ + while ((_ch = *_cp++) != 0) \ + VBUF_PUT((bp), _ch); \ + } while (0) + +/* vbuf_print - format string, vsprintf-like interface */ + +VBUF *vbuf_print(VBUF *bp, const char *format, va_list ap) +{ + const char *myname = "vbuf_print"; + static VSTRING *fmt; /* format specifier */ + unsigned char *cp; + int width; /* width and numerical precision */ + int prec; /* are signed for overflow defense */ + unsigned long_flag; /* long or plain integer */ + int ch; + char *s; + int saved_errno = errno; /* VBUF_SPACE() may clobber it */ + + /* + * Assume that format strings are short. + */ + if (fmt == 0) + fmt = vstring_alloc(INT_SPACE); + + /* + * Iterate over characters in the format string, picking up arguments + * when format specifiers are found. + */ + for (cp = (unsigned char *) format; *cp; cp++) { + if (*cp != '%') { + VBUF_PUT(bp, *cp); /* ordinary character */ + } else if (cp[1] == '%') { + VBUF_PUT(bp, *cp++); /* %% becomes % */ + } else { + + /* + * Handle format specifiers one at a time, since we can only deal + * with arguments one at a time. Try to determine the end of the + * format specifier. We do not attempt to fully parse format + * strings, since we are ging to let sprintf() do the hard work. + * In regular expression notation, we recognize: + * + * %-?+?0?([0-9]+|\*)?(\.([0-9]+|\*))?l?[a-zA-Z] + * + * which includes some combinations that do not make sense. Garbage + * in, garbage out. + */ + VSTRING_RESET(fmt); /* clear format string */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == '-') /* left-adjusted field? */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == '+') /* signed field? */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == '0') /* zero-padded field? */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == '*') { /* dynamic field width */ + width = va_arg(ap, int); + if (width < 0) { + msg_warn("%s: bad width %d in %.50s", + myname, width, format); + width = 0; + } else + VSTRING_ADDNUM(fmt, width); + cp++; + } else { /* hard-coded field width */ + for (width = 0; ch = *cp, ISDIGIT(ch); cp++) { + int digit = ch - '0'; + + if (width > INT_MAX / 10 + || (width *= 10) > INT_MAX - digit) + msg_panic("%s: bad width %d... in %.50s", + myname, width, format); + width += digit; + VSTRING_ADDCH(fmt, ch); + } + } + if (*cp == '.') { /* width/precision separator */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == '*') { /* dynamic precision */ + prec = va_arg(ap, int); + if (prec < 0) { + msg_warn("%s: bad precision %d in %.50s", + myname, prec, format); + prec = -1; + } else + VSTRING_ADDNUM(fmt, prec); + cp++; + } else { /* hard-coded precision */ + for (prec = 0; ch = *cp, ISDIGIT(ch); cp++) { + int digit = ch - '0'; + + if (prec > INT_MAX / 10 + || (prec *= 10) > INT_MAX - digit) + msg_panic("%s: bad precision %d... in %.50s", + myname, prec, format); + prec += digit; + VSTRING_ADDCH(fmt, ch); + } + } + } else { + prec = -1; + } + if ((long_flag = (*cp == 'l')) != 0)/* long whatever */ + VSTRING_ADDCH(fmt, *cp++); + if (*cp == 0) /* premature end, punt */ + break; + VSTRING_ADDCH(fmt, *cp); /* type (checked below) */ + VSTRING_TERMINATE(fmt); /* null terminate */ + + /* + * Execute the format string - let sprintf() do the hard work for + * non-trivial cases only. For simple string conversions and for + * long string conversions, do a direct copy to the output + * buffer. + */ + switch (*cp) { + case 's': /* string-valued argument */ + if (long_flag) + msg_panic("%s: %%l%c is not supported", myname, *cp); + s = va_arg(ap, char *); + if (prec >= 0 || (width > 0 && width > strlen(s))) { + VBUF_SNPRINTF(bp, (width > prec ? width : prec) + INT_SPACE, + vstring_str(fmt), s); + } else { + VBUF_STRCAT(bp, s); + } + break; + case 'c': /* integral-valued argument */ + if (long_flag) + msg_panic("%s: %%l%c is not supported", myname, *cp); + /* FALLTHROUGH */ + case 'd': + case 'u': + case 'o': + case 'x': + case 'X': + if (long_flag) + VBUF_SNPRINTF(bp, (width > prec ? width : prec) + INT_SPACE, + vstring_str(fmt), va_arg(ap, long)); + else + VBUF_SNPRINTF(bp, (width > prec ? width : prec) + INT_SPACE, + vstring_str(fmt), va_arg(ap, int)); + break; + case 'e': /* float-valued argument */ + case 'f': + case 'g': + /* C99 *printf ignore the 'l' modifier. */ + VBUF_SNPRINTF(bp, (width > prec ? width : prec) + DBL_SPACE, + vstring_str(fmt), va_arg(ap, double)); + break; + case 'm': + /* Ignore the 'l' modifier, width and precision. */ + VBUF_STRCAT(bp, strerror(saved_errno)); + break; + case 'p': + if (long_flag) + msg_panic("%s: %%l%c is not supported", myname, *cp); + VBUF_SNPRINTF(bp, (width > prec ? width : prec) + PTR_SPACE, + vstring_str(fmt), va_arg(ap, char *)); + break; + default: /* anything else is bad */ + msg_panic("vbuf_print: unknown format type: %c", *cp); + /* NOTREACHED */ + break; + } + } + } + return (bp); +} + +#ifdef TEST +#include <argv.h> +#include <msg_vstream.h> +#include <vstring.h> +#include <vstring_vstream.h> + +int main(int argc, char **argv) +{ + VSTRING *ibuf = vstring_alloc(100); + + msg_vstream_init(argv[0], VSTREAM_ERR); + + while (vstring_fgets_nonl(ibuf, VSTREAM_IN)) { + ARGV *args = argv_split(vstring_str(ibuf), CHARS_SPACE); + char *cp; + + if (args->argc == 0 || *(cp = args->argv[0]) == '#') { + /* void */ ; + } else if (args->argc != 2 || *cp != '%') { + msg_warn("usage: format number"); + } else { + char *fmt = cp++; + int lflag; + + /* Determine the vstring_sprintf() argument type. */ + cp += strspn(cp, "+-*0123456789."); + if ((lflag = (*cp == 'l')) != 0) + cp++; + if (cp[1] != 0) { + msg_warn("bad format: \"%s\"", fmt); + } else { + VSTRING *obuf = vstring_alloc(1); + char *val = args->argv[1]; + + /* Test the worst-case memory allocation. */ +#ifdef CA_VSTRING_CTL_EXACT + vstring_ctl(obuf, CA_VSTRING_CTL_EXACT, CA_VSTRING_CTL_END); +#endif + switch (*cp) { + case 'c': + case 'd': + case 'o': + case 'u': + case 'x': + case 'X': + if (lflag) + vstring_sprintf(obuf, fmt, atol(val)); + else + vstring_sprintf(obuf, fmt, atoi(val)); + msg_info("\"%s\"", vstring_str(obuf)); + break; + case 's': + vstring_sprintf(obuf, fmt, val); + msg_info("\"%s\"", vstring_str(obuf)); + break; + case 'f': + case 'g': + vstring_sprintf(obuf, fmt, atof(val)); + msg_info("\"%s\"", vstring_str(obuf)); + break; + default: + msg_warn("bad format: \"%s\"", fmt); + break; + } + vstring_free(obuf); + } + } + argv_free(args); + } + vstring_free(ibuf); + return (0); +} + +#endif |