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Move applets/applet.c into libbb, allows to get rid of --whole-archive

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(smaller code). Tested in static and shared mode.
This commit is contained in:
Denis Vlasenko 2007-10-10 14:41:07 +00:00
parent 82d38dab91
commit 724d196c75
4 changed files with 566 additions and 548 deletions
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541
applets/applets.c
View File

@ -1,21 +1,15 @@
/* vi: set sw=4 ts=4: */ /* vi: set sw=4 ts=4: */
/* /*
* Utility routines. * Stub for linking busybox binary against libbusybox.
* *
* Copyright (C) tons of folks. Tracking down who wrote what * Copyright (C) 2007 Denis Vlasenko
* 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 * Licensed under GPLv2, see file License in this tarball for details.
* Permission has been granted to redistribute this code under the GPL.
*
* Licensed under GPLv2 or later, see file License in this tarball for details.
*/ */
#include <assert.h> #include <assert.h>
#include "busybox.h" #include "busybox.h"
/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */ /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
#if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__) #if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
#warning Static linking against glibc produces buggy executables #warning Static linking against glibc produces buggy executables
@ -27,532 +21,9 @@
#error Aborting compilation. #error Aborting compilation.
#endif #endif
#if ENABLE_BUILD_LIBBUSYBOX
const char *applet_name;
#if !BB_MMU
bool re_execed;
#endif
USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
#if ENABLE_FEATURE_SUID_CONFIG
/* applets[] is const, so we have to define this "override" structure */
static struct BB_suid_config {
const struct bb_applet *m_applet;
uid_t m_uid;
gid_t m_gid;
mode_t m_mode;
struct BB_suid_config *m_next;
} *suid_config;
static bool suid_cfg_readable;
/* 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;
}
/* This should probably be a libbb routine. In that case,
* I'd probably rename it to something like bb_trimmed_slice.
*/
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);
}
/* Don't depend on the tools to combine strings. */
static const char config_file[] ALIGN1 = "/etc/busybox.conf";
/* We don't supply a value for the nul, so an index adjustment is
* necessary below. Also, we use unsigned short here to save some
* space even though these are really mode_t values. */
static const unsigned short mode_mask[] ALIGN2 = {
/* SST sst xxx --- */
S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
0, S_IXOTH, S_IXOTH, 0 /* other */
};
#define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
static void parse_config_file(void)
{
struct BB_suid_config *sct_head;
struct BB_suid_config *sct;
const struct bb_applet *applet;
FILE *f;
const char *errmsg;
char *s;
char *e;
int i;
unsigned lc;
smallint section;
char buffer[256];
struct stat st;
assert(!suid_config); /* Should be set to NULL by bss init. */
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(config_file, "r")) /* Cannot open? */
) {
return;
}
suid_cfg_readable = 1;
sct_head = NULL;
section = lc = 0;
while (1) {
s = buffer;
if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
if (ferror(f)) { /* Make sure it wasn't a read error. */
parse_error("reading");
}
fclose(f);
suid_config = sct_head; /* Success, so set the pointer. */
return;
}
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)) {
parse_error("line too long");
}
/* 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. */
e = strchr(s, ']');
if (!e /* Missing right bracket? */
|| e[1] /* Trailing characters? */
|| !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
) {
parse_error("section header");
}
/* 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). */
e = strchr(s, '=');
if (e) {
s = get_trimmed_slice(s, e);
}
if (!e || !*s) { /* Missing '=' or empty key. */
parse_error("keyword");
}
/* 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 = find_applet_by_name(s);
if (applet) {
/* 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 = xmalloc(sizeof(struct BB_suid_config));
sct->m_applet = applet;
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 + 1 nul for each of user/group/other. */
static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
const char *q;
q = strchrnul(mode_chars + 5*i, *e++);
