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![Shawn O. Pearce](/assets/img/avatar_default.png)
If stdout has already been closed by the CGI and die() gets called, the CGI will fail to write the "Status: 500 Internal Server Error" to the pipe, which results in die() being called again (via safe_write). This goes on in an infinite loop until the stack overflows and the process is killed by SIGSEGV. Instead set a flag on the first die() invocation and if we came back to the handler, just die silently, as it only means we failed to report the failure---we cannot report anything anyway in such a case. This way failures to write the error messages to the stdout pipe do not result in an infinite loop. We also now report on the death to stderr before we report to stdout, to increase the chances that the cause of the die() invocation will appear in the server's error log. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com> fixup! http-backend.c: Don't infinite loop Now die_webcgi() actually can return during a recursive call into it, causing http-backend.c:554: error: 'noreturn' function does return The only reason we would come back to the die handler is because we failed during it, so we cannot report anything anyway. Signed-off-by: Junio C Hamano <gitster@pobox.com>
663 lines
14 KiB
C
663 lines
14 KiB
C
#include "cache.h"
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#include "refs.h"
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#include "pkt-line.h"
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#include "object.h"
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#include "tag.h"
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#include "exec_cmd.h"
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#include "run-command.h"
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#include "string-list.h"
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static const char content_type[] = "Content-Type";
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static const char content_length[] = "Content-Length";
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static const char last_modified[] = "Last-Modified";
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static int getanyfile = 1;
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static struct string_list *query_params;
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struct rpc_service {
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const char *name;
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const char *config_name;
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signed enabled : 2;
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};
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static struct rpc_service rpc_service[] = {
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{ "upload-pack", "uploadpack", 1 },
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{ "receive-pack", "receivepack", -1 },
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};
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static int decode_char(const char *q)
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{
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int i;
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unsigned char val = 0;
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for (i = 0; i < 2; i++) {
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unsigned char c = *q++;
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val <<= 4;
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if (c >= '0' && c <= '9')
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val += c - '0';
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else if (c >= 'a' && c <= 'f')
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val += c - 'a' + 10;
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else if (c >= 'A' && c <= 'F')
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val += c - 'A' + 10;
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else
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return -1;
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}
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return val;
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}
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static char *decode_parameter(const char **query, int is_name)
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{
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const char *q = *query;
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struct strbuf out;
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strbuf_init(&out, 16);
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do {
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unsigned char c = *q;
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if (!c)
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break;
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if (c == '&' || (is_name && c == '=')) {
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q++;
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break;
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}
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if (c == '%') {
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int val = decode_char(q + 1);
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if (0 <= val) {
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strbuf_addch(&out, val);
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q += 3;
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continue;
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}
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}
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if (c == '+')
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strbuf_addch(&out, ' ');
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else
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strbuf_addch(&out, c);
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q++;
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} while (1);
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*query = q;
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return strbuf_detach(&out, NULL);
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}
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static struct string_list *get_parameters(void)
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{
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if (!query_params) {
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const char *query = getenv("QUERY_STRING");
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query_params = xcalloc(1, sizeof(*query_params));
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while (query && *query) {
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char *name = decode_parameter(&query, 1);
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char *value = decode_parameter(&query, 0);
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struct string_list_item *i;
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i = string_list_lookup(name, query_params);
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if (!i)
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i = string_list_insert(name, query_params);
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else
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free(i->util);
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i->util = value;
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}
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}
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return query_params;
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}
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static const char *get_parameter(const char *name)
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{
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struct string_list_item *i;
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i = string_list_lookup(name, get_parameters());
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return i ? i->util : NULL;
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}
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__attribute__((format (printf, 2, 3)))
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static void format_write(int fd, const char *fmt, ...)
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{
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static char buffer[1024];
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va_list args;
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unsigned n;
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va_start(args, fmt);
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n = vsnprintf(buffer, sizeof(buffer), fmt, args);
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va_end(args);
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if (n >= sizeof(buffer))
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die("protocol error: impossibly long line");
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safe_write(fd, buffer, n);
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}
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static void http_status(unsigned code, const char *msg)
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{
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format_write(1, "Status: %u %s\r\n", code, msg);
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}
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static void hdr_str(const char *name, const char *value)
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{
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format_write(1, "%s: %s\r\n", name, value);
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}
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static void hdr_int(const char *name, uintmax_t value)
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{
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format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
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}
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static void hdr_date(const char *name, unsigned long when)
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{
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const char *value = show_date(when, 0, DATE_RFC2822);
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hdr_str(name, value);
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}
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static void hdr_nocache(void)
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{
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hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
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hdr_str("Pragma", "no-cache");
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hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
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}
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static void hdr_cache_forever(void)
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{
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unsigned long now = time(NULL);
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hdr_date("Date", now);
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hdr_date("Expires", now + 31536000);
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hdr_str("Cache-Control", "public, max-age=31536000");
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}
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static void end_headers(void)
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{
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safe_write(1, "\r\n", 2);
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}
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__attribute__((format (printf, 1, 2)))
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static NORETURN void not_found(const char *err, ...)
