7221c8c22 — BusyBox

Subject

lineedit: reduce stack usage netstat: reduce stack usage; fix handling of NULs in unix socket filenames

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Architecture & Compiler Flags

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

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Commit Diff GitHub →

libbb/lineedit.c +43 -50 networking/netstat.c +37 -33

libbb/lineedit.c+43 -50

@@ -91,7 +91,6 @@ struct statics {

	const char *cmdedit_prompt;
	#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-	char *hostname_buf;
	int num_ok_lines; /* = 1; */
	#endif

@@ -136,7 +135,6 @@ static struct statics *const ptr_to_statics __attribute__ ((section (".data")));
	#define command_len (S.command_len )
	#define command_ps (S.command_ps )
	#define cmdedit_prompt (S.cmdedit_prompt )
-	#define hostname_buf (S.hostname_buf )
	#define num_ok_lines (S.num_ok_lines )
	#define user_buf (S.user_buf )
	#define home_pwd_buf (S.home_pwd_buf )
@@ -155,7 +153,6 @@ static struct statics *const ptr_to_statics __attribute__ ((section (".data")));
	static void deinit_S(void)
	{
	#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-	free(hostname_buf);
	/* This one is allocated only if FANCY_PROMPT is on
	* (otherwise it points to verbatim prompt (NOT malloced) */
	free((char*)cmdedit_prompt);
@@ -381,14 +378,14 @@ static void username_tab_completion(char ud, char with_shash_flg)
	if (with_shash_flg) { /* "~/..." or "~user/..." */
	char *sav_ud = ud - 1;
	char *home = NULL;
-	char *temp;

	if (ud == '/') { / "~/..." */
	home = home_pwd_buf;
	} else {
	/* "~user/..." */
+	char *temp;
	temp = strchr(ud, '/');
-	temp = 0; / ~user\0 */
+	temp = '\0'; / ~user\0 */
	entry = getpwnam(ud);
	temp = '/'; / restore ~user/... */
	ud = temp;
@@ -1163,21 +1160,23 @@ static void parse_and_put_prompt(const char *prmt_ptr)
	size_t cur_prmt_len = 0;
	char flg_not_length = '[';
	char *prmt_mem_ptr = xzalloc(1);
-	char *pwd_buf = xrealloc_getcwd_or_warn(NULL);
-	char buf2[PATH_MAX + 1];
-	char buf[2];
+	char *cwd_buf = xrealloc_getcwd_or_warn(NULL);
+	char cbuf[2];
	char c;
	char *pbuf;

	cmdedit_prmt_len = 0;

-	if (!pwd_buf) {
-	pwd_buf = (char *)bb_msg_unknown;
+	if (!cwd_buf) {
+	cwd_buf = (char *)bb_msg_unknown;
	}