if (!*q) {
parse_error("mode");
}
/* Adjust by -i to account for nul. */
sct->m_mode |= mode_mask[(q - mode_chars) - i];
}
/* Now get the the user/group info. */
s = skip_whitespace(e);
/* Note: we require whitespace between the mode and the
* user/group info. */
if ((s == e) || !(e = strchr(s, '.'))) {
parse_error("<uid>.<gid>");
}
*e++ = '\0';
/* We can't use get_ug_id here since it would exit()
* if a uid or gid was not found. Oh well... */
sct->m_uid = bb_strtoul(s, NULL, 10);
if (errno) {
struct passwd *pwd = getpwnam(s);
if (!pwd) {
parse_error("user");
}
sct->m_uid = pwd->pw_uid;
}
sct->m_gid = bb_strtoul(e, NULL, 10);
if (errno) {
struct group *grp;
grp = getgrnam(e);
if (!grp) {
parse_error("group");
}
sct->m_gid = grp->gr_gid;
}
}
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) {
parse_error("keyword outside section");
}
} /* while (1) */
pe_label:
fprintf(stderr, "Parse error in %s, line %d: %s\n",
config_file, lc, errmsg);
fclose(f);
/* Release any allocated memory before returning. */
while (sct_head) {
sct = sct_head->m_next;
free(sct_head);
sct_head = sct;
}
}
#else
static inline void parse_config_file(void)
{
USE_FEATURE_SUID(ruid = getuid();)
}
#endif /* FEATURE_SUID_CONFIG */
#if ENABLE_FEATURE_SUID
static void check_suid(const struct bb_applet *applet)
{
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 BB_suid_config *sct;
mode_t m;
for (sct = suid_config; sct; sct = sct->m_next) {
if (sct->m_applet == applet)
goto found;
}
/* default: drop all privileges */
xsetgid(rgid);
xsetuid(ruid);
return;
found:
m = sct->m_mode;
if (sct->m_uid == ruid)
/* same uid */
m >>= 6;
else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_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!");
/* _both_ sgid and group_exec have to be set for setegid */
if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
rgid = sct->m_gid;
/* else (no setegid) we will set egid = rgid */
/* We set effective AND saved ids. If saved-id is not set
* like we do below, seteiud(0) can still later succeed! */
if (setresgid(-1, rgid, rgid))
bb_perror_msg_and_die("setresgid");
/* do we have to set effective uid? */
uid = ruid;
if (sct->m_mode & S_ISUID)
uid = sct->m_uid;
/* else (no seteuid) we will set euid = ruid */
if (setresuid(-1, uid, uid))
bb_perror_msg_and_die("setresuid");
return;
}
#if !ENABLE_FEATURE_SUID_CONFIG_QUIET
{
static bool onetime = 0;
if (!onetime) {
onetime = 1;
fprintf(stderr, "Using fallback suid method\n");
}
}
#endif
#endif
if (applet->need_suid == _BB_SUID_ALWAYS) {
/* 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("applet requires root privileges!");
} else if (applet->need_suid == _BB_SUID_NEVER) {
xsetgid(rgid); /* drop all privileges */
xsetuid(ruid);
}
}
#else
#define check_suid(x) ((void)0)
#endif /* FEATURE_SUID */
#if ENABLE_FEATURE_INSTALLER
/* create (sym)links for each applet */
static void install_links(const char *busybox, int use_symbolic_links)
{
/* directory table
* this should be consistent w/ the enum,
* busybox.h::bb_install_loc_t, or else... */
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], /* "", equivalent to "/" for concat_path_file() */
&usr_bin [4], /* "/bin" */
&usr_sbin[4], /* "/sbin" */
usr_bin,
usr_sbin
};
int (*lf)(const char *, const char *) = link;
char *fpc;
int i;
int rc;
if (use_symbolic_links)
lf = symlink;
for (i = 0; applets[i].name != NULL; i++) {
fpc = concat_path_file(
install_dir[applets[i].install_loc],
applets[i].name);
rc = lf(busybox, fpc);
if (rc != 0 && errno != EEXIST) {
bb_simple_perror_msg(fpc);
}
free(fpc);
}
}
#else
#define install_links(x,y) ((void)0)
#endif /* FEATURE_INSTALLER */
/* If we were called as "busybox..." */
static int busybox_main(char **argv)
{
if (!argv[1]) {
/* Called without arguments */
const struct bb_applet *a;
int col, output_width;
help:
output_width = 80;
if (ENABLE_FEATURE_AUTOWIDTH) {
/* Obtain the terminal width */
get_terminal_width_height(0, &output_width, NULL);
}
/* leading tab and room to wrap */
output_width -= sizeof("start-stop-daemon, ") + 8;
printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
printf("Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n"
"Licensed under GPLv2. See source distribution for full notice.\n"
"\n"
"Usage: busybox [function] [arguments]...\n"
" or: [function] [arguments]...\n"
"\n"
"\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"
"\nCurrently defined functions:\n");