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{
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va_list params;
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http_status(404, "Not Found");
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hdr_nocache();
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end_headers();
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va_start(params, err);
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if (err && *err)
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vfprintf(stderr, err, params);
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va_end(params);
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exit(0);
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}
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__attribute__((format (printf, 1, 2)))
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static NORETURN void forbidden(const char *err, ...)
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{
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va_list params;
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http_status(403, "Forbidden");
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hdr_nocache();
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end_headers();
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va_start(params, err);
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if (err && *err)
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vfprintf(stderr, err, params);
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va_end(params);
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exit(0);
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}
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static void select_getanyfile(void)
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{
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if (!getanyfile)
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forbidden("Unsupported service: getanyfile");
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}
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static void send_strbuf(const char *type, struct strbuf *buf)
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{
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hdr_int(content_length, buf->len);
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hdr_str(content_type, type);
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end_headers();
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safe_write(1, buf->buf, buf->len);
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}
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static void send_local_file(const char *the_type, const char *name)
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{
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const char *p = git_path("%s", name);
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size_t buf_alloc = 8192;
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char *buf = xmalloc(buf_alloc);
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int fd;
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struct stat sb;
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fd = open(p, O_RDONLY);
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if (fd < 0)
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not_found("Cannot open '%s': %s", p, strerror(errno));
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if (fstat(fd, &sb) < 0)
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die_errno("Cannot stat '%s'", p);
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hdr_int(content_length, sb.st_size);
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hdr_str(content_type, the_type);
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hdr_date(last_modified, sb.st_mtime);
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end_headers();
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for (;;) {
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ssize_t n = xread(fd, buf, buf_alloc);
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if (n < 0)
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die_errno("Cannot read '%s'", p);
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if (!n)
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break;
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safe_write(1, buf, n);
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}
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close(fd);
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free(buf);
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}
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static void get_text_file(char *name)
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{
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select_getanyfile();
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hdr_nocache();
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send_local_file("text/plain", name);
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}
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static void get_loose_object(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-loose-object", name);
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}
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static void get_pack_file(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-packed-objects", name);
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}
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static void get_idx_file(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-packed-objects-toc", name);
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}
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static int http_config(const char *var, const char *value, void *cb)
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{
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if (!strcmp(var, "http.getanyfile")) {
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getanyfile = git_config_bool(var, value);
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return 0;
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}
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if (!prefixcmp(var, "http.")) {
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int i;
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for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
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struct rpc_service *svc = &rpc_service[i];
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if (!strcmp(var + 5, svc->config_name)) {
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svc->enabled = git_config_bool(var, value);
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return 0;
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}
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}
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}
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/* we are not interested in parsing any other configuration here */
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return 0;
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}
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static struct rpc_service *select_service(const char *name)
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{
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struct rpc_service *svc = NULL;
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int i;
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if (prefixcmp(name, "git-"))
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forbidden("Unsupported service: '%s'", name);
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for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
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struct rpc_service *s = &rpc_service[i];
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if (!strcmp(s->name, name + 4)) {
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svc = s;
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break;
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}
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}
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if (!svc)
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forbidden("Unsupported service: '%s'", name);
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if (svc->enabled < 0) {
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const char *user = getenv("REMOTE_USER");
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svc->enabled = (user && *user) ? 1 : 0;
