lineedit: reduce stack usage
authorDenis Vlasenko <vda.linux@googlemail.com>
Mon, 3 Dec 2007 10:45:14 +0000 (10:45 -0000)
committerDenis Vlasenko <vda.linux@googlemail.com>
Mon, 3 Dec 2007 10:45:14 +0000 (10:45 -0000)
netstat: reduce stack usage; fix handling of NULs in unix socket filenames

static.has_inode                                       1       -      -1
do_info                                              119     116      -3
deinit_S                                              60      51      -9
unix_do_one                                          578     451    -127
parse_and_put_prompt                                 966     825    -141
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/4 up/down: 0/-281)           Total: -281 bytes

libbb/lineedit.c
networking/netstat.c

index 07db6358dec2bf293a2656c1418b575790f0fb1f..1397409ccb9bba16d514689ecec803311b4becc3 100644 (file)
@@ -91,7 +91,6 @@ struct statics {
 
        const char *cmdedit_prompt;
 #if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-       char *hostname_buf;
        int num_ok_lines; /* = 1; */
 #endif
 
@@ -136,7 +135,6 @@ static struct statics *const ptr_to_statics __attribute__ ((section (".data")));
 #define command_len      (S.command_len     )
 #define command_ps       (S.command_ps      )
 #define cmdedit_prompt   (S.cmdedit_prompt  )
-#define hostname_buf     (S.hostname_buf    )
 #define num_ok_lines     (S.num_ok_lines    )
 #define user_buf         (S.user_buf        ) 
 #define home_pwd_buf     (S.home_pwd_buf    )
@@ -155,7 +153,6 @@ static struct statics *const ptr_to_statics __attribute__ ((section (".data")));
 static void deinit_S(void)
 {
 #if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-       free(hostname_buf);
        /* This one is allocated only if FANCY_PROMPT is on
         * (otherwise it points to verbatim prompt (NOT malloced) */
        free((char*)cmdedit_prompt);
@@ -381,14 +378,14 @@ static void username_tab_completion(char *ud, char *with_shash_flg)
        if (with_shash_flg) {           /* "~/..." or "~user/..." */
                char *sav_ud = ud - 1;
                char *home = NULL;
-               char *temp;
 
                if (*ud == '/') {       /* "~/..."     */
                        home = home_pwd_buf;
                } else {
                        /* "~user/..." */
+                       char *temp;
                        temp = strchr(ud, '/');
-                       *temp = 0;              /* ~user\0 */
+                       *temp = '\0';           /* ~user\0 */
                        entry = getpwnam(ud);
                        *temp = '/';            /* restore ~user/... */
                        ud = temp;
@@ -1163,21 +1160,23 @@ static void parse_and_put_prompt(const char *prmt_ptr)
        size_t cur_prmt_len = 0;
        char flg_not_length = '[';
        char *prmt_mem_ptr = xzalloc(1);
-       char *pwd_buf = xrealloc_getcwd_or_warn(NULL);
-       char buf2[PATH_MAX + 1];
-       char buf[2];
+       char *cwd_buf = xrealloc_getcwd_or_warn(NULL);
+       char cbuf[2];
        char c;
        char *pbuf;
 
        cmdedit_prmt_len = 0;
 
-       if (!pwd_buf) {
-               pwd_buf = (char *)bb_msg_unknown;
+       if (!cwd_buf) {
+               cwd_buf = (char *)bb_msg_unknown;
        }
 
