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ifupdown: reread state file before rewriting it.

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Fixes "ifup started another ifup" state corruption bug.
Patch by Natanael Copa <natanael.copa@gmail.com>.
This commit is contained in:
Denis Vlasenko 2007-05-02 21:38:44 +00:00
parent 4ac530c0ef
commit bd100b7478
1 changed files with 37 additions and 36 deletions
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65
networking/ifupdown.c
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@ -1083,15 +1083,33 @@ static llist_t *find_iface_state(llist_t *state_list, const char *iface)
return NULL;
}
/* read the previous state from the state file */
static llist_t *read_iface_state(void)
{
llist_t *state_list = NULL;
FILE *state_fp = fopen("/var/run/ifstate", "r");
if (state_fp) {
char *start, *end_ptr;
while ((start = xmalloc_fgets(state_fp)) != NULL) {
/* We should only need to check for a single character */
end_ptr = start + strcspn(start, " \t\n");
*end_ptr = '\0';
llist_add_to(&state_list, start);
}
fclose(state_fp);
}
return state_list;
}
int ifupdown_main(int argc, char **argv);
int ifupdown_main(int argc, char **argv)
{
int (*cmds)(struct interface_defn_t *) = NULL;
struct interfaces_file_t *defn;
llist_t *state_list = NULL;
llist_t *target_list = NULL;
const char *interfaces = "/etc/network/interfaces";
FILE *state_fp;
bool any_failures = 0;
cmds = iface_down;
@ -1118,32 +1136,9 @@ int ifupdown_main(int argc, char **argv)
startup_PATH = getenv("PATH");
if (!startup_PATH) startup_PATH = "";
/* Read the previous state from the state file */
state_fp = fopen("/var/run/ifstate", "r");
if (state_fp) {
char *start, *end_ptr;
while ((start = xmalloc_fgets(state_fp)) != NULL) {
/* We should only need to check for a single character */
end_ptr = start + strcspn(start, " \t\n");
*end_ptr = '\0';
llist_add_to(&state_list, start);
}
fclose(state_fp);
}
/* Create a list of interfaces to work on */
if (DO_ALL) {
if (cmds == iface_up) {
target_list = defn->autointerfaces;
} else {
/* iface_down */
const llist_t *list = state_list;
while (list) {
llist_add_to_end(&target_list, xstrdup(list->data));
list = list->link;
}
target_list = defn->autointerfaces;
}
} else {
llist_add_to_end(&target_list, argv[optind]);
}
@ -1170,6 +1165,7 @@ int ifupdown_main(int argc, char **argv)
}
if (!FORCE) {
llist_t *state_list = read_iface_state();
const llist_t *iface_state = find_iface_state(state_list, iface);
if (cmds == iface_up) {
@ -1185,6 +1181,7 @@ int ifupdown_main(int argc, char **argv)
continue;
}
}
llist_free(state_list, free);
}
#if ENABLE_FEATURE_IFUPDOWN_MAPPING
@ -1239,6 +1236,8 @@ int ifupdown_main(int argc, char **argv)
bb_error_msg("ignoring unknown interface %s", liface);
any_failures = 1;
} else {
/* update the state file */
llist_t *state_list = read_iface_state();
llist_t *iface_state = find_iface_state(state_list, iface);
if (cmds == iface_up) {
@ -1254,20 +1253,22 @@ int ifupdown_main(int argc, char **argv)
llist_unlink(&state_list, iface_state);
free(llist_pop(&iface_state));
}
}
}
/* Actually write the new state */
if (!NO_ACT) {
state_fp = xfopen("/var/run/ifstate", "w");
while (state_list) {
if (state_list->data) {
fprintf(state_fp, "%s\n", state_list->data);
FILE *state_fp = xfopen("/var/run/ifstate", "w");
llist_t *state = state_list;
while (state) {
if (state->data) {
fprintf(state_fp, "%s\n", state->data);
}
state_list = state_list->link;
state = state->link;
}
fclose(state_fp);
}
llist_free(state_list, free);
}
}
return any_failures;
}