[PATCH v3 19/27] remote-curl: avoid assigning string constant to non-const variable

[Patrick Steinhardt <ps@pks.im>]

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When processing remote options, we split the option line into two by
searching for a space. If there is one, we replace the space with '\0',
otherwise we implicitly assume that the value is "true" and thus assign
a string constant.

As the return value of strchr(3P) weirdly enough is a `char *` even
though it gets a `const char *` as input, the assigned-to variable also
is a non-constant. This is fine though because the argument is in fact
an allocated string, and thus we are allowed to modify it. But this will
break once we enable `-Wwrite-strings`.

Refactor the code stop splitting the fields with '\0' altogether.
Instead, we can pass the length of the option name to `set_option()` and
then use strncmp(3P) instead of strcmp(3P).

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 remote-curl.c | 53 ++++++++++++++++++++++++++-------------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/remote-curl.c b/remote-curl.c
index cae98384da..d0f767df8e 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -58,9 +58,9 @@ struct options {
 static struct options options;
 static struct string_list cas_options = STRING_LIST_INIT_DUP;
 
-static int set_option(const char *name, const char *value)
+static int set_option(const char *name, size_t namelen, const char *value)
 {
-	if (!strcmp(name, "verbosity")) {
+	if (!strncmp(name, "verbosity", namelen)) {
 		char *end;
 		int v = strtol(value, &end, 10);
 		if (value == end || *end)
@@ -68,7 +68,7 @@ static int set_option(const char *name, const char *value)
 		options.verbosity = v;
 		return 0;
 	}
-	else if (!strcmp(name, "progress")) {
+	else if (!strncmp(name, "progress", namelen)) {
 		if (!strcmp(value, "true"))
 			options.progress = 1;
 		else if (!strcmp(value, "false"))
@@ -77,7 +77,7 @@ static int set_option(const char *name, const char *value)
 			return -1;
 		return 0;
 	}
-	else if (!strcmp(name, "depth")) {
+	else if (!strncmp(name, "depth", namelen)) {
 		char *end;
 		unsigned long v = strtoul(value, &end, 10);
 		if (value == end || *end)
@@ -85,15 +85,15 @@ static int set_option(const char *name, const char *value)
 		options.depth = v;
 		return 0;
 	}
-	else if (!strcmp(name, "deepen-since")) {
+	else if (!strncmp(name, "deepen-since", namelen)) {
 		options.deepen_since = xstrdup(value);
 		return 0;
 	}
-	else if (!strcmp(name, "deepen-not")) {
+	else if (!strncmp(name, "deepen-not", namelen)) {
 		string_list_append(&options.deepen_not, value);
 		return 0;
 	}
-	else if (!strcmp(name, "deepen-relative")) {
+	else if (!strncmp(name, "deepen-relative", namelen)) {
 		if (!strcmp(value, "true"))
 			options.deepen_relative = 1;
 		else if (!strcmp(value, "false"))
@@ -102,7 +102,7 @@ static int set_option(const char *name, const char *value)
 			return -1;
 		return 0;
 	}
-	else if (!strcmp(name, "followtags")) {
+	else if (!strncmp(name, "followtags", namelen)) {
 		if (!strcmp(value, "true"))
 			options.followtags = 1;
 		else if (!strcmp(value, "false"))
@@ -111,7 +111,7 @@ static int set_option(const char *name, const char *value)
 			return -1;
 		return 0;
 	}
-	else if (!strcmp(name, "dry-run")) {
+	else if (!strncmp(name, "dry-run", namelen)) {
 		if (!strcmp(value, "true"))
 			options.dry_run = 1;
 		else if (!strcmp(value, "false"))
@@ -120,7 +120,7 @@ static int set_option(const char *name, const char *value)
 			return -1;
 		return 0;
 	}
-	else if (!strcmp(name, "check-connectivity")) {
+	else if (!strncmp(name, "check-connectivity", namelen)) {