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}
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if (!svc->enabled)
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forbidden("Service not enabled: '%s'", svc->name);
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return svc;
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}
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static void inflate_request(const char *prog_name, int out)
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{
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z_stream stream;
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unsigned char in_buf[8192];
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unsigned char out_buf[8192];
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unsigned long cnt = 0;
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int ret;
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memset(&stream, 0, sizeof(stream));
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ret = inflateInit2(&stream, (15 + 16));
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if (ret != Z_OK)
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die("cannot start zlib inflater, zlib err %d", ret);
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while (1) {
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ssize_t n = xread(0, in_buf, sizeof(in_buf));
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if (n <= 0)
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die("request ended in the middle of the gzip stream");
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stream.next_in = in_buf;
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stream.avail_in = n;
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while (0 < stream.avail_in) {
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int ret;
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stream.next_out = out_buf;
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stream.avail_out = sizeof(out_buf);
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ret = inflate(&stream, Z_NO_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END)
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die("zlib error inflating request, result %d", ret);
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n = stream.total_out - cnt;
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if (write_in_full(out, out_buf, n) != n)
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die("%s aborted reading request", prog_name);
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cnt += n;
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if (ret == Z_STREAM_END)
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goto done;
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}
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}
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done:
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inflateEnd(&stream);
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close(out);
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}
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static void run_service(const char **argv)
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{
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const char *encoding = getenv("HTTP_CONTENT_ENCODING");
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const char *user = getenv("REMOTE_USER");
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const char *host = getenv("REMOTE_ADDR");
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char *env[3];
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struct strbuf buf = STRBUF_INIT;
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int gzipped_request = 0;
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struct child_process cld;
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if (encoding && !strcmp(encoding, "gzip"))
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gzipped_request = 1;
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else if (encoding && !strcmp(encoding, "x-gzip"))
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gzipped_request = 1;
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if (!user || !*user)
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user = "anonymous";
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if (!host || !*host)
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host = "(none)";
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memset(&env, 0, sizeof(env));
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strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
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env[0] = strbuf_detach(&buf, NULL);
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strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
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env[1] = strbuf_detach(&buf, NULL);
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env[2] = NULL;
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memset(&cld, 0, sizeof(cld));
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cld.argv = argv;
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cld.env = (const char *const *)env;
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if (gzipped_request)
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cld.in = -1;
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cld.git_cmd = 1;
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if (start_command(&cld))
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exit(1);
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close(1);
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if (gzipped_request)
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inflate_request(argv[0], cld.in);
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else
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close(0);
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if (finish_command(&cld))
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exit(1);
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free(env[0]);
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free(env[1]);
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strbuf_release(&buf);
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}
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static int show_text_ref(const char *name, const unsigned char *sha1,
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int flag, void *cb_data)
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{
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struct strbuf *buf = cb_data;
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struct object *o = parse_object(sha1);
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if (!o)
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return 0;
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strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
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if (o->type == OBJ_TAG) {
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o = deref_tag(o, name, 0);
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if (!o)
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return 0;
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strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
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}
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return 0;
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}
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static void get_info_refs(char *arg)
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{
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const char *service_name = get_parameter("service");
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struct strbuf buf = STRBUF_INIT;
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hdr_nocache();
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if (service_name) {
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const char *argv[] = {NULL /* service name */,
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"--stateless-rpc", "--advertise-refs",
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".", NULL};
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struct rpc_service *svc = select_service(service_name);
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strbuf_addf(&buf, "application/x-git-%s-advertisement",