col = 0;
a = applets;
while (a->name) {
if (col > output_width) {
puts(",");
col = 0;
}
col += printf("%s%s", (col ? ", " : "\t"), a->name);
a++;
}
puts("\n");
return 0;
}
if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
const char *busybox;
busybox = xmalloc_readlink(bb_busybox_exec_path);
if (!busybox)
busybox = bb_busybox_exec_path;
/* -s makes symlinks */
install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
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);
bb_error_msg_and_die("applet not found");
}
void run_appletstruct_and_exit(const struct bb_applet *applet, char **argv)
{
int argc = 1;
while (argv[argc])
argc++;
/* Reinit some shared global data */
optind = 1;
xfunc_error_retval = EXIT_FAILURE;
applet_name = applet->name;
if (argc == 2 && !strcmp(argv[1], "--help"))
bb_show_usage();
if (ENABLE_FEATURE_SUID)
check_suid(applet);
exit(applet->main(argc, argv));
}
void run_applet_and_exit(const char *name, char **argv)
{
const struct bb_applet *applet = find_applet_by_name(name);
if (applet)
run_appletstruct_and_exit(applet, argv);
if (!strncmp(name, "busybox", 7))
exit(busybox_main(argv));
}
int main(int argc, char **argv) int main(int argc, char **argv)
{ {
bbox_prepare_main(argv); return libbusybox_main(argc, argv);
#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
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);
bb_error_msg_and_die("applet not found");
} }
#endif

3
include/busybox.h
View File

@ -52,5 +52,8 @@ struct bb_applet {
extern const struct bb_applet applets[]; extern const struct bb_applet applets[];
extern const unsigned short NUM_APPLETS; extern const unsigned short NUM_APPLETS;
void bbox_prepare_main(char **argv); void bbox_prepare_main(char **argv);
#if ENABLE_BUILD_LIBBUSYBOX
int libbusybox_main(int argc, char **argv);
#endif
#endif /* _BB_INTERNAL_H_ */ #endif /* _BB_INTERNAL_H_ */

553
libbb/appletlib.c
View File

@ -1,11 +1,15 @@
/* vi: set sw=4 ts=4: */ /* vi: set sw=4 ts=4: */
/* /*
* Support for main() which needs to end up in libbusybox, not busybox, * Utility routines.
* if one builds libbusybox.
* *
* Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com> * 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.
* *
* Licensed under GPLv2, see file License in this tarball for details. * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under the GPL.
*
* Licensed under GPLv2 or later, see file License in this tarball for details.
*/ */
#include <assert.h> #include <assert.h>
@ -140,3 +144,544 @@ void bbox_prepare_main(char **argv)
bb_show_usage(); bb_show_usage();
#endif #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
USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
#if ENABLE_FEATURE_SUID_CONFIG
/* applets[] is const, so we have to define this "override" structure */
static struct BB_suid_config {
const struct bb_applet *m_applet;
uid_t m_uid;
gid_t m_gid;
mode_t m_mode;
struct BB_suid_config *m_next;
} *suid_config;
static bool suid_cfg_readable;
/* 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;
}
/* This should probably be a libbb routine. In that case,
* I'd probably rename it to something like bb_trimmed_slice.
*/
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);
}
/* Don't depend on the tools to combine strings. */
static const char config_file[] ALIGN1 = "/etc/busybox.conf";
/* We don't supply a value for the nul, so an index adjustment is
* necessary below. Also, we use unsigned short here to save some
* space even though these are really mode_t values. */
static const unsigned short mode_mask[] ALIGN2 = {
/* SST sst xxx --- */
S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
0, S_IXOTH, S_IXOTH, 0 /* other */
};
#define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
static void parse_config_file(void)
{
struct BB_suid_config *sct_head;
struct BB_suid_config *sct;
const struct bb_applet *applet;
FILE *f;
const char *errmsg;
char *s;
char *e;
int i;
unsigned lc;
smallint section;
char buffer[256];
struct stat st;
assert(!suid_config); /* Should be set to NULL by bss init. */
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(config_file, "r")) /* Cannot open? */
) {
return;
}
suid_cfg_readable = 1;
sct_head = NULL;
section = lc = 0;
while (1) {
s = buffer;
if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
if (ferror(f)) { /* Make sure it wasn't a read error. */
parse_error("reading");
}
fclose(f);
