I cleaned up the code in 'netstat.c' as belows.

 - Adjust to 80 columns
 - remove a useless function(strchr_nul), variable, type casting and
   compile warnings(fgets)
 - clean up netstat command option condition
 - change useless double pointer to single point and dynamic memory
   allocation to static one
 - fix a ambiguous return type and typo

1 files changed, 131 insertions, 88 deletions

diff --git a/toys/pending/netstat.c b/toys/pending/netstat.c
index 3ee4c5a2..d6acd7a3 100644
--- a/toys/pending/netstat.c
+++ b/toys/pending/netstat.c
@@ -52,7 +52,7 @@ typedef union _iaddr6 {
   unsigned char b[16];
 } iaddr6;
 
-#define ADDR_LEN (INET6_ADDRSTRLEN + 1 + 5 + 1) //IPv6 addr len + : + port + '\0'
+#define ADDR_LEN (INET6_ADDRSTRLEN + 1 + 5 + 1)//IPv6 addr len + : + port + '\0'
 
 //For unix states
 enum {
@@ -68,21 +68,14 @@ typedef struct _pidlist {
   long inode;
   char name[21];
 } PID_LIST;
-PID_LIST *pid_list = NULL;
 
-/*
- * locate character in string.
- */
-static char *strchr_nul(char *s, int c)
-{
-  while(*s != '\0' && *s != c) s++;
-  return (char*)s;
-}
+PID_LIST *pid_list = NULL;
 
 /*
- * used to converts string into int and validate the input str for invalid int value or out-of-range.
+ * used to convert string into int and
+ * validate the input str for invalid int value or out-of-range.
  */
-static unsigned get_strtou(char *str, char **endp, int base)
+static unsigned long get_strtou(char *str, char **endp, int base)
 {
   unsigned long uli;
   char *endptr;
@@ -108,16 +101,20 @@ static unsigned get_strtou(char *str, char **endp, int base)
   }
   return uli;
 }
+
 /*
  * used to retrive pid name from pid list.
  */
 static const char *get_pid_name(unsigned long inode)
 {
   PID_LIST *tmp;
+
   for (tmp = pid_list; tmp; tmp = tmp->next)
     if (tmp->inode == inode) return tmp->name;
+
   return "-";
 }
+
 /*
  * For TCP/UDP/RAW display data.
  */
@@ -126,8 +123,9 @@ static void display_data(unsigned rport, char *label,
                          unsigned state, unsigned uid, unsigned long inode)
 {
   char *ss_state = "UNKNOWN", buf[12];
-  char *state_label[] = {"", "ESTABLISHED", "SYN_SENT", "SYN_RECV", "FIN_WAIT1", "FIN_WAIT2",
-  		                 "TIME_WAIT", "CLOSE", "CLOSE_WAIT", "LAST_ACK", "LISTEN", "CLOSING", "UNKNOWN"};
+  char *state_label[] = {"", "ESTABLISHED", "SYN_SENT", "SYN_RECV", "FIN_WAIT1",
+                         "FIN_WAIT2", "TIME_WAIT", "CLOSE", "CLOSE_WAIT",
+                         "LAST_ACK", "LISTEN", "CLOSING", "UNKNOWN"};
   char user[11];
   struct passwd *pw;
 
@@ -147,12 +145,14 @@ static void display_data(unsigned rport, char *label,
   } else snprintf(user, sizeof(user), "%d", uid);
 
