#include <stdlib.h>
-#include <stdio.h>
#include <limits.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
+#include <string.h>
+#include "syscall.h"
-char *realpath(const char *filename, char *resolved)
+void __procfdname(char *, unsigned);
+
+char *realpath(const char *restrict filename, char *restrict resolved)
{
int fd;
ssize_t r;
struct stat st1, st2;
char buf[15+3*sizeof(int)];
- int alloc = 0;
+ char tmp[PATH_MAX];
if (!filename) {
errno = EINVAL;
return 0;
}
- if (!resolved) {
- alloc = 1;
- resolved = malloc(PATH_MAX);
- if (!resolved) return 0;
- }
-
- fd = open(filename, O_RDONLY|O_NONBLOCK);
+ fd = sys_open(filename, O_PATH|O_NONBLOCK|O_CLOEXEC);
if (fd < 0) return 0;
- snprintf(buf, sizeof buf, "/proc/self/fd/%d", fd);
+ __procfdname(buf, fd);
- r = readlink(buf, resolved, PATH_MAX-1);
+ r = readlink(buf, tmp, sizeof tmp - 1);
if (r < 0) goto err;
- resolved[r] = 0;
+ tmp[r] = 0;
fstat(fd, &st1);
- r = stat(resolved, &st2);
+ r = stat(tmp, &st2);
if (r<0 || st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino) {
if (!r) errno = ELOOP;
goto err;
}
- close(fd);
- return resolved;
+ __syscall(SYS_close, fd);
+ return resolved ? strcpy(resolved, tmp) : strdup(tmp);
err:
- if (alloc) free(resolved);
- close(fd);
+ __syscall(SYS_close, fd);
return 0;
}