LibC: Implement getgr{gid,nam}_r
This commit is contained in:
parent
80ffde5e1e
commit
654e8bb7f6
|
|
@ -1,162 +1,213 @@
|
|||
#include <BAN/StringView.h>
|
||||
#include <BAN/Vector.h>
|
||||
|
||||
#include <ctype.h>
|
||||
#include <errno.h>
|
||||
#include <fcntl.h>
|
||||
#include <grp.h>
|
||||
#include <stdlib.h>
|
||||
#include <sys/mman.h>
|
||||
#include <sys/types.h>
|
||||
#include <string.h>
|
||||
#include <unistd.h>
|
||||
|
||||
static struct stat s_group_st;
|
||||
static char* s_group_mmap = nullptr;
|
||||
static int s_group_fd = -1;
|
||||
static FILE* s_grent_fp = nullptr;
|
||||
static group s_grent_struct;
|
||||
|
||||
static struct group s_group;
|
||||
static char* s_grent_buffer = nullptr;
|
||||
static size_t s_grent_buffer_size = 0;
|
||||
|
||||
id_t parse_id(BAN::StringView string)
|
||||
void endgrent(void)
|
||||
{
|
||||
id_t id = 0;
|
||||
for (char c : string)
|
||||
{
|
||||
if (!isdigit(c))
|
||||
return -1;
|
||||
id = (id * 10) + (c - '0');
|
||||
}
|
||||
return id;
|
||||
if (s_grent_fp)
|
||||
fclose(s_grent_fp);
|
||||
s_grent_fp = nullptr;
|
||||
|
||||
if (s_grent_buffer)
|
||||
free(s_grent_buffer);
|
||||
s_grent_buffer = nullptr;
|
||||
}
|
||||
|
||||
static bool open_group_file()
|
||||
void setgrent(void)
|
||||
{
|
||||
if (s_group_fd == -1)
|
||||
s_group_fd = open("/etc/group", O_RDONLY);
|
||||
if (s_group_fd == -1)
|
||||
return false;
|
||||
|
||||
if (fstat(s_group_fd, &s_group_st) == -1)
|
||||
return false;
|
||||
|
||||
if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
|
||||
s_group_mmap = (char*)mmap(nullptr, s_group_st.st_size, PROT_READ, MAP_PRIVATE, s_group_fd, 0);
|
||||
if (s_group_mmap == MAP_FAILED)
|
||||
return false;
|
||||
|
||||
s_group.gr_name = nullptr;
|
||||
s_group.gr_mem = nullptr;
|
||||
|
||||
return true;
|
||||
if (!s_grent_fp)
|
||||
return;
|
||||
fseek(s_grent_fp, 0, SEEK_SET);
|
||||
}
|
||||
|
||||
struct group* fill_group(const BAN::Vector<BAN::StringView>& parts)
|
||||
static int getgrent_impl(FILE* fp, struct group* grp, char* buffer, size_t bufsize, struct group** result)
|
||||
{
|
||||
if (parts.size() != 4)
|
||||
return nullptr;
|
||||
|
||||
if (s_group.gr_name)
|
||||
for (;;)
|
||||
{
|
||||
free(s_group.gr_name);
|
||||
s_group.gr_name = nullptr;
|
||||
if (fgets(buffer, bufsize, fp) == nullptr)
|
||||
{
|
||||
if (ferror(fp))
|
||||
return errno;
|
||||
*result = nullptr;
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (s_group.gr_mem)
|
||||
const size_t line_len = strlen(buffer);
|
||||
if (line_len == 0)
|
||||
continue;
|
||||
|
||||
if (buffer[line_len - 1] == '\n')
|
||||
buffer[line_len - 1] = '\0';
|
||||
else if (!feof(fp))
|
||||
return (errno = ERANGE);
|
||||
|
||||
#define GET_STRING() ({ \
|
||||
ptr = strchr(ptr, ':'); \
|
||||
if (ptr == nullptr) \
|
||||
continue; \
|
||||
*ptr++ = '\0'; \
|
||||
})
|
||||
|
||||
#define GET_INT() ({ \
|
||||
if (!isdigit(*ptr)) \
|
||||
continue; \
|
||||
long val = 0; \
|
||||
while (isdigit(*ptr)) \
|
||||
val = (val * 10) + (*ptr++ - '0'); \
|
||||
if (*ptr != ':') \
|
||||
continue; \
|
||||
*ptr++ = '\0'; \
|
||||
val; \
|
||||
})
|
||||
|
||||
char* ptr = buffer;
|
||||
|
||||
grp->gr_name = ptr;
|
||||
GET_STRING();
|
||||
|
||||
grp->gr_passwd = ptr;
|
||||
GET_STRING();
|
||||
|
||||
grp->gr_gid = GET_INT();
|
||||
|
||||
size_t offset = line_len + 1;
|
||||
if (auto rem = offset % alignof(char*))
|
||||
