From 43e5fbd8b78848c89c1d0305396464039e452688 Mon Sep 17 00:00:00 2001 From: Thiago Jung Bauermann Date: Thu, 18 Aug 2022 18:21:18 +0000 Subject: [PATCH] gdbserver: Add PID parameter to linux_get_auxv and linux_get_hwcap This patch doesn't change gdbserver behaviour, but after later changes are made it avoids a null pointer dereference when HWCAP needs to be obtained for a specific process while current_thread is nullptr. Fixing linux_read_auxv, linux_get_hwcap and linux_get_hwcap2 to take a PID parameter seems more correct than setting current_thread in one particular code path. Changes are propagated to allow passing the new parameter through the call chain. Approved-By: Simon Marchi --- gdbserver/linux-aarch64-low.cc | 7 ++++--- gdbserver/linux-arm-low.cc | 2 +- gdbserver/linux-low.cc | 18 +++++++++--------- gdbserver/linux-low.h | 21 ++++++++++----------- gdbserver/linux-ppc-low.cc | 6 +++--- gdbserver/linux-s390-low.cc | 2 +- gdbserver/netbsd-low.cc | 4 +--- gdbserver/netbsd-low.h | 2 +- gdbserver/server.cc | 3 ++- gdbserver/target.cc | 4 ++-- gdbserver/target.h | 4 ++-- 11 files changed, 36 insertions(+), 37 deletions(-) diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc index 3c09e086afe..2ed6e95562c 100644 --- a/gdbserver/linux-aarch64-low.cc +++ b/gdbserver/linux-aarch64-low.cc @@ -846,12 +846,13 @@ aarch64_target::low_arch_setup () if (is_elf64) { struct aarch64_features features; + int pid = current_thread->id.pid (); features.vq = aarch64_sve_get_vq (tid); /* A-profile PAC is 64-bit only. */ - features.pauth = linux_get_hwcap (8) & AARCH64_HWCAP_PACA; + features.pauth = linux_get_hwcap (pid, 8) & AARCH64_HWCAP_PACA; /* A-profile MTE is 64-bit only. */ - features.mte = linux_get_hwcap2 (8) & HWCAP2_MTE; + features.mte = linux_get_hwcap2 (pid, 8) & HWCAP2_MTE; features.tls = aarch64_tls_register_count (tid); current_process ()->tdesc = aarch64_linux_read_description (features); @@ -3322,7 +3323,7 @@ aarch64_target::supports_memory_tagging () #endif } - return (linux_get_hwcap2 (8) & HWCAP2_MTE) != 0; + return (linux_get_hwcap2 (current_thread->id.pid (), 8) & HWCAP2_MTE) != 0; } bool diff --git a/gdbserver/linux-arm-low.cc b/gdbserver/linux-arm-low.cc index 98ba0e02524..5975b44af0a 100644 --- a/gdbserver/linux-arm-low.cc +++ b/gdbserver/linux-arm-low.cc @@ -958,7 +958,7 @@ get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self) static const struct target_desc * arm_read_description (void) { - unsigned long arm_hwcap = linux_get_hwcap (4); + unsigned long arm_hwcap = linux_get_hwcap (current_thread->id.pid (), 4); if (arm_hwcap & HWCAP_IWMMXT) return arm_linux_read_description (ARM_FP_TYPE_IWMMXT); diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc index 7e1de397893..5cd22824e47 100644 --- a/gdbserver/linux-low.cc +++ b/gdbserver/linux-low.cc @@ -5483,12 +5483,11 @@ linux_process_target::supports_read_auxv () to debugger memory starting at MYADDR. */ int -linux_process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr, - unsigned int len) +linux_process_target::read_auxv (int pid, CORE_ADDR offset, + unsigned char *myaddr, unsigned int len) { char filename[PATH_MAX]; int fd, n; - int pid = lwpid_of (current_thread); xsnprintf (filename, sizeof filename, "/proc/%d/auxv", pid); @@ -6982,14 +6981,15 @@ linux_get_pc_64bit (struct regcache *regcache) /* See linux-low.h. */ int -linux_get_auxv (int wordsize, CORE_ADDR