   xprintf("%3s   %6d %6d ", label, rxq, txq);
-  xprintf((toys.optflags & FLAG_W) ? "%-51.51s %-51.51s " : "%-23.23s %-23.23s ", lip, rip);
+  xprintf((toys.optflags & FLAG_W) ? "%-51.51s %-51.51s " : "%-23.23s %-23.23s "
+           , lip, rip);
   xprintf("%-11s ", ss_state);
-  if ((toys.optflags & FLAG_e)) xprintf("%-10s %-11d ", user, inode);
+  if ((toys.optflags & FLAG_e)) xprintf("%-10s %-11ld ", user, inode);
   if ((toys.optflags & FLAG_p)) xprintf("%s", get_pid_name(inode));
   xputc('\n');
 }
+
 /*
  * For TCP/UDP/RAW show data.
  */
@@ -161,11 +161,15 @@ static void show_data(unsigned rport, char *label, unsigned rxq, unsigned txq,
                       unsigned long inode)
 {
   if (toys.optflags & FLAG_l) {
-    if (!rport && (state & 0xA)) display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
-  } else if (toys.optflags & FLAG_a) display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
+    if (!rport && (state & 0xA))
+      display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
+  } else if (toys.optflags & FLAG_a)
+    display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
   //rport && (TCP | UDP | RAW)
-  else if (rport & (0x10 | 0x20 | 0x40)) display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
+  else if (rport & (0x10 | 0x20 | 0x40))
+    display_data(rport, label, rxq, txq, lip, rip, state, uid, inode);
 }
+
 /*
  * used to get service name.
  */
@@ -177,6 +181,7 @@ static char *get_servname(int port, char *label)
   if (ser) return xmprintf("%s", ser->s_name);
   return xmprintf("%u", (unsigned)ntohs(lport));
 }
+
 /*
  * used to convert address into text format.
  */
@@ -210,7 +215,8 @@ static void addr2str(int af, void *addr, unsigned port, char *buf, char *label)
       else sock_len = sizeof(struct sockaddr_in6);
 
       for (rp = result; rp; rp = rp->ai_next)
-        if (!getnameinfo(rp->ai_addr, sock_len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf), NI_NUMERICSERV))
+        if (!getnameinfo(rp->ai_addr, sock_len, hbuf, sizeof(hbuf), sbuf,
+            sizeof(sbuf), NI_NUMERICSERV))
           break;
 
       freeaddrinfo(result);
@@ -228,17 +234,20 @@ static void addr2str(int af, void *addr, unsigned port, char *buf, char *label)
   else snprintf(ip+iplen, ADDR_LEN-iplen, ":%d", port);
   memcpy(buf, ip, ADDR_LEN);
 }
+
 /*
  * display ipv4 info for TCP/UDP/RAW.
  */
 static void show_ipv4(char *fname, char *label)
 {
-  FILE *fp = fopen((char *)fname, "r");
+  FILE *fp = fopen(fname, "r");
   if (!fp) {
      perror_msg("'%s'", fname);
      return;
   }
-  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+
+  if(!fgets(toybuf, sizeof(toybuf), fp)) return; //skip header.
+
   while (fgets(toybuf, sizeof(toybuf), fp)) {
     char lip[ADDR_LEN] = {0,}, rip[ADDR_LEN] = {0,};
     iaddr laddr, raddr;
@@ -246,7 +255,8 @@ static void show_ipv4(char *fname, char *label)
     unsigned long inode;
 
