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/*
* I'm tired of doing "vsnprintf()" etc just to open a
* file, so here's a "return static buffer with printf"
* interface for paths.
*
* It's obviously not thread-safe. Sue me. But it's quite
* useful for doing things like
*
* f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
*
* which is what it's designed for.
*/
#include "cache.h"
#include <pwd.h>
static char pathname[PATH_MAX];
static char bad_path[] = "/bad-path/";
static char *cleanup_path(char *path)
{
/* Clean it up */
if (!memcmp(path, "./", 2)) {
path += 2;
while (*path == '/')
path++;
}
return path;
}
char *mkpath(const char *fmt, ...)
{
va_list args;
unsigned len;
va_start(args, fmt);
len = vsnprintf(pathname, PATH_MAX, fmt, args);
va_end(args);
if (len >= PATH_MAX)
return bad_path;
return cleanup_path(pathname);
}
char *git_path(const char *fmt, ...)
{
const char *git_dir = get_git_dir();
va_list args;
unsigned len;
len = strlen(git_dir);
if (len > PATH_MAX-100)
return bad_path;
memcpy(pathname, git_dir, len);
if (len && git_dir[len-1] != '/')
pathname[len++] = '/';
va_start(args, fmt);
len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
va_end(args);
if (len >= PATH_MAX)
return bad_path;
return cleanup_path(pathname);
}
/* git_mkstemp() - create tmp file honoring TMPDIR variable */
int git_mkstemp(char *path, size_t len, const char *template)
{
char *env, *pch = path;
if ((env = getenv("TMPDIR")) == NULL) {
strcpy(pch, "/tmp/");
len -= 5;
pch += 5;
} else {
size_t n = snprintf(pch, len, "%s/", env);
len -= n;
pch += n;
}
safe_strncpy(pch, template, len);
return mkstemp(path);
}
char *safe_strncpy(char *dest, const char *src, size_t n)
{
strncpy(dest, src, n);
dest[n - 1] = '\0';
return dest;
}
int validate_symref(const char *path)
{
struct stat st;
char *buf, buffer[256];
int len, fd;
if (lstat(path, &st) < 0)
return -1;
/* Make sure it is a "refs/.." symlink */
if (S_ISLNK(st.st_mode)) {
len = readlink(path, buffer, sizeof(buffer)-1);
if (len >= 5 && !memcmp("refs/", buffer, 5))
return 0;
return -1;
}
/*
* Anything else, just open it and try to see if it is a symbolic ref.
*/
fd = open(path, O_RDONLY);
if (fd < 0)
return -1;
len = read(fd, buffer, sizeof(buffer)-1);
close(fd);
/*
* Is it a symbolic ref?
*/
if (len < 4 || memcmp("ref:", buffer, 4))
return -1;
buf = buffer + 4;
len -= 4;
while (len && isspace(*buf))
buf++, len--;
if (len >= 5 && !memcmp("refs/", buf, 5))
return 0;
return -1;
}
static char *current_dir()
{
return getcwd(pathname, sizeof(pathname));
}
static int user_chdir(char *path)
{
char *dir = path;
if(*dir == '~') { /* user-relative path */
struct passwd *pw;
char *slash = strchr(dir, '/');
dir++;
/* '~/' and '~' (no slash) means users own home-dir */
if(!*dir || *dir == '/')
pw = getpwuid(getuid());
else {
if (slash) {
*slash = '\0';
pw = getpwnam(dir);
*slash = '/';
}
else
pw = getpwnam(dir);
}
/* make sure we got something back that we can chdir() to */
if(!pw || chdir(pw->pw_dir) < 0)
return -1;
if(!slash || !slash[1]) /* no path following username */
return 0;
dir = slash + 1;
}
/* ~foo/path/to/repo is now path/to/repo and we're in foo's homedir */
if(chdir(dir) < 0)
return -1;
return 0;
}
char *enter_repo(char *path, int strict)
{
if(!path)
return NULL;
if (strict) {
if((path[0] != '/') || chdir(path) < 0)
return NULL;
}
else {
if (!*path)
; /* happy -- no chdir */
else if (!user_chdir(path))
; /* happy -- as given */
else if (!user_chdir(mkpath("%s.git", path)))
; /* happy -- uemacs --> uemacs.git */
else
return NULL;
(void)chdir(".git");
}
if(access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
validate_symref("HEAD") == 0) {
putenv("GIT_DIR=.");
return current_dir();
}
return NULL;
}
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