ifupdown: save some 100+ bytes of code in addstr()

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index f72e653b310b49ac581c4739d69c491cfab05167..d4e49c4c176274b0c3a400e4fde4001adad408c7 100644 (file)
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -125,6 +125,7 @@ static int count_netmask_bits(char *dotted_quad)
        /* Found a netmask...  Check if it is dotted quad */
        if (sscanf(dotted_quad, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
                return -1;
+       // FIXME: will be confused by e.g. 255.0.255.0
        result = count_bits(a);
        result += count_bits(b);
        result += count_bits(c);
@@ -133,32 +134,27 @@ static int count_netmask_bits(char *dotted_quad)
 }
 #endif
 
-static void addstr(char **buf, size_t *len, size_t *pos, const char *str, size_t str_length)
+static void addstr(char **bufp, const char *str, size_t str_length)
 {
-       if (*pos + str_length >= *len) {
-               char *newbuf;
-
-               newbuf = xrealloc(*buf, *len * 2 + str_length + 1);
-               *buf = newbuf;
-               *len = *len * 2 + str_length + 1;
-       }
-
-       while (str_length-- >= 1) {
-               (*buf)[(*pos)++] = *str;
-               str++;
-       }
-       (*buf)[*pos] = '\0';
+       /* xasprintf trick will be smaller, but we are often
+        * called with str_length == 1 - don't want to have
+        * THAT much of malloc/freeing! */
+       char *buf = *bufp;
+       int len = (buf ? strlen(buf) : 0);
+       str_length++;
+       buf = xrealloc(buf, len + str_length);
+       /* copies at most str_length-1 chars! */
+       safe_strncpy(buf + len, str, str_length);
+       *bufp = buf;
 }
 
 static int strncmpz(const char *l, const char *r, size_t llen)
 {
        int i = strncmp(l, r, llen);
 
-       if (i == 0) {
+       if (i == 0)
                return -r[llen];
-       } else {
-               return i;
-       }
+       return i;
 }
 
 static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
@@ -168,31 +164,27 @@ static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
        if (strncmpz(id, "iface", idlen) == 0) {
                char *result;
                static char label_buf[20];
-               strncpy(label_buf, ifd->iface, 19);
-               label_buf[19]=0;
+               safe_strncpy(label_buf, ifd->iface, sizeof(label_buf));
                result = strchr(label_buf, ':');
                if (result) {
-                       *result=0;
+                       *result = '\0';
                }
                return label_buf;
-       } else if (strncmpz(id, "label", idlen) == 0) {
+       }
+       if (strncmpz(id, "label", idlen) == 0) {
                return ifd->iface;
-       } else {
-               for (i = 0; i < ifd->n_options; i++) {
-                       if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
-                               return ifd->option[i].value;
-                       }
+       }
+       for (i = 0; i < ifd->n_options; i++) {
+               if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
+                       return ifd->option[i].value;
                }
        }
-
        return NULL;
 }
 
 static char *parse(const char *command, struct interface_defn_t *ifd)
 {
-
        char *result = NULL;
-       size_t pos = 0, len = 0;
        size_t old_pos[MAX_OPT_DEPTH] = { 0 };
        int okay[MAX_OPT_DEPTH] = { 1 };
        int opt_depth = 1;
@@ -200,26 +192,26 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
        while (*command) {
                switch (*command) {
                default:
-                       addstr(&result, &len, &pos, command, 1);
+                       addstr(&result, command, 1);
                        command++;
                        break;
                case '\\':
                        if (command[1]) {
-                               addstr(&result, &len, &pos, command + 1, 1);
+                               addstr(&result, command + 1, 1);
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, command, 1);
+                               addstr(&result, command, 1);
                                command++;
                        }
                        break;
                case '[':
                        if (command[1] == '[' && opt_depth < MAX_OPT_DEPTH) {
-                               old_pos[opt_depth] = pos;
+                               old_pos[opt_depth] = strlen(result);
                                okay[opt_depth] = 1;
                                opt_depth++;
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, "[", 1);
+                               addstr(&result, "[", 1);
                                command++;
                        }
                        break;
@@ -227,12 +219,11 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                        if (command[1] == ']' && opt_depth > 1) {
                                opt_depth--;
                                if (!okay[opt_depth]) {
-                                       pos = old_pos[opt_depth];
-                                       result[pos] = '\0';
+                                       result[old_pos[opt_depth]] = '\0';
                                }
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, "]", 1);
+                               addstr(&result, "]", 1);
                                command++;
                        }
                        break;
@@ -252,18 +243,17 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                                varvalue = get_var(command, nextpercent - command, ifd);
 
                                if (varvalue) {
-                                       addstr(&result, &len, &pos, varvalue, strlen(varvalue));
+                                       addstr(&result, varvalue, strlen(varvalue));
                                } else {
 #ifdef CONFIG_FEATURE_IFUPDOWN_IP
                                        /* Sigh...  Add a special case for 'ip' to convert from
                                         * dotted quad to bit count style netmasks.  */
                                        if (strncmp(command, "bnmask", 6)==0) {
-                                               int res;
+                                               unsigned res;
                                                varvalue = get_var("netmask", 7, ifd);
-                                               if (varvalue && (res=count_netmask_bits(varvalue)) > 0) {
-                                                       char argument[255];
-                                                       sprintf(argument, "%d", res);
-                                                       addstr(&result, &len, &pos, argument, strlen(argument));
+                                               if (varvalue && (res = count_netmask_bits(varvalue)) > 0) {
+                                                       const char *argument = utoa(res);
+                                                       addstr(&result, argument, strlen(argument));
                                                        command = nextpercent + 1;
                                                        break;
                                                }
@@ -567,7 +557,7 @@ static char *next_word(char **buf)
        unsigned short length;
        char *word;
 
-       if ((buf == NULL) || (*buf == NULL) || (**buf == '\0')) {
+       if (!buf || !*buf || !**buf) {
                return NULL;
        }