PKG_PRINTF(3) BSD Library Functions Manual PKG_PRINTF(3)NAME
pkg_printf, pkg_fprintf, pkg_dprintf, pkg_snprintf, pkg_asprintf,
pkg_sbuf_printf, pkg_vprintf, pkg_vfprintf, pkg_vdprintf, pkg_vsnprintf,
pkg_vasprintf, pkg_sbuf_vprintf — formatted output of package data
LIBRARY
library “libpkg”
SYNOPSIS
#include <pkg.h>
int
pkg_printf(const char * restrict format, ...);
int
pkg_fprintf(FILE * restrict stream, const char * restrict format, ...);
int
pkg_dprintf(int fd, const char * restrict format, ...);
int
pkg_snprintf(char * restrict str, size_t size,
const char * restrict format, ...);
int
pkg_asprintf(char **ret, const char * restrict format, ...);
struct sbuf *
pkg_sbuf_printf(struct sbuf * restrict sbuf,
const char * restrict format, ...);
#include <stdarg.h>
int
pkg_vprintf(const char * restrict format, va_list ap);
int
pkg_vfprintf(FILE * restrict stream, const char * restrict format,
va_list ap);
int
pkg_vdprintf(int fd, const char * restrict format, va_list ap);
int
pkg_vsnprintf(char * restrict str, size_t size,
const char * restrict format, va_list ap);
int
pkg_vasprintf(char **ret, const char * restrict format, va_list ap);
struct sbuf *
pkg_sbuf_vprintf(struct sbuf * restrict sbuf,
const char * restrict format, va_list ap);
DESCRIPTION
The pkg_printf() family of functions produces output of package data
according to a format as described below, analogously to the similarly
named printf(3) family of functions. The pkg_printf() and pkg_vprintf()
functions write output to stdout, the standard output stream;
pkg_fprintf() and pkg_vfprintf() write output to the given output stream;
pkg_dprintf() and pkg_vdprintf() write output to the given file descrip‐
tor; pkg_snprintf() and pkg_vsnprintf() write to the character string
str; pkg_asprintf() and pkg_vasprintf() dynamically allocate a new string
with malloc(3) to write to; pkg_sbuf_printf() and pkg_sbuf_vprintf()
write to the given sbuf structure.
These functions write the output under the control of a format string
that specifies how subsequent arguments (or arguments accessed via the
variable-length argument facilities of stdarg(3)) are converted for out‐
put.
These functions return the number of characters printed (not including
the trailing ‘\0’ used to end output to strings) or a negative value if
an output error occurs, except for pkg_snprintf() or pkg_vsnprintf()
which return the number of characters that would have been printed if the
size were unlimited (again, not including the final ‘\0’) and the two
functions pkg_sbuf_printf() and pkg_sbuf_vprintf() which return the given
sbuf pointer, or NULL in the case of errors.
The pkg_asprintf() and pkg_vasprintf() functions set *ret to be a pointer
to a buffer sufficiently large to hold the formatted string. This
pointer should be passed to free(3) to release the allocated storage when
it is no longer needed. If sufficient space cannot be allocated,
pkg_asprintf() and pkg_vasprintf() will return -1 and set ret to be a
NULL pointer.
The pkg_snprintf() and pkg_vsnprintf() functions will write at most
size-1 of the characters printed into the output string (the size'th
character then gets the terminating ‘\0’); if the return value is greater
than or equal to the size argument, the string was too short and some of
the printed characters were discarded. The output is always null-termi‐
nated.
The format string is composed of zero or more directives: ordinary char‐
acters (not %), which are copied unchanged to the output stream; and con‐
version specifications, each of which results in fetching zero or more
subsequent arguments. Each conversion specification is introduced by the
% character. The arguments must correspond properly with the conversion
specifier. After the %, the following appear in sequence:
· Zero or more of the following flags:
? The value should be converted to the “first alternate
form”.
For integer valued conversions (I, s, t and x) this is a
humanized form as a floating point value scaled to the
range 0 - 1000 followed by the SI powers-of-10 scale
factor. See SCALE FACTORS.
For array valued conversions (A, B, C, D, F, G, L, O, U,
d, and r) generate “0” if there are no items in the
array, “1” otherwise.
For formats returning file modes (Dp or Fp) print the
mode in the style of strmode(3).
For boolean valued formats (dk, rk, a and k) generate
either “yes” or “no” for ‘true’ and ‘false’ respec‐
tively.
For the licence logic format (l) generate “” (empty),
“&” or “|” for types ‘SINGLE’, ‘AND’ and ‘OR’ respec‐
tively.
# The value should be converted to the “second alternate
form”.
For the integer valued conversions (I, s, t, x) this is
a “humanized” form as a floating point value scaled to
the range 0 - 1024 followed by the IEE/IEC and SI pow‐
ers-of-2 scale factor. See SCALE FACTORS.
