#include <string.h>
#include <unistd.h>
-struct group_storage {
- struct group gr;
- char *members[];
-};
-
static int lockfd = -1;
static char group_dir[PATH_MAX];
static char group_file[PATH_MAX];
static char tempname[PATH_MAX];
static int initialized;
-
-static const char group_line_format[] = "%s:%s:%ju:";
+static size_t grmemlen(const struct group *, const char *, int *);
+static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);
/*
* Initialize statics
int
gr_init(const char *dir, const char *group)
{
- struct stat st;
if (dir == NULL) {
strcpy(group_dir, _PATH_ETC);
strcpy(group_file, group);
}
- if (stat(group_file, &st) == -1)
- return (-1);
-
- if (S_ISDIR(st.st_mode)) {
- errno = EISDIR;
- return (-1);
- }
-
initialized = 1;
return (0);
}
for (;;) {
struct stat st;
- lockfd = open(group_file, O_RDONLY, 0);
- if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1)
- err(1, "%s", group_file);
- if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
+ lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
+ if (lockfd == -1) {
if (errno == EWOULDBLOCK) {
errx(1, "the group file is busy");
} else {
size_t len;
int eof, readlen;
- sgr = gr;
+ if (old_gr == NULL && gr == NULL)
+ return(-1);
+
+ sgr = old_gr;
+ /* deleting a group */
if (gr == NULL) {
line = NULL;
- if (old_gr == NULL)
+ } else {
+ if ((line = gr_make(gr)) == NULL)
return (-1);
- sgr = old_gr;
- } else if ((line = gr_make(gr)) == NULL)
- return (-1);
+ }
+
+ /* adding a group */
+ if (sgr == NULL)
+ sgr = gr;
eof = 0;
len = 0;
int
gr_mkdb(void)
{
+ if (chmod(tempname, 0644) != 0)
+ return (-1);
+
return (rename(tempname, group_file));
}
/*
- * Clean up. Preserver errno for the caller's convenience.
+ * Clean up. Preserves errno for the caller's convenience.
*/
void
gr_fini(void)
{
int gr1_ndx;
int gr2_ndx;
- bool found;
/* Check that the non-member information is the same. */
if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
if (gr1->gr_gid != gr2->gr_gid)
return (false);
- /* Check all members in both groups. */
- if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) {
- if (gr1->gr_mem != gr2->gr_mem)
- return (false);
- } else {
- for (found = false, gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL;
- gr1_ndx++) {
- for (gr2_ndx = 0; gr2->gr_mem[gr2_ndx] != NULL;
- gr2_ndx++)
- if (strcmp(gr1->gr_mem[gr1_ndx],
- gr2->gr_mem[gr2_ndx]) == 0) {
- found = true;
- break;
- }
- if (!found)
+ /* Check all members in both groups.
+ * getgrnam can return gr_mem with a pointer to NULL.
+ * gr_dup and gr_add strip out this superfluous NULL, setting
+ * gr_mem to NULL for no members.
+ */
+ if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
+ int i;
+
+ for (i = 0; gr1->gr_mem[i] != NULL; i++) {
+ if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
return (false);
}
-
- /* Check that group2 does not have more members than group1. */
- if (gr2->gr_mem[gr1_ndx] != NULL)
- return (false);
}
+ /* Count number of members in both structs */
+ gr2_ndx = 0;
+ if (gr2->gr_mem != NULL)
+ for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++)
+ /* empty */;
+ gr1_ndx = 0;
+ if (gr1->gr_mem != NULL)
+ for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++)
+ /* empty */;
+ if (gr1_ndx != gr2_ndx)
+ return (false);
return (true);
}
char *
gr_make(const struct group *gr)
{
+ const char *group_line_format = "%s:%s:%ju:";
+ const char *sep;
char *line;
+ char *p;
size_t line_size;
int ndx;
}
/* Create the group line and fill it. */
- if ((line = malloc(line_size)) == NULL)
+ if ((line = p = malloc(line_size)) == NULL)
return (NULL);
- snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd,
+ p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
(uintmax_t)gr->gr_gid);
- if (gr->gr_mem != NULL)
+ if (gr->gr_mem != NULL) {
+ sep = "";
for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
- strcat(line, gr->gr_mem[ndx]);
- if (gr->gr_mem[ndx + 1] != NULL)
- strcat(line, ",");
+ p = stpcpy(p, sep);
+ p = stpcpy(p, gr->gr_mem[ndx]);
+ sep = ",";
}
+ }
return (line);
}
struct group *
gr_dup(const struct group *gr)
{
- char *dst;
+ return (gr_add(gr, NULL));
+}
+/*
+ * Add a new member name to a struct group.