+       cbuf[1] = '\0'; /* never changes */
+
        while (*prmt_ptr) {
-               pbuf = buf;
-               pbuf[1] = 0;
+               char *free_me = NULL;
+
+               pbuf = cbuf;
                c = *prmt_ptr++;
                if (c == '\\') {
                        const char *cp = prmt_ptr;
@@ -1188,6 +1187,7 @@ static void parse_and_put_prompt(const char *prmt_ptr)
                                if (*cp == '\0')
                                        break;
                                c = *prmt_ptr++;
+
                                switch (c) {
 #if ENABLE_FEATURE_GETUSERNAME_AND_HOMEDIR
                                case 'u':
@@ -1195,87 +1195,81 @@ static void parse_and_put_prompt(const char *prmt_ptr)
                                        break;
 #endif
                                case 'h':
-                                       pbuf = hostname_buf;
-                                       if (!pbuf) {
-                                               pbuf = xzalloc(256);
-                                               if (gethostname(pbuf, 255) < 0) {
-                                                       strcpy(pbuf, "?");
-                                               } else {
-                                                       char *s = strchr(pbuf, '.');
-                                                       if (s)
-                                                               *s = '\0';
-                                               }
-                                               hostname_buf = pbuf;
+                                       pbuf = free_me = xzalloc(256);
+                                       if (gethostname(pbuf, 255) < 0) {
+                                               pbuf[0] = '?';
+                                               pbuf[1] = '\0';
                                        }
+                                       *strchrnul(pbuf, '.') = '\0';
                                        break;
                                case '$':
                                        c = (geteuid() == 0 ? '#' : '$');
                                        break;
 #if ENABLE_FEATURE_GETUSERNAME_AND_HOMEDIR
                                case 'w':
-                                       pbuf = pwd_buf;
+                                       /* /home/user[/something] -> ~[/something] */
+                                       pbuf = cwd_buf;
                                        l = strlen(home_pwd_buf);
                                        if (l != 0
-                                        && strncmp(home_pwd_buf, pbuf, l) == 0
-                                        && (pbuf[l]=='/' || pbuf[l]=='\0')
-                                        && strlen(pwd_buf+l) < PATH_MAX
+                                        && strncmp(home_pwd_buf, cwd_buf, l) == 0
+                                        && (cwd_buf[l]=='/' || cwd_buf[l]=='\0')
+                                        && strlen(cwd_buf + l) < PATH_MAX
                                        ) {
-                                               pbuf = buf2;
-                                               *pbuf = '~';
-                                               strcpy(pbuf+1, pwd_buf+l);
+                                               pbuf = free_me = xasprintf("~%s", cwd_buf + l);
                                        }
                                        break;
 #endif
                                case 'W':
-                                       pbuf = pwd_buf;
+                                       pbuf = cwd_buf;
                                        cp = strrchr(pbuf, '/');
                                        if (cp != NULL && cp != pbuf)
                                                pbuf += (cp-pbuf) + 1;
                                        break;
                                case '!':
-                                       pbuf = buf2;
-                                       snprintf(buf2, sizeof(buf2), "%d", num_ok_lines);
+                                       pbuf = free_me = xasprintf("%d", num_ok_lines);
                                        break;
                                case 'e': case 'E':     /* \e \E = \033 */
                                        c = '\033';
                                        break;
-                               case 'x': case 'X':
+                               case 'x': case 'X': {
+                                       char buf2[4];
                                        for (l = 0; l < 3;) {
-                                               int h;
+                                               unsigned h;
                                                buf2[l++] = *prmt_ptr;
-                                               buf2[l] = 0;
-                                               h = strtol(buf2, &pbuf, 16);
+                                               buf2[l] = '\0';
+                                               h = strtoul(buf2, &pbuf, 16);
                                                if (h > UCHAR_MAX || (pbuf - buf2) < l) {
-                                                       l--;
+                                                       buf2[--l] = '\0';
                                                        break;
                                                }
                                                prmt_ptr++;
                                        }
-                                       buf2[l] = 0;
-                                       c = (char)strtol(buf2, NULL, 16);
+                                       c = (char)strtoul(buf2, NULL, 16);
                                        if (c == 0)
                                                c = '?';
-                                       pbuf = buf;
+                                       pbuf = cbuf;
                                        break;
+                               }
                                case '[': case ']':
                                        if (c == flg_not_length) {
                                                flg_not_length = (flg_not_length == '[' ? ']' : '[');
                                                continue;
                                        }
                                        break;
-                               }
-                       }
-               }
-               if (pbuf == buf)
-                       *pbuf = c;
+                               } /* switch */
+                       } /* if */
+               } /* if */
+               cbuf[0] = c;
                cur_prmt_len = strlen(pbuf);
                prmt_len += cur_prmt_len;
                if (flg_not_length != ']')
                        cmdedit_prmt_len += cur_prmt_len;
                prmt_mem_ptr = strcat(xrealloc(prmt_mem_ptr, prmt_len+1), pbuf);
-       }
-       if (pwd_buf != (char *)bb_msg_unknown)
-               free(pwd_buf);
+               free(free_me);
+       } /* while */
+
+       if (cwd_buf != (char *)bb_msg_unknown)
+               free(cwd_buf);
        cmdedit_prompt = prmt_mem_ptr;
        put_prompt();
 }
@@ -1397,7 +1391,6 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
                if (entry) {
                        user_buf = xstrdup(entry->pw_name);
                        home_pwd_buf = xstrdup(entry->pw_dir);
-                       /* They are not freed on exit (too small to bother) */
                }
        }
 #endif
index 11f1419470ec31df83dd870cdbe7617b77dd5980..d86c2ff5ea3f623abd807037a1793bbb1ca4d31f 100644 (file)
@@ -148,7 +148,7 @@ static char *ip_port_str(struct sockaddr *addr, int port, const char *proto, int
        return host_port;
 }
 