     int nitems = sscanf(toybuf, " %d: %x:%x %x:%x %x %x:%x %*X:%*X %*X %d %*d %ld",
-        &num, &laddr.u, &lport, &raddr.u, &rport, &state, &txq, &rxq, &uid, &inode);
+                        &num, &laddr.u, &lport, &raddr.u, &rport, &state, &txq,
+                        &rxq, &uid, &inode);
     if (nitems == 10) {
       addr2str(AF_INET, &laddr, lport, lip, label);
       addr2str(AF_INET, &raddr, rport, rip, label);
@@ -255,25 +265,31 @@ static void show_ipv4(char *fname, char *label)
   }//End of While
   fclose(fp);
 }
+
 /*
  * display ipv6 info for TCP/UDP/RAW.
  */
 static void show_ipv6(char *fname, char *label)
 {
-  FILE *fp = fopen((char *)fname, "r");
+  FILE *fp = fopen(fname, "r");
   if (!fp) {
     perror_msg("'%s'", fname);
     return;
   }
-  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+
+  if(!fgets(toybuf, sizeof(toybuf), fp)) return; //skip header.
+
   while (fgets(toybuf, sizeof(toybuf), fp)) {
     char lip[ADDR_LEN] = {0,}, rip[ADDR_LEN] = {0,};
     iaddr6 laddr6, raddr6;
     unsigned lport, rport, state, txq, rxq, num, uid;
     unsigned long inode;
-    int nitems = sscanf(toybuf, " %d: %8x%8x%8x%8x:%x %8x%8x%8x%8x:%x %x %x:%x %*X:%*X %*X %d %*d %ld",
-        &num, &laddr6.u.a, &laddr6.u.b, &laddr6.u.c, &laddr6.u.d, &lport, &raddr6.u.a, &raddr6.u.b,
-        &raddr6.u.c, &raddr6.u.d, &rport, &state, &txq, &rxq, &uid, &inode);
+    int nitems = sscanf(toybuf, " %d: %8x%8x%8x%8x:%x %8x%8x%8x%8x:%x %x %x:%x "
+                                "%*X:%*X %*X %d %*d %ld",
+                        &num, &laddr6.u.a, &laddr6.u.b, &laddr6.u.c,
+                        &laddr6.u.d, &lport, &raddr6.u.a, &raddr6.u.b,
+                        &raddr6.u.c, &raddr6.u.d, &rport, &state, &txq, &rxq,
+                        &uid, &inode);
     if (nitems == 16) {
       addr2str(AF_INET6, &laddr6, lport, lip, label);
       addr2str(AF_INET6, &raddr6, rport, rip, label);
@@ -282,6 +298,7 @@ static void show_ipv6(char *fname, char *label)
   }//End of While
   fclose(fp);
 }
+
 /*
  * display unix socket info.
  */
@@ -292,30 +309,39 @@ static void show_unix_sockets(char *fname, char *label)
     perror_msg("'%s'", fname);
     return;
   }
-  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+
+  if(!fgets(toybuf, sizeof(toybuf), fp)) return; //skip header.
+
   while (fgets(toybuf, sizeof(toybuf), fp)) {
-    unsigned long int refcount, label, flags, inode;
+    unsigned long refcount, label, flags, inode;
     int nitems = 0, path_offset = 0, type, state;
-    char sock_flags[32] = {0,}, *sock_type, *sock_state, *bptr = toybuf;
+    char sock_flags[32] = {0,}, *sock_type, *sock_state, *bptr = toybuf, *term;
 
     if (!toybuf[0]) continue;
+
     nitems = sscanf(toybuf, "%*p: %lX %lX %lX %X %X %lu %n",
         &refcount, &label, &flags, &type, &state, &inode, &path_offset);
+
     //for state one less
     if (nitems < 6) break;
+
     if (toys.optflags & FLAG_l) {
-      if ( !((state == SOCK_NOT_CONNECTED) && (flags & SOCK_ACCEPTCON)) ) continue;
+      if ( !((state == SOCK_NOT_CONNECTED) && (flags & SOCK_ACCEPTCON)) )
+        continue;
     } else if (!(toys.optflags & FLAG_a)) {
       if ((state == SOCK_NOT_CONNECTED) && (flags & SOCK_ACCEPTCON)) continue;
     }
 
     //prepare socket type, state and flags.
     {
-      char *ss_type[] = { "", "STREAM", "DGRAM", "RAW", "RDM", "SEQPACKET", "UNKNOWN"};
-      char *ss_state[] = { "FREE", "LISTENING", "CONNECTING", "CONNECTED", "DISCONNECTING", "UNKNOWN"};
+      char *ss_type[] = { "", "STREAM", "DGRAM", "RAW", "RDM", "SEQPACKET",
+                          "UNKNOWN"};
+      char *ss_state[] = { "FREE", "LISTENING", "CONNECTING", "CONNECTED",
+                           "DISCONNECTING", "UNKNOWN"};
 
       int sz = ARRAY_LEN(ss_type);//sizeof(ss_type)/sizeof(ss_type[0]);
-      if ( (type < SOCK_STREAM) || (type > SOCK_SEQPACKET) ) sock_type = ss_type[sz-1];
+      if ( (type < SOCK_STREAM) || (type > SOCK_SEQPACKET) )
+        sock_type = ss_type[sz-1];
       else sock_type = ss_type[type];
 
       sz = ARRAY_LEN(ss_state);//sizeof(ss_state)/sizeof(ss_state[0]);
@@ -331,15 +357,17 @@ static void show_unix_sockets(char *fname, char *label)
       if (flags & SOCK_NO_SPACE) strcat(sock_flags, "N ");
       strcat(sock_flags, "]");
     }
-    xprintf("%-5s %-6ld %-11s %-10s %-13s %8lu ", (!label ? "unix" : "??"), refcount, sock_flags, sock_type, sock_state, inode);
+    xprintf("%-5s %-6ld %-11s %-10s %-13s %8lu ", (!label ? "unix" : "??"),
+      refcount, sock_flags, sock_type, sock_state, inode);
     if (toys.optflags & FLAG_p) xprintf("%-20s", get_pid_name(inode));
 
     bptr += path_offset;
-    *strchr_nul(bptr, '\n') = '\0';
+    if ((term = strchr(bptr, '\n'))) *term = '\0';
     xprintf("%s\n", bptr);
   }//End of while
   fclose(fp);
 }
+
 /*
  * extract inode value from the link.
  */
@@ -359,16 +387,19 @@ static long ss_inode(char *link)
   }
   return inode;
 }
+
 /*
  * add inode and progname in the pid list.
  */
 static void add2list(long inode)
 {
   PID_LIST *node = pid_list;
+
   for(; node; node = node->next) {
     if(node->inode == inode)
       return;
   }
+
   PID_LIST *new = (PID_LIST *)xzalloc(sizeof(PID_LIST));
   new->inode = inode;
   xstrncpy(new->name, TT.current_name, sizeof(new->name));
@@ -423,6 +454,7 @@ static int scan_pids(struct dirtree *node)
 
   if (!node->parent) return DIRTREE_RECURSE;
   if ((pid = atol(node->name))) scan_pid(pid);
+
   return 0;
 }
 
@@ -438,12 +470,13 @@ static void clean_pid_list(void)
     pid_list = tmp;
   }
 }
+
 /*
  * For TCP/UDP/RAW show the header.
  */
 static void show_header(void)
 {
-  xprintf("\nProto Recv-Q Send-Q ");
+  xprintf("Proto Recv-Q Send-Q ");
   xprintf((toys.optflags & FLAG_W) ? "%-51s %-51s" : "%-23s %-23s",
           "Local Address", "Foreign Address");
   xprintf(" State      ");
@@ -451,13 +484,14 @@ static void show_header(void)
   if (toys.optflags & FLAG_p) xprintf(" PID/Program Name");
   xputc('\n');
 }
+
 /*
  * used to get the flag values for route command.
  */
-static void get_flag_value(char **flagstr, int flags)
+static void get_flag_value(char *flagstr, int flags)
 {
   int i = 0;
-  char *str = *flagstr;
+  char *str = flagstr;
   static const char flagchars[] = "GHRDMDAC";
   static const unsigned flagarray[] = {
     RTF_GATEWAY,
@@ -470,10 +504,12 @@ static void get_flag_value(char **flagstr, int flags)
     RTF_CACHE
   };
   *str++ = 'U';
+
   while ( (*str = flagchars[i]) ) {
     if (flags & flagarray[i++]) ++str;
   }
 }
+
 /*
  * extract inet4 route info from /proc/net/route file and display it.
  */
@@ -483,85 +519,87 @@ static void display_routes(int is_more_info, int notresolve)
   unsigned long dest, gate, mask;
   int flags, ref, use, metric, mss, win, irtt;
   char iface[64]={0,};
-  char *flag_val = xzalloc(10); //there are 9 flags "UGHRDMDAC" for route.
+  char flag_val[10]={0,}; //there are 9 flags "UGHRDMDAC" for route.
 
