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Merge branch 'rs/daemon-hostname-in-strbuf'
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Code in "git daemon" to parse out and hold hostnames used in
request interpolation has been simplified.

* rs/daemon-hostname-in-strbuf:
  daemon: deglobalize hostname information
  daemon: use strbuf for hostname info
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Junio C Hamano committed Mar 20, 2015
2 parents 38f6ae9 + 01cec54 commit 89ebf97
Showing 1 changed file with 82 additions and 83 deletions.
165 changes: 82 additions & 83 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 char *hostname;
static char *canon_hostname;
static char *ip_address;
static char *tcp_port;

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;
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;
lookup_hostname(hi);
return hi->ip_address.buf;
}

static void logreport(int priority, const char *err, va_list params)
Expand Down Expand Up @@ -122,38 +121,34 @@ static void NORETURN daemon_die(const char *err, va_list params)
exit(1);
}

static void strbuf_addstr_or_null(struct strbuf *sb, const char *s)
{
if (s)
strbuf_addstr(sb, s);
}

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_addstr_or_null(sb, hostname);
strbuf_addbuf(sb, &hi->hostname);
return 1;
case 'C':
if (placeholder[1] == 'H') {
strbuf_addstr_or_null(sb, get_canon_hostname());
strbuf_addstr(sb, get_canon_hostname(hi));
return 2;
}
break;
case 'I':
if (placeholder[1] == 'P') {
strbuf_addstr_or_null(sb, get_ip_address());
strbuf_addstr(sb, get_ip_address(hi));
return 2;
}
break;
case 'P':
strbuf_addstr_or_null(sb, tcp_port);
strbuf_addbuf(sb, &hi->tcp_port);
return 1;
case 'D':
strbuf_addstr(sb, context->directory);
Expand All @@ -162,7 +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 @@ -198,11 +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 @@ -292,7 +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 @@ -301,16 +298,14 @@ static int run_access_hook(struct daemon_service *service, const char *dir, cons
char *eol;
int seen_errors = 0;

#define STRARG(x) ((x) ? (x) : "")
*arg++ = access_hook;
*arg++ = service->name;
*arg++ = path;
*arg++ = STRARG(hostname);
*arg++ = STRARG(get_canon_hostname());
*arg++ = STRARG(get_ip_address());
*arg++ = STRARG(tcp_port);
*arg++ = hi->hostname.buf;
*arg++ = get_canon_hostname(hi);
*arg++ = get_ip_address(hi);
*arg++ = hi->tcp_port.buf;
*arg = NULL;
#undef STRARG

child.use_shell = 1;
child.argv = argv;
Expand Down Expand Up @@ -354,7 +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 @@ -368,7 +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 @@ -404,7 +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 @@ -542,7 +538,7 @@ static void parse_host_and_port(char *hostport, char **host,
* trailing and leading dots, which means that the client cannot escape
* our base path via ".." traversal.
*/
static void sanitize_client_strbuf(struct strbuf *out, const char *in)
static void sanitize_client(struct strbuf *out, const char *in)
{
for (; *in; in++) {
if (*in == '/')
Expand All @@ -556,36 +552,27 @@ static void sanitize_client_strbuf(struct strbuf *out, const char *in)
strbuf_setlen(out, out->len - 1);
}

static char *sanitize_client(const char *in)
{
struct strbuf out = STRBUF_INIT;
sanitize_client_strbuf(&out, in);
return strbuf_detach(&out, NULL);
}

/*
* Like sanitize_client, but we also perform any canonicalization
* to make life easier on the admin.
*/
static char *canonicalize_client(const char *in)
static void canonicalize_client(struct strbuf *out, const char *in)
{
struct strbuf out = STRBUF_INIT;
sanitize_client_strbuf(&out, in);
strbuf_tolower(&out);
return strbuf_detach(&out, NULL);
sanitize_client(out, in);
strbuf_tolower(out);
}

/*
* 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 @@ -594,13 +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) {
free(tcp_port);
tcp_port = sanitize_client(port);
}
free(hostname);
hostname = canonicalize_client(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 @@ -614,9 +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) {
if (!hi->hostname_lookup_done && hi->hostname.len) {
#ifndef NO_IPV6
struct addrinfo hints;
struct addrinfo *ai;
Expand All @@ -626,19 +610,20 @@ static void lookup_hostname(void)
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME;

gai = getaddrinfo(hostname, 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));
free(ip_address);
ip_address = xstrdup(addrbuf);
strbuf_addstr(&hi->ip_address, addrbuf);

free(canon_hostname);
canon_hostname = ai->ai_canonname ?
sanitize_client(ai->ai_canonname) :
xstrdup(ip_address);
if (ai->ai_canonname)
sanitize_client(&hi->canon_hostname,
ai->ai_canonname);
else
strbuf_addbuf(&hi->canon_hostname,
&hi->ip_address);

freeaddrinfo(ai);
}
Expand All @@ -648,7 +633,7 @@ static void lookup_hostname(void)
char **ap;
static char addrbuf[HOST_NAME_MAX + 1];

hent = gethostbyname(hostname);
hent = gethostbyname(hostname.buf);
if (hent) {
ap = hent->h_addr_list;
memset(&sa, 0, sizeof sa);
Expand All @@ -659,22 +644,39 @@ static void lookup_hostname(void)
inet_ntop(hent->h_addrtype, &sa.sin_addr,
addrbuf, sizeof(addrbuf));

free(canon_hostname);
canon_hostname = sanitize_client(hent->h_name);
free(ip_address);
ip_address = xstrdup(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 @@ -693,14 +695,8 @@ static int execute(void)
pktlen--;
}

free(hostname);
free(canon_hostname);
free(ip_address);
free(tcp_port);
hostname = canon_hostname = ip_address = tcp_port = NULL;

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 @@ -713,10 +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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