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busybox/libbb/appletlib.c
Denys Vlasenko fe93624fb6 Automatically disable FEATURE_COMPRESS_USAGE for small builds. 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-06 19:16:36 +01:00

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) tons of folks. Tracking down who wrote what
* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under GPL.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/* We are trying to not use printf, this benefits the case when selected
* applets are really simple. Example:
*
* $ ./busybox
* ...
* Currently defined functions:
* basename, false, true
*
* $ size busybox
* text data bss dec hex filename
* 4473 52 72 4597 11f5 busybox
*
* FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
*/
#include "busybox.h"
#if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
|| defined(__APPLE__) \
)
# include <malloc.h> /* for mallopt */
#endif
/* Declare <applet>_main() */
#define PROTOTYPES
#include "applets.h"
#undef PROTOTYPES
/* Include generated applet names, pointers to <applet>_main, etc */
#include "applet_tables.h"
/* ...and if applet_tables generator says we have only one applet... */
#ifdef SINGLE_APPLET_MAIN
# undef ENABLE_FEATURE_INDIVIDUAL
# define ENABLE_FEATURE_INDIVIDUAL 1
# undef IF_FEATURE_INDIVIDUAL
# define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
#endif
#include "usage_compressed.h"
/* "Do not compress usage text if uncompressed text is small
* and we don't include bunzip2 code for other reasons"
*
* Useful for mass one-applet rebuild (bunzip2 code is ~2.7k).
*
* Unlike BUNZIP2, if FEATURE_SEAMLESS_BZ2 is on, bunzip2 code is built but
* still may be unused if none of the selected applets calls open_zipped()
* or its friends; we test for (FEATURE_SEAMLESS_BZ2 && <APPLET>) instead.
* For example, only if TAR and FEATURE_SEAMLESS_BZ2 are both selected,
* then bunzip2 code will be linked in anyway, and disabling help compression
* would be not optimal:
*/
#if UNPACKED_USAGE_LENGTH < 4*1024 \
&& !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_TAR) \
&& !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_MODPROBE) \
&& !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_INSMOD) \
&& !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_DEPMOD) \
&& !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_MAN) \
&& !ENABLE_BUNZIP2 \
&& !ENABLE_BZCAT
# undef ENABLE_FEATURE_COMPRESS_USAGE
# define ENABLE_FEATURE_COMPRESS_USAGE 0
#endif
#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
#else
# define usage_messages 0
#endif
#if ENABLE_FEATURE_COMPRESS_USAGE
static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
# include "bb_archive.h"
static const char *unpack_usage_messages(void)
{
char *outbuf = NULL;
bunzip_data *bd;
int i;
i = start_bunzip(&bd,
/* src_fd: */ -1,
/* inbuf: */ packed_usage,
/* len: */ sizeof(packed_usage));
/* read_bunzip can longjmp to start_bunzip, and ultimately
* end up here with i != 0 on read data errors! Not trivial */
if (!i) {
/* Cannot use xmalloc: will leak bd in NOFORK case! */
outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
if (outbuf)
read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
}
dealloc_bunzip(bd);
return outbuf;
}
# define dealloc_usage_messages(s) free(s)
#else
# define unpack_usage_messages() usage_messages
# define dealloc_usage_messages(s) ((void)(s))
#endif /* FEATURE_COMPRESS_USAGE */
void FAST_FUNC bb_show_usage(void)
{
if (ENABLE_SHOW_USAGE) {
#ifdef SINGLE_APPLET_STR
/* Imagine that this applet is "true". Dont suck in printf! */
const char *usage_string = unpack_usage_messages();
if (*usage_string == '\b') {
full_write2_str("No help available.\n\n");
} else {
full_write2_str("Usage: "SINGLE_APPLET_STR" ");
full_write2_str(usage_string);
full_write2_str("\n\n");
}
if (ENABLE_FEATURE_CLEAN_UP)
dealloc_usage_messages((char*)usage_string);
#else
const char *p;
const char *usage_string = p = unpack_usage_messages();
int ap = find_applet_by_name(applet_name);
if (ap < 0) /* never happens, paranoia */
xfunc_die();
while (ap) {
while (*p++) continue;
ap--;
}
full_write2_str(bb_banner);
full_write2_str(" multi-call binary.\n");
if (*p == '\b')
full_write2_str("\nNo help available.\n\n");
else {
full_write2_str("\nUsage: ");
full_write2_str(applet_name);
full_write2_str(" ");
full_write2_str(p);
full_write2_str("\n");
}
if (ENABLE_FEATURE_CLEAN_UP)
dealloc_usage_messages((char*)usage_string);
#endif
}
xfunc_die();
}
int FAST_FUNC find_applet_by_name(const char *name)
{
unsigned i, max;
int j;
const char *p;
/* The commented-out word-at-a-time code is ~40% faster, but +160 bytes.
