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telnetd: fix problem with zombies (by Paul Fox <pgf@brightstareng.com>)

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syslogd: strip trailing NULs
This commit is contained in:
Denis Vlasenko 2007-11-06 01:38:46 +00:00
parent cb981638f5
commit 018b155ad9
3 changed files with 41 additions and 22 deletions
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2
archival/unzip.c
View File

@ -57,7 +57,7 @@ typedef union {
uint16_t filename_len; /* 22-23 */
uint16_t extra_len; /* 24-25 */
} formatted ATTRIBUTE_PACKED;
} zip_header_t;
} zip_header_t ATTRIBUTE_PACKED;
/* Check the offset of the last element, not the length. This leniency
* allows for poor packing, whereby the overall struct may be too long,

34
networking/telnetd.c
View File

@ -279,6 +279,10 @@ make_new_session(
/* make new session and process group */
setsid();
/* Restore default signal handling */
signal(SIGCHLD, SIG_DFL);
signal(SIGPIPE, SIG_DFL);
/* open the child's side of the tty. */
/* NB: setsid() disconnects from any previous ctty's. Therefore
* we must open child's side of the tty AFTER setsid! */
@ -302,14 +306,18 @@ make_new_session(
/* Uses FILE-based I/O to stdout, but does fflush(stdout),
* so should be safe with vfork.
* I fear, though, that some users will have ridiculously big
* issue files, and they may block writing to fd 1. */
* issue files, and they may block writing to fd 1,
* (parent is supposed to read it, but parent waits
* for vforked child to exec!) */
print_login_issue(issuefile, NULL);
/* Exec shell / login / whatever */
login_argv[0] = loginpath;
login_argv[1] = NULL;
execvp(loginpath, (char **)login_argv);
/* Safer with vfork, and we shouldn't send message
/* exec busybox applet (if PREFER_APPLETS=y), if that fails,
* exec external program */
BB_EXECVP(loginpath, (char **)login_argv);
/* _exit is safer with vfork, and we shouldn't send message
* to remote clients anyway */
_exit(1); /*bb_perror_msg_and_die("execv %s", loginpath);*/
}
@ -374,7 +382,7 @@ free_session(struct tsession *ts)
#else /* !FEATURE_TELNETD_STANDALONE */
/* Used in main() only, thus exits. */
/* Used in main() only, thus "return 0" actually is exit(0). */
#define free_session(ts) return 0
#endif
@ -384,20 +392,22 @@ static void handle_sigchld(int sig)
pid_t pid;
struct tsession *ts;
pid = waitpid(-1, &sig, WNOHANG);
if (pid > 0) {
/* Looping: more than one child may have exited */
while (1) {
pid = waitpid(-1, NULL, WNOHANG);
if (pid <= 0)
break;
ts = sessions;
while (ts) {
if (ts->shell_pid == pid) {
ts->shell_pid = -1;
return;
break;
}
ts = ts->next;
}
}
}
int telnetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int telnetd_main(int argc, char **argv)
{
@ -430,7 +440,7 @@ int telnetd_main(int argc, char **argv)
if (!(opt & OPT_FOREGROUND)) {
/* DAEMON_CHDIR_ROOT was giving inconsistent
* behavior with/without -F, -i */
bb_daemonize_or_rexec(0 /*DAEMON_CHDIR_ROOT*/, argv);
bb_daemonize_or_rexec(0 /*was DAEMON_CHDIR_ROOT*/, argv);
}
}
/* Redirect log to syslog early, if needed */
@ -466,6 +476,8 @@ int telnetd_main(int argc, char **argv)
if (opt & OPT_WATCHCHILD)
signal(SIGCHLD, handle_sigchld);
else /* prevent dead children from becoming zombies */
signal(SIGCHLD, SIG_IGN);
/*
This is how the buffers are used. The arrows indicate the movement
@ -497,7 +509,7 @@ int telnetd_main(int argc, char **argv)
while (ts) {
struct tsession *next = ts->next; /* in case we free ts. */
if (ts->shell_pid == -1) {
/* Child died ad we detected that */
/* Child died and we detected that */
free_session(ts);
} else {
if (ts->size1 > 0) /* can write to pty */
@ -514,7 +526,7 @@ int telnetd_main(int argc, char **argv)
if (!IS_INETD) {
FD_SET(master_fd, &rdfdset);
/* This is needed because free_session() does not
* take into account master_fd when it finds new
* take master_fd into account when it finds new
* maxfd among remaining fd's */
if (master_fd > maxfd)
maxfd = master_fd;

27
sysklogd/syslogd.c
View File

@ -381,8 +381,8 @@ static void parse_fac_prio_20(int pri, char *res20)
}
/* len parameter is used only for "is there a timestamp?" check.
* NB: some callers cheat and supply 0 when they know
* that there is no timestamp, short-cutting the test. */
* NB: some callers cheat and supply len==0 when they know
* that there is no timestamp, short-circuiting the test. */
static void timestamp_and_log(int pri, char *msg, int len)
{
char *timestamp;
@ -427,11 +427,11 @@ static void split_escape_and_log(char *tmpbuf, int len)
if (*p == '<') {
/* Parse the magic priority number */
pri = bb_strtou(p + 1, &p, 10);
if (*p == '>') p++;
if (pri & ~(LOG_FACMASK | LOG_PRIMASK)) {
if (*p == '>')
p++;
if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
pri = (LOG_USER | LOG_NOTICE);
}
}
while ((c = *p++)) {
if (c == '\n')
@ -526,14 +526,22 @@ static void do_syslogd(void)
for (;;) {
size_t sz;
read_again:
sz = safe_read(sock_fd, G.recvbuf, MAX_READ - 1);
if (sz <= 0) {
//if (sz == 0)
// continue; /* EOF from unix socket??? */
if (sz < 0) {
bb_perror_msg_and_die("read from /dev/log");
}
/* Drop trailing NULs (typically there is one NUL) */
while (1) {
if (sz == 0)
goto read_again;
if (G.recvbuf[sz-1])
break;
sz--;
}
G.recvbuf[sz] = '\0'; /* make sure it *is* NUL terminated */
/* TODO: maybe suppress duplicates? */
#if ENABLE_FEATURE_REMOTE_LOG
/* We are not modifying log messages in any way before send */
@ -549,7 +557,6 @@ static void do_syslogd(void)
}
}
#endif
G.recvbuf[sz] = '\0';
split_escape_and_log(G.recvbuf, sz);
} /* for */
}