Avoid undefined behavior in overflow check
[metze/wireshark/wip.git] / wiretap / radcom.c
index 96842d00bdc0e46145678f13e73850d003af6124..6a0b6f825931419e6c5be3976f4f60808d456f6c 100644 (file)
@@ -24,7 +24,6 @@
 #include <string.h>
 #include "wtap-int.h"
 #include "file_wrappers.h"
-#include "buffer.h"
 #include "radcom.h"
 
 struct frame_date {
@@ -54,7 +53,7 @@ static const guint8 encap_magic[4] = {
 };
 
 static const guint8 active_time_magic[11] = {
-       0x41, 0x63, 0x74, 0x69, 0x76, 0x65, 0x20, 0x54, 0x69, 0x6d, 0x65
+       'A', 'c', 't', 'i', 'v', 'e', ' ', 'T', 'i', 'm', 'e'
 };
 
 /* RADCOM record header - followed by frame data (perhaps including FCS).
@@ -90,12 +89,9 @@ static gboolean radcom_seek_read(wtap *wth, gint64 seek_off,
        struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info);
 static gboolean radcom_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr,
        Buffer *buf, int *err, gchar **err_info);
-static gboolean radcom_read_rec_data(FILE_T fh, guint8 *pd, int length,
-       int *err, gchar **err_info);
 
-int radcom_open(wtap *wth, int *err, gchar **err_info)
+wtap_open_return_val radcom_open(wtap *wth, int *err, gchar **err_info)
 {
-       int bytes_read;
        guint8 r_magic[8], t_magic[11], search_encap[7];
        struct frame_date start_date;
 #if 0
@@ -104,13 +100,10 @@ int radcom_open(wtap *wth, int *err, gchar **err_info)
 #endif
 
        /* Read in the string that should be at the start of a RADCOM file */
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(r_magic, 8, wth->fh);
-       if (bytes_read != 8) {
-               *err = file_error(wth->fh, err_info);
-               if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
-                       return -1;
-               return 0;
+       if (!wtap_read_bytes(wth->fh, r_magic, 8, err, err_info)) {
+               if (*err != WTAP_ERR_SHORT_READ)
+                       return WTAP_OPEN_ERROR;
+               return WTAP_OPEN_NOT_MINE;
        }
 
        /* XXX: bytes 2 and 3 of the "magic" header seem to be different in some
@@ -120,43 +113,66 @@ int radcom_open(wtap *wth, int *err, gchar **err_info)
        r_magic[1] = 0xD2;
        r_magic[2] = 0x00;
        if (memcmp(r_magic, radcom_magic, 8) != 0) {
-               return 0;
+               return WTAP_OPEN_NOT_MINE;
        }
 
        /* Look for the "Active Time" string. The "frame_date" structure should
         * be located 32 bytes before the beginning of this string */
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(t_magic, 11, wth->fh);
-       if (bytes_read != 11) {
-               *err = file_error(wth->fh, err_info);
-               if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
-                       return -1;
-               return 0;
+       if (!wtap_read_bytes(wth->fh, t_magic, 11, err, err_info)) {
+               if (*err != WTAP_ERR_SHORT_READ)
+                       return WTAP_OPEN_ERROR;
+               return WTAP_OPEN_NOT_MINE;
        }
        while (memcmp(t_magic, active_time_magic, 11) != 0)
        {
                if (file_seek(wth->fh, -10, SEEK_CUR, err) == -1)
-                       return -1;
-               errno = WTAP_ERR_CANT_READ;
-               bytes_read = file_read(t_magic, 11, wth->fh);
-               if (bytes_read != 11) {
-                       *err = file_error(wth->fh, err_info);
-                       if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
-                               return -1;
-                       return 0;
+                       return WTAP_OPEN_ERROR;
+               if (!wtap_read_bytes(wth->fh, t_magic, 11, err, err_info)) {
+                       if (*err != WTAP_ERR_SHORT_READ)
+                               return WTAP_OPEN_ERROR;
+                       return WTAP_OPEN_NOT_MINE;
                }
        }
-       if (file_seek(wth->fh, -43, SEEK_CUR, err) == -1) return -1;
+       if (file_seek(wth->fh, -43, SEEK_CUR, err) == -1)
+               return WTAP_OPEN_ERROR;
 
