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authorDenis Vlasenko2007-01-21 00:41:04 +0000
committerDenis Vlasenko2007-01-21 00:41:04 +0000
commit2f0c0d0b8829b8aea97bc09833e172c59b55cd94 (patch)
tree3e82c2dd94d674a723f3d7df350f32dc8892adc1
parentb3f3c23f786a2486a8545ef0d904061ac83e6453 (diff)
downloadbusybox-2f0c0d0b8829b8aea97bc09833e172c59b55cd94.zip
busybox-2f0c0d0b8829b8aea97bc09833e172c59b55cd94.tar.gz
Introduce FEATURE_EXEC_PREFER_APPLETS = "re-execute our own
executable if we asked to exec someting with argv[0] == known_applet" Use it in init. Also respect PATH in init, remove explicit "/sbin" etc from exec. Patch by Gabriel L. Somlo <somlo@cmu.edu>
-rw-r--r--Config.in10
-rw-r--r--init/init.c29
-rw-r--r--libbb/xfuncs.c7
-rw-r--r--scripts/defconfig1
-rw-r--r--shell/ash.c4
5 files changed, 39 insertions, 12 deletions
diff --git a/Config.in b/Config.in
index acdeccc..2066e42 100644
--- a/Config.in
+++ b/Config.in
@@ -231,6 +231,14 @@ config SELINUX
Most people will leave this set to 'N'.
+config FEATURE_EXEC_PREFER_APPLETS
+ bool "exec prefers applets"
+ default n
+ help
+ This is an experimental option which directs applets about to
+ call 'exec' to try and find an applicable busybox applet before
+ searching the executable path for a binary or symlink to execute.
+
config BUSYBOX_EXEC_PATH
string "Path to BusyBox executable"
default "/proc/self/exe"
@@ -439,7 +447,7 @@ config INSTALL_APPLET_HARDLINKS
config INSTALL_APPLET_DONT
bool
prompt "not installed"
- depends on FEATURE_INSTALLER || FEATURE_SH_STANDALONE_SHELL
+ depends on FEATURE_INSTALLER || FEATURE_SH_STANDALONE_SHELL || FEATURE_EXEC_PREFER_APPLETS
help
Do not install applet links. Useful when using the -install feature
or a standalone shell for rescue pruposes.
diff --git a/init/init.c b/init/init.c
index 6fc68af..7694b44 100644
--- a/init/init.c
+++ b/init/init.c
@@ -389,6 +389,7 @@ static pid_t run(const struct init_action *a)
#include CUSTOMIZED_BANNER
#endif
"\nPlease press Enter to activate this console. ";
+ char *prog;
/* Block sigchild while forking. */
sigemptyset(&nmask);
@@ -560,7 +561,10 @@ static pid_t run(const struct init_action *a)
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
- execv(cmdpath, cmd);
+ prog = cmdpath;
+ if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && find_applet_by_name(prog))
+ prog = CONFIG_BUSYBOX_EXEC_PATH;
+ execvp(prog, cmd);
/* We're still here? Some error happened. */
message(LOG | CONSOLE, "Bummer, cannot run '%s': %m", cmdpath);
@@ -678,6 +682,7 @@ static void exec_signal(int sig ATTRIBUTE_UNUSED)
{
struct init_action *a, *tmp;
sigset_t unblock_signals;
+ char *prog;
for (a = init_action_list; a; a = tmp) {
tmp = a->next;
@@ -713,7 +718,10 @@ static void exec_signal(int sig ATTRIBUTE_UNUSED)
dup(0);
messageD(CONSOLE | LOG, "Trying to re-exec %s", a->command);
- execl(a->command, a->command, NULL);
+ prog = a->command;
+ if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && find_applet_by_name(prog))
+ prog = CONFIG_BUSYBOX_EXEC_PATH;
+ execlp(prog, a->command, NULL);
message(CONSOLE | LOG, "exec of '%s' failed: %m",
a->command);
@@ -852,13 +860,13 @@ static void parse_inittab(void)
/* No inittab file -- set up some default behavior */
#endif
/* Reboot on Ctrl-Alt-Del */