* "Faster" here saves ~0.5 microsecond of real time - not worth it.
*/
#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
uint32_t n32;
/* Handle all names < 2 chars long early */
if (name[0] == '\0')
return -1; /* "" is not a valid applet name */
if (name[1] == '\0') {
if (!ENABLE_TEST)
return -1; /* 1-char name is not valid */
if (name[0] != ']')
return -1; /* 1-char name which isn't "[" is not valid */
/* applet "[" is always applet #0: */
return 0;
}
#endif
p = applet_names;
i = 0;
#if KNOWN_APPNAME_OFFSETS <= 0
max = NUM_APPLETS;
#else
max = NUM_APPLETS * KNOWN_APPNAME_OFFSETS;
for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
const char *pp = applet_names + applet_nameofs[j];
if (strcmp(name, pp) >= 0) {
//bb_error_msg("name:'%s' >= pp:'%s'", name, pp);
p = pp;
i = max - NUM_APPLETS;
break;
}
max -= NUM_APPLETS;
}
max /= (unsigned)KNOWN_APPNAME_OFFSETS;
i /= (unsigned)KNOWN_APPNAME_OFFSETS;
//bb_error_msg("name:'%s' starting from:'%s' i:%u max:%u", name, p, i, max);
#endif
/* Open-coded linear search without strcmp/strlen calls for speed */
#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
/* skip "[\0" name, it's surely not it */
if (ENABLE_TEST && LONE_CHAR(p, '['))
i++, p += 2;
/* All remaining applet names in p[] are at least 2 chars long */
/* name[] is also at least 2 chars long */
n32 = (name[0] << 0) | (name[1] << 8) | (name[2] << 16);
while (i < max) {
uint32_t p32;
char ch;
/* Quickly check match of the first 3 bytes */
move_from_unaligned32(p32, p);
p += 3;
if ((p32 & 0x00ffffff) != n32) {
/* Most likely case: 3 first bytes do not match */
i++;
if ((p32 & 0x00ff0000) == '\0')
continue; // p[2] was NUL
p++;
if ((p32 & 0xff000000) == '\0')
continue; // p[3] was NUL
/* p[0..3] aren't matching and none is NUL, check the rest */
while (*p++ != '\0')
continue;
continue;
}
/* Unlikely branch: first 3 bytes ([0..2]) match */
if ((p32 & 0x00ff0000) == '\0') {
/* name is 2-byte long, it is full match */
//bb_error_msg("found:'%s' i:%u", name, i);
return i;
}
/* Check remaining bytes [3..NUL] */
ch = (p32 >> 24);
j = 3;
while (ch == name[j]) {
if (ch == '\0') {
//bb_error_msg("found:'%s' i:%u", name, i);
return i;
}
ch = *++p;
j++;
}
/* Not a match. Skip it, including NUL */
while (ch != '\0')
ch = *++p;
p++;
i++;
}
return -1;
#else
while (i < max) {
char ch;
j = 0;
/* Do we see "name\0" in applet_names[p] position? */
while ((ch = *p) == name[j]) {
if (ch == '\0') {
//bb_error_msg("found:'%s' i:%u", name, i);
return i; /* yes */
}
p++;
j++;
}
/* No.
* p => 1st non-matching char in applet_names[],
* skip to and including NUL.