+	cbuf[1] = '\0'; /* never changes */
+
	while (*prmt_ptr) {
-	pbuf = buf;
-	pbuf[1] = 0;
+	char *free_me = NULL;
+
+	pbuf = cbuf;
	c = *prmt_ptr++;
	if (c == '\\') {
	const char *cp = prmt_ptr;
@@ -1188,6 +1187,7 @@ static void parse_and_put_prompt(const char *prmt_ptr)
	if (*cp == '\0')
	break;
	c = *prmt_ptr++;
+
	switch (c) {
	#if ENABLE_FEATURE_GETUSERNAME_AND_HOMEDIR
	case 'u':
@@ -1195,87 +1195,81 @@ static void parse_and_put_prompt(const char *prmt_ptr)
	break;
	#endif
	case 'h':
-	pbuf = hostname_buf;
-	if (!pbuf) {
-	pbuf = xzalloc(256);
-	if (gethostname(pbuf, 255) < 0) {
-	strcpy(pbuf, "?");
-	} else {
-	char *s = strchr(pbuf, '.');
-	if (s)
-	*s = '\0';
-	}
-	hostname_buf = pbuf;
+	pbuf = free_me = xzalloc(256);
+	if (gethostname(pbuf, 255) < 0) {
+	pbuf[0] = '?';
+	pbuf[1] = '\0';
	}
+	*strchrnul(pbuf, '.') = '\0';
	break;
	case '$':
	c = (geteuid() == 0 ? '#' : '$');
	break;
	#if ENABLE_FEATURE_GETUSERNAME_AND_HOMEDIR
	case 'w':
-	pbuf = pwd_buf;
+	/* /home/user[/something] -> ~[/something] */
+	pbuf = cwd_buf;
	l = strlen(home_pwd_buf);
	if (l != 0
-	&& strncmp(home_pwd_buf, pbuf, l) == 0
-	&& (pbuf[l]=='/' \|\| pbuf[l]=='\0')
-	&& strlen(pwd_buf+l) < PATH_MAX
+	&& strncmp(home_pwd_buf, cwd_buf, l) == 0
+	&& (cwd_buf[l]=='/' \|\| cwd_buf[l]=='\0')
+	&& strlen(cwd_buf + l) < PATH_MAX
	) {
-	pbuf = buf2;
-	*pbuf = '~';
-	strcpy(pbuf+1, pwd_buf+l);
+	pbuf = free_me = xasprintf("~%s", cwd_buf + l);
	}
	break;
	#endif
	case 'W':
-	pbuf = pwd_buf;
+	pbuf = cwd_buf;
	cp = strrchr(pbuf, '/');
	if (cp != NULL && cp != pbuf)
	pbuf += (cp-pbuf) + 1;
	break;
	case '!':
-	pbuf = buf2;
-	snprintf(buf2, sizeof(buf2), "%d", num_ok_lines);
+	pbuf = free_me = xasprintf("%d", num_ok_lines);
	break;
	case 'e': case 'E': /* \e \E = \033 */
	c = '\033';
	break;
-	case 'x': case 'X':
+	case 'x': case 'X': {
+	char buf2[4];
	for (l = 0; l < 3;) {
-	int h;
+	unsigned h;
	buf2[l++] = *prmt_ptr;
-	buf2[l] = 0;
-	h = strtol(buf2, &pbuf, 16);
+	buf2[l] = '\0';
+	h = strtoul(buf2, &pbuf, 16);
	if (h > UCHAR_MAX \|\| (pbuf - buf2) < l) {
-	l--;
+	buf2[--l] = '\0';
	break;
	}
	prmt_ptr++;
	}
-	buf2[l] = 0;
-	c = (char)strtol(buf2, NULL, 16);
+	c = (char)strtoul(buf2, NULL, 16);
	if (c == 0)
	c = '?';
-	pbuf = buf;
+	pbuf = cbuf;
	break;
+	}
	case '[': case ']':
	if (c == flg_not_length) {
	flg_not_length = (flg_not_length == '[' ? ']' : '[');
	continue;
	}
	break;
-	}
-	}
-	}
-	if (pbuf == buf)
-	*pbuf = c;
+	} /* switch */
+	} /* if */
+	} /* if */
+	cbuf[0] = c;
	cur_prmt_len = strlen(pbuf);
	prmt_len += cur_prmt_len;
	if (flg_not_length != ']')
	cmdedit_prmt_len += cur_prmt_len;
	prmt_mem_ptr = strcat(xrealloc(prmt_mem_ptr, prmt_len+1), pbuf);
-	}
-	if (pwd_buf != (char *)bb_msg_unknown)
-	free(pwd_buf);
+	free(free_me);
+	} /* while */
+
+	if (cwd_buf != (char *)bb_msg_unknown)
+	free(cwd_buf);
	cmdedit_prompt = prmt_mem_ptr;
	put_prompt();
	}
@@ -1397,7 +1391,6 @@ int read_line_input(const char prompt, char command, int maxsize, line_input_t
	if (entry) {
	user_buf = xstrdup(entry->pw_name);
	home_pwd_buf = xstrdup(entry->pw_dir);
-	/* They are not freed on exit (too small to bother) */
	}
	}
	#endif

networking/netstat.c+37 -33

@@ -148,7 +148,7 @@ static char ip_port_str(struct sockaddr addr, int port, const char *proto, int
	return host_port;
	}

-	static void tcp_do_one(int lnr, const char *line)
+	static void tcp_do_one(int lnr, char *line)
	{
	char local_addr[64], rem_addr[64];
	char more[512];
@@ -201,7 +201,7 @@ static void tcp_do_one(int lnr, const char *line)
	}
	}