+ */
+struct group *
+gr_add(const struct group *gr, const char *newmember)
+{
+ char *mem;
size_t len;
- struct group_storage *gs;
- int ndx;
int num_mem;
- /* Calculate size of the group. */
- len = sizeof(*gs);
- if (gr->gr_name != NULL)
- len += strlen(gr->gr_name) + 1;
- if (gr->gr_passwd != NULL)
- len += strlen(gr->gr_passwd) + 1;
- if (gr->gr_mem != NULL) {
- for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++)
- len += strlen(gr->gr_mem[num_mem]) + 1;
- len += (num_mem + 1) * sizeof(*gr->gr_mem);
- } else
- num_mem = -1;
-
+ num_mem = 0;
+ len = grmemlen(gr, newmember, &num_mem);
/* Create new group and copy old group into it. */
- if ((gs = calloc(1, len)) == NULL)
+ if ((mem = malloc(len)) == NULL)
return (NULL);
- dst = (char *)&gs->members[num_mem + 1];
+ return (grcopy(gr, mem, newmember, num_mem));
+}
+
+/* It is safer to walk the pointers given at gr_mem since there is no
+ * guarantee the gr_mem + strings are contiguous in the given struct group
+ * but compactify the new group into the following form.
+ *
+ * The new struct is laid out like this in memory. The example given is
+ * for a group with two members only.
+ *
+ * {
+ * (char *name)
+ * (char *passwd)
+ * (int gid)
+ * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
+ * gr_mem area
+ * (member1 *)
+ * (member2 *)
+ * (NULL)
+ * (name string)
+ * (passwd string)
+ * (member1 string)
+ * (member2 string)
+ * }
+ */
+/*
+ * Copy the contents of a group plus given name to a preallocated group struct
+ */
+static struct group *
+grcopy(const struct group *gr, char *dst, const char *name, int ndx)
+{
+ int i;
+ struct group *newgr;
+
+ newgr = (struct group *)(void *)dst; /* avoid alignment warning */
+ dst += sizeof(*newgr);
+ if (ndx != 0) {
+ newgr->gr_mem = (char **)(void *)(dst); /* avoid alignment warning */
+ dst += (ndx + 1) * sizeof(*newgr->gr_mem);
+ } else
+ newgr->gr_mem = NULL;
if (gr->gr_name != NULL) {
- gs->gr.gr_name = dst;
- dst = stpcpy(gs->gr.gr_name, gr->gr_name) + 1;
- }
+ newgr->gr_name = dst;
+ dst = stpcpy(dst, gr->gr_name) + 1;
+ } else
+ newgr->gr_name = NULL;
if (gr->gr_passwd != NULL) {
- gs->gr.gr_passwd = dst;
- dst = stpcpy(gs->gr.gr_passwd, gr->gr_passwd) + 1;
- }
- gs->gr.gr_gid = gr->gr_gid;
+ newgr->gr_passwd = dst;
+ dst = stpcpy(dst, gr->gr_passwd) + 1;
+ } else
+ newgr->gr_passwd = NULL;
+ newgr->gr_gid = gr->gr_gid;
+ i = 0;
+ /* Original group struct might have a NULL gr_mem */
if (gr->gr_mem != NULL) {
- gs->gr.gr_mem = gs->members;
- for (ndx = 0; ndx < num_mem; ndx++) {
- gs->gr.gr_mem[ndx] = dst;
- dst = stpcpy(gs->gr.gr_mem[ndx], gr->gr_mem[ndx]) + 1;
+ for (; gr->gr_mem[i] != NULL; i++) {
+ newgr->gr_mem[i] = dst;
+ dst = stpcpy(dst, gr->gr_mem[i]) + 1;
}
- gs->gr.gr_mem[ndx] = NULL;
}
+ /* If name is not NULL, newgr->gr_mem is known to be not NULL */
+ if (name != NULL) {
+ newgr->gr_mem[i++] = dst;
+ dst = stpcpy(dst, name) + 1;
+ }
+ /* if newgr->gr_mem is not NULL add NULL marker */
+ if (newgr->gr_mem != NULL)
+ newgr->gr_mem[i] = NULL;
- return (&gs->gr);
+ return (newgr);
+}
+
+/*
+ * Calculate length of a struct group + given name
+ */
+static size_t
+grmemlen(const struct group *gr, const char *name, int *num_mem)
+{
+ size_t len;
+ int i;
+
+ if (gr == NULL)
+ return (0);
+ /* Calculate size of the group. */
+ len = sizeof(*gr);
+ if (gr->gr_name != NULL)
+ len += strlen(gr->gr_name) + 1;
+ if (gr->gr_passwd != NULL)
+ len += strlen(gr->gr_passwd) + 1;
+ i = 0;
+ if (gr->gr_mem != NULL) {
+ for (; gr->gr_mem[i] != NULL; i++) {
+ len += strlen(gr->gr_mem[i]) + 1;
+ len += sizeof(*gr->gr_mem);
+ }
+ }
+ if (name != NULL) {
+ i++;
+ len += strlen(name) + 1;
+ len += sizeof(*gr->gr_mem);
+ }
+ /* Allow for NULL pointer */
+ if (i != 0)
+ len += sizeof(*gr->gr_mem);
+ *num_mem = i;
+ return(len);
}
/*
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