diff options
| -rw-r--r-- | libpwdgrp/pwd_grp.c | 58 |
1 files changed, 32 insertions, 26 deletions
diff --git a/libpwdgrp/pwd_grp.c b/libpwdgrp/pwd_grp.c index 1b2418a..4b61b61 100644 --- a/libpwdgrp/pwd_grp.c +++ b/libpwdgrp/pwd_grp.c @@ -34,24 +34,21 @@ struct const_passdb { const char *filename; - const char def[9]; - const uint8_t off[9]; + const char def[7 + 2*ENABLE_USE_BB_SHADOW]; + const uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW]; uint8_t numfields; + uint8_t size_of; }; struct passdb { const char *filename; - const char def[9]; - const uint8_t off[9]; + const char def[7 + 2*ENABLE_USE_BB_SHADOW]; + const uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW]; uint8_t numfields; + uint8_t size_of; FILE *fp; char *malloced; - char struct_result[ - /* Should be max(sizeof passwd,group,spwd), but this will do: */ - IF_NOT_USE_BB_SHADOW(sizeof(struct passwd)) - IF_USE_BB_SHADOW(sizeof(struct spwd)) - ]; }; -/* Note: for shadow db, def[9] will not contain terminating NUL, +/* Note: for shadow db, def[] will not contain terminating NUL, * but convert_to_struct() logic detects def[] end by "less than SP?", * not by "is it NUL?" condition; and off[0] happens to be zero * for every db anyway, so there _is_ in fact a terminating NUL there. @@ -76,7 +73,7 @@ static const struct const_passdb const_pw_db = { offsetof(struct passwd, pw_dir), /* 5 S */ offsetof(struct passwd, pw_shell) /* 6 S */ }, - sizeof(PW_DEF)-1 + sizeof(PW_DEF)-1, sizeof(struct passwd) }; static const struct const_passdb const_gr_db = { _PATH_GROUP, GR_DEF, @@ -86,7 +83,7 @@ static const struct const_passdb const_gr_db = { offsetof(struct group, gr_gid), /* 2 I */ offsetof(struct group, gr_mem) /* 3 m (char **) */ }, - sizeof(GR_DEF)-1 + sizeof(GR_DEF)-1, sizeof(struct group) }; #if ENABLE_USE_BB_SHADOW static const struct const_passdb const_sp_db = { @@ -102,19 +99,20 @@ static const struct const_passdb const_sp_db = { offsetof(struct spwd, sp_expire), /* 7 l */ offsetof(struct spwd, sp_flag) /* 8 r Reserved */ }, - sizeof(SP_DEF)-1 + sizeof(SP_DEF)-1, sizeof(struct spwd) }; #endif /* We avoid having big global data. */ struct statics { - /* It's ok to use same buffer (db[0].struct_result) for getpwuid and getpwnam. + /* It's ok to use same buffer (db[0].malloced) for getpwuid and getpwnam. * Manpage says: * "The return value may point to a static area, and may be overwritten * by subsequent calls to getpwent(), getpwnam(), or getpwuid()." */ struct passdb db[2 + ENABLE_USE_BB_SHADOW]; char *tokenize_end; + unsigned string_size; }; static struct statics *ptr_to_statics; @@ -205,21 +203,21 @@ static char *parse_common(FILE *fp, const char *filename, bb_error_msg("bad record at %s:%u", filename, count); goto free_and_next; } + S.string_size = S.tokenize_end - buf; -/* Ugly hack: group db requires aqdditional buffer space +/* Ugly hack: group db requires additional buffer space * for members[] array. If there is only one group, we need space * for 3 pointers: alignment padding, group name, NULL. * +1 for every additional group. */ if (n_fields == sizeof(GR_DEF)-1) { /* if we read group file */ - int resize = 3; + int cnt = 3; char *p = buf; while (*p) if (*p++ == ',') - resize++; - resize *= sizeof(char**); - resize += S.tokenize_end - buf; - buf = xrealloc(buf, resize); + cnt++; + S.string_size += cnt * sizeof(char*); + buf = xrealloc(buf, S.string_size); } if (!key) { @@ -258,8 +256,8 @@ static void *convert_to_struct(struct passdb *db, const char *def = db->def; const uint8_t *off = db->off; -/* TODO? for consistency, zero out all fields */ -/* memset(result, 0, size_of_result);*/ + /* For consistency, zero out all fields */ + memset(result, 0, db->size_of); for (;;) { void *member = (char*)result + (*off++); @@ -305,7 +303,7 @@ static void *convert_to_struct(struct passdb *db, /* def "r" does nothing */ def++; - if ((unsigned char)*def < (unsigned char)' ') + if ((unsigned char)*def <= (unsigned char)' ') break; buffer += strlen(buffer) + 1; } @@ -328,7 +326,9 @@ static int FAST_FUNC getXXnam_r(const char *name, uintptr_t db_and_field_pos, db = &S.db[db_and_field_pos >> 2]; *(void**)result = NULL; - buf = parse_file(db->filename, db->numfields, name, db_and_field_pos & 3); + buf = parse_file(db->filename, db->numfields, name, 0 /*db_and_field_pos & 3*/); + /* "db_and_field_pos & 3" is commented out since so far we don't implement + * getXXXid_r() functions which would use that to pass 2 here */ if (buf) { size_t size = S.tokenize_end - buf; if (size > buflen) { @@ -433,8 +433,14 @@ static void* FAST_FUNC getXXnam(const char *name, unsigned db_and_field_pos) buf = parse_common(db->fp, db->filename, db->numfields, name, db_and_field_pos & 3); if (buf) { free(db->malloced); - db->malloced = buf; - result = convert_to_struct(db, buf, db->struct_result); + /* We enlarge buf and move string data up, freeing space + * for struct passwd/group/spwd at the beginning. This way, + * entire result of getXXnam is in a single malloced block. + * This enables easy creation of xmalloc_getpwnam() API. + */ + db->malloced = buf = xrealloc(buf, db->size_of + S.string_size); + memmove(buf + db->size_of, buf, S.string_size); + result = convert_to_struct(db, buf + db->size_of, buf); } return result; } |