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5acf5e1f8

Denys Vlasenko
Denys Vlasenko
2021-10-11
SUCCESS Duration: 155s

Subject

shell: fix script's comm field if ENABLE_FEATURE_PREFER_APPLETS=y

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/libbb.h +2 -0libbb/appletlib.c +8 -2libbb/vfork_daemon_rexec.c +16 -0shell/ash_test/ash-comm/comm.right +6 -0shell/ash_test/ash-comm/comm.tests +20 -0shell/hush_test/hush-comm/comm.right +6 -0shell/hush_test/hush-comm/comm.tests +20 -0
include/libbb.h+2 -0
@@ -1271,8 +1271,10 @@ void run_applet_no_and_exit(int a, const char *name, char **argv) NORETURN FAST_
#endif
void show_usage_if_dash_dash_help(int applet_no, char **argv) FAST_FUNC;
#if defined(__linux__)
+int re_execed_comm(void) FAST_FUNC;
void set_task_comm(const char *comm) FAST_FUNC;
#else
+# define re_execed_comm() 0
# define set_task_comm(name) ((void)0)
#endif
libbb/appletlib.c+8 -2
@@ -1112,8 +1112,14 @@ int main(int argc UNUSED_PARAM, char **argv)
|| ENABLE_FEATURE_PREFER_APPLETS
|| !BB_MMU
) {
- if (NUM_APPLETS > 1)
- set_task_comm(applet_name);
+ if (NUM_APPLETS > 1) {
+ /* Careful, do not trash comm of "SCRIPT.sh" -
+ * the case when started from e.g. #!/bin/ash script.
+ * (not limited to shells - #!/bin/awk scripts also exist)
+ */
+ if (re_execed_comm())
+ set_task_comm(applet_name);
+ }
}
parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
libbb/vfork_daemon_rexec.c+16 -0
@@ -28,6 +28,22 @@
# ifndef PR_GET_NAME
# define PR_GET_NAME 16
# endif
+# if ENABLE_FEATURE_SH_STANDALONE || ENABLE_FEATURE_PREFER_APPLETS || !BB_MMU
+int FAST_FUNC re_execed_comm(void)
+{
+ const char *e, *expected_comm;
+ char comm[16];
+
+ BUILD_BUG_ON(CONFIG_BUSYBOX_EXEC_PATH[0] != '/');
+ e = CONFIG_BUSYBOX_EXEC_PATH;
+ /* Hopefully (strrchr(e) - e) evaluates to constant at compile time: */
+ expected_comm = bb_busybox_exec_path + (strrchr(e, '/') - e) + 1;
+
+ prctl(PR_GET_NAME, (long)comm, 0, 0, 0);
+ //bb_error_msg("comm:'%.*s' expected:'%s'", 16, comm, expected_comm);
+ return strcmp(comm, expected_comm) == 0;
+}
+# endif
void FAST_FUNC set_task_comm(const char *comm)
{
/* okay if too long (truncates) */
shell/ash_test/ash-comm/comm.right+6 -0
@@ -0,0 +1,6 @@
+./SCRIPT.sh:
+ /proc/N/comm: SCRIPT.sh
+exec ./SCRIPT.sh:
+ /proc/N/comm: SCRIPT.sh
+sh ./SCRIPT.sh:
+ /proc/N/comm: ash
shell/ash_test/ash-comm/comm.tests+20 -0
@@ -0,0 +1,20 @@
+{
+echo "#!$THIS_SH"
+echo 'procdir=/proc/$$'
+#echo 'echo " /proc/N/exe: $(basename $(readlink $procdir/exe))"'
+echo 'echo " /proc/N/comm: $(cat $procdir/comm)"'
+} >SCRIPT.sh
+chmod 755 SCRIPT.sh
+
+# comm field was wrong if CONFIG_FEATURE_PREFER_APPLETS=y
+echo './SCRIPT.sh:'
+./SCRIPT.sh
+
+# comm field was wrong if CONFIG_FEATURE_PREFER_APPLETS=y
+echo 'exec ./SCRIPT.sh:'
+(exec ./SCRIPT.sh)
+
+echo 'sh ./SCRIPT.sh:'
+$THIS_SH ./SCRIPT.sh
+
+rm SCRIPT.sh
shell/hush_test/hush-comm/comm.right+6 -0
@@ -0,0 +1,6 @@
+./SCRIPT.sh:
+ /proc/N/comm: SCRIPT.sh
+exec ./SCRIPT.sh:
+ /proc/N/comm: SCRIPT.sh
+sh ./SCRIPT.sh:
+ /proc/N/comm: hush
shell/hush_test/hush-comm/comm.tests+20 -0
@@ -0,0 +1,20 @@
+{
+echo "#!$THIS_SH"
+echo 'procdir=/proc/$$'
+#echo 'echo " /proc/N/exe: $(basename $(readlink $procdir/exe))"'
+echo 'echo " /proc/N/comm: $(cat $procdir/comm)"'
+} >SCRIPT.sh
+chmod 755 SCRIPT.sh
+
+# comm field was wrong if CONFIG_FEATURE_PREFER_APPLETS=y
+echo './SCRIPT.sh:'
+./SCRIPT.sh
+
+# comm field was wrong if CONFIG_FEATURE_PREFER_APPLETS=y
+echo 'exec ./SCRIPT.sh:'
+(exec ./SCRIPT.sh)
+
+echo 'sh ./SCRIPT.sh:'
+$THIS_SH ./SCRIPT.sh
+
+rm SCRIPT.sh