Mercurial > hg > toybox
view toys/pending/printf.c @ 1572:da1bf31ed322 draft
Tweak the "ignoring return value" fortify workaround for readlinkat.
We zero the buffer and if the link read fails that's left alone, so
it's ok for the symlink not to be there. Unfortunately, typecasting the
return value to (void) doesn't shut up gcc, and having an if(); with the
semicolon on the same line doesn't shut up llvm. (The semicolon on a new
line would, but C does not have significant whitespace and I'm not going
to humor llvm if it plans to start.)
So far, empty curly brackets consistently get the warning to shut up.
author | Rob Landley <rob@landley.net> |
---|---|
date | Mon, 24 Nov 2014 17:23:23 -0600 |
parents | 2fe64bc16a61 |
children | 54c092c3ee38 |
line wrap: on
line source
/* printf.c - Format and Print the data. * * Copyright 2014 Sandeep Sharma <sandeep.jack2756@gmail.com> * Copyright 2014 Kyungwan Han <asura321@gmail.com> * * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html USE_PRINTF(NEWTOY(printf, "<1", TOYFLAG_USR|TOYFLAG_BIN)) config PRINTF bool "printf" default n help usage: printf Format [Arguments..] Format and print ARGUMENT(s) according to FORMAT. Format is 'C' control output as 'C' printf. */ #define FOR_printf #include "toys.h" GLOBALS( char *hv_w; char *hv_p; int encountered; ) // Calculate width and precision from format string static int get_w_p() { char *ptr, *str = *toys.optargs; errno = 0; if (*str == '-') str++; long value = strtol(str, &ptr, 10); if (errno || (ptr && (*ptr != '\0' || ptr == str))) perror_msg("Invalid num %s", *toys.optargs); if (*--str == '-') return (int)(-1 * value); return value; } // Add ll and L to Interger and floating point formats respectively. static char *get_format(char *f) { int len = strlen(f); char last = f[--len], *post = ""; f[len] = '\0'; if (strchr("diouxX", last)) post = "ll"; // add ll to integer modifier. else if (strchr("feEgG", last)) post = "L"; // add L to float modifier. return xmprintf("%s%s%c", f, post, last); } // Print arguments with corresponding conversion and width and precision. static void print(char *fmt, int w, int p, int l) { char *ptr = (fmt+l-1), *ep = NULL, *format = NULL; long long val; long double dval; errno = 0; switch (*ptr) { case 'd': /*FALL_THROUGH*/ case 'i': /*FALL_THROUGH*/ case 'o': /*FALL_THROUGH*/ case 'u': /*FALL_THROUGH*/ case 'x': /*FALL_THROUGH*/ case 'X': if (!*toys.optargs) val = 0; else { if (**toys.optargs == '\'' || **toys.optargs == '"') val = *((*toys.optargs) + 1); else { val = strtoll(*toys.optargs, &ep, 0); if (errno || (ep && (*ep != '\0' || ep == *toys.optargs))) { perror_msg("Invalid num %s", *toys.optargs); val = 0; } } } format = get_format(fmt); TT.hv_w ? (TT.hv_p ? printf(format, w, p, val) : printf(format, w, val)) : (TT.hv_p ? printf(format, p, val) : printf(format, val)); break; case 'g': /*FALL_THROUGH*/ case 'e': /*FALL_THROUGH*/ case 'E': /*FALL_THROUGH*/ case 'G': /*FALL_THROUGH*/ case 'f': if (*toys.optargs) { dval = strtold(*toys.optargs, &ep); if (errno || (ep && (*ep != '\0' || ep == *toys.optargs))) { perror_msg("Invalid num %s", *toys.optargs); dval = 0; } } else dval = 0; format = get_format(fmt); TT.hv_w ? (TT.hv_p ? printf(format, w, p, dval):printf(format, w, dval)) : (TT.hv_p ? printf(format, p, dval) : printf(format, dval)); break; case 