   FILE *fp = xfopen("/proc/net/route", "r");
+
+  if(!fgets(toybuf, sizeof(toybuf), fp)) return; //skip header.
+
   xprintf("Kernel IP routing table\n"
-                   "Destination     Gateway         Genmask         Flags %s Iface\n",
-  	                        is_more_info ? "  MSS Window  irtt" : "Metric Ref    Use");
-  fgets(toybuf, sizeof(toybuf), fp); //skip 1st line.
+          "Destination     Gateway         Genmask         Flags %s Iface\n",
+          is_more_info ? "  MSS Window  irtt" : "Metric Ref    Use");
+
   while (fgets(toybuf, sizeof(toybuf), fp)) {
      int nitems = 0;
      char *destip = NULL, *gateip = NULL, *maskip = NULL;
-     memset(flag_val, 0, 10);
 
-     nitems = sscanf(toybuf, "%63s%lx%lx%X%d%d%d%lx%d%d%d\n",
-                 iface, &dest, &gate, &flags, &ref, &use, &metric, &mask, &mss, &win, &irtt);
+     nitems = sscanf(toybuf, "%63s%lx%lx%X%d%d%d%lx%d%d%d\n", iface, &dest,
+       &gate, &flags, &ref, &use, &metric, &mask, &mss, &win, &irtt);
      if (nitems != 11) {//EOF with no (nonspace) chars read.
        if ((nitems < 0) && feof(fp)) break;
       perror_exit("sscanf");
     }
+
     //skip down interfaces.
     if (!(flags & RTF_UP)) continue;
 
     if (dest) {//For Destination
-      if (inet_ntop(AF_INET, &dest, toybuf, sizeof(toybuf)) ) destip = xstrdup(toybuf);
+      if (inet_ntop(AF_INET, &dest, toybuf, sizeof(toybuf)) )
+        destip = xstrdup(toybuf);
     } else {
       if (!notresolve) destip = xstrdup("default");
       else destip = xstrdup("0.0.0.0");
     }
+
     if (gate) {//For Gateway
-      if (inet_ntop(AF_INET, &gate, toybuf, sizeof(toybuf)) ) gateip = xstrdup(toybuf);
+      if (inet_ntop(AF_INET, &gate, toybuf, sizeof(toybuf)) )
+        gateip = xstrdup(toybuf);
     } else {
       if (!notresolve) gateip = xstrdup("*");
       else gateip = xstrdup("0.0.0.0");
     }
+
     //For Mask
-    if (inet_ntop(AF_INET, &mask, toybuf, sizeof(toybuf)) ) maskip = xstrdup(toybuf);
+    if (inet_ntop(AF_INET, &mask, toybuf, sizeof(toybuf)) )
+      maskip = xstrdup(toybuf);
 
     //Get flag Values
-    get_flag_value(&flag_val, (flags & IPV4_MASK));
+    get_flag_value(flag_val, flags & IPV4_MASK);
     if (flags & RTF_REJECT) flag_val[0] = '!';
+
     xprintf("%-15.15s %-15.15s %-16s%-6s", destip, gateip, maskip, flag_val);
+    if (is_more_info) xprintf("%5d %-5d %6d %s\n", mss, win, irtt, iface);
+    else xprintf("%-6d %-2d %7d %s\n", metric, ref, use, iface);
+
     if (destip) free(destip);
     if (gateip) free(gateip);
     if (maskip) free(maskip);
-    if (is_more_info) xprintf("%5d %-5d %6d %s\n", mss, win, irtt, iface);
-    else xprintf("%-6d %-2d %7d %s\n", metric, ref, use, iface);
   }//end of while.
   fclose(fp);
-  if (flag_val) free(flag_val);
 #undef IPV4_MASK
-  return;
 }
+
 /*
- * netstat utily main function.
+ * netstat utility main function.
  */
 void netstat_main(void)
 {
-#define IS_NETSTAT_PROTO_FLAGS_UP (toys.optflags & (FLAG_t | FLAG_u | FLAG_w | FLAG_x))
-  int flag_listen_and_all = 0;
+#define IS_NETSTAT_PROTO_FLAGS_UP (toys.optflags & (FLAG_t | FLAG_u | FLAG_w \
+                                                    | FLAG_x))
+
+  // For no parameter, add 't', 'u', 'w', 'x' options as default
   if (!toys.optflags) toys.optflags = FLAG_t | FLAG_u | FLAG_w | FLAG_x;
 
