From 14d2069a321cdd2b06f1982e6832c8c5661febf4 Mon Sep 17 00:00:00 2001 From: Gary Benson Date: Wed, 10 Jun 2015 14:28:44 +0100 Subject: [PATCH] Implement vFile:setfs in gdbserver This commit implements the "vFile:setfs" packet in gdbserver. gdb/gdbserver/ChangeLog: * target.h (struct target_ops) : New field. : Likewise. : Likewise. * linux-low.c (nat/linux-namespaces.h): New include. (linux_target_ops): Initialize the_target->multifs_open, the_target->multifs_unlink and the_target->multifs_readlink. * hostio.h (hostio_handle_new_gdb_connection): New declaration. * hostio.c (hostio_fs_pid): New static variable. (hostio_handle_new_gdb_connection): New function. (handle_setfs): Likewise. (handle_open): Use the_target->multifs_open as appropriate. (handle_unlink): Use the_target->multifs_unlink as appropriate. (handle_readlink): Use the_target->multifs_readlink as appropriate. (handle_vFile): Handle vFile:setfs packets. * server.c (handle_query): Call hostio_handle_new_gdb_connection after target_handle_new_gdb_connection. --- gdb/gdbserver/ChangeLog | 20 +++++++++++ gdb/gdbserver/hostio.c | 70 +++++++++++++++++++++++++++++++++++++-- gdb/gdbserver/hostio.h | 3 ++ gdb/gdbserver/linux-low.c | 4 +++ gdb/gdbserver/server.c | 3 +- gdb/gdbserver/target.h | 21 ++++++++++++ 6 files changed, 117 insertions(+), 4 deletions(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index cb21f4b989a..5c3e44f720e 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,23 @@ +2015-06-10 Gary Benson + + * target.h (struct target_ops) : New field. + : Likewise. + : Likewise. + * linux-low.c (nat/linux-namespaces.h): New include. + (linux_target_ops): Initialize the_target->multifs_open, + the_target->multifs_unlink and the_target->multifs_readlink. + * hostio.h (hostio_handle_new_gdb_connection): New declaration. + * hostio.c (hostio_fs_pid): New static variable. + (hostio_handle_new_gdb_connection): New function. + (handle_setfs): Likewise. + (handle_open): Use the_target->multifs_open as appropriate. + (handle_unlink): Use the_target->multifs_unlink as appropriate. + (handle_readlink): Use the_target->multifs_readlink as + appropriate. + (handle_vFile): Handle vFile:setfs packets. + * server.c (handle_query): Call hostio_handle_new_gdb_connection + after target_handle_new_gdb_connection. + 2015-06-10 Gary Benson * configure.ac (AC_CHECK_FUNCS): Add setns. diff --git a/gdb/gdbserver/hostio.c b/gdb/gdbserver/hostio.c index 811f95825b4..b38a6bd0564 100644 --- a/gdb/gdbserver/hostio.c +++ b/gdb/gdbserver/hostio.c @@ -243,6 +243,55 @@ hostio_reply_with_data (char *own_buf, char *buffer, int len, return input_index; } +/* Process ID of inferior whose filesystem hostio functions + that take FILENAME arguments will use. Zero means to use + our own filesystem. */ + +static int hostio_fs_pid; + +/* See hostio.h. */ + +void +hostio_handle_new_gdb_connection (void) +{ + hostio_fs_pid = 0; +} + +/* Handle a "vFile:setfs:" packet. */ + +static void +handle_setfs (char *own_buf) +{ + char *p; + int pid; + + /* If the target doesn't have any of the in-filesystem-of methods + then there's no point in GDB sending "vFile:setfs:" packets. We + reply with an empty packet (i.e. we pretend we don't understand + "vFile:setfs:") and that should stop GDB sending any more. */ + if (the_target->multifs_open == NULL + && the_target->multifs_unlink == NULL + && the_target->multifs_readlink == NULL) + { + own_buf[0] = '\0'; + return; + } + + p = own_buf + strlen ("vFile:setfs:"); + + if (require_int (&p, &pid) + || pid < 0 + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + hostio_fs_pid = pid; + + hostio_reply (own_buf, 0); +} + static void handle_open (char *own_buf) { @@ -269,7 +318,11 @@ handle_open (char *own_buf) /* We do not need to convert MODE, since the fileio protocol uses the standard values. */ - fd = open (filename, flags, mode); + if (hostio_fs_pid != 0 && the_target->multifs_open != NULL) + fd = the_target->multifs_open (hostio_fs_pid, filename, + flags, mode); + else + fd = open (filename, flags, mode); if (fd == -1) { @@ -473,7 +526,10 @@ handle_unlink (char *own_buf) return; } - ret = unlink (filename); + if (hostio_fs_pid != 0 && the_target->multifs_unlink != NULL) + ret = the_target->multifs_unlink (hostio_fs_pid, filename); + else + ret = unlink (filename); if (ret == -1) { @@ -500,7 +556,13 @@ handle_readlink (char *own_buf, int *new_packet_len) return; } - ret = readlink (filename, linkname, sizeof (linkname) - 1); + if (hostio_fs_pid != 0 && the_target->multifs_readlink != NULL) + ret = the_target->multifs_readlink (hostio_fs_pid, filename, + linkname, + sizeof (linkname) - 1); + else + ret = readlink (filename, linkname, sizeof (linkname) - 1); + if (ret == -1) { hostio_error (own_buf); @@ -534,6 +596,8 @@ handle_vFile (char *own_buf, int packet_len, int *new_packet_len) handle_unlink (own_buf); else if (startswith (own_buf, "vFile:readlink:")) handle_readlink (own_buf, new_packet_len); + else if (startswith (own_buf, "vFile:setfs:")) + handle_setfs (own_buf); else return 0; diff --git a/gdb/gdbserver/hostio.h b/gdb/gdbserver/hostio.h index ce951f0c8a6..1cb552c362a 100644 --- a/gdb/gdbserver/hostio.h +++ b/gdb/gdbserver/hostio.h @@ -19,6 +19,9 @@ #ifndef HOSTIO_H #define HOSTIO_H +/* Per-connection setup. */ +extern void hostio_handle_new_gdb_connection (void); + /* Functions from hostio.c. */ extern int handle_vFile (char *, int, int *); diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c index d763c66e5b1..3774d1700cd 100644 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -52,6 +52,7 @@ definition of elf_fpregset_t. */ #include #endif +#include "nat/linux-namespaces.h" #ifndef SPUFS_MAGIC #define SPUFS_MAGIC 0x23c9b64e @@ -6644,6 +6645,9 @@ static struct target_ops linux_target_ops = { #endif linux_supports_range_stepping, linux_proc_pid_to_exec_file, + linux_mntns_open_cloexec, + linux_mntns_unlink, + linux_mntns_readlink, }; static void diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c index 39692672134..70fbefbd65d 100644 --- a/gdb/gdbserver/server.c +++ b/gdb/gdbserver/server.c @@ -2160,7 +2160,8 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p) if (the_target->pid_to_exec_file != NULL) strcat (own_buf, ";qXfer:exec-file:read+"); - /* Reinitialize the target as needed for the new connection. */ + /* Reinitialize components as needed for the new connection. */ + hostio_handle_new_gdb_connection (); target_handle_new_gdb_connection (); return; diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h index e9c6be06e64..9a4086708cf 100644 --- a/gdb/gdbserver/target.h +++ b/gdb/gdbserver/target.h @@ -415,6 +415,27 @@ struct target_ops string should be copied into a buffer by the client if the string will not be immediately used, or if it must persist. */ char *(*pid_to_exec_file) (int pid); + + /* Multiple-filesystem-aware open. Like open(2), but operating in + the filesystem as it appears to process PID. Systems where all + processes share a common filesystem should set this to NULL. + If NULL, the caller should fall back to open(2). */ + int (*multifs_open) (int pid, const char *filename, + int flags, mode_t mode); + + /* Multiple-filesystem-aware unlink. Like unlink(2), but operates + in the filesystem as it appears to process PID. Systems where + all processes share a common filesystem should set this to NULL. + If NULL, the caller should fall back to unlink(2). */ + int (*multifs_unlink) (int pid, const char *filename); + + /* Multiple-filesystem-aware readlink. Like readlink(2), but + operating in the filesystem as it appears to process PID. + Systems where all processes share a common filesystem should + set this to NULL. If NULL, the caller should fall back to + readlink(2). */ + ssize_t (*multifs_readlink) (int pid, const char *filename, + char *buf, size_t bufsiz); }; extern struct target_ops *the_target; -- 2.30.2