Implement vFile:setfs in gdbserver From: Gary Benson 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/linux-low.c | 4 +++ gdb/gdbserver/server.c | 2 + gdb/gdbserver/target.h | 21 ++++++++++++++ 5 files changed, 114 insertions(+), 3 deletions(-) Index: gdb-7.6.1/gdb/gdbserver/hostio.c =================================================================== --- gdb-7.6.1.orig/gdb/gdbserver/hostio.c 2013-01-01 07:33:00.000000000 +0100 +++ gdb-7.6.1/gdb/gdbserver/hostio.c 2016-03-06 23:38:57.315483217 +0100 @@ -263,6 +263,55 @@ return 0; } +/* 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) { @@ -287,7 +336,11 @@ /* 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) { @@ -455,7 +508,10 @@ 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) { @@ -483,7 +539,13 @@ 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); @@ -518,6 +580,8 @@ handle_unlink (own_buf); else if (strncmp (own_buf, "vFile:readlink:", 15) == 0) handle_readlink (own_buf, new_packet_len); + else if (strncmp (own_buf, "vFile:setfs:", 12) == 0) + handle_setfs (own_buf); else return 0; Index: gdb-7.6.1/gdb/gdbserver/linux-low.c =================================================================== --- gdb-7.6.1.orig/gdb/gdbserver/linux-low.c 2016-03-06 23:38:57.259482835 +0100 +++ gdb-7.6.1/gdb/gdbserver/linux-low.c 2016-03-06 23:38:57.317483230 +0100 @@ -50,6 +50,7 @@ definition of elf_fpregset_t. */ #include #endif +#include "../nat/linux-namespaces.h" #ifndef SPUFS_MAGIC #define SPUFS_MAGIC 0x23c9b64e @@ -6019,6 +6020,9 @@ NULL, #endif linux_proc_pid_to_exec_file, + linux_mntns_open_cloexec, + linux_mntns_unlink, + linux_mntns_readlink, }; static void Index: gdb-7.6.1/gdb/gdbserver/server.c =================================================================== --- gdb-7.6.1.orig/gdb/gdbserver/server.c 2016-03-06 23:38:57.278482965 +0100 +++ gdb-7.6.1/gdb/gdbserver/server.c 2016-03-06 23:41:53.678684044 +0100 @@ -1873,6 +1873,11 @@ if (the_target->pid_to_exec_file != NULL) strcat (own_buf, ";qXfer:exec-file:read+"); + /* Reinitialize components as needed for the new connection. */ +{ +extern void hostio_handle_new_gdb_connection (void); + hostio_handle_new_gdb_connection (); +} return; } Index: gdb-7.6.1/gdb/gdbserver/target.h =================================================================== --- gdb-7.6.1.orig/gdb/gdbserver/target.h 2016-03-06 23:38:57.261482849 +0100 +++ gdb-7.6.1/gdb/gdbserver/target.h 2016-03-06 23:38:57.318483237 +0100 @@ -421,6 +421,27 @@ 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;