 		if (!strcmp(value, "true"))
 			options.check_self_contained_and_connected = 1;
 		else if (!strcmp(value, "false"))
@@ -129,7 +129,7 @@ static int set_option(const char *name, const char *value)
 			return -1;
 		return 0;
 	}
-	else if (!strcmp(name, "cas")) {
+	else if (!strncmp(name, "cas", namelen)) {
 		struct strbuf val = STRBUF_INIT;
 		strbuf_addstr(&val, "--force-with-lease=");
 		if (*value != '"')
@@ -139,7 +139,7 @@ static int set_option(const char *name, const char *value)
 		string_list_append(&cas_options, val.buf);
 		strbuf_release(&val);
 		return 0;
-	} else if (!strcmp(name, TRANS_OPT_FORCE_IF_INCLUDES)) {
+	} else if (!strncmp(name, TRANS_OPT_FORCE_IF_INCLUDES, namelen)) {
 		if (!strcmp(value, "true"))
 			options.force_if_includes = 1;
 		else if (!strcmp(value, "false"))
@@ -147,7 +147,7 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "cloning")) {
+	} else if (!strncmp(name, "cloning", namelen)) {
 		if (!strcmp(value, "true"))
 			options.cloning = 1;
 		else if (!strcmp(value, "false"))
@@ -155,7 +155,7 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "update-shallow")) {
+	} else if (!strncmp(name, "update-shallow", namelen)) {
 		if (!strcmp(value, "true"))
 			options.update_shallow = 1;
 		else if (!strcmp(value, "false"))
@@ -163,7 +163,7 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "pushcert")) {
+	} else if (!strncmp(name, "pushcert", namelen)) {
 		if (!strcmp(value, "true"))
 			options.push_cert = SEND_PACK_PUSH_CERT_ALWAYS;
 		else if (!strcmp(value, "false"))
@@ -173,7 +173,7 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "atomic")) {
+	} else if (!strncmp(name, "atomic", namelen)) {
 		if (!strcmp(value, "true"))
 			options.atomic = 1;
 		else if (!strcmp(value, "false"))
@@ -181,7 +181,7 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "push-option")) {
+	} else if (!strncmp(name, "push-option", namelen)) {
 		if (*value != '"')
 			string_list_append(&options.push_options, value);
 		else {
@@ -192,7 +192,7 @@ static int set_option(const char *name, const char *value)
 						 strbuf_detach(&unquoted, NULL));
 		}
 		return 0;
-	} else if (!strcmp(name, "family")) {
+	} else if (!strncmp(name, "family", namelen)) {
 		if (!strcmp(value, "ipv4"))
 			git_curl_ipresolve = CURL_IPRESOLVE_V4;
 		else if (!strcmp(value, "ipv6"))
@@ -202,16 +202,16 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
-	} else if (!strcmp(name, "from-promisor")) {
+	} else if (!strncmp(name, "from-promisor", namelen)) {
 		options.from_promisor = 1;
 		return 0;
-	} else if (!strcmp(name, "refetch")) {
+	} else if (!strncmp(name, "refetch", namelen)) {
 		options.refetch = 1;
 		return 0;
-	} else if (!strcmp(name, "filter")) {
+	} else if (!strncmp(name, "filter", namelen)) {
 		options.filter = xstrdup(value);
 		return 0;
-	} else if (!strcmp(name, "object-format")) {
+	} else if (!strncmp(name, "object-format", namelen)) {
 		options.object_format = 1;
 		if (strcmp(value, "true"))
 			die(_("unknown value for object-format: %s"), value);
@@ -1588,15 +1588,16 @@ int cmd_main(int argc, const char **argv)
 			parse_push(&buf);
 
 		} else if (skip_prefix(buf.buf, "option ", &arg)) {
-			char *value = strchr(arg, ' ');
+			const char *value = strchrnul(arg, ' ');
+			size_t arglen = value - arg;
 			int result;
 
-			if (value)
-				*value++ = '\0';
+			if (*value)
+				value++; /* skip over SP */
 			else
 				value = "true";
 
-			result = set_option(arg, value);
+			result = set_option(arg, arglen, value);
 			if (!result)
 				printf("ok\n");
 			else if (result < 0)
-- 
2.45.1.410.g58bac47f8e.dirty


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