library: sysstat and vmstat api changes

Use the standard libc declarations.
For protecting the headers for C++ procps used to have its
own defines, this change makes them use the standard libc ones.

getstat() -> procps_stat_*
vminfo() -> procps_vmstat_*
These two components of the library now use the newer version of
the API with less exposed global variables. The old methods are
there for now.

Signed-off-by: Craig Small <csmall@enc.com.au>

proc/vmstat.c

@@ -0,0 +1,153 @@
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <proc/vmstat.h>
+#include "procps-private.h"
+
+#define VMSTAT_FILE "/proc/vmstat"
+#define ROW_NAME_LEN 32
+
+struct vmstat_data {
+    unsigned long pgpgin;
+    unsigned long pgpgout;
+    unsigned long pswpin;
+    unsigned long pswpout;
+};
+
+struct mem_table_struct {
+    const char *name;
+    unsigned long *slot;
+};
+
+struct vmstat_info {
+    int refcount;
+    int vmstat_fd;
+    struct vmstat_data data;
+};
+
+/*
+ * procps_vmstat_new:
+ *
+ * Create a new container to hold the vmstat information
+ *
+ * The initial refcount is 1, and needs to be decremented
+ * to release the resources of the structure.
+ *
+ * Returns: a new vmstat info container
+ */
+PROCPS_EXPORT int procps_vmstat_new(struct vmstat_info **info)
+{
+    struct vmstat_info *v;
+    v = calloc(1, sizeof(struct vmstat_info));
+    if (!v)
+	return -ENOMEM;
+
+    v->refcount = 1;
+    v->vmstat_fd = -1;
+    *info = v;
+    return 0;
+}
+
+/*
+ * procps_vmstat_read:
+ *
+ * Read the data out of /proc/vmstat putting the information
+ * into the supplied info structure
+ */
+PROCPS_EXPORT int procps_vmstat_read(struct vmstat_info *info)
+{
+    char buf[8192];
+    char *head, *tail;
+    int size;
+    unsigned long *valptr;
+
+    if (info == NULL)
+	return -1;
+
+    memset(&(info->data), 0, sizeof(struct vmstat_data));
+    /* read in the data */
+
+    if (-1 == info->vmstat_fd && (info->vmstat_fd = open(VMSTAT_FILE, O_RDONLY)) == -1) {
+	return -errno;
+    }
+    if (lseek(info->vmstat_fd, 0L, SEEK_SET) == -1) {
+	return -errno;
+    }
+    if ((size = read(info->vmstat_fd, buf, sizeof(buf)-1)) < 0) {
+	return -1;
+    }
+    buf[size] = '\0';
+
+    /* Scan the file */
+    head = buf;
+    do {
+	tail = strchr(head, ' ');
+	if (!tail)
+	    break;
+	*tail = '\0';
+	valptr = NULL;
+	if (0 == strcmp(head, "pgpgin")) {
+	    valptr = &(info->data.pgpgin);
+	}else if (0 == strcmp(head, "pgpgout")) {
+	    valptr = &(info->data.pgpgout);
+	}else if (0 == strcmp(head, "pswpin")) {
+	    valptr = &(info->data.pswpin);
+	}else if (0 == strcmp(head, "pswpout")) {
+	    valptr = &(info->data.pswpout);
+	}
+	head = tail+1;
+	if (valptr) {
+	    *valptr = strtoul(head, &tail, 10);
+	}
+
+	tail = strchr(head, '\n');
+	if (!tail)
+	    break;
+	head = tail + 1;
+    } while(tail);
+    return 0;
+}
+
+PROCPS_EXPORT struct vmstat_info *procps_vmstat_ref(struct vmstat_info *info)
+{
+    if (info == NULL)
+	return NULL;
+    info->refcount++;
+    return info;
+}
+
+PROCPS_EXPORT struct vmstat_info *procps_vmstat_unref(struct vmstat_info *info)
+{
+    if (info == NULL)
+	return NULL;
+    info->refcount--;
+    if (info->refcount > 0)
+	return NULL;
+    free(info);
+    return NULL;
+}
+
+/* Accessor functions */
+PROCPS_EXPORT unsigned long procps_vmstat_get(
+	struct vmstat_info *info,
+	enum vmstat_item item)
+{
+    switch(item) {
+	case VMSTAT_INFO_PGPGIN:
+	    return info->data.pgpgin;
+	case VMSTAT_INFO_PGPGOUT:
+	    return info->data.pgpgout;
+	case VMSTAT_INFO_PSWPIN:
+	    return info->data.pswpin;
+	case VMSTAT_INFO_PSWPOUT:
+	    return info->data.pswpout;
+    }
+    return 0;
+}
+