match, CORE_ADDR *valp) +linux_get_auxv (int pid, int wordsize, CORE_ADDR match, CORE_ADDR *valp) { gdb_byte *data = (gdb_byte *) alloca (2 * wordsize); int offset = 0; gdb_assert (wordsize == 4 || wordsize == 8); - while (the_target->read_auxv (offset, data, 2 * wordsize) == 2 * wordsize) + while (the_target->read_auxv (pid, offset, data, 2 * wordsize) + == 2 * wordsize) { if (wordsize == 4) { @@ -7019,20 +7019,20 @@ linux_get_auxv (int wordsize, CORE_ADDR match, CORE_ADDR *valp) /* See linux-low.h. */ CORE_ADDR -linux_get_hwcap (int wordsize) +linux_get_hwcap (int pid, int wordsize) { CORE_ADDR hwcap = 0; - linux_get_auxv (wordsize, AT_HWCAP, &hwcap); + linux_get_auxv (pid, wordsize, AT_HWCAP, &hwcap); return hwcap; } /* See linux-low.h. */ CORE_ADDR -linux_get_hwcap2 (int wordsize) +linux_get_hwcap2 (int pid, int wordsize) { CORE_ADDR hwcap2 = 0; - linux_get_auxv (wordsize, AT_HWCAP2, &hwcap2); + linux_get_auxv (pid, wordsize, AT_HWCAP2, &hwcap2); return hwcap2; } diff --git a/gdbserver/linux-low.h b/gdbserver/linux-low.h index aebfe05707e..e672855a7f2 100644 --- a/gdbserver/linux-low.h +++ b/gdbserver/linux-low.h @@ -178,7 +178,7 @@ public: bool supports_read_auxv () override; - int read_auxv (CORE_ADDR offset, unsigned char *myaddr, + int read_auxv (int pid, CORE_ADDR offset, unsigned char *myaddr, unsigned int len) override; int insert_point (enum raw_bkpt_type type, CORE_ADDR addr, @@ -941,22 +941,21 @@ bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len); extern int have_ptrace_getregset; -/* Search for the value with type MATCH in the auxv vector with - entries of length WORDSIZE bytes. If found, store the value in - *VALP and return 1. If not found or if there is an error, return - 0. */ +/* Search for the value with type MATCH in the auxv vector, with entries of + length WORDSIZE bytes, of process with pid PID. If found, store the + value in *VALP and return 1. If not found or if there is an error, + return 0. */ -int linux_get_auxv (int wordsize, CORE_ADDR match, - CORE_ADDR *valp); +int linux_get_auxv (int pid, int wordsize, CORE_ADDR match, CORE_ADDR *valp); /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length - WORDSIZE. If no entry was found, return zero. */ + WORDSIZE, of process with pid PID. If no entry was found, return 0. */ -CORE_ADDR linux_get_hwcap (int wordsize); +CORE_ADDR linux_get_hwcap (int pid, int wordsize); /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length - WORDSIZE. If no entry was found, return zero. */ + WORDSIZE, of process with pid PID. If no entry was found, return 0. */ -CORE_ADDR linux_get_hwcap2 (int wordsize); +CORE_ADDR linux_get_hwcap2 (int pid, int wordsize); #endif /* GDBSERVER_LINUX_LOW_H */ diff --git a/gdbserver/linux-ppc-low.cc b/gdbserver/linux-ppc-low.cc index fdf74727e39..f8dd770b8eb 100644 --- a/gdbserver/linux-ppc-low.cc +++ b/gdbserver/linux-ppc-low.cc @@ -894,8 +894,8 @@ ppc_target::low_arch_setup () /* The value of current_process ()->tdesc needs to be set for this call. */ - ppc_hwcap = linux_get_hwcap (features.wordsize); - ppc_hwcap2 = linux_get_hwcap2 (features.wordsize); + ppc_hwcap = linux_get_hwcap (current_thread->id.pid (), features.wordsize); + ppc_hwcap2 = linux_get_hwcap2 (current_thread->id.pid (), features.wordsize); features.isa205 = ppc_linux_has_isa205 (ppc_hwcap); @@ -1097,7 +1097,7 @@ is_elfv2_inferior (void) const struct target_desc *tdesc = current_process ()->tdesc; int wordsize = register_size (tdesc, 0); - if (!linux_get_auxv (wordsize, AT_PHDR, &phdr)) + if (!linux_get_auxv (current_thread->id.pid (), wordsize, AT_PHDR, &phdr)) return def_res; /* Assume ELF header is at the beginning of the page where program headers diff --git a/gdbserver/linux-s390-low.cc b/gdbserver/linux-s390-low.cc index b3ccdff3e57..48f64ef7bb3 100644 --- a/gdbserver/linux-s390-low.cc +++ b/gdbserver/linux-s390-low.cc @@ -592,7 +592,7 @@ s390_target::low_arch_setup () /* Determine word size and HWCAP. */ int pid = pid_of (current_thread); int wordsize = s390_get_wordsize (pid); - unsigned long hwcap = linux_get_hwcap (wordsize); + unsigned long hwcap = linux_get_hwcap (pid, wordsize); /* Check whether the kernel supports extra register sets. */ int have_regset_last_break diff --git a/gdbserver/netbsd-low.cc b/gdbserver/netbsd-low.cc index 15afa36d115..4defd79eee4 100644 --- a/gdbserver/netbsd-low.cc +++ b/gdbserver/netbsd-low.cc @@ -581,11 +581,9 @@ netbsd_read_auxv(pid_t pid, void *offs, void *addr, size_t len) to debugger memory starting at MYADDR. */ int -netbsd_process_target::read_auxv (CORE_ADDR offset, +netbsd_process_target::read_auxv (int pid, CORE_ADDR offset, unsigned char *myaddr, unsigned int len) { - pid_t pid = pid_of (current_thread); - return netbsd_read_auxv (pid, (void *) (intptr_t) offset, myaddr, len); } diff --git a/gdbserver/netbsd-low.h b/gdbserver/netbsd-low.h index daefc302785..050b43fc54f 100644 --- a/gdbserver/netbsd-low.h +++ b/gdbserver/netbsd-low.h @@ -77,7 +77,7 @@ public: bool supports_read_auxv () override; - int read_auxv (CORE_ADDR offset, unsigned char *myaddr, + int read_auxv (int pid, CORE_ADDR offset, unsigned char *myaddr, unsigned int len) override; bool supports_hardware_single_step () override; diff --git a/gdbserver/server.cc b/gdbserver/server.cc index d802e8b4a34..21fb51a45d1 100644 --- a/gdbserver/server.cc +++ b/gdbserver/server.cc @@ -1443,7 +1443,8 @@ handle_qxfer_auxv (const char *annex, if (annex[0] != '\0' || current_thread == NULL) return -1; - return the_target->read_auxv (offset, readbuf, len); + return the_target->read_auxv (current_thread->id.pid (), offset, readbuf, + len); } /* Handle qXfer:exec-file:read. */ diff --git a/gdbserver/target.cc b/gdbserver/target.cc index 720a61d636a..2658a359897 100644 --- a/gdbserver/target.cc +++ b/gdbserver/target.cc @@ -346,8 +346,8 @@ process_stratum_target::supports_read_auxv () } int -process_stratum_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr, - unsigned int len) +process_stratum_target::read_auxv (int pid, CORE_ADDR offset, + unsigned char *myaddr, unsigned int len) { gdb_assert_not_reached ("target op read_auxv not supported"); } diff --git a/gdbserver/target.h b/gdbserver/target.h index 6d92f0f5cd8..01002c2d6aa 100644 --- a/gdbserver/target.h +++ b/gdbserver/target.h @@ -172,10 +172,10 @@ public: /* Return true if the read_auxv target op is supported. */ virtual bool supports_read_auxv (); - /* Read auxiliary vector data from the inferior process. + /* Read auxiliary vector data from the process with pid PID. Read LEN bytes at OFFSET into a buffer at MYADDR. */ - virtual int read_auxv (CORE_ADDR offset, unsigned char *myaddr, + virtual int read_auxv (int pid, CORE_ADDR offset, unsigned char *myaddr, unsigned int len); /* Returns true if GDB Z breakpoint type TYPE is supported, false -- 2.30.2