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daemon: deglobalize hostname information
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Move the variables related to the client-supplied hostname into its own
struct, let execute() own an instance of that instead of storing the
information in global variables and pass the struct to any function that
needs to access it as a parameter.

The lifetime of the variables is easier to see this way.  Allocated
memory is released within execute().  The strbufs don't have to be reset
anymore because they are written to only once at most: parse_host_arg()
is only called once by execute() and lookup_hostname() guards against
being called twice using hostname_lookup_done.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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René Scharfe authored and Junio C Hamano committed Mar 10, 2015
1 parent 7a646ce commit 01cec54
Showing 1 changed file with 74 additions and 59 deletions.
133 changes: 74 additions & 59 deletions daemon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -43,9 +43,6 @@ static const char *base_path;
static const char *interpolated_path;
static int base_path_relaxed;

/* Flag indicating client sent extra args. */
static int saw_extended_args;

/* If defined, ~user notation is allowed and the string is inserted
* after ~user/. E.g. a request to git://host/~alice/frotz would
* go to /home/alice/pub_git/frotz with --user-path=pub_git.
Expand All @@ -56,25 +53,27 @@ static const char *user_path;
static unsigned int timeout;
static unsigned int init_timeout;

static struct strbuf hostname = STRBUF_INIT;
static struct strbuf canon_hostname = STRBUF_INIT;
static struct strbuf ip_address = STRBUF_INIT;
static struct strbuf tcp_port = STRBUF_INIT;

static int hostname_lookup_done;
struct hostinfo {
struct strbuf hostname;
struct strbuf canon_hostname;
struct strbuf ip_address;
struct strbuf tcp_port;
unsigned int hostname_lookup_done:1;
unsigned int saw_extended_args:1;
};

static void lookup_hostname(void);
static void lookup_hostname(struct hostinfo *hi);

static const char *get_canon_hostname(void)
static const char *get_canon_hostname(struct hostinfo *hi)
{
lookup_hostname();
return canon_hostname.buf;
lookup_hostname(hi);
return hi->canon_hostname.buf;
}

static const char *get_ip_address(void)
static const char *get_ip_address(struct hostinfo *hi)
{
lookup_hostname();
return ip_address.buf;
lookup_hostname(hi);
return hi->ip_address.buf;
}

static void logreport(int priority, const char *err, va_list params)
Expand Down Expand Up @@ -124,30 +123,32 @@ static void NORETURN daemon_die(const char *err, va_list params)

struct expand_path_context {
const char *directory;
struct hostinfo *hostinfo;
};

static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
{
struct expand_path_context *context = ctx;
struct hostinfo *hi = context->hostinfo;

switch (placeholder[0]) {
case 'H':
strbuf_addbuf(sb, &hostname);
strbuf_addbuf(sb, &hi->hostname);
return 1;
case 'C':
if (placeholder[1] == 'H') {
strbuf_addstr(sb, get_canon_hostname());
strbuf_addstr(sb, get_canon_hostname(hi));
return 2;
}
break;
case 'I':
if (placeholder[1] == 'P') {
strbuf_addstr(sb, get_ip_address());
strbuf_addstr(sb, get_ip_address(hi));
return 2;
}
break;
case 'P':
strbuf_addbuf(sb, &tcp_port);
strbuf_addbuf(sb, &hi->tcp_port);
return 1;
case 'D':
strbuf_addstr(sb, context->directory);
Expand All @@ -156,7 +157,7 @@ static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
return 0;
}

static const char *path_ok(const char *directory)
static const char *path_ok(const char *directory, struct hostinfo *hi)
{
static char rpath[PATH_MAX];
static char interp_path[PATH_MAX];
Expand Down Expand Up @@ -192,11 +193,12 @@ static const char *path_ok(const char *directory)
dir = rpath;
}
}
else if (interpolated_path && saw_extended_args) {
else if (interpolated_path && hi->saw_extended_args) {
struct strbuf expanded_path = STRBUF_INIT;
struct expand_path_context context;

context.directory = directory;
context.hostinfo = hi;

if (*dir != '/') {
/* Allow only absolute */
Expand Down Expand Up @@ -286,7 +288,8 @@ static int daemon_error(const char *dir, const char *msg)

static const char *access_hook;

static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
static int run_access_hook(struct daemon_service *service, const char *dir,
const char *path, struct hostinfo *hi)
{
struct child_process child = CHILD_PROCESS_INIT;
struct strbuf buf = STRBUF_INIT;
Expand All @@ -298,10 +301,10 @@ static int run_access_hook(struct daemon_service *service, const char *dir, cons
*arg++ = access_hook;
*arg++ = service->name;
*arg++ = path;
*arg++ = hostname.buf;
*arg++ = get_canon_hostname();
*arg++ = get_ip_address();
*arg++ = tcp_port.buf;
*arg++ = hi->hostname.buf;
*arg++ = get_canon_hostname(hi);
*arg++ = get_ip_address(hi);
*arg++ = hi->tcp_port.buf;
*arg = NULL;

child.use_shell = 1;
Expand Down Expand Up @@ -346,7 +349,8 @@ static int run_access_hook(struct daemon_service *service, const char *dir, cons
return -1;
}

static int run_service(const char *dir, struct daemon_service *service)
static int run_service(const char *dir, struct daemon_service *service,
struct hostinfo *hi)
{
const char *path;
int enabled = service->enabled;
Expand All @@ -360,7 +364,7 @@ static int run_service(const char *dir, struct daemon_service *service)
return daemon_error(dir, "service not enabled");
}

if (!(path = path_ok(dir)))
if (!(path = path_ok(dir, hi)))
return daemon_error(dir, "no such repository");