suid_config = sct_head; /* Success, so set the pointer. */
return;
}
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)) {
parse_error("line too long");
}
/* 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. */
e = strchr(s, ']');
if (!e /* Missing right bracket? */
|| e[1] /* Trailing characters? */
|| !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
) {
parse_error("section header");
}
/* 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). */
e = strchr(s, '=');
if (e) {
s = get_trimmed_slice(s, e);
}
if (!e || !*s) { /* Missing '=' or empty key. */
parse_error("keyword");
}
/* 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 = find_applet_by_name(s);
if (applet) {
/* 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 = xmalloc(sizeof(struct BB_suid_config));
sct->m_applet = applet;
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 + 1 nul for each of user/group/other. */
static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
const char *q;
q = strchrnul(mode_chars + 5*i, *e++);
if (!*q) {
parse_error("mode");
}
/* Adjust by -i to account for nul. */
sct->m_mode |= mode_mask[(q - mode_chars) - i];
}
/* Now get the the user/group info. */
s = skip_whitespace(e);
/* Note: we require whitespace between the mode and the
* user/group info. */
if ((s == e) || !(e = strchr(s, '.'))) {
parse_error("<uid>.<gid>");
}
*e++ = '\0';
/* We can't use get_ug_id here since it would exit()
* if a uid or gid was not found. Oh well... */
sct->m_uid = bb_strtoul(s, NULL, 10);
if (errno) {
struct passwd *pwd = getpwnam(s);
if (!pwd) {
parse_error("user");
}
sct->m_uid = pwd->pw_uid;
}
sct->m_gid = bb_strtoul(e, NULL, 10);
if (errno) {
struct group *grp;
grp = getgrnam(e);
if (!grp) {
parse_error("group");
}
sct->m_gid = grp->gr_gid;
}
}
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) {
parse_error("keyword outside section");
}
} /* while (1) */
pe_label:
fprintf(stderr, "Parse error in %s, line %d: %s\n",
config_file, lc, errmsg);
fclose(f);
/* Release any allocated memory before returning. */
while (sct_head) {
sct = sct_head->m_next;
free(sct_head);
sct_head = sct;
}
}
#else
static inline void parse_config_file(void)
{
USE_FEATURE_SUID(ruid = getuid();)
}
#endif /* FEATURE_SUID_CONFIG */
#if ENABLE_FEATURE_SUID
static void check_suid(const struct bb_applet *applet)
{
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 BB_suid_config *sct;
mode_t m;
for (sct = suid_config; sct; sct = sct->m_next) {
if (sct->m_applet == applet)
goto found;
}
/* default: drop all privileges */
xsetgid(rgid);
xsetuid(ruid);
return;
found:
m = sct->m_mode;
if (sct->m_uid == ruid)
/* same uid */
m >>= 6;
else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_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!");
/* _both_ sgid and group_exec have to be set for setegid */
if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
rgid = sct->m_gid;
/* else (no setegid) we will set egid = rgid */
/* We set effective AND saved ids. If saved-id is not set
* like we do below, seteiud(0) can still later succeed! */
if (setresgid(-1, rgid, rgid))
bb_perror_msg_and_die("setresgid");
/* do we have to set effective uid? */
uid = ruid;
if (sct->m_mode & S_ISUID)
uid = sct->m_uid;
/* else (no seteuid) we will set euid = ruid */
if (setresuid(-1, uid, uid))
bb_perror_msg_and_die("setresuid");
return;
}
#if !ENABLE_FEATURE_SUID_CONFIG_QUIET
{
static bool onetime = 0;
if (!onetime) {
onetime = 1;
fprintf(stderr, "Using fallback suid method\n");
}
}
#endif
#endif
if (applet->need_suid == _BB_SUID_ALWAYS) {
/* 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("applet requires root privileges!");
} else if (applet->need_suid == _BB_SUID_NEVER) {
xsetgid(rgid); /* drop all privileges */
xsetuid(ruid);
}
}
#else
#define check_suid(x) ((void)0)
#endif /* FEATURE_SUID */
#if ENABLE_FEATURE_INSTALLER
/* create (sym)links for each applet */
static void install_links(const char *busybox, int use_symbolic_links)
{
/* directory table
* this should be consistent w/ the enum,
* busybox.h::bb_install_loc_t, or else... */
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], /* "", equivalent to "/" for concat_path_file() */
&usr_bin [4], /* "/bin" */
&usr_sbin[4], /* "/sbin" */
usr_bin,
usr_sbin
};
int (*lf)(const char *, const char *) = link;
char *fpc;
int i;
int rc;
if (use_symbolic_links)
lf = symlink;
for (i = 0; applets[i].name != NULL; i++) {
fpc = concat_path_file(