offset += alignof(char*) - rem;
|
||||
grp->gr_mem = reinterpret_cast<char**>(buffer + offset);
|
||||
|
||||
const size_t mem_max = (bufsize - offset) / sizeof(char*);
|
||||
size_t mem_idx = 0;
|
||||
|
||||
while (*ptr && mem_idx + 1 <= mem_max)
|
||||
{
|
||||
for (size_t i = 0; s_group.gr_mem && s_group.gr_mem[i]; i++)
|
||||
free(s_group.gr_mem[i]);
|
||||
free(s_group.gr_mem);
|
||||
s_group.gr_mem = nullptr;
|
||||
grp->gr_mem[mem_idx++] = ptr;
|
||||
|
||||
ptr = strchrnul(ptr, ',');
|
||||
if (*ptr == ',')
|
||||
*ptr++ = '\0';
|
||||
}
|
||||
|
||||
auto groups_or_error = parts[3].split(',');
|
||||
if (groups_or_error.is_error())
|
||||
return nullptr;
|
||||
auto groups = groups_or_error.release_value();
|
||||
if (mem_idx + 1 > mem_max)
|
||||
return (errno = ERANGE);
|
||||
|
||||
s_group.gr_gid = parse_id(parts[2]);
|
||||
if (s_group.gr_gid == -1)
|
||||
return nullptr;
|
||||
|
||||
s_group.gr_name = (char*)malloc(parts[0].size() + 1);
|
||||
if (s_group.gr_name == nullptr)
|
||||
return nullptr;
|
||||
memcpy(s_group.gr_name, parts[0].data(), parts[0].size());
|
||||
s_group.gr_name[parts[0].size()] = '\0';
|
||||
|
||||
s_group.gr_mem = (char**)malloc((groups.size() + 1) * sizeof(char*));
|
||||
if (s_group.gr_mem == nullptr)
|
||||
return nullptr;
|
||||
|
||||
for (size_t i = 0; i < groups.size(); i++)
|
||||
{
|
||||
s_group.gr_mem[i] = (char*)malloc(groups[i].size() + 1);
|
||||
if (s_group.gr_mem[i] == nullptr)
|
||||
{
|
||||
for (size_t j = 0; j < i; j++)
|
||||
free(s_group.gr_mem[j]);
|
||||
free(s_group.gr_mem);
|
||||
s_group.gr_mem = nullptr;
|
||||
return nullptr;
|
||||
grp->gr_mem[mem_idx] = nullptr;
|
||||
*result = grp;
|
||||
return 0;
|
||||
}
|
||||
memcpy(s_group.gr_mem[i], groups[i].data(), groups[i].size());
|
||||
s_group.gr_mem[i][groups[i].size()] = '\0';
|
||||
}
|
||||
s_group.gr_mem[groups.size()] = nullptr;
|
||||
|
||||
return &s_group;
|
||||
}
|
||||
|
||||
struct group* getgrnam(const char* name)
|
||||
struct group* getgrent(void)
|
||||
{
|
||||
if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
|
||||
if (!open_group_file())
|
||||
return nullptr;
|
||||
|
||||
off_t start = 0;
|
||||
off_t end = 0;
|
||||
while (start < s_group_st.st_size)
|
||||
if (s_grent_fp == nullptr)
|
||||
{
|
||||
while (end < s_group_st.st_size && s_group_mmap[end] != '\n')
|
||||
end++;
|
||||
|
||||
BAN::StringView line(s_group_mmap + start, end - start);
|
||||
start = ++end;
|
||||
|
||||
auto parts_or_error = line.split(':', true);
|
||||
if (parts_or_error.is_error())
|
||||
s_grent_fp = fopen("/etc/group", "r");
|
||||
if (s_grent_fp == nullptr)
|
||||
return nullptr;
|
||||
|
||||
auto parts = parts_or_error.release_value();
|
||||
if (parts.size() == 4 && parts[0] == name)
|
||||
return fill_group(parts);
|
||||
}
|
||||
|
||||
if (s_grent_buffer == nullptr)
|
||||
{
|
||||
long size = sysconf(_SC_GETGR_R_SIZE_MAX);
|
||||
if (size == -1)
|
||||
size = 512;
|
||||
|
||||
s_grent_buffer = static_cast<char*>(malloc(size));
|
||||
if (s_grent_buffer == nullptr)
|
||||
return nullptr;
|
||||
s_grent_buffer_size = size;
|
||||
}
|
||||
|
||||
const off_t old_offset = ftello(s_grent_fp);
|
||||
|
||||
group* result;
|
||||
for (;;)
|
||||
{
|
||||
const int error = getgrent_impl(s_grent_fp, &s_grent_struct, s_grent_buffer, s_grent_buffer_size, &result);
|
||||
if (error == 0)
|
||||
break;
|
||||
fseeko(s_grent_fp, old_offset, SEEK_SET);
|
||||
