sysctl: fix file parsing, do not require -w for VAR=VAL

function                                             old     new   delta
sysctl_act_on_setting                                  -     451    +451
sysctl_main                                          222     282     +60
packed_usage                                       31744   31793     +49
config_read                                          604     639     +35
sysctl_act_recursive                                 612     163    -449
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/1 up/down: 595/-449)          Total: 146 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 77 insertions, 32 deletions

diff --git a/libbb/parse_config.c b/libbb/parse_config.c
index 307ae2cd2..da7482c6d 100644
--- a/libbb/parse_config.c
+++ b/libbb/parse_config.c
@@ -201,10 +201,10 @@ int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const
 		/* Combine remaining arguments? */
 		if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
 			/* Vanilla token, find next delimiter */
-			line += strcspn(line, delims[0] ? delims : delims + 1);
+			line += strcspn(line, (delims[0] && (flags & PARSE_EOL_COMMENTS)) ? delims : delims + 1);
 		} else {
 			/* Combining, find comment char if any */
-			line = strchrnul(line, PARSE_EOL_COMMENTS ? delims[0] : '\0');
+			line = strchrnul(line, (flags & PARSE_EOL_COMMENTS) ? delims[0] : '\0');
 
 			/* Trim any extra delimiters from the end */
 			if (flags & PARSE_TRIM) {
@@ -214,10 +214,10 @@ int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const
 		}
 
 		/* Token not terminated? */
-		if (*line == delims[0])
-			*line = '\0';
+		if ((flags & PARSE_EOL_COMMENTS) && *line == delims[0])
+			*line = '\0'; /* ends with comment char: this line is done */
 		else if (*line != '\0')
-			*line++ = '\0';
+			*line++ = '\0'; /* token is done, continue parsing line */
 
 #if 0 /* unused so far */
 		if (flags & PARSE_ESCAPE) {
diff --git a/procps/sysctl.c b/procps/sysctl.c
index b17f5e896..619f4f1e4 100644
--- a/procps/sysctl.c
+++ b/procps/sysctl.c
@@ -21,17 +21,17 @@
 //kbuild:lib-$(CONFIG_BB_SYSCTL) += sysctl.o
 
 //usage:#define sysctl_trivial_usage
-//usage:       "[OPTIONS] [KEY[=VALUE]]..."
+//usage:       "-p [-enq] [FILE...] / [-enqaw] [KEY[=VALUE]]..."
 //usage:#define sysctl_full_usage "\n\n"
 //usage:       "Show/set kernel parameters\n"
+//usage:     "\n	-p	Set values from FILEs (default /etc/sysctl.conf)"
 //usage:     "\n	-e	Don't warn about unknown keys"
 //usage:     "\n	-n	Don't show key names"
+//usage:     "\n	-q      Quiet"
 //usage:     "\n	-a	Show all values"
 /* Same as -a, no need to show it */
 /* //usage:     "\n	-A	Show all values in table form" */
 //usage:     "\n	-w	Set values"
-//usage:     "\n	-p FILE	Set values from FILE (default /etc/sysctl.conf)"
-//usage:     "\n	-q      Set values silently"
 //usage:
 //usage:#define sysctl_example_usage
 //usage:       "sysctl [-n] [-e] variable...\n"
@@ -48,7 +48,7 @@ enum {
 	FLAG_TABLE_FORMAT    = 1 << 2, /* not implemented */
 	FLAG_SHOW_ALL        = 1 << 3,
 	FLAG_PRELOAD_FILE    = 1 << 4,
-/* TODO: procps 3.2.8 seems to not require -w for KEY=VAL to work: */
+	/* NB: procps 3.2.8 does not require -w for KEY=VAL to work, it only rejects non-KEY=VAL form */
 	FLAG_WRITE           = 1 << 5,
 	FLAG_QUIET           = 1 << 6,
 };
@@ -104,6 +104,7 @@ static int sysctl_act_on_setting(char *setting)
 	int fd, retval = EXIT_SUCCESS;
 	char *cptr, *outname;
 	char *value = value; /* for compiler */
+	bool writing = (option_mask32 & FLAG_WRITE);
 
 	outname = xstrdup(setting);
 
@@ -114,8 +115,10 @@ static int sysctl_act_on_setting(char *setting)
 		cptr++;
 	}
 