        /* Get capture start time */
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(&start_date, sizeof(struct frame_date),
-                              wth->fh);
-       if (bytes_read != sizeof(struct frame_date)) {
-               *err = file_error(wth->fh, err_info);
-               if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
-                       return -1;
-               return 0;
+       if (!wtap_read_bytes(wth->fh, &start_date, sizeof(struct frame_date),
+           err, err_info)) {
+               if (*err != WTAP_ERR_SHORT_READ)
+                       return WTAP_OPEN_ERROR;
+               return WTAP_OPEN_NOT_MINE;
+       }
+
+       if (file_seek(wth->fh, sizeof(struct frame_date), SEEK_CUR, err) == -1)
+               return WTAP_OPEN_ERROR;
+
+       for (;;) {
+               if (!wtap_read_bytes(wth->fh, search_encap, 4,
+                   err, err_info)) {
+                       if (*err != WTAP_ERR_SHORT_READ)
+                               return WTAP_OPEN_ERROR;
+                       return WTAP_OPEN_NOT_MINE;
+               }
+
+               if (memcmp(encap_magic, search_encap, 4) == 0)
+                       break;
+
+               /*
+                * OK, that's not it, go forward 1 byte - reading
+                * the magic moved us forward 4 bytes, so seeking
+                * backward 3 bytes moves forward 1 byte - and
+                * try the 4 bytes at that offset.
+                */
+               if (file_seek(wth->fh, -3, SEEK_CUR, err) == -1)
+                       return WTAP_OPEN_ERROR;
+       }
+       if (file_seek(wth->fh, 12, SEEK_CUR, err) == -1)
+               return WTAP_OPEN_ERROR;
+       if (!wtap_read_bytes(wth->fh, search_encap, 4, err, err_info)) {
+               if (*err != WTAP_ERR_SHORT_READ)
+                       return WTAP_OPEN_ERROR;
+               return WTAP_OPEN_NOT_MINE;
        }
 
        /* This is a radcom file */
@@ -164,7 +180,7 @@ int radcom_open(wtap *wth, int *err, gchar **err_info)
        wth->subtype_read = radcom_read;
        wth->subtype_seek_read = radcom_seek_read;
        wth->snapshot_length = 0; /* not available in header, only in frame */
-       wth->tsprecision = WTAP_FILE_TSPREC_USEC;
+       wth->file_tsprec = WTAP_TSPREC_USEC;
 
 #if 0
        tm.tm_year = pletoh16(&start_date.year)-1900;
@@ -176,30 +192,7 @@ int radcom_open(wtap *wth, int *err, gchar **err_info)
        tm.tm_sec = sec%60;
        tm.tm_isdst = -1;
 #endif
-       if (file_seek(wth->fh, sizeof(struct frame_date), SEEK_CUR, err) == -1)
-               return -1;
 
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(search_encap, 4, wth->fh);
-       if (bytes_read != 4) {
-               goto read_error;
-       }
-       while (memcmp(encap_magic, search_encap, 4)) {
-               if (file_seek(wth->fh, -3, SEEK_CUR, err) == -1)
-                       return -1;
-               errno = WTAP_ERR_CANT_READ;
-               bytes_read = file_read(search_encap, 4, wth->fh);
-               if (bytes_read != 4) {
-                       goto read_error;
-               }
-       }
-       if (file_seek(wth->fh, 12, SEEK_CUR, err) == -1)
-               return -1;
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(search_encap, 4, wth->fh);
-       if (bytes_read != 4) {
-               goto read_error;
-       }
        if (memcmp(search_encap, "LAPB", 4) == 0)
                wth->file_encap = WTAP_ENCAP_LAPB;
        else if (memcmp(search_encap, "Ethe", 4) == 0)
@@ -207,55 +200,43 @@ int radcom_open(wtap *wth, int *err, gchar **err_info)
        else if (memcmp(search_encap, "ATM/", 4) == 0)
                wth->file_encap = WTAP_ENCAP_ATM_RFC1483;
        else {
-               *err = WTAP_ERR_UNSUPPORTED_ENCAP;
+               *err = WTAP_ERR_UNSUPPORTED;
                *err_info = g_strdup_printf("radcom: network type \"%.4s\" unknown", search_encap);
-               return -1;
+               return WTAP_OPEN_ERROR;
        }
 