For array valued conversions (A, B, C, D, F, G, L, O, U,
d, and r) generate the number of items in the array.
For formats returning file modes (Dp or Fp) print the
mode as an octal integer with a leading 0.
For boolean valued formats (dk, rk, a and k) generate
either “(*)” or “” (empty) for ‘true’ and ‘false’
respectively.
For the licence logic format (l) generate “==”, “&&” or
“||” for types ‘SINGLE’, ‘AND’ and ‘OR’ respectively.
0 (zero) Zero padding. For all integer valued conversions and
humanized numbers the converted value is padded on the
left with zeros rather than blanks. For string valued
conversions, this has no effect and the converted value
is padded on the left with blanks.
- A negative field width flag; the converted value is to
be left adjusted on the field boundary. The converted
value is padded on the right with blanks, rather than on
the left with blanks or zeros. Applies to all scalar-
valued conversions. “-” overrides a “0” if both are
given.
‘ ’ (space) A blank should be left before a positive number produced
by a signed conversion (I, s, t, or x).
+ A sign must always be placed before an integer or human‐
ized number produced by a numerical conversion. A “+”
overrides a space if both are used.
‘'’ Numerical (integer) conversions should be grouped and
separated by thousands using the non-monetary separator
returned by localeconv(3). Has no visible effect in the
default “C” locale.
· An optional decimal digit string specifying a minimum field width.
If the converted value has fewer characters than the field width, it
will be padded with spaces (or zeroes, if the zero-padding flag has
been given and the conversion supports it) on the left (or spaces on
the right, if the left-adjustment flag has been given) to fill out
the field width.
· One or two characters that specify the type of conversion to be
applied.
· An optional “row format” for array valued conversions (A, B, C, D, F,
G, L, O, U, d, and r) or the timestamp value conversion (t). Which
conversion characters are permissible in the row format is context
dependent. See the FORMAT CODES section for details.
SCALE FACTORS
Humanized number conversions scale the number to lie within the range 1 -
1000 (power of ten conversions using the ? format modifier) or 1 - 1024
(power of two conversions using the # format modifier) and append a scale
factor as follows:
The SI power of ten suffixes are
Suffix Description Multiplier
(none) 1
k kilo 1,000
M mega 1,000,000
G giga 1,000,000,000
T tera 1,000,000,000,000
P peta 1,000,000,000,000,000
E exa 1,000,000,000,000,000,000
The IEE/IEC (and now also SI) power of two suffixes are:
Suffix Description Multiplier
(none) 1
Ki kibi 1,024
Mi mebi 1,048,576
Gi gibi 1,073,741,824
Ti tebi 1,099,511,627,776
Pi pebi 1,125,899,906,842,624
Ei exbi 1,152,921,504,606,846,976
FORMAT CODES
Format codes will format the output classified as the type shown in
square brackets. %I is unique in that it can only be used inside a “row
format.” All other format codes may be used stand-alone. When used in
this fashion they will consume one argument of the indicated type from
the function's argument list.
The array valued format codes (A, B, C, D, F, G, L, O, U, d, and r) and
the timestamp format code (t) can be followed by a “row format”. They
will use a default row format (detailed below) if one is not given
explicitly.
The row format is bracketed by the character sequences %{ and %} and, for
array values only, may be optionally divided into two by the character
sequence %|. For array values, it contains one or two strings containing
any number of a context sensitive subset of format conversions from those
described here. For timestamp values it contains any number of format
conversion specifiers with meanings as described in strftime(3).
The first or only format string is repeatedly processed for each of the
array items in turn. The optional second format string is processed as a
separator between each of the array items. If no row format is given,
output will be generated according to a default format, detailed below.
Within a “row format” string, you may use any of the single-character
non-array valued format codes except for %S, but only the two-character
format codes which correspond to the parent item and have the same first
character. Array valued format codes may not be used within row formats,
nor may you embed one “row format” within another. Only one argument, a
struct pkg * pointer is consumed from the argument list. Thus this is a
legal format string:
"%B%{%n-%v:%Bn%|\n%}"
which serves to print out a list of the shared libraries required by the
programs within the package, each prefixed by the package name and ver‐
sion.
The conversion specifiers and their meanings are:
%A Annotations [array] struct pkg *
Default row format %A%{%An: %Av\n%|%}
%An Annotation tag name [string] struct pkg_note *
%Av Annotation value [string] struct pkg_note *
%B Required shared libraries [array] struct pkg *
Default row format: %B%{%Bn\n%|%}
%Bn Required shared library name [string] struct pkg_shlib *
%C Categories [array] struct pkg *
Default row format: %C%{%Cn%|, %}
%Cn Category name [string] struct pkg_category *
%D Directories [array] struct pkg *
Default row format: %D%{%Dn\n%|%}
%Dg Directory ownership: group name [string] struct pkg_dir *
%Dn Directory path name [string] struct pkg_dir *
%Dp Directory permissions [mode] struct pkg_dir *
%Du Directory ownership: user name [string] struct pkg_dir *
%F Files [array] struct pkg *
Default row format: %F%{%Fn\n%|%}
%Fg File ownership: group name [string] struct pkg_file *
%Fn File path name [string] struct pkg_file *
%Fp File permissions [mode] struct pkg_file *
%Fs File SHA256 checksum [string] struct pkg_file *
%Fu File ownership: user name [string] struct pkg_file *
%G Groups [array] struct pkg *
Default row format: %G%{%Gn\n%|%}
%Gn Group name [string] struct pkg_group *
%I Row counter [integer].
This format code may only be used as part of a “row format.”
%L Licenses [array] struct pkg *
Default row format: %L%{%Ln%| %l %}
%Ln Licence name [string] struct pkg_license *
%M Package message [string] struct pkg *
%N Repository identity [string] struct pkg *
%O Options [array] struct pkg *
Default row format: %O%{%On %Ov\n%|%}
%On Option name [string] struct pkg_option *
%Ov Option value [string] struct pkg_option *
%Od Option default value [string] (if known: will produce an empty
string if not.) struct pkg_option *
%OD Option description [string] (if known: will produce an empty string
if not.) struct pkg_option *
%R Repository path - the path relative to the repository root that
package may be downloaded from [string]. struct pkg *
%S Arbitrary character string [string] const char *
%U Users [array] struct pkg *
Default row format: %U%{%Un\n%|%}
%Un User name [string] struct pkg_user *
%V Old version [string]. Valid only during operations when one version
of a package is being replaced by another. struct pkg *
%a Autoremove flag [boolean] struct pkg *
%b Provided shared libraries [array] struct pkg *
Default row format: %b%{%bn\n%|%}
%bn Provided shared library name [string] struct pkg_shlib *
%c Comment [string] struct pkg *
%d Dependencies [array] struct pkg *
Default row format: %d%{%dn-%dv\n%|%}
%dk Dependency lock status [boolean] struct pkg_dep *
%dn Dependency name [string] struct pkg_dep *
%do Dependency origin [string] struct pkg_dep *
%dv Dependency version [string] struct pkg_dep *
%e Description [string] struct pkg *
%i Additional information [string] struct pkg *
%k Locking status [boolean] struct pkg *
%l License logic [licence-logic] struct pkg *
%m Maintainer [string] struct pkg *
%n Package name [string] struct pkg *
%o Origin [string] struct pkg *
%p Prefix [string] struct pkg *
%r Requirements [array] struct pkg *
Default row format: %r%{%rn-%rv\n%|%}
%rk Requirement lock status [boolean] struct pkg_dep *
%rn Requirement name [string] struct pkg_dep *
%ro Requirement origin [string] struct pkg_dep *
%rv Requirement version [string] struct pkg_dep *
%s Package flat size [integer] struct pkg *
%t Installation timestamp [date-time] struct pkg *
%u Package checksum [string] struct pkg *
%v Package version [string] struct pkg *
%w Home page URL [string] struct pkg *
%x Package tarball size [integer] struct pkg *
%z Package short checksum [string] struct pkg *
%% A ‘%’ is written. No argument is converted. The complete conver‐
sion specification is ‘%%’.
The decimal point character is defined in the program's locale (category
LC_NUMERIC).
In no case does a non-existent or small field width cause truncation of a
numeric field; if the result of a conversion is wider than the field
width, the field is expanded to contain the conversion result.
ARRAY VALUES
Effective format modifiers:
? First Alternate Form: 0 if the array is empty, 1 if it has any
number of elements within it
# Second Alternate Form: The number of elements in the array
STRING VALUES
Effective format modifiers:
- Left align
INTEGER VALUES
Effective format modifiers:
- Left align
? First Alternate Form: humanized number (decimal)
# Second Alternate Form: humanized number (binary)
0 Zero pad
‘ ’ Blank for plus
+ Explicit + or - sign
‘'’ Thousands separator
BOOLEAN VALUES
The two possible values ‘true’ or ‘false’ may be output in one of three
different styles: plain; or alternate forms 1 and 2 specified using for‐
mat modifiers.
Value Plain (%a) Alt 1 (%?a) Alt 2 (%#a)
FALSE false no
TRUE true yes (*)
The second alternate form produces no output for false.
