summaryrefslogtreecommitdiffstats
path: root/lib/libstand/libstand.3
blob: 7d0c65ac4970acc9d95bcfcc0a6cfc2972d3ddcd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
.\" Copyright (c) Michael Smith
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR Ohttp://wafu.netgate.net/tama/unix/indexe.htmlTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd June 22, 1998
.Dt LIBSTAND 3
.Os FreeBSD 3.0
.Sh NAME
.Nm libstand
.Nd support library for standalone executables
.Sh SYNOPSIS
.Fd #include <stand.h>
.Sh DESCRIPTION
.Nm
provides a set of supporting functions for standalone
applications, mimicking where possible the standard BSD programming 
environment.  The following sections group these functions by kind.
Unless specifically described here, see the corresponding section 3
manpages for the given functions.
.Sh STRING FUNCTIONS
String functions are available as documented in
.Xr string 3 
and
.Xr bstring 3 .
.Sh MEMORY ALLOCATION
.Bl -hang -width 10n
.It Fn "void *malloc" "size_t size"
.Pp
Allocate
.Fa size
bytes of memory from the heap using a best-fit algorithm.
.It Fn "void free" "void *ptr"
.Pp
Free the allocated object at
.Fa ptr .
.It Fn "void setheap" "void *start" "void *limit"
.Pp
Initialise the heap.  This function must be called before calling
.Fn alloc
for the first time.  The region between
.Fa start
and
.Fa limit
will be used for the heap; attempting to allocate beyond this will result
in a panic.
.It Fn "char *sbrk" "int junk"
.Pp
Provides the behaviour of
.Fn sbrk 0 ,
ie. returns the highest point that the heap has reached.  This value can
be used during testing to determine the actual heap usage.  The
.Fa junk
argument is ignored.
.El
.Sh ENVIRONMENT
A set of functions are provided for manipulating a flat variable space similar
to the traditional shell-supported evironment.  Major enhancements are support
for set/unset hook functions.
.Bl -hang -width 10n
.It Fn "char *getenv" "const char *name"
.It Fn "int setenv" "const char *name" "char *value" "int overwrite"
.It Fn "int putenv" "const char *string"
.It Fn "int unsetenv" "const char *name"
.Pp
These functions behave similarly to their standard library counterparts.
.It Fn "struct env_var *env_getenv" "const char *name"
.Pp
Looks up a variable in the environment and returns its entire 
data structure.
.It Fn "int env_setenv" "const char *name" "int flags" "char *value" "ev_sethook_t sethook" "ev_unsethook_t unsethook"
.Pp
Creates a new or sets an existing environment variable called
.Fa name .
If creating a new variable, the 
.Fa sethook
and
.Fa unsethook
arguments may be specified.
.Pp
The set hook is invoked whenever an attempt
is made to set the variable, unless the EV_NOHOOK flag is set.  Typically
a set hook will validate the
.Fa value
argument, and then call
.Fn env_setenv
again with EV_NOHOOK set to actually save the value.  The predefined function
.Fn env_noset
may be specified to refuse all attempts to set a variable.
.Pp
The unset hook is invoked when an attempt is made to unset a variable.
If it 
returns zero, the  variable will be unset.  The predefined function
.Fa env_nounset
may be used to prevent a variable being unset.
.El
.Sh STANDARD LIBRARY SUPPORT
.Bl -hang -width 10n
.It Fn "int getopt" "int argc" "char * const *argv" "cont char *optstring"
.It Fn "long strtol" "const char *nptr" "char **endptr" "int base"
.It Fn "void srandom" "unsigned long seed"
.It Fn "unsigned long random" "void"
.It Fn "char *strerror" "int error"
.Pp
Returns error messages for the subset of errno values supported by
.Nm No .
.It Fn "assert" "expression"
.Pp
Requires
.Fd #include <assert.h>
.It Fn "int setjmp" "jmp_buf env"
.It Fn "void longjmp" "jmp_buf env" "int val"
.Pp
Defined as
.Fn _setjmp
and 
.Fn _lonjmp
respectively as there is no signal state to manipulate.  Requires
.Fd #include <setjmp.h>
.El
.Sh CHARACTER I/O
.Bl -hang -width 10n
.It Fn "void gets" "char *buf"
.Pp
Read characters from the console into
.Fa buf .
All of the standard cautions apply to this function.
.It Fn "void ngets" "char *buf" "size_t size"
.Pp
Read at most
.Fa size
- 1 characters from the console into
.Fa buf .
If
.Fa size
is less than 1, the function's behaviour is as for
.Fn gets .
.It Fn "int fgetstr" "char *buf" "int size" "int fd"
.Pp
Read a line of at most
.Fa size
characters into
.Fa buf .