 #if 0
-       bytes_read = file_read(&next_date, sizeof(struct frame_date), wth->fh);
-       errno = WTAP_ERR_CANT_READ;
-       if (bytes_read != sizeof(struct frame_date)) {
-               goto read_error;
-       }
+       if (!wtap_read_bytes(wth->fh, &next_date, sizeof(struct frame_date),
+           err, err_info))
+               return WTAP_OPEN_ERROR;
 
        while (memcmp(&start_date, &next_date, 4)) {
                if (file_seek(wth->fh, 1-sizeof(struct frame_date), SEEK_CUR, err) == -1)
-                       return -1;
-               errno = WTAP_ERR_CANT_READ;
-               bytes_read = file_read(&next_date, sizeof(struct frame_date),
-                                  wth->fh);
-               if (bytes_read != sizeof(struct frame_date)) {
-                       goto read_error;
-               }
+                       return WTAP_OPEN_ERROR;
+               if (!wtap_read_bytes(wth->fh, &next_date, sizeof(struct frame_date),
+                   err, err_info))
+                       return WTAP_OPEN_ERROR;
        }
 #endif
 
        if (wth->file_encap == WTAP_ENCAP_ETHERNET) {
                if (file_seek(wth->fh, 294, SEEK_CUR, err) == -1)
-                       return -1;
+                       return WTAP_OPEN_ERROR;
        } else if (wth->file_encap == WTAP_ENCAP_LAPB) {
                if (file_seek(wth->fh, 297, SEEK_CUR, err) == -1)
-                       return -1;
+                       return WTAP_OPEN_ERROR;
        } else if (wth->file_encap == WTAP_ENCAP_ATM_RFC1483) {
                if (file_seek(wth->fh, 504, SEEK_CUR, err) == -1)
-                       return -1;
+                       return WTAP_OPEN_ERROR;
        }
 
-       return 1;
-
-read_error:
-       *err = file_error(wth->fh, err_info);
-       if (*err != 0)
-               return -1;
-       return 0;
+       return WTAP_OPEN_MINE;
 }
 
 /* Read the next packet */
 static gboolean radcom_read(wtap *wth, int *err, gchar **err_info,
                            gint64 *data_offset)
 {
-       int     bytes_read;
        char    fcs[2];
 
        *data_offset = file_tell(wth->fh);
@@ -272,14 +253,8 @@ static gboolean radcom_read(wtap *wth, int *err, gchar **err_info,
                   XXX - should we have some way of indicating the
                   presence and size of an FCS to our caller?
                   That'd let us handle other file types as well. */
-               errno = WTAP_ERR_CANT_READ;
-               bytes_read = file_read(&fcs, sizeof fcs, wth->fh);
-               if (bytes_read != sizeof fcs) {
-                       *err = file_error(wth->fh, err_info);
-                       if (*err == 0)
-                               *err = WTAP_ERR_SHORT_READ;
+               if (!wtap_read_bytes(wth->fh, &fcs, sizeof fcs, err, err_info))
                        return FALSE;
-               }
        }
 
        return TRUE;
@@ -311,20 +286,13 @@ radcom_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
                int *err, gchar **err_info)
 {
        struct radcomrec_hdr hdr;
-       int     bytes_read;
        guint16 data_length, real_length, length;
        guint32 sec;
        struct tm tm;
        guint8  atmhdr[8];
 
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(&hdr, sizeof hdr, fh);
-       if (bytes_read != sizeof hdr) {
-               *err = file_error(fh, err_info);
-               if (*err == 0 && bytes_read != 0)
-                       *err = WTAP_ERR_SHORT_READ;
+       if (!wtap_read_bytes_or_eof(fh, &hdr, sizeof hdr, err, err_info))
                return FALSE;
-       }
 
        data_length = pletoh16(&hdr.data_length);
        if (data_length == 0) {
@@ -372,7 +340,7 @@ radcom_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
                 * XXX - is this stuff a pseudo-header?
                 * The direction appears to be in the "hdr.dce" field.
                 */
-               if (!radcom_read_rec_data(wth->fh, atmhdr, sizeof atmhdr, err,
+               if (!wtap_read_bytes(fh, atmhdr, sizeof atmhdr, err,
                    err_info))
                        return FALSE;   /* Read error */
                length -= 8;
@@ -392,20 +360,15 @@ radcom_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
        return TRUE;
 }
 
-static gboolean
-radcom_read_rec_data(FILE_T fh, guint8 *pd, int length, int *err,
-                    gchar **err_info)
-{
-       int     bytes_read;
-
-       errno = WTAP_ERR_CANT_READ;
-       bytes_read = file_read(pd, length, fh);
-
-       if (bytes_read != length) {
-               *err = file_error(fh, err_info);
-               if (*err == 0)
-                       *err = WTAP_ERR_SHORT_READ;
-               return FALSE;
-       }
-       return TRUE;
-}
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */