filtertest: Plug a few resource leaks.

Make the variables that need to be managed global, add a function to
deallocate all resources if required and call it before exit() both in
main() and in error().  This improves Valgrind SNR and resolves the
following in particular:

$ valgrind --leak-check=full --show-leak-kinds=all --quiet \
  ./testprogs/filtertest EN10MB 'invalid syntax'
filtertest: can't parse filter expression: syntax error
==411153== 15 bytes in 1 blocks are still reachable in loss record 1 of 2
==411153==    at 0x48417B4: malloc (vg_replace_malloc.c:381)
==411153==    by 0x10EFCB: copy_argv (filtertest.c:229)
==411153==    by 0x10EFCB: main (filtertest.c:419)
==411153==
==411153== 648 bytes in 1 blocks are still reachable in loss record 2 of 2
==411153==    at 0x48465EF: calloc (vg_replace_malloc.c:1328)
==411153==    by 0x117651: pcap_open_dead_with_tstamp_precision (pcap.c:4476)
==411153==    by 0x10EE7B: main (filtertest.c:392)
==411153==

diff --git a/testprogs/filtertest.c b/testprogs/filtertest.c
index d136e62799bffb77d3add8a92cc942327d036313..99dc564fafb40cf7e83f8f7adbc5d283955e3de7 100644 (file)
--- a/testprogs/filtertest.c
+++ b/testprogs/filtertest.c
@@ -99,6 +99,25 @@ static void warn(const char *, ...) PCAP_PRINTFLIKE(1, 2);
 #define O_BINARY       0
 #endif
 
+static char *cmdbuf;
+static pcap_t *pd;
+static struct bpf_program fcode;
+
+/*
+ * atexit() is broken on Linux/ARMv7 with TinyCC, work around by calling this
+ * function explicitly just before exit() if there is a possibility any of
+ * these resources have been allocated.
+ */
+static void
+cleanup(void)
+{
+       if (cmdbuf)
+               free(cmdbuf);
+       pcap_freecode (&fcode);
+       if (pd)
+               pcap_close(pd);
+}
+
 // Replace "# comment" with spaces.
 static void
 blank_comments(char *cp, const size_t size)
@@ -110,7 +129,7 @@ blank_comments(char *cp, const size_t size)
        }
 }
 
-static char *
+static void
 read_infile(char *fname)
 {
        int fd, cc;
@@ -135,6 +154,7 @@ read_infile(char *fname)
                error(EX_DATAERR, "%s is larger than %d bytes; that's too large", fname,
                    INT_MAX - 1);
        cp = malloc((u_int)buf.st_size + 1);
+       cmdbuf = cp;
        if (cp == NULL)
                error(EX_OSERR, "malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
                        fname, pcap_strerror(errno));
@@ -147,29 +167,24 @@ read_infile(char *fname)
        close(fd);
        blank_comments(cp, (size_t)cc);
        cp[cc] = '\0';
-       return (cp);
 }
 
 // Copy stdin into a size-limited buffer.
-static char *
+static void
 read_stdin(void)
 {
        char *buf = calloc(1, MAX_STDIN + 1);
+       cmdbuf = buf;
        if (buf == NULL)
                error(EX_OSERR, "%s: calloc", __func__);
        size_t readsize = fread(buf, 1, MAX_STDIN, stdin);
-       if (! feof(stdin)) {
-               free(buf);
+       if (! feof(stdin))
                error(EX_DATAERR, "received more than %u bytes on stdin", MAX_STDIN);
-       }
-       if (ferror(stdin)) {
-               free(buf);
+       if (ferror(stdin))
                error(EX_IOERR, "failed reading from stdin after %zd bytes", readsize);
-       }
        fclose(stdin);
        // No error, all data is within the buffer and NUL-terminated.
        blank_comments(buf, readsize);
-       return buf;
 }
 
 /* VARARGS */
@@ -187,6 +202,7 @@ error(const int status, const char *fmt, ...)
                if (fmt[-1] != '\n')
                        (void)fputc('\n', stderr);
        }
+       cleanup();
        exit(status);
        /* NOTREACHED */
 }
@@ -211,7 +227,7 @@ warn(const char *fmt, ...)
 /*
  * Copy arg vector into a new buffer, concatenating arguments with spaces.
  */
-static char *
+static void
 copy_argv(register char **argv)
 {
        register char **p;
@@ -221,12 +237,13 @@ copy_argv(register char **argv)
 
        p = argv;
        if (*p == 0)
-               return 0;
+               return;
 
        while (*p)
                len += strlen(*p++) + 1;
 
        buf = (char *)malloc(len);
+       cmdbuf = buf;
        if (buf == NULL)
                error(EX_OSERR, "%s: malloc", __func__);
 
@@ -238,8 +255,6 @@ copy_argv(register char **argv)
                dst[-1] = ' ';
        }
        dst[-1] = '\0';
-
-       return buf;
 }
 
 int
@@ -260,9 +275,6 @@ main(int argc, char **argv)
        int snaplen = MAXIMUM_SNAPLEN;
        char *p;
        bpf_u_int32 netmask = PCAP_NETMASK_UNKNOWN;
-       char *cmdbuf;
-       pcap_t *pd;
-       struct bpf_program fcode;
 
 #ifdef _WIN32
        WSADATA wsaData;
@@ -413,10 +425,12 @@ main(int argc, char **argv)
 #endif
        }
 
-       if (infile)
-               cmdbuf = strcmp(infile, "-") ? read_infile(infile) : read_stdin();
+       if (! infile)
+               copy_argv(&argv[optind]);
+       else if (strcmp(infile, "-"))
+               read_infile(infile);
        else
-               cmdbuf = copy_argv(&argv[optind]);
+               read_stdin();
 
        if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
                error(EX_DATAERR, "%s", pcap_geterr(pd));
@@ -449,9 +463,7 @@ main(int argc, char **argv)
                                error(EX_IOERR, "pcap_next_ex() failed: %d", ret);
                }
        }
-       free(cmdbuf);
-       pcap_freecode (&fcode);
-       pcap_close(pd);
+       cleanup();
 #ifdef _WIN32
        WSACleanup();
 #endif