*/
while (ch != '\0')
ch = *++p;
p++;
i++;
}
return -1;
#endif
}
void lbb_prepare(const char *applet
IF_FEATURE_INDIVIDUAL(, char **argv))
MAIN_EXTERNALLY_VISIBLE;
void lbb_prepare(const char *applet
IF_FEATURE_INDIVIDUAL(, char **argv))
{
#ifdef __GLIBC__
(*(int **)&bb_errno) = __errno_location();
barrier();
#endif
applet_name = applet;
if (ENABLE_LOCALE_SUPPORT)
setlocale(LC_ALL, "");
#if ENABLE_FEATURE_INDIVIDUAL
/* Redundant for busybox (run_applet_and_exit covers that case)
* but needed for "individual applet" mode */
if (argv[1]
&& !argv[2]
&& strcmp(argv[1], "--help") == 0
&& !is_prefixed_with(applet, "busybox")
) {
/* Special case. POSIX says "test --help"
* should be no different from e.g. "test --foo". */
if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
bb_show_usage();
}
#endif
}
/* The code below can well be in applets/applets.c, as it is used only
* for busybox binary, not "individual" binaries.
* However, keeping it here and linking it into libbusybox.so
* (together with remaining tiny applets/applets.o)
* makes it possible to avoid --whole-archive at link time.
* This makes (shared busybox) + libbusybox smaller.
* (--gc-sections would be even better....)
*/
const char *applet_name;
#if !BB_MMU
bool re_execed;
#endif
/* If not built as a single-applet executable... */
#if !defined(SINGLE_APPLET_MAIN)
IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
# if ENABLE_FEATURE_SUID_CONFIG
static struct suid_config_t {
/* next ptr must be first: this struct needs to be llist-compatible */
struct suid_config_t *m_next;
struct bb_uidgid_t m_ugid;
int m_applet;
mode_t m_mode;
} *suid_config;
static bool suid_cfg_readable;
/* libbb candidate */
static char *get_trimmed_slice(char *s, char *e)
{
/* First, consider the value at e to be nul and back up until we
* reach a non-space char. Set the char after that (possibly at
* the original e) to nul. */
while (e-- > s) {
if (!isspace(*e)) {
break;
}
}
e[1] = '\0';
/* Next, advance past all leading space and return a ptr to the
* first non-space char; possibly the terminating nul. */
return skip_whitespace(s);
}
static void parse_config_file(void)
{
/* Don't depend on the tools to combine strings. */
static const char config_file[] ALIGN1 = "/etc/busybox.conf";
struct suid_config_t *sct_head;
int applet_no;
FILE *f;
const char *errmsg;
unsigned lc;
smallint section;
struct stat st;
ruid = getuid();
if (ruid == 0) /* run by root - don't need to even read config file */
return;
if ((stat(config_file, &st) != 0) /* No config file? */
|| !S_ISREG(st.st_mode) /* Not a regular file? */
|| (st.st_uid != 0) /* Not owned by root? */
|| (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
|| !(f = fopen_for_read(config_file)) /* Cannot open? */
) {
return;
}
suid_cfg_readable = 1;
sct_head = NULL;
section = lc = 0;
while (1) {
char buffer[256];
char *s;
if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
// Looks like bloat
//if (ferror(f)) { /* Make sure it wasn't a read error. */
// errmsg = "reading";
// goto pe_label;
//}
fclose(f);
suid_config = sct_head; /* Success, so set the pointer. */
return;
}
s = buffer;
lc++; /* Got a (partial) line. */
/* If a line is too long for our buffer, we consider it an error.
* The following test does mistreat one corner case though.
* If the final line of the file does not end with a newline and
* yet exactly fills the buffer, it will be treated as too long
* even though there isn't really a problem. But it isn't really
* worth adding code to deal with such an unlikely situation, and
* we do err on the side of caution. Besides, the line would be
* too long if it did end with a newline. */
if (!strchr(s, '\n') && !feof(f)) {
errmsg = "line too long";
goto pe_label;
}
/* Trim leading and trailing whitespace, ignoring comments, and
* check if the resulting string is empty. */
s = get_trimmed_slice(s, strchrnul(s, '#'));
if (!*s) {
continue;
}
/* Check for a section header. */
if (*s == '[') {
/* Unlike the old code, we ignore leading and trailing
* whitespace for the section name. We also require that
* there are no stray characters after the closing bracket. */
char *e = strchr(s, ']');
if (!e /* Missing right bracket? */
|| e[1] /* Trailing characters? */
|| !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
) {
errmsg = "section header";
goto pe_label;
}
/* Right now we only have one section so just check it.