-	if (option_mask32 & FLAG_WRITE) {
-		cptr = strchr(setting, '=');
+	cptr = strchr(setting, '=');
+	if (cptr)
+		writing = 1;
+	if (writing) {
 		if (cptr == NULL) {
 			bb_error_msg("error: '%s' must be of the form name=value",
 				outname);
@@ -147,7 +150,7 @@ static int sysctl_act_on_setting(char *setting)
 			break;
 		default:
 			bb_perror_msg("error %sing key '%s'",
-					option_mask32 & FLAG_WRITE ?
+					writing ?
 						"sett" : "read",
 					outname);
 			break;
@@ -156,7 +159,7 @@ static int sysctl_act_on_setting(char *setting)
 		goto end;
 	}
 
-	if (option_mask32 & FLAG_WRITE) {
+	if (writing) {
 //TODO: procps 3.2.7 writes "value\n", note trailing "\n"
 		xwrite_str(fd, value);
 		close(fd);
@@ -238,22 +241,27 @@ static int sysctl_handle_preload_file(const char *filename)
 {
 	char *token[2];
 	parser_t *parser;
+	int parse_flags;
 
 	parser = config_open(filename);
 	/* Must do it _after_ config_open(): */
 	xchdir("/proc/sys");
-	/* xchroot("/proc/sys") - if you are paranoid */
 
 //TODO: ';' is comment char too
-//TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
-// (but _whitespace_ from ends should be trimmed first (and we do it right))
-//TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
-// can it be fixed by removing PARSE_COLLAPSE bit?
-	while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) {
+//TODO: <space><tab><space>#comment is also comment, not strictly 1st char only
+	parse_flags = 0;
+	parse_flags &= ~PARSE_COLLAPSE;   // NO (var==val is not var=val) - treat consecutive delimiters as one
+	parse_flags &= ~PARSE_TRIM;       // NO - trim leading and trailing delimiters
+	parse_flags |= PARSE_GREEDY;      // YES - last token takes entire remainder of the line
+	parse_flags &= ~PARSE_MIN_DIE;    // NO - die if < min tokens found
+	parse_flags &= ~PARSE_EOL_COMMENTS; // NO (only first char) - comments are recognized even if not first char
+	while (config_read(parser, token, 2, 2, "#=", parse_flags)) {
 		char *tp;
+		trim(token[0]);
+		trim(token[1]);
 		sysctl_dots_to_slashes(token[0]);
 		tp = xasprintf("%s=%s", token[0], token[1]);
-		sysctl_act_recursive(tp);
+		sysctl_act_on_setting(tp);
 		free(tp);
 	}
 	if (ENABLE_FEATURE_CLEAN_UP)
@@ -273,12 +281,19 @@ int sysctl_main(int argc UNUSED_PARAM, char **argv)
 	option_mask32 = opt;
 
