Fix xmalloc_fgets_str so that it really does NOT strip terminator.

Add xmalloc_fgetline_str which does strip terminator,
and use it in dpkg instead of xmalloc_fgets_str.
netstat: use xmalloc_fgets_str - allows to eat strings with NULs
(this fixes bug with some weird /proc/net/unix input)

function                                             old     new   delta
xmalloc_fgets_internal                                 -     191    +191
xmalloc_fgetline_str                                   -      18     +18
do_info                                              116     120      +4
unix_do_one                                          451     447      -4
tcp_do_one                                           423     419      -4
send_tree                                            369     365      -4
xmalloc_fgets_str                                    178      15    -163
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 1/4 up/down: 213/-175)           Total: 38 bytes
   text    data     bss     dec     hex filename
 778445     832    7344  786621   c00bd busybox_old
 778483     832    7344  786659   c00e3 busybox_unstripped

archival/dpkg.c

@@ -602,7 +602,7 @@ static unsigned fill_package_struct(char *control_buffer)
 				&field_name, &field_value);
 
 		if (field_name == NULL) {
-			goto fill_package_struct_cleanup; /* Oh no, the dreaded goto statement! */
+			goto fill_package_struct_cleanup;
 		}
 
 		field_num = index_in_strings(field_names, field_name);
@@ -745,7 +745,7 @@ static void index_status_file(const char *filename)
 	unsigned status_num;
 
 	status_file = xfopen(filename, "r");
-	while ((control_buffer = xmalloc_fgets_str(status_file, "\n\n")) != NULL) {
+	while ((control_buffer = xmalloc_fgetline_str(status_file, "\n\n")) != NULL) {
 		const unsigned package_num = fill_package_struct(control_buffer);
 		if (package_num != -1) {
 			status_node = xmalloc(sizeof(status_node_t));
@@ -798,7 +798,7 @@ static void write_status_file(deb_file_t **deb_file)
 	int i = 0;
 
 	/* Update previously known packages */
-	while ((control_buffer = xmalloc_fgets_str(old_status_file, "\n\n")) != NULL) {
+	while ((control_buffer = xmalloc_fgetline_str(old_status_file, "\n\n")) != NULL) {
 		tmp_string = strstr(control_buffer, "Package:");
 		if (tmp_string == NULL) {
 			continue;

include/libbb.h

@@ -464,9 +464,12 @@ extern void xwrite(int fd, const void *buf, size_t count);
 
 /* Reads and prints to stdout till eof, then closes FILE. Exits on error: */
 extern void xprint_and_close_file(FILE *file);
-extern char *xmalloc_fgets(FILE *file);
+/* Reads up to (and including) TERMINATING_STRING: */
-/* Read up to (and including) TERMINATING_STRING: */
 extern char *xmalloc_fgets_str(FILE *file, const char *terminating_string);
+/* Chops off TERMINATING_STRING: from the end: */
+extern char *xmalloc_fgetline_str(FILE *file, const char *terminating_string);
+/* Reads up to (and including) "\n" or NUL byte */
+extern char *xmalloc_fgets(FILE *file);
 /* Chops off '\n' from the end, unlike fgets: */
 extern char *xmalloc_getline(FILE *file);
 extern char *bb_get_chunk_from_file(FILE *file, int *end);

libbb/fgets_str.c

@@ -10,10 +10,7 @@
 
 #include "libbb.h"
 
-/* Read up to (and including) TERMINATING_STRING from FILE and return it.
+static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string, int chop_off)
- * Return NULL on EOF.  */
-
-char *xmalloc_fgets_str(FILE *file, const char *terminating_string)
 {
 	char *linebuf = NULL;
 	const int term_length = strlen(terminating_string);
@@ -25,12 +22,12 @@ char *xmalloc_fgets_str(FILE *file, const char *terminating_string)
 	while (1) {
 		ch = fgetc(file);
 		if (ch == EOF) {
-			free(linebuf);
+			if (idx == 0)
-			return NULL;
+				return linebuf; /* NULL */
+			break;
 		}
 
-		/* grow the line buffer as necessary */
+		if (idx >= linebufsz) {
-		while (idx > linebufsz - 2) {
 			linebufsz += 200;
 			linebuf = xrealloc(linebuf, linebufsz);
 		}
@@ -40,14 +37,30 @@ char *xmalloc_fgets_str(FILE *file, const char *terminating_string)
 