* If more sections are added in the future, please don't
* resort to cascading ifs with multiple strcasecmp calls.
* That kind of bloated code is all too common. A loop
* and a string table would be a better choice unless the
* number of sections is very small. */
if (strcasecmp(s, "SUID") == 0) {
section = 1;
continue;
}
section = -1; /* Unknown section so set to skip. */
continue;
}
/* Process sections. */
if (section == 1) { /* SUID */
/* Since we trimmed leading and trailing space above, we're
* now looking for strings of the form
* <key>[::space::]*=[::space::]*<value>
* where both key and value could contain inner whitespace. */
/* First get the key (an applet name in our case). */
char *e = strchr(s, '=');
if (e) {
s = get_trimmed_slice(s, e);
}
if (!e || !*s) { /* Missing '=' or empty key. */
errmsg = "keyword";
goto pe_label;
}
/* Ok, we have an applet name. Process the rhs if this
* applet is currently built in and ignore it otherwise.
* Note: this can hide config file bugs which only pop
* up when the busybox configuration is changed. */
applet_no = find_applet_by_name(s);
if (applet_no >= 0) {
unsigned i;
struct suid_config_t *sct;
/* Note: We currently don't check for duplicates!
* The last config line for each applet will be the
* one used since we insert at the head of the list.
* I suppose this could be considered a feature. */
sct = xzalloc(sizeof(*sct));
sct->m_applet = applet_no;
/*sct->m_mode = 0;*/
sct->m_next = sct_head;
sct_head = sct;
/* Get the specified mode. */
e = skip_whitespace(e+1);
for (i = 0; i < 3; i++) {
/* There are 4 chars for each of user/group/other.
* "x-xx" instead of "x-" are to make
* "idx > 3" check catch invalid chars.
*/
static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
static const unsigned short mode_mask[] ALIGN2 = {
S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
S_IXOTH, 0 /* x- */
};
const char *q = strchrnul(mode_chars + 4*i, *e);
unsigned idx = q - (mode_chars + 4*i);
if (idx > 3) {
errmsg = "mode";
goto pe_label;
}
sct->m_mode |= mode_mask[q - mode_chars];
e++;
}
/* Now get the user/group info. */
s = skip_whitespace(e);
/* Default is 0.0, else parse USER.GROUP: */
if (*s) {
/* We require whitespace between mode and USER.GROUP */
if ((s == e) || !(e = strchr(s, '.'))) {
errmsg = "uid.gid";
goto pe_label;
}
*e = ':'; /* get_uidgid needs USER:GROUP syntax */
if (get_uidgid(&sct->m_ugid, s) == 0) {
errmsg = "unknown user/group";
goto pe_label;
}
}
}
continue;
}
/* Unknown sections are ignored. */
/* Encountering configuration lines prior to seeing a
* section header is treated as an error. This is how
* the old code worked, but it may not be desirable.
