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authorDenys Vlasenko <vda.linux@googlemail.com>2013-08-16 09:48:48 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2013-08-16 09:48:48 (GMT)
commitd2e07bc16cbd68bc2771f9f163e610e4e327c67c (patch)
tree737d5309821fd44427754223965ec596bfa1fcf8
parent73fbe9dc86df6c7db425c2c3939ff98c8c44974e (diff)
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init: don't use fixed size buffer for command
We store init actions forever. 256 bytes per action means that a typical inittab of ~10 commands uses 2.5k just to remember command strings - which are usually _much_ shorter than 256 bytes. At a cost of a bit more code, it's possible to allocate only actually needed amount. function old new delta init_exec 224 248 +24 new_init_action 140 142 +2 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--init/init.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/init/init.c b/init/init.c
index f3a35d5..05ed4f7 100644
--- a/init/init.c
+++ b/init/init.c
@@ -140,7 +140,6 @@
* not fully functional init by switching it on! */
#define DEBUG_INIT 0
-#define COMMAND_SIZE 256
#define CONSOLE_NAME_SIZE 32
/* Default sysinit script. */
@@ -195,7 +194,7 @@ struct init_action {
pid_t pid;
uint8_t action_type;
char terminal[CONSOLE_NAME_SIZE];
- char command[COMMAND_SIZE];
+ char command[1];
};
static struct init_action *init_action_list = NULL;
@@ -398,7 +397,7 @@ static void reset_sighandlers_and_unblock_sigs(void)
}
/* Wrapper around exec:
- * Takes string (max COMMAND_SIZE chars).
+ * Takes string.
* If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
* Otherwise splits words on whitespace, deals with leading dash,
* and uses plain exec().
@@ -406,10 +405,15 @@ static void reset_sighandlers_and_unblock_sigs(void)
*/
static void init_exec(const char *command)
{
- char *cmd[COMMAND_SIZE / 2];
- char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
- int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
-
+ /* +8 allows to write VLA sizes below more efficiently: */
+ unsigned command_size = strlen(command) + 8;
+ /* strlen(command) + strlen("exec ")+1: */
+ char buf[command_size];
+ /* strlen(command) / 2 + 4: */
+ char *cmd[command_size / 2];
+ int dash;
+
+ dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
command += dash;
/* See if any special /bin/sh requiring characters are present */
@@ -626,13 +630,13 @@ static void new_init_action(uint8_t action_type, const char *command, const char
nextp = &a->next;
}
- a = xzalloc(sizeof(*a));
+ a = xzalloc(sizeof(*a) + strlen(command));
/* Append to the end of the list */
append:
*nextp = a;
a->action_type = action_type;
- safe_strncpy(a->command, command, sizeof(a->command));
+ strcpy(a->command, command);
safe_strncpy(a->terminal, cons, sizeof(a->terminal));
dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
a->command, a->action_type, a->terminal);