diff options
Diffstat (limited to 'lib/libutil/gr_util.c')
-rw-r--r-- | lib/libutil/gr_util.c | 193 |
1 files changed, 119 insertions, 74 deletions
diff --git a/lib/libutil/gr_util.c b/lib/libutil/gr_util.c index 3f7e19901e2a..6f7450778f12 100644 --- a/lib/libutil/gr_util.c +++ b/lib/libutil/gr_util.c @@ -49,6 +49,8 @@ static char group_dir[PATH_MAX]; static char group_file[PATH_MAX]; static char tempname[PATH_MAX]; static int initialized; +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 @@ -359,26 +361,30 @@ gr_equal(const struct group *gr1, const struct group *gr2) 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 (gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++) { - for (gr2_ndx = 0;; gr2_ndx++) { - if (gr2->gr_mem[gr2_ndx] == NULL) - return (false); - if (strcmp(gr1->gr_mem[gr1_ndx], - gr2->gr_mem[gr2_ndx]) == 0) { - break; - } - } + /* 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); } @@ -429,90 +435,129 @@ gr_make(const struct group *gr) struct group * gr_dup(const struct group *gr) { - struct group *newgr; - 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; - int ndx; int num_mem; - /* Calculate size of the group. */ - len = sizeof(*newgr); - 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 ((newgr = malloc(len)) == NULL) + if ((mem = malloc(len)) == NULL) return (NULL); - /* point new gr_mem to end of struct + 1 */ - if (gr->gr_mem != NULL) - newgr->gr_mem = (char **)(newgr + 1); - else + 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; - /* point dst after the end of all the gr_mem pointers in newgr */ - dst = (char *)&newgr->gr_mem[num_mem + 1]; if (gr->gr_name != NULL) { newgr->gr_name = dst; dst = stpcpy(dst, gr->gr_name) + 1; - } else { + } else newgr->gr_name = NULL; - } if (gr->gr_passwd != NULL) { newgr->gr_passwd = dst; dst = stpcpy(dst, gr->gr_passwd) + 1; - } else { + } 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) { - for (ndx = 0; ndx < num_mem; ndx++) { - newgr->gr_mem[ndx] = dst; - dst = stpcpy(dst, 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; } - newgr->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 (newgr); } /* - * Add a new member name to a struct group. + * Calculate length of a struct group + given name */ -struct group * -gr_add(struct group *gr, char *newmember) +static size_t +grmemlen(const struct group *gr, const char *name, int *num_mem) { - size_t mlen; - int num_mem=0; - char **members; - struct group *newgr; - - if (newmember == NULL) - return(gr_dup(gr)); + 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 (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) { - if (strcmp(gr->gr_mem[num_mem], newmember) == 0) { - errno = EEXIST; - return (NULL); - } + for (; gr->gr_mem[i] != NULL; i++) { + len += strlen(gr->gr_mem[i]) + 1; + len += sizeof(*gr->gr_mem); } } - /* Allocate enough for current pointers + 1 more and NULL marker */ - mlen = (num_mem + 2) * sizeof(*gr->gr_mem); - if ((members = malloc(mlen)) == NULL) - return (NULL); - memcpy(members, gr->gr_mem, num_mem * sizeof(*gr->gr_mem)); - members[num_mem++] = newmember; - members[num_mem] = NULL; - gr->gr_mem = members; - newgr = gr_dup(gr); - free(members); - return (newgr); + 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); } /* |