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svc->name);
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hdr_str(content_type, buf.buf);
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end_headers();
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packet_write(1, "# service=git-%s\n", svc->name);
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packet_flush(1);
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argv[0] = svc->name;
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run_service(argv);
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} else {
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select_getanyfile();
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for_each_ref(show_text_ref, &buf);
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send_strbuf("text/plain", &buf);
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}
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strbuf_release(&buf);
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}
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static void get_info_packs(char *arg)
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{
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size_t objdirlen = strlen(get_object_directory());
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struct strbuf buf = STRBUF_INIT;
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struct packed_git *p;
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size_t cnt = 0;
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select_getanyfile();
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prepare_packed_git();
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for (p = packed_git; p; p = p->next) {
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if (p->pack_local)
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cnt++;
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}
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strbuf_grow(&buf, cnt * 53 + 2);
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for (p = packed_git; p; p = p->next) {
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if (p->pack_local)
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strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
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}
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strbuf_addch(&buf, '\n');
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hdr_nocache();
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send_strbuf("text/plain; charset=utf-8", &buf);
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strbuf_release(&buf);
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}
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static void check_content_type(const char *accepted_type)
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{
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const char *actual_type = getenv("CONTENT_TYPE");
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if (!actual_type)
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actual_type = "";
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if (strcmp(actual_type, accepted_type)) {
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http_status(415, "Unsupported Media Type");
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hdr_nocache();
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end_headers();
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format_write(1,
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"Expected POST with Content-Type '%s',"
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" but received '%s' instead.\n",
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accepted_type, actual_type);
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exit(0);
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}
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}
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static void service_rpc(char *service_name)
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{
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const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
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struct rpc_service *svc = select_service(service_name);
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struct strbuf buf = STRBUF_INIT;
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strbuf_reset(&buf);
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strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
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check_content_type(buf.buf);
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hdr_nocache();
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strbuf_reset(&buf);
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strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
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hdr_str(content_type, buf.buf);
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end_headers();
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argv[0] = svc->name;
|
|
run_service(argv);
|
|
strbuf_release(&buf);
|
|
}
|
|
|
|
static NORETURN void die_webcgi(const char *err, va_list params)
|
|
{
|
|
static int dead;
|
|
|
|
if (!dead) {
|
|
char buffer[1000];
|
|
dead = 1;
|
|
|
|
vsnprintf(buffer, sizeof(buffer), err, params);
|
|
fprintf(stderr, "fatal: %s\n", buffer);
|
|
http_status(500, "Internal Server Error");
|
|
hdr_nocache();
|
|
end_headers();
|
|
}
|
|
exit(0); /* we successfully reported a failure ;-) */
|
|
}
|
|
|
|
static char* getdir(void)
|
|
{
|
|
struct strbuf buf = STRBUF_INIT;
|
|
char *pathinfo = getenv("PATH_INFO");
|
|
char *root = getenv("GIT_PROJECT_ROOT");
|
|
char *path = getenv("PATH_TRANSLATED");
|
|
|
|
if (root && *root) {
|
|
if (!pathinfo || !*pathinfo)
|
|
die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
|
|
if (daemon_avoid_alias(pathinfo))
|
|
die("'%s': aliased", pathinfo);
|
|
strbuf_addstr(&buf, root);
|
|
if (buf.buf[buf.len - 1] != '/')
|
|
strbuf_addch(&buf, '/');
|
|
if (pathinfo[0] == '/')
|
|
pathinfo++;
|
|
strbuf_addstr(&buf, pathinfo);
|
|
return strbuf_detach(&buf, NULL);
|
|
} else if (path && *path) {
|
|
return xstrdup(path);
|
|
} else
|
|
die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
|
|
return NULL;
|
|
}
|
|
|
|
static struct service_cmd {
|
|
const char *method;
|
|
const char *pattern;
|
|
void (*imp)(char *);
|
|
} services[] = {
|
|
{"GET", "/HEAD$", get_text_file},
|
|
{"GET", "/info/refs$", get_info_refs},
|
|
{"GET", "/objects/info/alternates$", get_text_file},
|
|
{"GET", "/objects/info/http-alternates$", get_text_file},
|
|
{"GET", "/objects/info/packs$", get_info_packs},
|
|
{"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
|
|
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
|
|
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
|
|
|
|
{"POST", "/git-upload-pack$", service_rpc},
|
|
{"POST", "/git-receive-pack$", service_rpc}
|
|
};
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
char *method = getenv("REQUEST_METHOD");
|
|
char *dir;
|
|
struct service_cmd *cmd = NULL;
|
|
char *cmd_arg = NULL;
|
|
int i;
|
|
|
|
git_extract_argv0_path(argv[0]);
|
|
set_die_routine(die_webcgi);
|
|
|
|
if (!method)
|
|
die("No REQUEST_METHOD from server");
|
|
if (!strcmp(method, "HEAD"))
|
|
method = "GET";
|
|
dir = getdir();
|
|
|
|
for (i = 0; i < ARRAY_SIZE(services); i++) {
|
|
struct service_cmd *c = &services[i];
|
|
regex_t re;
|
|
regmatch_t out[1];
|
|
|
|
if (regcomp(&re, c->pattern, REG_EXTENDED))
|
|
die("Bogus regex in service table: %s", c->pattern);
|
|
if (!regexec(&re, dir, 1, out, 0)) {
|
|
size_t n;
|
|
|
|
if (strcmp(method, c->method)) {
|
|
const char *proto = getenv("SERVER_PROTOCOL");
|
|
if (proto && !strcmp(proto, "HTTP/1.1"))
|
|
http_status(405, "Method Not Allowed");
|
|
else
|
|
http_status(400, "Bad Request");
|
|
hdr_nocache();
|
|
end_headers();
|
|
return 0;
|
|
}
|
|
|
|
cmd = c;
|
|
n = out[0].rm_eo - out[0].rm_so;
|
|
cmd_arg = xmalloc(n);
|
|
memcpy(cmd_arg, dir + out[0].rm_so + 1, n-1);
|
|
cmd_arg[n-1] = '\0';
|
|
dir[out[0].rm_so] = 0;
|
|
break;
|
|
}
|
|
regfree(&re);
|
|
}
|
|
|
|
if (!cmd)
|
|
not_found("Request not supported: '%s'", dir);
|
|
|
|
setup_path();
|
|
if (!enter_repo(dir, 0))
|
|
not_found("Not a git repository: '%s'", dir);
|
|
if (!getenv("GIT_HTTP_EXPORT_ALL") &&
|
|
access("git-daemon-export-ok", F_OK) )
|
|
not_found("Repository not exported: '%s'", dir);
|
|
|
|
git_config(http_config, NULL);
|
|
cmd->imp(cmd_arg);
|
|
return 0;
|
|
}
|