* We may want to simply ignore such lines in case they
* are used in some future version of busybox. */
if (!section) {
errmsg = "keyword outside section";
goto pe_label;
}
} /* while (1) */
pe_label:
fclose(f);
bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
/* Release any allocated memory before returning. */
llist_free((llist_t*)sct_head, NULL);
}
# else
static inline void parse_config_file(void)
{
IF_FEATURE_SUID(ruid = getuid();)
}
# endif /* FEATURE_SUID_CONFIG */
# if ENABLE_FEATURE_SUID && NUM_APPLETS > 0
# if ENABLE_FEATURE_SUID_CONFIG
/* check if u is member of group g */
static int ingroup(uid_t u, gid_t g)
{
struct group *grp = getgrgid(g);
if (grp) {
char **mem;
for (mem = grp->gr_mem; *mem; mem++) {
struct passwd *pwd = getpwnam(*mem);
if (pwd && (pwd->pw_uid == u))
return 1;
}
}
return 0;
}
# endif
static void check_suid(int applet_no)
{
gid_t rgid; /* real gid */
if (ruid == 0) /* set by parse_config_file() */
return; /* run by root - no need to check more */
rgid = getgid();
# if ENABLE_FEATURE_SUID_CONFIG
if (suid_cfg_readable) {
uid_t uid;
struct suid_config_t *sct;
mode_t m;
for (sct = suid_config; sct; sct = sct->m_next) {
if (sct->m_applet == applet_no)
goto found;
}
goto check_need_suid;
found:
/* Is this user allowed to run this applet? */
m = sct->m_mode;
if (sct->m_ugid.uid == ruid)
/* same uid */
m >>= 6;
else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
/* same group / in group */
m >>= 3;
if (!(m & S_IXOTH)) /* is x bit not set? */
bb_error_msg_and_die("you have no permission to run this applet");
/* We set effective AND saved ids. If saved-id is not set
* like we do below, seteuid(0) can still later succeed! */
/* Are we directed to change gid
* (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
*/
if (sct->m_mode & S_ISGID)
rgid = sct->m_ugid.gid;
/* else: we will set egid = rgid, thus dropping sgid effect */
if (setresgid(-1, rgid, rgid))
bb_perror_msg_and_die("setresgid");
/* Are we directed to change uid
* (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
*/
uid = ruid;
if (sct->m_mode & S_ISUID)
uid = sct->m_ugid.uid;
/* else: we will set euid = ruid, thus dropping suid effect */
if (setresuid(-1, uid, uid))
bb_perror_msg_and_die("setresuid");
goto ret;
}
# if !ENABLE_FEATURE_SUID_CONFIG_QUIET
{
static bool onetime = 0;
if (!onetime) {
onetime = 1;
bb_error_msg("using fallback suid method");
}
}
# endif
check_need_suid:
# endif
if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
/* Real uid is not 0. If euid isn't 0 too, suid bit
* is most probably not set on our executable */
if (geteuid())
bb_error_msg_and_die("must be suid to work properly");
} else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
xsetgid(rgid); /* drop all privileges */
xsetuid(ruid);
}
# if ENABLE_FEATURE_SUID_CONFIG
ret: ;
llist_free((llist_t*)suid_config, NULL);
# endif
}
# else
# define check_suid(x) ((void)0)
# endif /* FEATURE_SUID */
# if ENABLE_FEATURE_INSTALLER
static const char usr_bin [] ALIGN1 = "/usr/bin/";
static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
static const char *const install_dir[] = {
&usr_bin [8], /* "/" */
&usr_bin [4], /* "/bin/" */
&usr_sbin[4] /* "/sbin/" */
# if !ENABLE_INSTALL_NO_USR
,usr_bin
,usr_sbin
# endif
};
/* create (sym)links for each applet */
static void install_links(const char *busybox, int use_symbolic_links,
char *custom_install_dir)
{
/* directory table
* this should be consistent w/ the enum,
* busybox.h::bb_install_loc_t, or else... */
int (*lf)(const char *, const char *);
char *fpc;
const char *appname = applet_names;
unsigned i;
int rc;
lf = link;
if (use_symbolic_links)
lf = symlink;
for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
fpc = concat_path_file(
custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
appname);
// debug: bb_error_msg("%slinking %s to busybox",
// use_symbolic_links ? "sym" : "", fpc);
rc = lf(busybox, fpc);
if (rc != 0 && errno != EEXIST) {
bb_simple_perror_msg(fpc);
}
free(fpc);
while (*appname++ != '\0')
