dmesg: print_buffer() refactoring

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index eeafd6e009f03b7fbee4875b94e4e272cba6aa73..5cf69dbafcb75218463c75fa7a3a49f26443f7be 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -105,6 +105,17 @@ struct dmesg_control {
        int     notime:1;               /* don't print timestamp */
 };
 
+struct dmesg_record {
+       const char      *mesg;
+       size_t          mesg_size;
+
+       int             level;
+       int             facility;
+
+       const char      *next;          /* buffer with next unparsed record */
+       size_t          next_size;      /* size of the next buffer */
+};
+
 static void __attribute__((__noreturn__)) usage(FILE *out)
 {
        int i;
@@ -394,36 +405,33 @@ static void safe_fwrite(const char *buf, size_t size, FILE *out)
        }
 }
 
-/*
- * Prints the 'buf' kernel ring buffer; the messages are filtered out according
- * to 'levels' and 'facilities' bitarrays.
- */
-static void print_buffer(const char *buf, size_t size,
-                        struct dmesg_control *ctl)
+static int get_next_record(struct dmesg_control *ctl, struct dmesg_record *rec)
 {
        int i;
        const char *begin = NULL;
 
-       if (ctl->raw) {
-               /* print whole buffer */
-               safe_fwrite(buf, size, stdout);
-               if (buf[size - 1] != '\n')
-                       putchar('\n');
-               return;
-       }
+       if (!rec->next || !rec->next_size)
+               return 1;
 
-       for (i = 0; i < size; i++) {
-               const char *p = buf + i, *end = NULL;
-               int fac = -1, lev = -1;
+       rec->mesg = NULL;
+       rec->mesg_size = 0;
+       rec->facility = -1;
+       rec->level = -1;
+
+       for (i = 0; i < rec->next_size; i++) {
+               const char *p = rec->next + i;
+               const char *end = NULL;
 
                if (!begin)
                        begin = p;
                if (*p == '\n')
                        end = p;
-               if (i + 1 == size) {
+               if (i + 1 == rec->next_size) {
                        end = p + 1;
                        i++;
                }
+               if (begin && !*begin)
+                       begin = NULL;   /* zero(s) at the end of the buffer? */
                if (!begin || !end)
                        continue;
                if (end <= begin)
@@ -432,7 +440,8 @@ static void print_buffer(const char *buf, size_t size,
                if (*begin == '<') {
                        if (ctl->fltr_lev || ctl->fltr_fac || ctl->decode) {
                                /* parse facility and level */
-                               begin = parse_faclev(begin + 1, &fac, &lev);
+                               begin = parse_faclev(begin + 1, &rec->facility,
+                                                    &rec->level);
                        } else {
                                /* ignore facility and level */
                                while (begin < end) {
@@ -443,35 +452,77 @@ static void print_buffer(const char *buf, size_t size,
                        }
                }
 
-               if (begin < end &&
-                   (lev < 0 || !ctl->fltr_lev || isset(ctl->levels, lev)) &&
-                   (fac < 0 || !ctl->fltr_fac || isset(ctl->facilities, fac))) {
-                       size_t sz;
+               if (end <= begin)
+                       return -1;      /* error */
 
-                       if (ctl->notime && *begin == '[' &&
-                           (*(begin + 1) == ' ' || isdigit(*(begin + 1)))) {
-                               /* ignore timestamp */
-                               while (begin < end) {
-                                       begin++;
-                                       if (*(begin - 1) == ']')
-                                               break;
-                               }
+               if (ctl->notime && *begin == '[' &&
+                   (*(begin + 1) == ' ' || isdigit(*(begin + 1)))) {
+                       /* ignore timestamp */
+                       while (begin < end) {
+                               begin++;
+                               if (*(begin - 1) == ']')
+                                       break;
                        }
+               }
 
-                       if (*begin == ' ')
-                               begin++;
+               if (begin < end && *begin == ' ')
+                       begin++;
 
-                       sz =  end - begin;
+               rec->mesg = begin;
+               rec->mesg_size = end - begin;
 
-                       if (ctl->decode && lev >= 0 && fac >= 0) {
-                               printf("%-6s:%-6s: ", facility_names[fac].name,
-                                               level_names[lev].name);
-                       }
-                       safe_fwrite(begin, sz, stdout);
-                       if (*(begin + sz - 1) != '\n')
-                               putchar('\n');
-               }
-               begin = NULL;
+               rec->next_size -= end - rec->next;
+               rec->next = rec->next_size > 0 ? end + 1 : NULL;
+
+               return 0;
+       }
+
+       return 1;
+}
+
+static int accept_record(struct dmesg_control *ctl, struct dmesg_record *rec)
+{
+       if (ctl->fltr_lev && (rec->facility < 0 ||
+                             !isset(ctl->levels, rec->level)))
+               return 0;
+
+       if (ctl->fltr_fac && (rec->facility < 0 ||
+                             !isset(ctl->facilities, rec->facility)))
+               return 0;
+
+       return 1;
+}
+
+/*
+ * Prints the 'buf' kernel ring buffer; the messages are filtered out according
+ * to 'levels' and 'facilities' bitarrays.
+ */
+static void print_buffer(const char *buf, size_t size,
+                        struct dmesg_control *ctl)
+{
+       struct dmesg_record rec = { .next = buf, .next_size = size };
+
+       if (ctl->raw) {
+               /* print whole buffer */
+               safe_fwrite(buf, size, stdout);
+               if (buf[size - 1] != '\n')
+                       putchar('\n');
+               return;
+       }
+
+       while (get_next_record(ctl, &rec) == 0 && rec.mesg_size) {
+
+               if (!accept_record(ctl, &rec))
+                       continue;
+
+               if (ctl->decode && rec.level >= 0 && rec.facility >= 0)
+                       printf("%-6s:%-6s: ", facility_names[rec.facility].name,
+                                             level_names[rec.level].name);
+
+               safe_fwrite(rec.mesg, rec.mesg_size, stdout);
+
+               if (*(rec.mesg + rec.mesg_size - 1) != '\n')
+                       putchar('\n');
        }
 }