 	if (opt & FLAG_PRELOAD_FILE) {
+		int cur_dir_fd;
 		option_mask32 |= FLAG_WRITE;
-		/* xchdir("/proc/sys") is inside */
-		return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf");
+		if (!*argv)
+			*--argv = (char*)"/etc/sysctl.conf";
+		cur_dir_fd = xopen(".", O_RDONLY | O_DIRECTORY);
+		do {
+			/* xchdir("/proc/sys") is inside */
+			sysctl_handle_preload_file(*argv);
+			xfchdir(cur_dir_fd); /* files can be relative, must restore cwd */
+		} while (*++argv);
+		return 0; /* procps-ng 3.3.10 does not flag parse errors */
 	}
 	xchdir("/proc/sys");
-	/* xchroot("/proc/sys") - if you are paranoid */
 	if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) {
 		return sysctl_act_recursive(".");
 	}
diff --git a/testsuite/mdev.tests b/testsuite/mdev.tests
index 8515aff31..8e53ec564 100755
--- a/testsuite/mdev.tests
+++ b/testsuite/mdev.tests
@@ -168,7 +168,7 @@ SKIP=
 # continuing to use directory structure from prev test
 rm -rf mdev.testdir/dev/*
 echo "sda 0:0 644 @echo @echo TEST" >mdev.testdir/etc/mdev.conf
-optional STATIC FEATURE_MDEV_CONF FEATURE_MDEV_EXEC FEATURE_LS_RECURSIVE FEATURE_LS_TIMESTAMPS FEATURE_LS_USERNAME FEATURE_SH_IS_ASH ASH_ECHO
+optional STATIC FEATURE_MDEV_CONF FEATURE_MDEV_EXEC FEATURE_LS_RECURSIVE FEATURE_LS_TIMESTAMPS FEATURE_LS_USERNAME SH_IS_ASH ASH_ECHO
 testing "mdev command" \
 	"env - PATH=$PATH ACTION=add DEVPATH=/block/sda chroot mdev.testdir /mdev 2>&1;
 	ls -lnR mdev.testdir/dev | $FILTER_LS" \
@@ -183,7 +183,7 @@ SKIP=
 # continuing to use directory structure from prev test
 rm -rf mdev.testdir/dev/*
 echo "sda 0:0 644 =block/ @echo @echo TEST:\$MDEV" >mdev.testdir/etc/mdev.conf
-optional STATIC FEATURE_MDEV_CONF FEATURE_MDEV_RENAME FEATURE_MDEV_EXEC FEATURE_LS_RECURSIVE FEATURE_LS_TIMESTAMPS FEATURE_LS_USERNAME FEATURE_SH_IS_ASH
+optional STATIC FEATURE_MDEV_CONF FEATURE_MDEV_RENAME FEATURE_MDEV_EXEC FEATURE_LS_RECURSIVE FEATURE_LS_TIMESTAMPS FEATURE_LS_USERNAME SH_IS_ASH
 testing "mdev move and command" \
 	"env - PATH=$PATH ACTION=add DEVPATH=/block/sda chroot mdev.testdir /mdev 2>&1;
 	ls -lnR mdev.testdir/dev | $FILTER_LS2" \
diff --git a/testsuite/parse.tests b/testsuite/parse.tests
index 904e1a17a..2cbed6f31 100755
--- a/testsuite/parse.tests
+++ b/testsuite/parse.tests
@@ -5,13 +5,13 @@
 
 . ./testing.sh
 
-COLLAPSE=$(( 0x00010000))
-TRIM=$((     0x00020000))
-GREEDY=$((   0x00040000))
-MIN_DIE=$((  0x00100000))
-KEEP_COPY=$((0x00200000))
-ESCAPE=$((   0x00400000))
-NORMAL=$((   COLLAPSE | TRIM | GREEDY))
+COLLAPSE=$((    0x00010000))
+TRIM=$((        0x00020000))
+GREEDY=$((      0x00040000))
+MIN_DIE=$((     0x00100000))
+KEEP_COPY=$((   0x00200000))
+EOL_COMMENTS=$((0x00400000))
+NORMAL=$((   COLLAPSE | TRIM | GREEDY | EOL_COMMENTS))
 
 # testing "description" "command" "result" "infile" "stdin"
 
@@ -27,6 +27,34 @@ testing "parse notrim" \
 	"-" \
 	" sda 0:0 644 @echo @echo TEST \n"
 
+testing "parse comments" \
+	"parse -n 4 -m 3 -f $((NORMAL - EOL_COMMENTS)) -" \
+	"[sda][0:0][644][@echo @echo TEST #this is not eaten]\n" \
+	"-" \
+	"\
+# sda 0:0 644 @echo @echo TEST - this gets eaten
+ sda 0:0 644 @echo @echo TEST #this is not eaten
+"
+
+testing "parse bad comment" \
+	"parse -n 2 -m 2 -d '#=' -f $((GREEDY)) - 2>&1" \
+	"\
+[var][val]
+parse: bad line 3: 1 tokens found, 2 needed
+[  #this][ok]
+[  #this][=ok]
+[  #this][=ok=ok=ok=]
+" \
+	"-" \
+	"\
+# this gets eaten
+var=val
+  #this causes error msg
+  #this=ok
+  #this==ok
+  #this==ok=ok=ok=
+"
+
 FILE=__parse
 cat >$FILE <<EOF
 #
@@ -96,6 +124,8 @@ cat >$FILE.res <<EOF
 [option][dns][129.219.13.81]
 [option][domain][local]
 [option][lease][864000]
+[option][msstaticroutes][10.0.0.0/8][10.127.0.1]
+[option][staticroutes][10.0.0.0/8][10.127.0.1,][10.11.12.0/24][10.11.12.1]
 [option][0x08][01020304]
 EOF