continue;
}
}
# elif ENABLE_BUSYBOX
static void install_links(const char *busybox UNUSED_PARAM,
int use_symbolic_links UNUSED_PARAM,
char *custom_install_dir UNUSED_PARAM)
{
}
# endif
# if ENABLE_BUSYBOX
static void run_applet_and_exit(const char *name, char **argv) NORETURN;
/* If we were called as "busybox..." */
static int busybox_main(char **argv)
{
if (!argv[1]) {
/* Called without arguments */
const char *a;
int col;
unsigned output_width;
help:
output_width = 80;
if (ENABLE_FEATURE_AUTOWIDTH) {
/* Obtain the terminal width */
output_width = get_terminal_width(2);
}
dup2(1, 2);
full_write2_str(bb_banner); /* reuse const string */
full_write2_str(" multi-call binary.\n"); /* reuse */
full_write2_str(
"BusyBox is copyrighted by many authors between 1998-2015.\n"
"Licensed under GPLv2. See source distribution for detailed\n"
"copyright notices.\n"
"\n"
"Usage: busybox [function [arguments]...]\n"
" or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
IF_FEATURE_INSTALLER(
" or: busybox --install [-s] [DIR]\n"
)
" or: function [arguments]...\n"
"\n"
IF_NOT_FEATURE_SH_STANDALONE(
"\tBusyBox is a multi-call binary that combines many common Unix\n"
"\tutilities into a single executable. Most people will create a\n"
"\tlink to busybox for each function they wish to use and BusyBox\n"
"\twill act like whatever it was invoked as.\n"
)
IF_FEATURE_SH_STANDALONE(
"\tBusyBox is a multi-call binary that combines many common Unix\n"
"\tutilities into a single executable. The shell in this build\n"
"\tis configured to run built-in utilities without $PATH search.\n"
"\tYou don't need to install a link to busybox for each utility.\n"
"\tTo run external program, use full path (/sbin/ip instead of ip).\n"
)
"\n"
"Currently defined functions:\n"
);
col = 0;
a = applet_names;
/* prevent last comma to be in the very last pos */
output_width--;
while (*a) {
int len2 = strlen(a) + 2;
if (col >= (int)output_width - len2) {
full_write2_str(",\n");
col = 0;
}
if (col == 0) {
col = 6;
full_write2_str("\t");
} else {
full_write2_str(", ");
}
full_write2_str(a);
col += len2;
a += len2 - 1;
}
full_write2_str("\n");
return 0;
}
if (is_prefixed_with(argv[1], "--list")) {
unsigned i = 0;
const char *a = applet_names;
dup2(1, 2);
while (*a) {
# if ENABLE_FEATURE_INSTALLER
if (argv[1][6]) /* --list-full? */
full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
# endif
full_write2_str(a);
full_write2_str("\n");
i++;
while (*a++ != '\0')
continue;
}
return 0;
}
if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
int use_symbolic_links;
const char *busybox;
busybox = xmalloc_readlink(bb_busybox_exec_path);
if (!busybox) {
/* bb_busybox_exec_path is usually "/proc/self/exe".
* In chroot, readlink("/proc/self/exe") usually fails.
* In such case, better use argv[0] as symlink target
* if it is a full path name.
*/
if (argv[0][0] != '/')
bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
busybox = argv[0];
}
/* busybox --install [-s] [DIR]:
* -s: make symlinks
* DIR: directory to install links to
*/
use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
install_links(busybox, use_symbolic_links, argv[2]);
return 0;
}
if (strcmp(argv[1], "--help") == 0) {
/* "busybox --help [<applet>]" */
if (!argv[2])
goto help;
/* convert to "<applet> --help" */
argv[0] = argv[2];
argv[2] = NULL;
} else {
/* "busybox <applet> arg1 arg2 ..." */
argv++;
}
/* We support "busybox /a/path/to/applet args..." too. Allows for
* "#!/bin/busybox"-style wrappers */
applet_name = bb_get_last_path_component_nostrip(argv[0]);
run_applet_and_exit(applet_name, argv);
}
# endif
# if NUM_APPLETS > 0
void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
{
int argc = 1;
while (argv[argc])
argc++;
/* Reinit some shared global data */
xfunc_error_retval = EXIT_FAILURE;
applet_name = bb_get_last_path_component_nostrip(argv[0]);
/* Special case. POSIX says "test --help"
* should be no different from e.g. "test --foo".
* Thus for "test", we skip --help check.
* "true" and "false" are also special.