Line terminating characters are stripped, and the buffer is always nul
terminated.  Returns the number of characters in
.Fa buf
if successful, or -1 if a read error occurs.
.It Fn "int printf" "const char *fmt" "..."
.It Fn "void vprintf" "const char *fmt" "va_list ap"
.It Fn "int sprintf" "char *buf" "const char *fmt" "..."
.It Fn "void vsprintf" "char *buf" "const char *fmt" "va_list ap"
.Pp
The *printf functions implement a subset of the standard
.Fn printf
family functionality and some extensions.  The following standard conversions 
are supported: c,d,n,o,p,s,u,x.  The following modifiers are supported: 
+,-,#,*,0,field width,precision,l.
.Pp
The
.Li b
conversion is provided to decode error registers.  Its usage is:
.Pp
.Bd -offset indent
printf( 
.Qq reg=%b\en , 
regval, 
.Qq <base><arg>*
);
.Ed

where <base> is the output expressed as a control character, eg. \e10 gives
octal, \e20 gives hex.  Each <arg> is a sequence of characters, the first of
which gives the bit number to be inspected (origin 1) and the next characters
(up to a character less than 32) give the text to be displayed if the bit is set.
Thus
.Pp
.Bd -offset indent
printf(
.Qq reg=%b\en
3
.Qq \e10\e2BITTWO\e1BITONE\en
);
.Ed

would give the output
.Pp
.Bd -offset indent
reg=3<BITTWO,BITONE>
.Ed
.Pp
The
.Li D
conversion provides a hexdump facility, eg.
.Pp
.Bd -offset indent -literal
printf(
.Qq %6D ,
ptr,
.Qq \:
);  gives  
.Qq XX:XX:XX:XX:XX:XX
.Ed
.Bd -offset indent -literal
printf(
.Qq %*D ,
len,
ptr,
.Qq "\ "
);  gives  
.Qq XX XX XX ...
.Ed
.El
.Sh CHARACTER TESTS AND CONVERSIONS
.Bl -hang -width 10n
.It Fn "int isupper" "int c"
.It Fn "int islower" "int c"
.It Fn "int isspace" "int c"
.It Fn "int isdigit" "int c"
.It Fn "int isxdigit" "int c"
.It Fn "int isascii" "int c"
.It Fn "int isalpha" "int c"
.It Fn "int toupper" "int c"
.It Fn "int tolower" "int c"
.El
.Sh FILE I/O
.Bl -hang -width 10n
.It Fn "int open" "const char *path" "int flags"
.Pp
Similar to the behaviour as specified in
.Xr open 2 ,
except that file creation is not supported, so the mode parameter is not
required.  The
.Fa flags
argument may be one of O_RDONLY, O_WRONLY and O_RDWR (although no filesystems
currently support writing).
.It Fn "int close" "int fd"
.It Fn "void closeall" "void"
.Pp
Close all open files.
.It Fn "ssize_t read" "int fd" "void *buf" "size_t len"
.It Fn "ssize_t write" "int fd" "void *buf" "size_t len"
.Pp
(No filesystems currently support writing.)
.It Fn "off_t lseek" "int fd" "off_t offset" "int whence"
.Pp
Files being automatically uncompressed during reading cannot seek backwards
from the current point.
.It Fn "int stat" "const char *path" "struct stat *sb"
.It Fn "int fstat" "int fd" "struct stat *sb"
.Pp
The
.Fn stat
and
.Fn fstat
functions only fill out the following fields in the
.Fa sb
structure: st_mode,st_nlink,st_uid,st_gid,st_size.  The 
.Nm tftp
filesystem cannot provide meaningful values for this call, and the 
.Nm cd9660
filesystem always reports files having uid/gid of zero.
.El
.Sh PAGER
.Nm
supplies a simple internal pager to ease reading the output of large commands.
.Bl -hang -width 10n
.It Fn "void pager_open"
.Pp
Initialises the pager and tells it that the next line output will be the top of the
display.  The environment variable LINES is consulted to determine the number of
lines to be displayed before pausing.
.It Fn "void pager_close" "void"
.Pp
Closes the pager.
.It Fn "void pager_output" "char *lines"
.Pp
Sends the lines in the nul-terminated buffer at
.Fa lines
to the pager.  Newline characters are counted in order to determine the number
of lines being output (wrapped lines are not accounted for).
.Fn pager_output
will return zero when all of the lines have been output, or nonzero if the
display was paused and the user elected to quit.
.It Fn "int pager_file" "char *fname"
.Pp
Attempts to open and display the file
.Fa fname.
