From: Neil Horman <nhorman@redhat.com>
Date: Fri, 24 Aug 2007 11:12:10 -0400
Subject: [fs] proc: add /proc/<pid>/limits
Message-id: 20070824151210.GF8835@hmsendeavour.rdu.redhat.com
O-Subject: [RHEL5.2 PATCH] proc: add /proc/<pid>/limits
Bugzilla: 253762

Hey-
     This is the RHEL 5.2 version of the upstream /proc/pid/limits patch.
Resolves bz 253762

Regards
Neil

Acked-by: Larry Woodman <lwoodman@redhat.com>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index aed7683..fbb1718 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -76,6 +76,7 @@
 #include <linux/tracehook.h>
 #include <linux/rcupdate.h>
 #include <linux/delayacct.h>
+#include <linux/resource.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -499,3 +500,77 @@ int proc_pid_statm(struct task_struct *task, char *buffer)
 	return sprintf(buffer,"%d %d %d %d %d %d %d\n",
 		       size, resident, shared, text, lib, data, 0);
 }
+
+
+struct limit_names {
+	char *name;
+	char *unit;
+};
+
+static const struct limit_names lnames[RLIM_NLIMITS] = {
+	[RLIMIT_CPU] = {"Max cpu time", "seconds"},
+	[RLIMIT_FSIZE] = {"Max file size", "bytes"},
+	[RLIMIT_DATA] = {"Max data size", "bytes"},
+	[RLIMIT_STACK] = {"Max stack size", "bytes"},
+	[RLIMIT_CORE] = {"Max core file size", "bytes"},
+	[RLIMIT_RSS] = {"Max resident set", "bytes"},
+	[RLIMIT_NPROC] = {"Max processes", "processes"},
+	[RLIMIT_NOFILE] = {"Max open files", "files"},
+	[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
+	[RLIMIT_AS] = {"Max address space", "bytes"},
+	[RLIMIT_LOCKS] = {"Max file locks", "locks"},
+	[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
+	[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
+	[RLIMIT_NICE] = {"Max nice priority", NULL},
+	[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
+};
+
+/* Display limits for a process */
+
+int proc_pid_limits(struct task_struct *task, char *buffer)
+{
+	unsigned int i;
+	int count = 0;
+	unsigned long flags;
+	char *bufptr = buffer;
+
+	struct rlimit rlim[RLIM_NLIMITS];
+
+	rcu_read_lock();
+	if (!lock_task_sighand(task,&flags)) {
+		rcu_read_unlock();
+		return 0;
+	}
+	memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
+	unlock_task_sighand(task, &flags);
+	rcu_read_unlock();
+
+	/*
+	 * print the file header
+	 */
+	count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
+			"Limit", "Soft Limit", "Hard Limit", "Units");
+
+	for (i = 0; i < RLIM_NLIMITS; i++) {
+		if (rlim[i].rlim_cur == RLIM_INFINITY)
+			count += sprintf(&bufptr[count], "%-25s %-20s ",
+					 lnames[i].name, "unlimited");
+		else
+			count += sprintf(&bufptr[count], "%-25s %-20lu ",
+					 lnames[i].name, rlim[i].rlim_cur);
+
+		if (rlim[i].rlim_max == RLIM_INFINITY)
+			count += sprintf(&bufptr[count], "%-20s ", "unlimited");
+		else
+			count += sprintf(&bufptr[count], "%-20lu ",
+					 rlim[i].rlim_max);
+
+		if (lnames[i].unit)
+			count += sprintf(&bufptr[count], "%-10s\n",
+					 lnames[i].unit);
+		else
+			count += sprintf(&bufptr[count], "\n");
+	}
+
+	return count;
+}
diff --git a/fs/proc/base.c b/fs/proc/base.c
index f051e75..5b8a40f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -182,7 +182,8 @@ enum pid_directory_inos {
 #endif
 	PROC_TID_OOM_SCORE,
 	PROC_TID_OOM_ADJUST,
-
+	PROC_TGID_LIMITS,
+	PROC_TID_LIMITS,
 	/* Add new entries before this */
 	PROC_TID_FD_DIR = 0x8000,	/* 0x8000-0xffff */
 };
@@ -241,6 +242,9 @@ static struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_AUDITSYSCALL
 	E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 #endif
+	E(PROC_TGID_LIMITS, "limits", S_IFREG|S_IRUSR),
+	E(PROC_TID_LIMITS, "limits", S_IFREG|S_IRUSR),
+
 	{0,0,NULL,0}
 };
 static struct pid_entry tid_base_stuff[] = {
@@ -283,6 +287,9 @@ static struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_AUDITSYSCALL
 	E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 #endif
+	E(PROC_TGID_LIMITS, "limits", S_IFREG|S_IRUSR),
+	E(PROC_TID_LIMITS, "limits", S_IFREG|S_IRUSR),
+
 	{0,0,NULL,0}
 };
 
@@ -1830,6 +1837,11 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
 			inode->i_fop = &proc_info_file_operations;
 			ei->op.proc_read = proc_pid_status;
 			break;
+		case PROC_TID_LIMITS:
+		case PROC_TGID_LIMITS:
+			inode->i_fop = &proc_info_file_operations;
+			ei->op.proc_read = proc_pid_limits;
+			break;
 		case PROC_TID_STAT:
 			inode->i_fop = &proc_info_file_operations;
 			ei->op.proc_read = proc_tid_stat;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index c0bf3d8..a836865 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -38,6 +38,7 @@ extern int proc_tid_stat(struct task_struct *,  char *);
 extern int proc_tgid_stat(struct task_struct *, char *);
 extern int proc_pid_status(struct task_struct *, char *);
 extern int proc_pid_statm(struct task_struct *, char *);
+extern int proc_pid_limits(struct task_struct *, char *);
 
 extern struct file_operations proc_maps_operations;
 extern struct file_operations proc_numa_maps_operations;