Effective format modifiers:
? First Alternate Form
# Second Alternate Form
- Left align
FILE MODE VALUES
The file mode is a bitmap representing setid, user, group and other per‐
missions. The plain format prints it as an octal value, for example:
4755
The first alternate form is similar but adds a leading zero:
04755
Whilst the second alternate form produces a string in the style of
strmode(3):
-rwsr-xr-x
Note: there is always a space at the end of the strmode(3) output.
Effective format modifiers (all forms):
- Left align
Additionally, when the value is printed as an integer (i.e., plain or
alternate form 1), these additional modifiers take effect:
? First Alternate Form: add leading zero to octal integer
0 Zero pad
LICENSE LOGIC VALUES
License-logic is a three-valued type: one of ‘SINGLE’, ‘OR’ or ‘AND’,
which shows whether the package is distributed under the terms of a sin‐
gle license, or when there are several applicable licenses, whether these
should be treated as alternatives or applied in aggregate. There are
three different output styles: plain; or alternate forms 1 and 2 speci‐
fied using format modifiers.
Logic Plain (%l) Alt 1 (%?l) Alt 2 (%#l)
SINGLE single ==
OR or | ||
AND and & &&
Effective format modifiers:
? First Alternate Form
# Second Alternate Form
- Left align
DATE-TIME VALUES
When used outside of a “row format” string may be followed by an optional
strftime(3) format, enclosed in %{ and %}, which will be used to format
the timestamp. Otherwise the timestamp is printed as an integer value of
the number of seconds since the Epoch (00:00:00 UTC, 1 January 1970; see
time(3).)
Effective format modifiers:
- Left align
Additionally, when the value is printed as an integer (i.e., without
strftime(3) format codes enclosed in %{ and %}, the following format mod‐
ifiers are also effective:
? First Alternate Form: humanized number (decimal)
# Second Alternate Form: humanized number (binary)
0 Zero pad
‘ ’ Blank for plus
+ Explicit + or - sign
‘'’ Thousands separator
EXAMPLES
To print the package installation timestamp in the form “Sunday, July 3,
10:02”,
#include <pkg.h>
pkg_fprintf(stdout, "%t%{%A, %B %e, %R%}\n", pkg);
To print the package name and version, followed by the name and version
of all of the packages it depends upon, one per line, each indented by
one tab stop:
#include <pkg.h>
pkg_printf("%n-%v\n%d%{\t%dn-%dv%|%\n%}\n", pkg, pkg, pkg);
Note that the item separator part of the row format is only printed
between individual row items. Thus to fill the character array buf with
a one-line string listing all of the licenses for the package separated
by “and” or “or” as appropriate:
#include <pkg.h>
char buf[256];
pkg_snprintf(buf, sizeof(buf), "%L%{%Ln%| %l %}", pkg);
ERRORS
In addition to the errors documented for the write(2) system call, the
pkg_printf() family of functions may fail if:
[EILSEQ] An invalid wide character code was encountered.
[ENOMEM] Insufficient storage space is available.
SEE ALSOprintf(1), printf(3), strftime(3), setlocale(3)pkg_repos(3),
pkg-repository(5), pkg.conf(5), pkg(8), pkg-add(8), pkg-annotate(8),
pkg-audit(8), pkg-autoremove(8), pkg-backup(8), pkg-check(8),
pkg-clean(8), pkg-config(8), pkg-convert(8), pkg-create(8),
pkg-delete(8), pkg-fetch(8), pkg-info(8), pkg-install(8), pkg-lock(8),
pkg-query(8), pkg-register(8), pkg-repo(8), pkg-rquery(8), pkg-search(8),
pkg-set(8), pkg-shell(8), pkg-shlib(8), pkg-ssh(8), pkg-stats(8),
pkg-update(8), pkg-updating(8), pkg-upgrade(8), pkg-version(8),
pkg-which(8)BUGS
The pkg_printf family of functions do not correctly handle multibyte
characters in the format argument.
There is no way to sort the output of array valued items.
SECURITY CONSIDERATIONS
Equivalents to the sprintf() and vsprintf() functions are not supplied.
Instead, use pkg_snprintf() to write into a fixed length buffer without
danger of overflow.
The pkg_printf() family, like the printf() family of functions it is mod‐
elled on, is also easily misused in a manner allowing malicious users to
arbitrarily change a running program's functionality by either causing
the program to print potentially sensitive data “left on the stack”, or
causing it to generate a memory fault or bus error by dereferencing an
invalid pointer.
Programmers are therefore strongly advised to never pass untrusted
strings as the format argument, as an attacker can put format specifiers
in the string to mangle your stack, leading to a possible security hole.
This holds true even if the string was built using a function like
snprintf(), as the resulting string may still contain user-supplied con‐
version specifiers for later interpolation by pkg_printf().
Always use the proper secure idiom:
pkg_snprintf(buffer, sizeof(buffer), "%s", string);
BSD August 15, 2015 BSD