*/
if (1
# if defined APPLET_NO_test
&& applet_no != APPLET_NO_test
# endif
# if defined APPLET_NO_true
&& applet_no != APPLET_NO_true
# endif
# if defined APPLET_NO_false
&& applet_no != APPLET_NO_false
# endif
) {
if (argc == 2 && strcmp(argv[1], "--help") == 0) {
/* Make "foo --help" exit with 0: */
xfunc_error_retval = 0;
bb_show_usage();
}
}
if (ENABLE_FEATURE_SUID)
check_suid(applet_no);
xfunc_error_retval = applet_main[applet_no](argc, argv);
/* Note: applet_main() may also not return (die on a xfunc or such) */
xfunc_die();
}
# endif /* NUM_APPLETS > 0 */
# if ENABLE_BUSYBOX || NUM_APPLETS > 0
static NORETURN void run_applet_and_exit(const char *name, char **argv)
{
# if ENABLE_BUSYBOX
if (is_prefixed_with(name, "busybox"))
exit(busybox_main(argv));
# endif
# if NUM_APPLETS > 0
/* find_applet_by_name() search is more expensive, so goes second */
{
int applet = find_applet_by_name(name);
if (applet >= 0)
run_applet_no_and_exit(applet, argv);
}
# endif
/*bb_error_msg_and_die("applet not found"); - links in printf */
full_write2_str(applet_name);
full_write2_str(": applet not found\n");
/* POSIX: "If a command is not found, the exit status shall be 127" */
exit(127);
}
# endif
#endif /* !defined(SINGLE_APPLET_MAIN) */
#if ENABLE_BUILD_LIBBUSYBOX
int lbb_main(char **argv)
#else
int main(int argc UNUSED_PARAM, char **argv)
#endif
{
#if 0
/* TODO: find a use for a block of memory between end of .bss
* and end of page. For example, I'm getting "_end:0x812e698 2408 bytes"
* - more than 2k of wasted memory (in this particular build)
* *per each running process*!
* (If your linker does not generate "_end" name, weak attribute
* makes &_end == NULL, end_len == 0 here.)
*/
extern char _end[] __attribute__((weak));
unsigned end_len = (-(int)_end) & 0xfff;
printf("_end:%p %u bytes\n", &_end, end_len);
#endif
/* Tweak malloc for reduced memory consumption */
#ifdef M_TRIM_THRESHOLD
/* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
* to keep before releasing to the OS
* Default is way too big: 256k
*/
mallopt(M_TRIM_THRESHOLD, 8 * 1024);
#endif
#ifdef M_MMAP_THRESHOLD
/* M_MMAP_THRESHOLD is the request size threshold for using mmap()
* Default is too big: 256k
*/
mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
#endif
#if 0 /*def M_TOP_PAD*/
/* When the program break is increased, then M_TOP_PAD bytes are added
* to the sbrk(2) request. When the heap is trimmed because of free(3),
* this much free space is preserved at the top of the heap.
* glibc default seems to be way too big: 128k, but need to verify.
*/
mallopt(M_TOP_PAD, 8 * 1024);
#endif
#if !BB_MMU
/* NOMMU re-exec trick sets high-order bit in first byte of name */
if (argv[0][0] & 0x80) {
re_execed = 1;
argv[0][0] &= 0x7f;
}
#endif
#if defined(SINGLE_APPLET_MAIN)
/* Only one applet is selected in .config */
if (argv[1] && is_prefixed_with(argv[0], "busybox")) {
/* "busybox <applet> <params>" should still work as expected */
argv++;
}
/* applet_names in this case is just "applet\0\0" */
lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
return SINGLE_APPLET_MAIN(argc, argv);
#elif !ENABLE_BUSYBOX && NUM_APPLETS == 0
full_write2_str(bb_basename(argv[0]));
full_write2_str(": no applets enabled\n");
exit(127);
#else
lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
# if !ENABLE_BUSYBOX
if (argv[1] && is_prefixed_with(bb_basename(argv[0]), "busybox"))
argv++;
# endif
applet_name = argv[0];
if (applet_name[0] == '-')
applet_name++;
applet_name = bb_basename(applet_name);
parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
run_applet_and_exit(applet_name, argv);
#endif
}
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