if (error != ERANGE)
|
||||
return nullptr;
|
||||
|
||||
const size_t new_size = s_grent_buffer_size * 2;
|
||||
char* new_buffer = static_cast<char*>(realloc(s_grent_buffer, new_size));
|
||||
if (new_buffer == nullptr)
|
||||
return nullptr;
|
||||
|
||||
s_grent_buffer = new_buffer;
|
||||
s_grent_buffer_size = new_size;
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
struct group* getgrgid(gid_t gid)
|
||||
{
|
||||
if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
|
||||
if (!open_group_file())
|
||||
group* grp;
|
||||
setgrent();
|
||||
while ((grp = getgrent()))
|
||||
if (grp->gr_gid == gid)
|
||||
return grp;
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
off_t start = 0;
|
||||
off_t end = 0;
|
||||
while (start < s_group_st.st_size)
|
||||
struct group* getgrnam(const char* name)
|
||||
{
|
||||
while (end < s_group_st.st_size && s_group_mmap[end] != '\n')
|
||||
end++;
|
||||
|
||||
BAN::StringView line(s_group_mmap + start, end - start);
|
||||
start = ++end;
|
||||
|
||||
auto parts_or_error = line.split(':', true);
|
||||
if (parts_or_error.is_error())
|
||||
return nullptr;
|
||||
|
||||
auto parts = parts_or_error.release_value();
|
||||
if (parts.size() == 4 && parse_id(parts[2]) == gid)
|
||||
return fill_group(parts);
|
||||
}
|
||||
|
||||
group* grp;
|
||||
setgrent();
|
||||
while ((grp = getgrent()))
|
||||
if (strcmp(grp->gr_name, name) == 0)
|
||||
return grp;
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
int getgrgid_r(gid_t gid, struct group* grp, char* buffer, size_t bufsize, struct group** result)
|
||||
{
|
||||
FILE* fp = fopen("/etc/group", "r");
|
||||
if (fp == nullptr)
|
||||
return errno;
|
||||
|
||||
int ret = 0;
|
||||
for (;;)
|
||||
{
|
||||
if ((ret = getgrent_impl(fp, grp, buffer, bufsize, result)))
|
||||
break;
|
||||
if (*result == nullptr)
|
||||
break;
|
||||
if (grp->gr_gid == gid)
|
||||
break;
|
||||
}
|
||||
|
||||
fclose(fp);
|
||||
return ret;
|
||||
}
|
||||
|
||||
int getgrnam_r(const char* name, struct group* grp, char* buffer, size_t bufsize, struct group** result)
|
||||
{
|
||||
FILE* fp = fopen("/etc/group", "r");
|
||||
if (fp == nullptr)
|
||||
return errno;
|
||||
|
||||
int ret = 0;
|
||||
for (;;)
|
||||
{
|
||||
if ((ret = getgrent_impl(fp, grp, buffer, bufsize, result)))
|
||||
break;
|
||||
if (*result == nullptr)
|
||||
break;
|
||||
if (strcmp(grp->gr_name, name) == 0)
|
||||
break;
|
||||
}
|
||||
|
||||
fclose(fp);
|
||||
return ret;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -14,6 +14,7 @@ __BEGIN_DECLS
|
|||
struct group
|
||||
{
|
||||
char* gr_name; /* The name of the group. */
|
||||
char* gr_passwd;/* The password of the group */
|
||||
gid_t gr_gid; /* Numerical group ID. */
|
||||
char** gr_mem; /* Pointer to a null-terminated array of character pointers to member names. */
|
||||
};
|
||||
|
|
@ -21,7 +22,7 @@ struct group
|
|||
void endgrent(void);
|
||||
struct group* getgrent(void);
|
||||
struct group* getgrgid(gid_t gid);
|
||||
int getgrgit_r(gid_t gid, struct group* grp, char* buffer, size_t bufsize, struct group** result);
|
||||
int getgrgid_r(gid_t gid, struct group* grp, char* buffer, size_t bufsize, struct group** result);
|
||||
struct group* getgrnam(const char* name);
|
||||
int getgrnam_r(const char* name, struct group* grp, char* buffer, size_t bufsize, struct group** result);
|
||||
void setgrent(void);
|
||||
|
|
|
|||
Loading…
Reference in New Issue