-static void tcp_do_one(int lnr, const char *line)
+static void tcp_do_one(int lnr, char *line)
 {
        char local_addr[64], rem_addr[64];
        char more[512];
@@ -201,7 +201,7 @@ static void tcp_do_one(int lnr, const char *line)
        }
 }
 
-static void udp_do_one(int lnr, const char *line)
+static void udp_do_one(int lnr, char *line)
 {
        char local_addr[64], rem_addr[64];
        const char *state_str;
@@ -283,7 +283,7 @@ static void udp_do_one(int lnr, const char *line)
        }
 }
 
-static void raw_do_one(int lnr, const char *line)
+static void raw_do_one(int lnr, char *line)
 {
        char local_addr[64], rem_addr[64];
        char more[512];
@@ -339,31 +339,37 @@ static void raw_do_one(int lnr, const char *line)
        }
 }
 
-static void unix_do_one(int nr, const char *line)
+static void unix_do_one(int nr, char *line)
 {
-       static smallint has_inode = 0;
-
-       char path[PATH_MAX], ss_flags[32];
-       const char *ss_proto, *ss_state, *ss_type;
-       int num, state, type, inode;
-       void *d;
        unsigned long refcnt, proto, unix_flags;
+       unsigned long inode;
+       int type, state;
+       int num, path_ofs;
+       void *d;
+       const char *ss_proto, *ss_state, *ss_type;
+       char ss_flags[32];
 
-       if (nr == 0) {
-               if (strstr(line, "Inode"))
-                       has_inode = 1;
-               return;
+       if (nr == 0)
+               return; /* skip header */
+
+       {
+               char *last = last_char_is(line, '\n');
+               if (last)
+                       *last = '\0';
        }
-       path[0] = '\0';
-       num = sscanf(line, "%p: %lX %lX %lX %X %X %d %s",
-                       &d, &refcnt, &proto, &unix_flags, &type, &state, &inode, path);
-       if (num < 6) {
-               bb_error_msg("warning, got bogus unix line");
+
+       /* 2.6.15 may report lines like "... @/tmp/fam-user-^@^@^@^@^@^@^@..."
+        * (those ^@ are NUL bytes). fgets sees them as tons of empty lines. */
+       if (!line[0])
                return;
-       }
-       if (!has_inode)
-               sprintf(path, "%d", inode);
 
+       path_ofs = 0; /* paranoia */
+       num = sscanf(line, "%p: %lX %lX %lX %X %X %lu %n",
+                       &d, &refcnt, &proto, &unix_flags, &type, &state, &inode, &path_ofs);
+       if (num < 7) {
+               bb_error_msg("got bogus unix line '%s'", line);
+               return;
+       }
        if ((flags & (NETSTAT_LISTENING|NETSTAT_CONNECTED)) != (NETSTAT_LISTENING|NETSTAT_CONNECTED)) {
                if ((state == SS_UNCONNECTED) && (unix_flags & SO_ACCEPTCON)) {
                        if (!(flags & NETSTAT_LISTENING))
@@ -439,13 +445,9 @@ static void unix_do_one(int nr, const char *line)
                strcat(ss_flags, "N ");
        strcat(ss_flags, "]");
 
-       printf("%-5s %-6ld %-11s %-10s %-13s ",
-                  ss_proto, refcnt, ss_flags, ss_type, ss_state);
-       if (has_inode)
-               printf("%-6d ", inode);
-       else
-               printf("-      ");
-       puts(path);
+       printf("%-5s %-6ld %-11s %-10s %-13s %6lu %s\n",
+               ss_proto, refcnt, ss_flags, ss_type, ss_state, inode,
+               line + path_ofs);
 }
 
 #define _PATH_PROCNET_UDP "/proc/net/udp"
@@ -456,10 +458,11 @@ static void unix_do_one(int nr, const char *line)
 #define _PATH_PROCNET_RAW6 "/proc/net/raw6"
 #define _PATH_PROCNET_UNIX "/proc/net/unix"
 
-static void do_info(const char *file, const char *name, void (*proc)(int, const char *))
+static void do_info(const char *file, const char *name, void (*proc)(int, char *))
 {
-       int lnr = 0;
+       int lnr;
        FILE *procinfo;
+       char *buffer;
 
        procinfo = fopen(file, "r");
        if (procinfo == NULL) {
@@ -470,13 +473,14 @@ static void do_info(const char *file, const char *name, void (*proc)(int, const
                }
                return;
        }
+       lnr = 0;
        do {
-               char *buffer = xmalloc_fgets(procinfo);
+               buffer = xmalloc_fgets(procinfo);
                if (buffer) {
                        (proc)(lnr++, buffer);
                        free(buffer);
                }
-       } while (!feof(procinfo));
+       } while (buffer);
        fclose(procinfo);
 }