/*
Expand Down Expand Up @@ -396,7 +400,7 @@ static int run_service(const char *dir, struct daemon_service *service)
* Optionally, a hook can choose to deny access to the
* repository depending on the phase of the moon.
*/
if (access_hook && run_access_hook(service, dir, path))
if (access_hook && run_access_hook(service, dir, path, hi))
return -1;

/*
Expand Down Expand Up @@ -561,14 +565,14 @@ static void canonicalize_client(struct strbuf *out, const char *in)
/*
* Read the host as supplied by the client connection.
*/
static void parse_host_arg(char *extra_args, int buflen)
static void parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
{
char *val;
int vallen;
char *end = extra_args + buflen;

if (extra_args < end && *extra_args) {
saw_extended_args = 1;
hi->saw_extended_args = 1;
if (strncasecmp("host=", extra_args, 5) == 0) {
val = extra_args + 5;
vallen = strlen(val) + 1;
Expand All @@ -577,13 +581,10 @@ static void parse_host_arg(char *extra_args, int buflen)
char *host;
char *port;
parse_host_and_port(val, &host, &port);
if (port) {
strbuf_reset(&tcp_port);
sanitize_client(&tcp_port, port);
}
strbuf_reset(&hostname);
canonicalize_client(&hostname, host);
hostname_lookup_done = 0;
if (port)
sanitize_client(&hi->tcp_port, port);
canonicalize_client(&hi->hostname, host);
hi->hostname_lookup_done = 0;
}

/* On to the next one */
Expand All @@ -597,9 +598,9 @@ static void parse_host_arg(char *extra_args, int buflen)
/*
* Locate canonical hostname and its IP address.
*/
static void lookup_hostname(void)
static void lookup_hostname(struct hostinfo *hi)
{
if (!hostname_lookup_done && hostname.len) {
if (!hi->hostname_lookup_done && hi->hostname.len) {
#ifndef NO_IPV6
struct addrinfo hints;
struct addrinfo *ai;
Expand All @@ -609,21 +610,20 @@ static void lookup_hostname(void)
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME;

gai = getaddrinfo(hostname.buf, NULL, &hints, &ai);
gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
if (!gai) {
struct sockaddr_in *sin_addr = (void *)ai->ai_addr;

inet_ntop(AF_INET, &sin_addr->sin_addr,
addrbuf, sizeof(addrbuf));
strbuf_reset(&ip_address);
strbuf_addstr(&ip_address, addrbuf);
strbuf_addstr(&hi->ip_address, addrbuf);

strbuf_reset(&canon_hostname);
if (ai->ai_canonname)
sanitize_client(&canon_hostname,
sanitize_client(&hi->canon_hostname,
ai->ai_canonname);
else
strbuf_addbuf(&canon_hostname, &ip_address);
strbuf_addbuf(&hi->canon_hostname,
&hi->ip_address);

freeaddrinfo(ai);
}
Expand All @@ -644,22 +644,39 @@ static void lookup_hostname(void)
inet_ntop(hent->h_addrtype, &sa.sin_addr,
addrbuf, sizeof(addrbuf));

strbuf_reset(&canon_hostname);
sanitize_client(&canon_hostname, hent->h_name);
strbuf_reset(&ip_address);
strbuf_addstr(&ip_address, addrbuf);
sanitize_client(&hi->canon_hostname, hent->h_name);
strbuf_addstr(&hi->ip_address, addrbuf);
}
#endif
hostname_lookup_done = 1;
hi->hostname_lookup_done = 1;
}
}

static void hostinfo_init(struct hostinfo *hi)
{
memset(hi, 0, sizeof(*hi));
strbuf_init(&hi->hostname, 0);
strbuf_init(&hi->canon_hostname, 0);
strbuf_init(&hi->ip_address, 0);
strbuf_init(&hi->tcp_port, 0);
}

static void hostinfo_clear(struct hostinfo *hi)
{
strbuf_release(&hi->hostname);
strbuf_release(&hi->canon_hostname);
strbuf_release(&hi->ip_address);
strbuf_release(&hi->tcp_port);
}

static int execute(void)
{
char *line = packet_buffer;
int pktlen, len, i;
char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
struct hostinfo hi;

hostinfo_init(&hi);

if (addr)
loginfo("Connection from %s:%s", addr, port);
Expand All @@ -678,13 +695,8 @@ static int execute(void)
pktlen--;
}

strbuf_release(&hostname);
strbuf_release(&canon_hostname);
strbuf_release(&ip_address);
strbuf_release(&tcp_port);

if (len != pktlen)
parse_host_arg(line + len + 1, pktlen - len - 1);
parse_host_arg(&hi, line + len + 1, pktlen - len - 1);

for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
struct daemon_service *s = &(daemon_service[i]);
Expand All @@ -697,10 +709,13 @@ static int execute(void)
* Note: The directory here is probably context sensitive,
* and might depend on the actual service being performed.
*/
return run_service(arg, s);
int rc = run_service(arg, s, &hi);
hostinfo_clear(&hi);
return rc;
}
}

hostinfo_clear(&hi);
logerror("Protocol error: '%s'", line);
return -1;
}
Expand Down

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