Commit d1a2fa2a4 (ash: catch error in arithmetic expansion in PS1)
catches all exceptions raised by expandarg(). Some exceptions, such as
the EXEXIT raised when command expansion is used, are expected:
export PS1='$(echo "$ ")'
These should be processed normally or the shell hangs at the prompt.
function old new delta
expandstr 344 353 +9
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(add/remove: 0/0 grow/shrink: 1/0 up/down: 9/0) Total: 9 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().
This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.
Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.
This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.
The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):
Arm: -92 bytes
MIPS: -52 bytes
PPC: -1836 bytes
x86_64: -938 bytes
Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.
Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
"env - hush SCRIPT" invocation (that is, with empty environment)
should not show PS1/2 in "set" output.
function old new delta
hush_main 1070 1075 +5
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Assignments / exports / unsets of variables are far more frequent than
prompt printing, and if we show prompt, we are likely to be limited by
user typing speed - do not optimize for that scenario.
Just re-query $PS1 / $PS2 values when need to show the prompt.
function old new delta
fgetc_interactive 236 259 +23
set_vars_and_save_old 150 147 -3
pseudo_exec_argv 597 594 -3
hush_main 1110 1105 -5
enter_var_nest_level 38 32 -6
builtin_local 56 50 -6
run_pipe 1857 1834 -23
leave_var_nest_level 127 98 -29
handle_changed_special_names 111 79 -32
cmdedit_update_prompt 57 - -57
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(add/remove: 0/1 grow/shrink: 1/8 up/down: 23/-164) Total: -141 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Setting PS1 to:
PS1='$((123+))'
causes the shell to enter an infinite error loop:
sh: arithmetic syntax error
Catch any exception raised by expandarg() in expandstr() and allow
processing to continue.
function old new delta
expandstr 262 344 +82
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(add/remove: 0/0 grow/shrink: 1/0 up/down: 82/0) Total: 82 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Setting PS1 to:
PS1='`xxx(`'
causes the shell to terminate with the error:
sh: syntax error: unexpected end of file (expecting ")")
This happens because old-style backquotes require the input to be reread
and thus call setinputstring() a second time. Prevent the problem by
unwinding all recently opened files in expandstr().
function old new delta
unwindfiles - 22 +22
expandstr 247 262 +15
forkchild 631 625 -6
evalcommand 1694 1685 -9
ash_main 1346 1336 -10
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(add/remove: 1/0 grow/shrink: 1/3 up/down: 37/-25) Total: 12 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Bash 5.0 added the dynamic variable EPOCHSECONDS and EPOCHREALTIME
which return the number of seconds since the Unix Epoch as an
integer or float. These are useful for logging or tracing.
function old new delta
change_epoch - 78 +78
.rodata 175167 175235 +68
varinit_data 264 312 +48
change_seconds - 24 +24
change_realtime - 24 +24
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(add/remove: 3/0 grow/shrink: 2/0 up/down: 242/0) Total: 242 bytes
text data bss dec hex filename
938508 4203 1888 944599 e69d7 busybox_old
938702 4203 1888 944793 e6a99 busybox_unstripped
v2: Cast tv_sec and tv_usec to unsigned quantities.
Add brackets to macros.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Commit b28d4c346 (ash: [VAR] Move unsetvar functionality into setvareq)
dropped the code that caused dynamic variables to lose their special
properties when unset. Add it back again.
function old new delta
setvareq 346 360 +14
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(add/remove: 0/0 grow/shrink: 1/0 up/down: 14/0) Total: 14 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Bash 5.0 added the dynamic variable EPOCHSECONDS and EPOCHREALTIME
which return the number of seconds since the Unix Epoch as an
integer or float. These are useful for logging or tracing.
function old new delta
get_local_var_value 207 302 +95
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(add/remove: 0/0 grow/shrink: 1/0 up/down: 95/0) Total: 95 bytes
text data bss dec hex filename
938702 4203 1888 944793 e6a99 busybox_old
938797 4203 1888 944888 e6af8 busybox_unstripped
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add a specific define to indicate which bash compatibility code
implements 'wait -n'.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The following constructs result in ever-increasing memory usage:
while true; do { true; } </dev/null; done
while true; do ( true; ) </dev/null; done
For comparison, bash displays static memory usage in both cases.
This has been fixed in dash by commit 2bc6caa. The maintainer
writes:
I have simplified evaltree so that it simply sets the stack mark
unconditionally. This allows us to remove the stack marks in the
functions called by evaltree.
Closes BusyBox bug 7748.
function old new delta
evaltree 606 632 +26
evalcommand 1724 1696 -28
evalcase 382 351 -31
evalfor 230 196 -34
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(add/remove: 0/0 grow/shrink: 1/3 up/down: 26/-93) Total: -67 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Embedded scripts require a shell to be present in the BusyBox
binary. Allow either ash or hush to be used for this purpose.
If both are enabled ash takes precedence.
