library: Add procps_meminfo_* functions

New set of functions that read the /proc/meminfo file. Still needs
work.

Makefile.am

@@ -158,6 +158,8 @@ proc_libprocps_la_SOURCES = \
 	proc/escape.c \
 	proc/escape.h \
 	proc/procps-private.h \
+	proc/meminfo.c \
+	proc/meminfo.h \
 	proc/procps.h \
 	proc/pwcache.c \
 	proc/pwcache.h \

proc/libprocps.sym

@@ -60,6 +60,11 @@ global:
 	uptime;
 	user_from_uid;
 	procps_linux_version;
+	procps_meminfo_new;
+	procps_meminfo_read;
+	procps_meminfo_ref;
+	procps_meminfo_unref;
+	procps_meminfo_get;
 	procps_stat_new;
 	procps_stat_read;
 	procps_stat_ref;

proc/meminfo.c

@@ -0,0 +1,177 @@
+
+#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/meminfo.h>
+#include "procps-private.h"
+
+#define MEMINFO_FILE "/proc/meminfo"
+
+struct meminfo_data {
+    unsigned long active;
+    unsigned long inactive;
+    unsigned long high_free;
+    unsigned long high_total;
+    unsigned long low_free;
+    unsigned long low_total;
+    unsigned long main_available;
+    unsigned long main_buffers;
+    unsigned long main_cached;
+    unsigned long main_free;
+    unsigned long main_shared;
+    unsigned long main_total;
+    unsigned long main_used;
+    unsigned long swap_free;
+    unsigned long swap_total;
+    unsigned long swap_used;
+};
+
+struct procps_meminfo {
+    int refcount;
+    int meminfo_fd;
+    struct meminfo_data data;
+};
+
+
+/*
+ * procps_meminfo_new:
+ *
+ * Create a new container to hold the meminfo information
+ *
+ * The initial refcount is 1, and needs to be decremented
+ * to release the resources of the structure.
+ *
+ * Returns: a new meminfo info container
+ */
+PROCPS_EXPORT int procps_meminfo_new(struct procps_meminfo **info)
+{
+    struct procps_meminfo *m;
+    m = calloc(1, sizeof(struct procps_meminfo));
+    if (!m)
+	return -ENOMEM;
+
+    m->refcount = 1;
+    m->meminfo_fd = -1;
+    *info = m;
+    return 0;
+}
+
+/*
+ * procps_meminfo_read:
+ *
+ * Read the data out of /proc/meminfo putting the information
+ * into the supplied info structure
+ */
+PROCPS_EXPORT int procps_meminfo_read(struct procps_meminfo *info)
+{
+    char buf[8192];
+    char *head, *tail;
+    int size;
+    unsigned long *valptr;
+
+    if (info == NULL)
+	return -1;
+
+    memset(&(info->data), 0, sizeof(struct meminfo_data));
+    /* read in the data */
+
+    if (-1 == info->meminfo_fd && (info->meminfo_fd = open(MEMINFO_FILE, O_RDONLY)) == -1) {
+	return -errno;
+    }
+    if (lseek(info->meminfo_fd, 0L, SEEK_SET) == -1) {
+	return -errno;
+    }
+    if ((size = read(info->meminfo_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, "Active:")) {
+	    valptr = &(info->data.active);
+	} else if (0 == strcmp(head, "Inactive:")) {
+	    valptr = &(info->data.inactive);
+	} else if (0 == strcmp(head, "HighFree:")) {
+	    valptr = &(info->data.high_free);
+	} else if (0 == strcmp(head, "HighTotal:")) {
+	    valptr = &(info->data.high_total);
+	} else if (0 == strcmp(head, "LowFree:")) {
+	    valptr = &(info->data.low_free);
+	} else if (0 == strcmp(head, "LowTotal:")) {
+	    valptr = &(info->data.low_total);
+	} else if (0 == strcmp(head, "MemAvailable:")) {
+	    valptr = &(info->data.main_available);
+	} else if (0 == strcmp(head, "Buffers:")) {
+	    valptr = &(info->data.main_buffers);
+	} else if (0 == strcmp(head, "Cached:")) {
+	    valptr = &(info->data.main_cached);
+	} else if (0 == strcmp(head, "MemFree:")) {
+	    valptr = &(info->data.main_free);
+	} else if (0 == strcmp(head, "Shmem:")) {
+	    valptr = &(info->data.main_shared);
+	} else if (0 == strcmp(head, "MemTotal:")) {
+	    valptr = &(info->data.main_total);
+	} else if (0 == strcmp(head, "SwapFree:")) {
+	    valptr = &(info->data.swap_free);
+	} else if (0 == strcmp(head, "SwapTotal:")) {
+	    valptr = &(info->data.swap_total);
+	}
+	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 procps_meminfo *procps_meminfo_ref(struct procps_meminfo *info)
+{
+    if (info == NULL)
+	return NULL;
+    info->refcount++;
+    return info;
+}
+
+PROCPS_EXPORT struct procps_meminfo *procps_meminfo_unref(struct procps_meminfo *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_meminfo_get(
+	struct procps_meminfo *info,
+	enum meminfo_item item)
+{
+    switch(item) {
+	case PROCPS_MEMINFO_ACTIVE:
+	    return info->data.active;
+	case PROCPS_MEMINFO_SWAP_USED:
+	    if (info->data.swap_free > info->data.swap_total)
+		return 0;
+	    return info->data.swap_total - info->data.swap_free;
+    }
+    return 0;
+}

proc/meminfo.h

@@ -0,0 +1,54 @@
+/*
+ * libprocps - Library to read proc filesystem
+ * meminfo - Parse /proc/meminfo
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef PROC_MEMINFO_H
+#define PROC_MEMINFO_H
+
+#include <proc/procps.h>
+
+__BEGIN_DECLS
+
+struct procps_meminfo;
+int procps_meminfo_new(struct procps_meminfo **info);
+int procps_meminfo_read(struct procps_meminfo *info);
+struct procps_meminfo *procps_meminfo_ref(struct procps_meminfo *info);
+struct procps_meminfo *procps_meminfo_unref(struct procps_meminfo *info);
+
+enum meminfo_item {
+    PROCPS_MEMINFO_ACTIVE,
+    PROCPS_MEMINFO_INACTIVE,
+    PROCPS_MEMINFO_HIGH_FREE,
+    PROCPS_MEMINFO_HIGH_TOTAL,
+    PROCPS_MEMINFO_LOW_FREE,
+    PROCPS_MEMINFO_LOW_TOTAL,
+    PROCPS_MEMINFO_MAIN_AVAILABLE,
+    PROCPS_MEMINFO_MAIN_BUFFERS,
+    PROCPS_MEMINFO_MAIN_CACHED,
+    PROCPS_MEMINFO_MAIN_FREE,
+    PROCPS_MEMINFO_MAIN_SHARED,
+    PROCPS_MEMINFO_MAIN_TOTAL,
+    PROCPS_MEMINFO_MAIN_USED,
+    PROCPS_MEMINFO_SWAP_FREE,
+    PROCPS_MEMINFO_SWAP_TOTAL,
+    PROCPS_MEMINFO_SWAP_USED,
+};
+unsigned long procps_meminfo_get(struct procps_meminfo *info, enum meminfo_item item);
+
+__END_DECLS
+#endif
+