- new_init_action(CTRLALTDEL, "/sbin/reboot", "");
+ new_init_action(CTRLALTDEL, "reboot", "");
/* Umount all filesystems on halt/reboot */
- new_init_action(SHUTDOWN, "/bin/umount -a -r", "");
+ new_init_action(SHUTDOWN, "umount -a -r", "");
/* Swapoff on halt/reboot */
- if(ENABLE_SWAPONOFF) new_init_action(SHUTDOWN, "/sbin/swapoff -a", "");
+ if(ENABLE_SWAPONOFF) new_init_action(SHUTDOWN, "swapoff -a", "");
/* Prepare to restart init when a HUP is received */
- new_init_action(RESTART, "/sbin/init", "");
+ new_init_action(RESTART, "init", "");
/* Askfirst shell on tty1-4 */
new_init_action(ASKFIRST, bb_default_login_shell, "");
new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
@@ -1039,9 +1047,9 @@ int init_main(int argc, char **argv)
{
message(CONSOLE,"Low memory: forcing swapon.");
/* swapon -a requires /proc typically */
- new_init_action(SYSINIT, "/bin/mount -t proc proc /proc", "");
+ new_init_action(SYSINIT, "mount -t proc proc /proc", "");
/* Try to turn on swap */
- new_init_action(SYSINIT, "/sbin/swapon -a", "");
+ new_init_action(SYSINIT, "swapon -a", "");
run_actions(SYSINIT); /* wait and removing */
}
}
@@ -1068,7 +1076,10 @@ int init_main(int argc, char **argv)
putenv("SELINUX_INIT=YES");
if (selinux_init_load_policy(&enforce) == 0) {
- execv(argv[0], argv);
+ char *prog = argv[0];
+ if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && find_applet_by_name(prog))
+ prog = CONFIG_BUSYBOX_EXEC_PATH;
+ execvp(prog, argv);
} else if (enforce > 0) {
/* SELinux in enforcing mode but load_policy failed */
/* At this point, we probably can't open /dev/console, so log() won't work */
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index 240ac5d..4252e76 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -183,14 +183,17 @@ pid_t spawn(char **argv)
/* Why static? */
static int failed;
pid_t pid;
- void *app = ENABLE_FEATURE_SH_STANDALONE_SHELL ? find_applet_by_name(argv[0]) : 0;
+ char *prog;
// Be nice to nommu machines.
failed = 0;
pid = vfork();
if (pid < 0) return pid;
if (!pid) {
- execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);
+ prog = argv[0];
+ if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && find_applet_by_name(prog))
+ prog = CONFIG_BUSYBOX_EXEC_PATH;
+ execvp(prog, argv);
// We're sharing a stack with blocked parent, let parent know we failed
// and then exit to unblock parent (but don't run atexit() stuff, which
diff --git a/scripts/defconfig b/scripts/defconfig
index 2c82ed4..fc43deb 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -27,6 +27,7 @@ CONFIG_FEATURE_SYSLOG=y
CONFIG_FEATURE_SUID_CONFIG=y
CONFIG_FEATURE_SUID_CONFIG_QUIET=y
# CONFIG_SELINUX is not set
+#CONFIG_FEATURE_EXEC_PREFER_APPLETS is not set
CONFIG_BUSYBOX_EXEC_PATH="/proc/self/exe"
#
diff --git a/shell/ash.c b/shell/ash.c
index 8ef8c46..2db3302 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -6528,6 +6528,10 @@ setjobctl(int on)
int ofd;
ofd = fd = open(_PATH_TTY, O_RDWR);
if (fd < 0) {
+ /* BTW, bash will try to open(ttyname(0)) if open("/dev/tty") fails.
+ * That sometimes helps to acquire controlling tty.
+ * Obviously, a workaround for bugs when someone
+ * failed to provide a controlling tty to bash! :) */
fd += 3;
while (!isatty(fd) && --fd >= 0)
;