The size of the binary is unchanged in the default configuration:
both ash and hush are present but support for embedded scripts
isn't compiled into hush.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The parser reads from an already freed memory location, thereby causing
unpredictable results, in the following situation:
- ENABLE_ASH_EXPAND_PRMT is enabled
- heredoc is being parsed
- command substitution is used within heredoc
Examples where this bug crops up are (PS2 is set to "> "):
$ cat <<EOF
> `echo abc`
> EOF
-sh: O: not found
$ cat <<EOF
> $(echo abc)
> EOF
-sh: {garbage}: not found
The presumable reason is that setprompt_if() causes a nested expansion when
ENABLE_ASH_EXPAND_PRMT is enabled, therefore leaving "wordtext" in an unusable
state. However, when parseheredoc() is called, "tokpushback" is non-zero, which
causes the next call to xxreadtoken() to return TWORD, causing the caller to
use the invalid "wordtoken" instead of reading the next valid token.
The call chain is:
list()
-> peektoken() [sets tokpushback to 1]
-> parseheredoc()
-> setprompt_if()
-> pushstackmark()
-> expandstr()
-> readtoken1()
[sets lasttoken to TWORD, wordtoken points to expanded prompt]
-> popstackmark() [invalidates wordtoken, leaves lasttoken as is]
-> readtoken1()
-> ...parsebackq
-> list()
-> andor()
-> pipeline()
-> readtoken()
-> xxreadtoken()
[tokpushback non-zero, reuse lasttoken and wordtext]
Note that in almost all other contexts, each call to setprompt_if() is preceded
by setting "tokpushback" to zero. One exception is "oldstyle" backquote parsing
in readtoken1(), but there "tokpushback" is reset afterwards. The other
exception is nlprompt(), but this function is only used within readtoken1()
(but in contexts where no nested calls to xxreadtoken() occur) and xxreadtoken()
(where "tokpushback" is guaranteed to be zero).
function old new delta
parseheredoc 124 131 +7
Signed-off-by: Christoph Schulz <develop@kristov.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
BusyBox has support for embedded shell scripts. Two types can be
distinguished: custom scripts and scripts implementing applets.
Custom scripts should be placed in the 'embed' directory at build
time. They are given a default applet configuration and appear
as applets to the user but no further configuration is possible.
Applet scripts are integrated with the BusyBox build system and
are intended to be used to ship standard applets that just happen
to be implemented as scripts. They can be configured at build time
and appear just like native applets.
Such scripts should be placed in the 'applets_sh' directory. A stub
C program should be written to provide the usual applet configuration
details and placed in a suitable subsystem directory. It may be
helpful to have a configuration option to enable any dependencies the
script requires: see the 'nologin' applet for an example.
function old new delta
scripted_main - 41 +41
applet_names 2773 2781 +8
applet_main 1600 1604 +4
i2cdetect_main 672 674 +2
applet_suid 100 101 +1
applet_install_loc 200 201 +1
applet_flags 100 101 +1
packed_usage 33180 33179 -1
tryexec 159 152 -7
evalcommand 1661 1653 -8
script_names 9 - -9
packed_scripts 123 114 -9
complete_cmd_dir_file 826 811 -15
shellexec 271 254 -17
find_command 1007 990 -17
busybox_main 642 624 -18
run_applet_and_exit 100 78 -22
find_script_by_name 51 - -51
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(add/remove: 1/2 grow/shrink: 6/9 up/down: 58/-174) Total: -116 bytes
text data bss dec hex filename
950034 477 7296 957807 e9d6f busybox_old
949918 477 7296 957691 e9cfb busybox_unstripped
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
When a variable is unset by calling setvar(name, NULL, 0) the code
to initialise the new, empty variable fails to initialise the last
character of the string.
Attempts to read the contents of the unset variable will result
in the uninitialised character at the end of the string being
accessed.
For example, running BusyBox under Valgrind and unsetting PATH:
$ valgrind ./busybox_unstripped sh
==21249== Memcheck, a memory error detector
==21249== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==21249== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==21249== Command: ./busybox_unstripped sh
==21249==
/data2/git/build_fix_8721 $ unset PATH
/data2/git/build_fix_8721 $ 0
==21249== Conditional jump or move depends on uninitialised value(s)
==21249== at 0x451371: path_advance (ash.c:2555)
==21249== by 0x456E22: find_command (ash.c:13407)
==21249== by 0x458425: evalcommand (ash.c:10139)
==21249== by 0x454CBC: evaltree (ash.c:9131)
==21249== by 0x456C80: cmdloop (ash.c:13164)
Closes https://bugs.busybox.net/show_bug.cgi?id=8721
v2: On the dash mailing list Harald van Dijk was kind enough to point
out a flaw in my reasoning and provide an alternative patch. Sadly
his patch adds 2 bytes of bloat. Using xzalloc to zero the whole
string gives a bloat of -3 bytes.
function old new delta
setvar 172 169 -3
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