install_dir[applets[i].install_loc],
applets[i].name);
rc = lf(busybox, fpc);
if (rc != 0 && errno != EEXIST) {
bb_simple_perror_msg(fpc);
}
free(fpc);
}
}
#else
#define install_links(x,y) ((void)0)
#endif /* FEATURE_INSTALLER */
/* If we were called as "busybox..." */
static int busybox_main(char **argv)
{
if (!argv[1]) {
/* Called without arguments */
const struct bb_applet *a;
int col, output_width;
help:
output_width = 80;
if (ENABLE_FEATURE_AUTOWIDTH) {
/* Obtain the terminal width */
get_terminal_width_height(0, &output_width, NULL);
}
/* leading tab and room to wrap */
output_width -= sizeof("start-stop-daemon, ") + 8;
printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
printf("Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n"
"Licensed under GPLv2. See source distribution for full notice.\n"
"\n"
"Usage: busybox [function] [arguments]...\n"
" or: [function] [arguments]...\n"
"\n"
"\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"
"\nCurrently defined functions:\n");
col = 0;
a = applets;
while (a->name) {
if (col > output_width) {
puts(",");
col = 0;
}
col += printf("%s%s", (col ? ", " : "\t"), a->name);
a++;
}
puts("\n");
return 0;
}
if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
const char *busybox;
busybox = xmalloc_readlink(bb_busybox_exec_path);
if (!busybox)
busybox = bb_busybox_exec_path;
/* -s makes symlinks */
install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
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);
bb_error_msg_and_die("applet not found");
}
void run_appletstruct_and_exit(const struct bb_applet *applet, char **argv)
{
int argc = 1;
while (argv[argc])
argc++;
/* Reinit some shared global data */
optind = 1;
xfunc_error_retval = EXIT_FAILURE;
applet_name = applet->name;
if (argc == 2 && !strcmp(argv[1], "--help"))
bb_show_usage();
if (ENABLE_FEATURE_SUID)
check_suid(applet);
exit(applet->main(argc, argv));
}
void run_applet_and_exit(const char *name, char **argv)
{
const struct bb_applet *applet = find_applet_by_name(name);
if (applet)
run_appletstruct_and_exit(applet, argv);
if (!strncmp(name, "busybox", 7))
exit(busybox_main(argv));
}
#if ENABLE_BUILD_LIBBUSYBOX
int libbusybox_main(int argc, char **argv)
#else
int main(int argc, char **argv)
#endif
{
bbox_prepare_main(argv);
#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
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);
bb_error_msg_and_die("applet not found");
}

17
scripts/trylink
View File

@ -19,18 +19,16 @@ debug=false
# List of files to link: # List of files to link:
# $l_list == --start-group -llib1 -llib2 --end-group # $l_list == --start-group -llib1 -llib2 --end-group
# --start-group $O_FILES $A_FILES --end-group # --start-group $O_FILES $A_FILES --end-group
# or for shlib:
# --start-group --whole-archive $A_FILES --no-whole-archive --end-group
# otherwise we don't pull in all parts of *.a files. Now we pull in too much.
# FIXME: make it work without --whole-archive, or better, with --gc-sections.
# #
# Shared library link: # Shared library link:
# -shared self-explanatory # -shared self-explanatory
# -fPIC position-independent code # -fPIC position-independent code
# -Wl,--enable-new-dtags ? # --enable-new-dtags ?
# -Wl,-z,combreloc ? # -z,combreloc ?
# -Wl,-soname="libbusybox.so.$BB_VER" # -soname="libbusybox.so.$BB_VER"
# -static Not used, but may be useful! manpage: # --undefined=libbusybox_main Seed name to start pulling from
# (otherwise we'll need --whole-archive)
# -static Not used, but may be useful! manpage:
# "... This option can be used with -shared. # "... This option can be used with -shared.
# Doing so means that a shared library # Doing so means that a shared library
# is being created but that all of the library's # is being created but that all of the library's
@ -174,9 +172,10 @@ if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
-Wl,--enable-new-dtags \ -Wl,--enable-new-dtags \
-Wl,-z,combreloc \ -Wl,-z,combreloc \
-Wl,-soname="libbusybox.so.$BB_VER" \ -Wl,-soname="libbusybox.so.$BB_VER" \
-Wl,--undefined=libbusybox_main \
-Wl,--sort-common \ -Wl,--sort-common \
-Wl,--sort-section -Wl,alignment \ -Wl,--sort-section -Wl,alignment \
-Wl,--start-group -Wl,--whole-archive $A_FILES -Wl,--no-whole-archive -Wl,--end-group \ -Wl,--start-group $A_FILES -Wl,--end-group \
$l_list \ $l_list \
-Wl,--warn-common \ -Wl,--warn-common \
-Wl,-Map -Wl,$EXE.map \ -Wl,-Map -Wl,$EXE.map \