feat: add /proc/fd file to dump the pid/fd/path information

1, for users with privilege, display all users' fd info with the template "Pid  Fd  SysFd Path"
2, for normal user, display its own fd info with the template "Pid Fd Path"

close #I3WB5U
Signed-off-by: Nchenwei <chenwei26@huawei.com>

fs/proc/include/internal.h

@@ -65,6 +65,8 @@ extern void ProcUptimeInit(void);
 
 extern void ProcFsCacheInit(void);
 
+extern void ProcFdInit(void);
+
 #ifdef __cplusplus
 #if __cplusplus
 }

fs/proc/os_adapt/fd_proc.c

+/*
+ * Copyright (c) 2021-2021 Huawei Device Co., Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *    of conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used
+ *    to endorse or promote products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "proc_fs.h"
+
+#include <stdbool.h>
+#include "fs/file.h"
+#include "vfs_config.h"
+#include "internal.h"
+
+#include "fs/fd_table.h"
+#include "los_process.h"
+#include "capability_api.h"
+#include "capability_type.h"
+
+
+/*
+ * Template: Pid    Fd  [SysFd ] Name
+ */
+static void FillFdInfo(struct SeqBuf *seqBuf, struct filelist *fileList, unsigned int pid, bool hasPrivilege)
+{
+    int fd;
+    int sysFd;
+    char *name = NULL;
+    struct file *filp = NULL;
+
+    struct fd_table_s *fdt = LOS_GetFdTable(pid);
+    if ((fdt == NULL) || (fdt->proc_fds == NULL)) {
+        return;
+    }
+
+    (void)sem_wait(&fdt->ft_sem);
+
+    for (fd = MIN_START_FD; fd < fdt->max_fds; fd++) {
+        if (FD_ISSET(fd, fdt->proc_fds)) {
+            sysFd = fdt->ft_fds[fd].sysFd;
+            if (sysFd < CONFIG_NFILE_DESCRIPTORS) {
+                filp = &fileList->fl_files[sysFd];
+                name = filp->f_path;
+            } else if (sysFd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS)) {
+                name = "(socks)";
+            } else if (sysFd < (FD_SETSIZE + CONFIG_NTIME_DESCRIPTORS)) {
+                name = "(timer)";
+            } else if (sysFd < (MQUEUE_FD_OFFSET + CONFIG_NQUEUE_DESCRIPTORS)) {
+                name = "(mqueue)";
+            } else {
+                name = "(unknown)";
+            }
+
+            if (hasPrivilege) {
+                (void)LosBufPrintf(seqBuf, "%u\t%d\t%d\t%s\n", pid, fd, sysFd, name);
+            } else {
+                (void)LosBufPrintf(seqBuf, "%u\t%d\t%s\n", pid, fd, name);
+            }
+        }
+    }
+
+    (void)sem_post(&fdt->ft_sem);
+}
+
+static int FdProcFill(struct SeqBuf *seqBuf, void *v)
+{
+    int pidNum;
+    bool hasPrivilege;
+    unsigned int pidMaxNum;
+    unsigned int *pidList = NULL;
+
+    /* privilege user */
+    if (IsCapPermit(CAP_DAC_READ_SEARCH)) {
+        pidMaxNum = LOS_GetSystemProcessMaximum();
+        pidList = (unsigned int *)malloc(pidMaxNum * sizeof(unsigned int));
+        if (pidList == NULL) {
+            return -ENOMEM;
+        }
+        pidNum = LOS_GetUsedPIDList(pidList, pidMaxNum);
+        hasPrivilege = true;
+        (void)LosBufPrintf(seqBuf, "Pid\tFd\tSysFd\tName\n");
+    } else {
+        pidNum = 1;
+        pidList = (unsigned int *)malloc(pidNum * sizeof(unsigned int));
+        if (pidList == NULL) {
+            return -ENOMEM;
+        }
+        pidList[0] = LOS_GetCurrProcessID();
+        hasPrivilege = false;
+        (void)LosBufPrintf(seqBuf, "Pid\tFd\tName\n");
+    }
+
+    struct filelist *fileList = &tg_filelist;
+    (void)sem_wait(&fileList->fl_sem);
+
+    for (int i = 0; i < pidNum; i++) {
+        FillFdInfo(seqBuf, fileList, pidList[i], hasPrivilege);
+    }
+
+    free(pidList);
+    (void)sem_post(&fileList->fl_sem);
+    return 0;
+}
+
+static const struct ProcFileOperations FD_PROC_FOPS = {
+    .read       = FdProcFill,
+};
+
+void ProcFdInit(void)
+{
+    struct ProcDirEntry *pde = CreateProcEntry("fd", 0, NULL);
+    if (pde == NULL) {
+        PRINT_ERR("creat /proc/fd error.\n");
+        return;
+    }
+
+    pde->procFileOps = &FD_PROC_FOPS;
+}
+

