github.com/afumu/libc@v0.0.6/musl/src/passwd/getgr_r.c (about)

     1  #include "pwf.h"
     2  #include <pthread.h>
     3  
     4  #define FIX(x) (gr->gr_##x = gr->gr_##x-line+buf)
     5  
     6  static int getgr_r(const char *name, gid_t gid, struct group *gr, char *buf, size_t size, struct group **res)
     7  {
     8  	char *line = 0;
     9  	size_t len = 0;
    10  	char **mem = 0;
    11  	size_t nmem = 0;
    12  	int rv = 0;
    13  	size_t i;
    14  	int cs;
    15  
    16  	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
    17  
    18  	rv = __getgr_a(name, gid, gr, &line, &len, &mem, &nmem, res);
    19  	if (*res && size < len + (nmem+1)*sizeof(char *) + 32) {
    20  		*res = 0;
    21  		rv = ERANGE;
    22  	}
    23  	if (*res) {
    24  		buf += (16-(uintptr_t)buf)%16;
    25  		gr->gr_mem = (void *)buf;
    26  		buf += (nmem+1)*sizeof(char *);
    27  		memcpy(buf, line, len);
    28  		FIX(name);
    29  		FIX(passwd);
    30  		for (i=0; mem[i]; i++)
    31  			gr->gr_mem[i] = mem[i]-line+buf;
    32  		gr->gr_mem[i] = 0;
    33  	}
    34   	free(mem);
    35   	free(line);
    36  	pthread_setcancelstate(cs, 0);
    37  	if (rv) errno = rv;
    38  	return rv;
    39  }
    40  
    41  int getgrnam_r(const char *name, struct group *gr, char *buf, size_t size, struct group **res)
    42  {
    43  	return getgr_r(name, 0, gr, buf, size, res);
    44  }
    45  
    46  int getgrgid_r(gid_t gid, struct group *gr, char *buf, size_t size, struct group **res)
    47  {
    48  	return getgr_r(0, gid, gr, buf, size, res);
    49  }