-	static void udp_do_one(int lnr, const char *line)
+	static void udp_do_one(int lnr, char *line)
	{
	char local_addr[64], rem_addr[64];
	const char *state_str;
@@ -283,7 +283,7 @@ static void udp_do_one(int lnr, const char *line)
	}
	}

-	static void raw_do_one(int lnr, const char *line)
+	static void raw_do_one(int lnr, char *line)
	{
	char local_addr[64], rem_addr[64];
	char more[512];
@@ -339,31 +339,37 @@ static void raw_do_one(int lnr, const char *line)
	}
	}

-	static void unix_do_one(int nr, const char *line)
+	static void unix_do_one(int nr, char *line)
	{
-	static smallint has_inode = 0;
-
-	char path[PATH_MAX], ss_flags[32];
-	const char ss_proto, ss_state, *ss_type;
-	int num, state, type, inode;
-	void *d;
	unsigned long refcnt, proto, unix_flags;
+	unsigned long inode;
+	int type, state;
+	int num, path_ofs;
+	void *d;
+	const char ss_proto, ss_state, *ss_type;
+	char ss_flags[32];

-	if (nr == 0) {
-	if (strstr(line, "Inode"))
-	has_inode = 1;
-	return;
+	if (nr == 0)
+	return; /* skip header */
+
+	{
+	char *last = last_char_is(line, '\n');
+	if (last)
+	*last = '\0';
	}
-	path[0] = '\0';
-	num = sscanf(line, "%p: %lX %lX %lX %X %X %d %s",
-	&d, &refcnt, &proto, &unix_flags, &type, &state, &inode, path);
-	if (num < 6) {
-	bb_error_msg("warning, got bogus unix line");
+
+	/* 2.6.15 may report lines like "... @/tmp/fam-user-^@^@^@^@^@^@^@..."
+	* (those ^@ are NUL bytes). fgets sees them as tons of empty lines. */
+	if (!line[0])
	return;
-	}
-	if (!has_inode)
-	sprintf(path, "%d", inode);

+	path_ofs = 0; /* paranoia */
+	num = sscanf(line, "%p: %lX %lX %lX %X %X %lu %n",
+	&d, &refcnt, &proto, &unix_flags, &type, &state, &inode, &path_ofs);
+	if (num < 7) {
+	bb_error_msg("got bogus unix line '%s'", line);
+	return;
+	}
	if ((flags & (NETSTAT_LISTENING\|NETSTAT_CONNECTED)) != (NETSTAT_LISTENING\|NETSTAT_CONNECTED)) {
	if ((state == SS_UNCONNECTED) && (unix_flags & SO_ACCEPTCON)) {
	if (!(flags & NETSTAT_LISTENING))
@@ -439,13 +445,9 @@ static void unix_do_one(int nr, const char *line)
	strcat(ss_flags, "N ");
	strcat(ss_flags, "]");

-	printf("%-5s %-6ld %-11s %-10s %-13s ",
-	ss_proto, refcnt, ss_flags, ss_type, ss_state);
-	if (has_inode)
-	printf("%-6d ", inode);
-	else
-	printf("- ");
-	puts(path);
+	printf("%-5s %-6ld %-11s %-10s %-13s %6lu %s\n",
+	ss_proto, refcnt, ss_flags, ss_type, ss_state, inode,
+	line + path_ofs);
	}

	#define _PATH_PROCNET_UDP "/proc/net/udp"
@@ -456,10 +458,11 @@ static void unix_do_one(int nr, const char *line)
	#define _PATH_PROCNET_RAW6 "/proc/net/raw6"
	#define _PATH_PROCNET_UNIX "/proc/net/unix"

-	static void do_info(const char file, const char name, void (proc)(int, const char ))
+	static void do_info(const char file, const char name, void (proc)(int, char ))
	{
-	int lnr = 0;
+	int lnr;
	FILE *procinfo;
+	char *buffer;

	procinfo = fopen(file, "r");
	if (procinfo == NULL) {
@@ -470,13 +473,14 @@ static void do_info(const char file, const char name, void (*proc)(int, const
	}
	return;
	}
+	lnr = 0;
	do {
-	char *buffer = xmalloc_fgets(procinfo);
+	buffer = xmalloc_fgets(procinfo);
	if (buffer) {
	(proc)(lnr++, buffer);
	free(buffer);
	}
-	} while (!feof(procinfo));
+	} while (buffer);
	fclose(procinfo);
	}