git/receive-pack.c

322 lines
6.6 KiB
C
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#include "cache.h"
#include <sys/wait.h>
static const char receive_pack_usage[] = "git-receive-pack [--unpack=executable] <git-dir> [heads]";
static const char *unpacker = "git-unpack-objects";
static int path_match(const char *path, int nr, char **match)
{
int i;
int pathlen = strlen(path);
for (i = 0; i < nr; i++) {
char *s = match[i];
int len = strlen(s);
if (!len || len > pathlen)
continue;
if (memcmp(path + pathlen - len, s, len))
continue;
if (pathlen > len && path[pathlen - len - 1] != '/')
continue;
*s = 0;
return 1;
}
return 0;
}
static void safe_write(int fd, const void *buf, unsigned n)
{
while (n) {
int ret = write(fd, buf, n);
if (ret > 0) {
buf += ret;
n -= ret;
continue;
}
if (!ret)
die("write error (disk full?)");
if (errno == EAGAIN || errno == EINTR)
continue;
die("write error (%s)", strerror(errno));
}
}
/*
* If we buffered things up above (we don't, but we should),
* we'd flush it here
*/
static void flush_safe(int fd)
{
}
/*
* Write a packetized stream, where each line is preceded by
* its length (including the header) as a 4-byte hex number.
* A length of 'zero' means end of stream (and a length of 1-3
* would be an error).
*/
#define hex(a) (hexchar[(a) & 15])
static void packet_write(const char *fmt, ...)
{
static char buffer[1000];
static char hexchar[] = "0123456789abcdef";
va_list args;
unsigned n;
va_start(args, fmt);
n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
va_end(args);
if (n >= sizeof(buffer)-4)
die("protocol error: impossibly long line");
n += 4;
buffer[0] = hex(n >> 12);
buffer[1] = hex(n >> 8);
buffer[2] = hex(n >> 4);
buffer[3] = hex(n);
safe_write(1, buffer, n);
}
static void show_ref(const char *path, unsigned char *sha1)
{
packet_write("%s %s\n", sha1_to_hex(sha1), path);
}
static int read_ref(const char *path, unsigned char *sha1)
{
int ret = -1;
int fd = open(path, O_RDONLY);
if (fd >= 0) {
char buffer[60];
if (read(fd, buffer, sizeof(buffer)) >= 40)
ret = get_sha1_hex(buffer, sha1);
close(fd);
}
return ret;
}
static void write_head_info(const char *base, int nr, char **match)
{
DIR *dir = opendir(base);
if (dir) {
struct dirent *de;
int baselen = strlen(base);
char *path = xmalloc(baselen + 257);
memcpy(path, base, baselen);
while ((de = readdir(dir)) != NULL) {
char sha1[20];
struct stat st;
int namelen;
if (de->d_name[0] == '.')
continue;
namelen = strlen(de->d_name);
if (namelen > 255)
continue;
memcpy(path + baselen, de->d_name, namelen+1);
if (lstat(path, &st) < 0)
continue;
if (S_ISDIR(st.st_mode)) {
path[baselen + namelen] = '/';
path[baselen + namelen + 1] = 0;
write_head_info(path, nr, match);
continue;
}
if (read_ref(path, sha1) < 0)
continue;
if (nr && !path_match(path, nr, match))
continue;
show_ref(path, sha1);
}
free(path);
closedir(dir);
}
}
/*
* This is all pretty stupid, but we use this packetized line
* format to make a streaming format possible without ever
* over-running the read buffers. That way we'll never read
* into what might be the pack data (which should go to another
* process entirely).
*
* The writing side could use stdio, but since the reading
* side can't, we stay with pure read/write interfaces.
*/
static void safe_read(int fd, void *buffer, unsigned size)
{
int n = 0;
while (n < size) {
int ret = read(0, buffer + n, size - n);
if (ret < 0) {
if (errno == EINTR || errno == EAGAIN)
continue;
die("read error (%s)", strerror(errno));
}
if (!ret)
die("unexpected EOF");
n += ret;
}
}
static int safe_read_line(char *buffer, unsigned size)
{
int n, len;
safe_read(0, buffer, 4);
len = 0;
for (n = 0; n < 4; n++) {
unsigned char c = buffer[n];
len <<= 4;
if (c >= '0' && c <= '9') {
len += c - '0';
continue;
}
if (c >= 'a' && c <= 'f') {
len += c - 'a' + 10;
continue;
}
if (c >= 'A' && c <= 'F') {
len += c - 'A' + 10;
continue;
}
die("protocol error: bad line length character");
}
if (!len)
return 0;
if (len < 4 || len >= size)
die("protocol error: bad line length %d", len);
safe_read(0, buffer + 4, len - 4);
buffer[len] = 0;
return len;
}
struct line {
struct line *next;
char data[0];
};
struct line *commands = NULL;
/*
* This gets called after(if) we've successfully
* unpacked the data payload.
*/
static void execute_commands(void)
{
struct line *line = commands;
while (line) {
printf("%s", line->data);
line = line->next;
}
}
static void read_head_info(void)
{
struct line **p = &commands;
for (;;) {
static char line[1000];
int len = safe_read_line(line, sizeof(line));
struct line *n;
if (!len)
break;
n = xmalloc(sizeof(struct line) + len);
n->next = NULL;
memcpy(n->data, line + 4, len - 3);
*p = n;
p = &n->next;
}
}
static void unpack(void)
{
pid_t pid = fork();
if (pid < 0)
die("unpack fork failed");
if (!pid) {
char *const envp[] = { "GIT_DIR=.", NULL };
execle(unpacker, unpacker, NULL, envp);
die("unpack execute failed");
}
for (;;) {
int status, code;
int retval = waitpid(pid, &status, 0);
if (retval < 0) {
if (errno == EINTR)
continue;
die("waitpid failed (%s)", strerror(retval));
}
if (retval != pid)
die("waitpid is confused");
if (WIFSIGNALED(status))
die("%s died of signal %d", unpacker, WTERMSIG(status));
if (!WIFEXITED(status))
die("%s died out of really strange complications", unpacker);
code = WEXITSTATUS(status);
if (code)
die("%s exited with error code %d", unpacker, code);
return;
}
}
int main(int argc, char **argv)
{
int i, nr_heads = 0;
const char *dir = NULL;
char **heads = NULL;
argv++;
for (i = 1; i < argc; i++) {
const char *arg = *argv++;
if (*arg == '-') {
if (!strncmp(arg, "--unpack=", 9)) {
unpacker = arg+9;
continue;
}
/* Do flag handling here */
usage(receive_pack_usage);
}
dir = arg;
heads = argv;
nr_heads = argc - i - 1;
break;
}
if (!dir)
usage(receive_pack_usage);
/* chdir to the directory. If that fails, try appending ".git" */
if (chdir(dir) < 0) {
static char path[PATH_MAX];
snprintf(path, sizeof(path), "%s.git", dir);
if (chdir(path) < 0)
die("unable to cd to %s", dir);
}
/* If we have a ".git" directory, chdir to it */
chdir(".git");
if (access("objects", X_OK) < 0 || access("refs/heads", X_OK) < 0)
die("%s doesn't appear to be a git directory", dir);
write_head_info("refs/", nr_heads, heads);
/* EOF */
safe_write(1, "0000", 4);
flush_safe(1);
read_head_info();
unpack();
execute_commands();
return 0;
}