-  //When a is set
-  if (toys.optflags & FLAG_a) flag_listen_and_all = 1;
-  //when a and l both are set
-  if ( (toys.optflags & FLAG_a) && (toys.optflags & FLAG_l) )
-    toys.optflags &= ~FLAG_l;
-  //when only a is set
-  if ( (toys.optflags & FLAG_a) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
-    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
-  //when only l is set
-  if ( (toys.optflags & FLAG_l) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
-    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
-  //when only e/n is set
-  if( ((toys.optflags & FLAG_e) || (toys.optflags & FLAG_n)) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
-	  toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
-  //when W is set
-  if ( (toys.optflags & FLAG_W) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
-    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
-   //when p is set
-  if ( (toys.optflags & FLAG_p) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+  // For both 'a' and 'l' are set, remove 'l' option
+  if (toys.optflags & FLAG_a && toys.optflags & FLAG_l)
+      toys.optflags &= ~FLAG_l;
+
+  // For each 'a', 'l', 'e', 'n', 'W', 'p' options
+  // without any 't', 'u', 'w', 'x' option, add 't', 'u', 'w', 'x' options
+  if (((toys.optflags & FLAG_a) || (toys.optflags & FLAG_l) ||
+       (toys.optflags & FLAG_e) || (toys.optflags & FLAG_n) ||
+       (toys.optflags & FLAG_W) || (toys.optflags & FLAG_p)) &&
+         (!IS_NETSTAT_PROTO_FLAGS_UP) )
     toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
 
   //Display routing table.
@@ -581,12 +619,13 @@ void netstat_main(void)
   }
 
   //For TCP/UDP/RAW.
-  if ( (toys.optflags & FLAG_t) || (toys.optflags & FLAG_u) || (toys.optflags & FLAG_w) ) {
+  if ( (toys.optflags & FLAG_t) || (toys.optflags & FLAG_u) ||
+       (toys.optflags & FLAG_w) ) {
     xprintf("Active Internet connections ");
 
-    if (flag_listen_and_all) xprintf("(servers and established)");
-    else if (toys.optflags & FLAG_l) xprintf("(only servers)");
-    else xprintf("(w/o servers)");
+    if (toys.optflags & FLAG_a) xprintf("(servers and established)\n");
+    else if (toys.optflags & FLAG_l) xprintf("(only servers)\n");
+    else xprintf("(w/o servers)\n");
 
     show_header();
     if (toys.optflags & FLAG_t) {//For TCP
@@ -602,14 +641,18 @@ void netstat_main(void)
       show_ipv6("/proc/net/raw6", "raw");
     }
   }
-  if (toys.optflags & FLAG_x) {//For UNIX.
+  if (toys.optflags & FLAG_x) {//For UNIX
     xprintf("Active UNIX domain sockets ");
-    if (flag_listen_and_all) xprintf("(servers and established)");
-    else if (toys.optflags & FLAG_l) xprintf("(only servers)");
-    else xprintf("(w/o servers)");
-
-    if (toys.optflags & FLAG_p) xprintf("\nProto RefCnt Flags       Type       State           I-Node PID/Program Name    Path\n");
-    else xprintf("\nProto RefCnt Flags       Type       State           I-Node Path\n");
+    if (toys.optflags & FLAG_a) xprintf("(servers and established)\n");
+    else if (toys.optflags & FLAG_l) xprintf("(only servers)\n");
+    else xprintf("(w/o servers)\n");
+
+    if (toys.optflags & FLAG_p)
+      xprintf("Proto RefCnt Flags       Type       State           "
+              "I-Node PID/Program Name    Path\n");
+    else
+      xprintf("Proto RefCnt Flags       Type       State           "
+              "I-Node Path\n");
     show_unix_sockets("/proc/net/unix", "unix");
   }
   if (toys.optflags & FLAG_p) clean_pid_list();