 		/* Check for terminating string */
 		end_string_offset = idx - term_length;
-		if (end_string_offset > 0
+		if (end_string_offset >= 0
 		 && memcmp(&linebuf[end_string_offset], terminating_string, term_length) == 0
 		) {
-			idx -= term_length;
+			if (chop_off)
+				idx -= term_length;
 			break;
 		}
 	}
+	/* Grow/shrink *first*, then store NUL */
 	linebuf = xrealloc(linebuf, idx + 1);
 	linebuf[idx] = '\0';
 	return linebuf;
 }
+
+/* Read up to TERMINATING_STRING from FILE and return it,
+ * including terminating string.
+ * Non-terminated string can be returned if EOF is reached.
+ * Return NULL if EOF is reached immediately.  */
+char *xmalloc_fgets_str(FILE *file, const char *terminating_string)
+{
+	return xmalloc_fgets_internal(file, terminating_string, 0);
+}
+
+char *xmalloc_fgetline_str(FILE *file, const char *terminating_string)
+{
+	return xmalloc_fgets_internal(file, terminating_string, 1);
+}

libbb/get_line_from_file.c

@@ -12,11 +12,10 @@
 #include "libbb.h"
 
 /* This function reads an entire line from a text file, up to a newline
- * or NUL byte, inclusive.  It returns a malloc'ed char * which must be
+ * or NUL byte, inclusive.  It returns a malloc'ed char * which
- * stored and free'ed by the caller.  If end is NULL '\n' isn't considered
+ * must be free'ed by the caller.  If end is NULL '\n' isn't considered
  * end of line.  If end isn't NULL, length of the chunk read is stored in it.
  * Return NULL if EOF/error */
-
 char *bb_get_chunk_from_file(FILE *file, int *end)
 {
 	int ch;

networking/netstat.c

@@ -170,6 +170,11 @@ static void tcp_do_one(int lnr, char *line)
 			rem_addr, &rem_port, &state,
 			&txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);
 
+	if (num < 10) {
+		bb_error_msg("warning, got bogus tcp line");
+		return;
+	}
+
 	if (strlen(local_addr) > 8) {
 #if ENABLE_FEATURE_IPV6
 		build_ipv6_addr(local_addr, &localaddr);
@@ -180,11 +185,6 @@ static void tcp_do_one(int lnr, char *line)
 		build_ipv4_addr(rem_addr, &remaddr);
 	}
 
-	if (num < 10) {
-		bb_error_msg("warning, got bogus tcp line");
-		return;
-	}
-
 	if ((rem_port && (flags & NETSTAT_CONNECTED))
 	 || (!rem_port && (flags & NETSTAT_LISTENING))
 	) {
@@ -349,17 +349,16 @@ static void unix_do_one(int nr, char *line)
 	const char *ss_proto, *ss_state, *ss_type;
 	char ss_flags[32];
 
+	/* TODO: currently we stop at first NUL byte. Is it a problem? */
+
 	if (nr == 0)
 		return; /* skip header */
 
-	{
+	*strchrnul(line, '\n') = '\0';
-		char *last = last_char_is(line, '\n');
-		if (last)
-			*last = '\0';
-	}
 
 	/* 2.6.15 may report lines like "... @/tmp/fam-user-^@^@^@^@^@^@^@..."
-	 * (those ^@ are NUL bytes). fgets sees them as tons of empty lines. */
+	 * Other users report long lines filled by NUL bytes. 
+	 * (those ^@ are NUL bytes too). We see them as empty lines. */
 	if (!line[0])
 		return;
 
@@ -474,20 +473,14 @@ static void do_info(const char *file, const char *name, void (*proc)(int, char *
 		return;
 	}
 	lnr = 0;
-	do {
+	/* Why? because xmalloc_fgets_str doesn't stop on NULs */
-		buffer = xmalloc_fgets(procinfo);
+	while ((buffer = xmalloc_fgets_str(procinfo, "\n")) != NULL) {
-		if (buffer) {
+		(proc)(lnr++, buffer);
-			(proc)(lnr++, buffer);
+		free(buffer);
-			free(buffer);
+	}
-		}
-	} while (buffer);
 	fclose(procinfo);
 }
 
-/*
- * Our main function.
- */
-
 int netstat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int netstat_main(int argc, char **argv)
 {