's': { char *str = (*toys.optargs ? *toys.optargs : ""); TT.hv_w ? (TT.hv_p ? printf(fmt,w,p,str): printf(fmt, w, str)) : (TT.hv_p ? printf(fmt, p, str) : printf(fmt, str)); } break; case 'c': printf(fmt, (*toys.optargs ? **toys.optargs : '\0')); break; } if (format) free(format); } // Handle the escape sequences. static int handle_slash(char **esc_val) { char *ptr = *esc_val; int esc_length = 0; unsigned base = 0, num = 0, result = 0, count = 0; /* * Hex escape sequence have only 1 or 2 digits, xHH. Oct escape sequence * have 1,2 or 3 digits, xHHH. Leading "0" (\0HHH) we are ignoring. */ if (*ptr == 'x') { ptr++; esc_length++; base = 16; } else if (isdigit(*ptr)) base = 8; while (esc_length < 3 && base) { num = tolower(*ptr) - '0'; if (num > 10) num += ('0' - 'a' + 10); if (num >= base) { if (base == 16) { esc_length--; if (!esc_length) {// Invalid hex value eg. /xvd, print as it is /xvd result = '\\'; ptr--; } } break; } esc_length++; count = result = (count * base) + num; ptr++; } if (base) { ptr--; *esc_val = ptr; return (char)result; } else { switch (*ptr) { case 'n': result = '\n'; break; case 't': result = '\t'; break; case 'e': result = (char)27; break; case 'b': result = '\b'; break; case 'a': result = '\a'; break; case 'f': result = '\f'; break; case 'v': result = '\v'; break; case 'r': result = '\r'; break; case '\\': result = '\\'; break; default : result = '\\'; ptr--; // Let pointer pointing to / we will increment after returning. break; } } *esc_val = ptr; return (char)result; } // Handle "%b" option with '\' interpreted. static void print_esc_str(char *str) { for (; *str; str++) { if (*str == '\\') { str++; xputc(handle_slash(&str)); //print corresponding char } else xputc(*str); } } // Prase the format string and print. static void parse_print(char *f) { char *start, *p, format_specifiers[] = "diouxXfeEgGcs"; int len = 0, width = 0, prec = 0; while (*f) { switch (*f) { case '%': start = f++; len++; if (*f == '%') { xputc('%'); break; } if (*f == 'b') { if (*toys.optargs) { print_esc_str(*toys.optargs++); TT.encountered = 1; } else print_esc_str(""); break; } if (strchr("-+# ", *f)) f++, len++; if (*f == '*') { f++, len++; if (*toys.optargs) { width = get_w_p(); toys.optargs++; } } else { while (isdigit(*f)) f++, len++; } if (*f == '.') { f++, len++; if (*f == '*') { f++, len++; if (*toys.optargs) { prec = get_w_p(); toys.optargs++; } } else { while (isdigit(*f)) f++, len++; } } if (!(p = strchr(format_specifiers, *f))) perror_exit("Missing OR Invalid format specifier"); else { len++; TT.hv_p = strstr(start, ".*"); TT.hv_w = strchr(start, '*'); //pitfall: handle diff b/w * and .* if ((TT.hv_w-1) == TT.hv_p) TT.hv_w = NULL; memcpy((p = xzalloc(len+1)), start, len); print(p, width, prec, len); if (*toys.optargs) toys.optargs++; free(p); p = NULL; } TT.encountered = 1; break; case '\\': if (f[1]) { if (*++f == 'c') exit(0); //Got '\c', so no further output xputc(handle_slash(&f)); } else xputc(*f); break; default: xputc(*f); break; } f++; len = 0; } } void printf_main(void) { char *format = *toys.optargs++; TT.encountered = 0; parse_print(format); //printf acc. to format. //Re-use FORMAT arg as necessary to convert all given ARGS. while (*toys.optargs && TT.encountered) parse_print(format); xflush(); }