fs/proc/os_adapt/proc_init.c

@@ -65,6 +65,7 @@ void ProcFsInit(void)
     ProcUptimeInit();
     ProcKernelTraceInit();
     ProcFsCacheInit();
+    ProcFdInit();
 }
 
 LOS_MODULE_INIT(ProcFsInit, LOS_INIT_LEVEL_KMOD_EXTENDED);

kernel/base/core/los_process.c

@@ -1794,6 +1794,52 @@ LITE_OS_SEC_TEXT VOID LOS_Exit(INT32 status)
     OsProcessExit(OsCurrTaskGet(), (UINT32)status);
 }
 
+LITE_OS_SEC_TEXT INT32 LOS_GetUsedPIDList(UINT32 *pidList, INT32 pidMaxNum)
+{
+    LosProcessCB *pcb = NULL;
+    INT32 num = 0;
+    UINT32 intSave;
+    UINT32 pid = 1;
+
+    if (pidList == NULL) {
+        return 0;
+    }
+    SCHEDULER_LOCK(intSave);
+    while (OsProcessIDUserCheckInvalid(pid) == false) {
+        pcb = OS_PCB_FROM_PID(pid);
+        pid++;
+        if (OsProcessIsUnused(pcb)) {
+            continue;
+        }
+        pidList[num] = pcb->processID;
+        num++;
+        if (num >= pidMaxNum) {
+            break;
+        }
+    }
+    SCHEDULER_UNLOCK(intSave);
+    return num;
+}
+
+#ifdef LOSCFG_FS_VFS
+LITE_OS_SEC_TEXT struct fd_table_s *LOS_GetFdTable(UINT32 pid)
+{
+    LosProcessCB *pcb = NULL;
+    struct files_struct *files = NULL;
+
+    if (OS_PID_CHECK_INVALID(pid)) {
+        return NULL;
+    }
+    pcb = OS_PCB_FROM_PID(pid);
+    files = pcb->files;
+    if (files == NULL) {
+        return NULL;
+    }
+
+    return files->fdt;
+}
+#endif
+
 LITE_OS_SEC_TEXT UINT32 LOS_GetCurrProcessID(VOID)
 {
     return OsCurrProcessGet()->processID;

kernel/include/los_process.h

@@ -34,6 +34,10 @@
 
 #include "los_task.h"
 
+#ifdef LOSCFG_FS_VFS
+#include "fs/fd_table.h"
+#endif
+
 #ifdef __cplusplus
 #if __cplusplus
     extern "C" {
@@ -68,6 +72,12 @@ extern BOOL LOS_CheckInGroups(UINT32 gid);
 extern INT32 LOS_GetUserID(VOID);
 extern INT32 LOS_GetGroupID(VOID);
 
+extern INT32 LOS_GetUsedPIDList(UINT32 *pidList, INT32 pidMaxNum);
+
+#ifdef LOSCFG_FS_VFS
+struct fd_table_s *LOS_GetFdTable(UINT32 pid);
+#endif
+
 #ifdef __cplusplus
 #if __cplusplus
 }