From 0cd83283dfd2a22b3f95cbee6eaef196e6bde77d Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Tue, 26 Sep 2017 16:56:19 -0700 Subject: [PATCH] connect: in ref advertisement, shallows are last Currently, get_remote_heads() parses the ref advertisement in one loop, allowing refs and shallow lines to intersperse, despite this not being allowed by the specification. Refactor get_remote_heads() to use two loops instead, enforcing that refs come first, and then shallows. This also makes it easier to teach get_remote_heads() to interpret other lines in the ref advertisement, which will be done in a subsequent patch. As part of this change, this patch interprets capabilities only on the first line in the ref advertisement, printing a warning message when encountering capabilities on other lines. Signed-off-by: Jonathan Tan Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano --- connect.c | 189 +++++++++++++++++++++++++++++++++++------------------- 1 file changed, 123 insertions(+), 66 deletions(-) diff --git a/connect.c b/connect.c index df56c0cbff..8e2e276b68 100644 --- a/connect.c +++ b/connect.c @@ -11,6 +11,7 @@ #include "string-list.h" #include "sha1-array.h" #include "transport.h" +#include "strbuf.h" static char *server_capabilities; static const char *parse_feature_value(const char *, const char *, int *); @@ -107,6 +108,104 @@ static void annotate_refs_with_symref_info(struct ref *ref) string_list_clear(&symref, 0); } +/* + * Read one line of a server's ref advertisement into packet_buffer. + */ +static int read_remote_ref(int in, char **src_buf, size_t *src_len, + int *responded) +{ + int len = packet_read(in, src_buf, src_len, + packet_buffer, sizeof(packet_buffer), + PACKET_READ_GENTLE_ON_EOF | + PACKET_READ_CHOMP_NEWLINE); + const char *arg; + if (len < 0) + die_initial_contact(*responded); + if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg)) + die("remote error: %s", arg); + + *responded = 1; + + return len; +} + +#define EXPECTING_FIRST_REF 0 +#define EXPECTING_REF 1 +#define EXPECTING_SHALLOW 2 + +static void process_capabilities(int *len) +{ + int nul_location = strlen(packet_buffer); + if (nul_location == *len) + return; + server_capabilities = xstrdup(packet_buffer + nul_location + 1); + *len = nul_location; +} + +static int process_dummy_ref(void) +{ + struct object_id oid; + const char *name; + + if (parse_oid_hex(packet_buffer, &oid, &name)) + return 0; + if (*name != ' ') + return 0; + name++; + + return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}"); +} + +static void check_no_capabilities(int len) +{ + if (strlen(packet_buffer) != len) + warning("Ignoring capabilities after first line '%s'", + packet_buffer + strlen(packet_buffer)); +} + +static int process_ref(int len, struct ref ***list, unsigned int flags, + struct oid_array *extra_have) +{ + struct object_id old_oid; + const char *name; + + if (parse_oid_hex(packet_buffer, &old_oid, &name)) + return 0; + if (*name != ' ') + return 0; + name++; + + if (extra_have && !strcmp(name, ".have")) { + oid_array_append(extra_have, &old_oid); + } else if (!strcmp(name, "capabilities^{}")) { + die("protocol error: unexpected capabilities^{}"); + } else if (check_ref(name, flags)) { + struct ref *ref = alloc_ref(name); + oidcpy(&ref->old_oid, &old_oid); + **list = ref; + *list = &ref->next; + } + check_no_capabilities(len); + return 1; +} + +static int process_shallow(int len, struct oid_array *shallow_points) +{ + const char *arg; + struct object_id old_oid; + + if (!skip_prefix(packet_buffer, "shallow ", &arg)) + return 0; + + if (get_oid_hex(arg, &old_oid)) + die("protocol error: expected shallow sha-1, got '%s'", arg); + if (!shallow_points) + die("repository on the other end cannot be shallow"); + oid_array_append(shallow_points, &old_oid); + check_no_capabilities(len); + return 1; +} + /* * Read all the refs from the other end */ @@ -123,76 +222,34 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len, * willing to talk to us. A hang-up before seeing any * response does not necessarily mean an ACL problem, though. */ - int saw_response; - int got_dummy_ref_with_capabilities_declaration = 0; + int responded = 0; + int len; + int state = EXPECTING_FIRST_REF; *list = NULL; - for (saw_response = 0; ; saw_response = 1) { - struct ref *ref; - struct object_id old_oid; - char *name; - int len, name_len; - char *buffer = packet_buffer; - const char *arg; - - len = packet_read(in, &src_buf, &src_len, - packet_buffer, sizeof(packet_buffer), - PACKET_READ_GENTLE_ON_EOF | - PACKET_READ_CHOMP_NEWLINE); - if (len < 0) - die_initial_contact(saw_response); - - if (!len) - break; - - if (len > 4 && skip_prefix(buffer, "ERR ", &arg)) - die("remote error: %s", arg); - - if (len == GIT_SHA1_HEXSZ + strlen("shallow ") && - skip_prefix(buffer, "shallow ", &arg)) { - if (get_oid_hex(arg, &old_oid)) - die("protocol error: expected shallow sha-1, got '%s'", arg); - if (!shallow_points) - die("repository on the other end cannot be shallow"); - oid_array_append(shallow_points, &old_oid); - continue; - } - if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) || - buffer[GIT_SHA1_HEXSZ] != ' ') - die("protocol error: expected sha/ref, got '%s'", buffer); - name = buffer + GIT_SHA1_HEXSZ + 1; - - name_len = strlen(name); - if (len != name_len + GIT_SHA1_HEXSZ + 1) { - free(server_capabilities); - server_capabilities = xstrdup(name + name_len + 1); - } - - if (extra_have && !strcmp(name, ".have")) { - oid_array_append(extra_have, &old_oid); - continue; - } - - if (!strcmp(name, "capabilities^{}")) { - if (saw_response) - die("protocol error: unexpected capabilities^{}"); - if (got_dummy_ref_with_capabilities_declaration) - die("protocol error: multiple capabilities^{}"); - got_dummy_ref_with_capabilities_declaration = 1; - continue; + while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) { + switch (state) { + case EXPECTING_FIRST_REF: + process_capabilities(&len); + if (process_dummy_ref()) { + state = EXPECTING_SHALLOW; + break; + } + state = EXPECTING_REF; + /* fallthrough */ + case EXPECTING_REF: + if (process_ref(len, &list, flags, extra_have)) + break; + state = EXPECTING_SHALLOW; + /* fallthrough */ + case EXPECTING_SHALLOW: + if (process_shallow(len, shallow_points)) + break; + die("protocol error: unexpected '%s'", packet_buffer); + default: + die("unexpected state %d", state); } - - if (!check_ref(name, flags)) - continue; - - if (got_dummy_ref_with_capabilities_declaration) - die("protocol error: unexpected ref after capabilities^{}"); - - ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1); - oidcpy(&ref->old_oid, &old_oid); - *list = ref; - list = &ref->next; } annotate_refs_with_symref_info(*orig_list); -- 2.47.1