 Returns -1 on error, 0 at EOF, or 1 if the user elects to quit while reading.
.El
.Sh MISC
.Bl -hang -width 10n
.It Fn "void twiddle" "void"
.Pp
Successive calls emit the characters in the sequence |,/,-,\\ followed by a 
backspace in order to provide reassurance to the user.
.El
.Sh REQUIRED LOW-LEVEL SUPPORT
The following resources are consumed by
.Nm
- stack, heap, console and devices.
.Pp
The stack must be established before
.Nm
functions can be invoked.  Stack requirements vary depending on the functions
and filesystems used by the consumer and the support layer functions detailed
below.
.Pp
The heap must be established before calling 
.Fn alloc
or 
.Fn open
by calling
.Fn setheap .
Heap usage will vary depending on the number of simultaneously open files,
as well as client behaviour.  Automatic decompression will allocate more
than 64K of data per open file.
.Pp
Console access is performed via the 
.Fn getchar ,
.Fn putchar
and
.Fn ischar
functions detailed below.
.Pp
Device access is initiated via
.Fn devopen
and is performed through the
.Fn dv_strategy ,
.Fn dv_ioctl
and
.Fn dv_close
functions in the device switch structure that
.Fn devopen
returns.
.Pp
The consumer must provide the following support functions:
.Bl -hang -width 10n
.It Fn "int getchar" "void"
.Pp
Return a character from the console, used by
.Fn gets ,
.Fn ngets
and pager functions.
.It Fn "int ischar" "void"
.Pp
Returns nonzero if a character is waiting from the console.
.It Fn "void putchar" "int"
.Pp
Write a character to the console, used by
.Fn gets , 
.Fn ngets , 
.Fn *printf , 
.Fn panic
and
.Fn twiddle
and thus by many other functions for debugging and informational output.
.It Fn "int devopen" "struct open_file *of" "const char *name" "char **file"
.Pp
Open the appropriate device for the file named in
.Fa name ,
returning in
.Fa file
a pointer to the remaining body of 
.Fa name
which does not refer to the device.  The
.Va f_dev
field in 
.Fa of
will be set to point to the
.Dv devsw
structure for the opened device if successful.  Device identifiers must
always precede the path component, but may otherwise be arbitrarily formatted.
Used by
.Fn open
and thus for all device-related I/O.
.It Fn "int devclose" "struct open_file *of"
Close the device allocated for
.Fa of .
The device driver itself will already have been called for the close; this call
should clean up any allocation made by devopen only.
.It Fn "void panic" "const char *msg" "..."
.Pp
Signal a fatal and unrecoverable error condition.  The
.Fa msg ...
arguments are as for
.Fn printf .
.El
.Sh INTERNAL FILESYSTEMS
Internal filesystems are enabled by the consumer exporting the array
.Dv struct fs_ops *file_system[], which should be initialised with pointers
to
.Dv struct fs_ops
structures.  The following filesystem handlers are supplied by
.Nm No ,
the consumer may supply other filesystems of their own:
.Bl -hang -width "cd9660_fsops "
.It ufs_fsops
The BSD UFS.
.It ext2fs_fsops
Linux ext2fs filesystem.
.It tftp_fsops
File access via TFTP.
.It nfs_fsops
File access via NFS.
.It cd9660_fsops
ISO 9660 (CD-ROM) filesystem.
.It zipfs_fsops
Stacked filesystem supporting gzipped files.
When trying the zipfs filesystem,
.Nm
appends
.Li .gz
to the end of the filename, and then tries to locate the file using the other
filesystems.  Placement of this filesystem in the
.Dv file_system[]
array determines whether gzipped files will be opened in preference to non-gzipped
files.  It is only possible to seek a gzipped file forwards, and
.Fn stat
and
.Fn fstat
on gzipped files will report an invalid length.
.El
.Pp
The array of
.Dv struct fs_ops
pointers should be terminated with a NULL.
.Sh DEVICES
Devices are exported by the supporting code via the array
.Dv struct devsw *devsw[]
which is a NULL terminated array of pointers to device switch structures.
.Sh BUGS
.Pp
The lack of detailed memory usage data is unhelpful.
.Sh HISTORY
.Nm
contains contributions from many sources, including:
.Bl -bullet -compact
.It 
.Nm libsa
from
.Nx
.It
.Nm libc
and
.Nm libkern
from
.Fx 3.0 .
.It
.Nm zalloc
from
.An Matthew Dillon Aq dillon@backplane.com
.El
.Pp
The reorganisation and port to
.Fx 3.0 ,
the environment functions and this manpage were written by
.An Mike Smith Aq msmith@freebsd.org .
OpenPOWER on IntegriCloud