From 9a89470449a5171eb1bd06f681361e0888d15cf7 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 28 Apr 2022 12:04:44 -0700 Subject: [PATCH] semihosting: Split out semihost_sys_lseek Split out the non-ARM specific portions of SYS_SEEK to a reusable function. This handles all GuestFD. Isolate the curious ARM-specific return value processing to a new callback, common_semi_seek_cb. Expand the internal type of the offset to int64_t, and provide the whence argument, which will be required by m68k and nios2 semihosting. Note that gdb_do_syscall %x reads target_ulong, not int. Reviewed-by: Luc Michel Signed-off-by: Richard Henderson --- include/exec/gdbstub.h | 5 +++ include/semihosting/syscalls.h | 3 ++ semihosting/arm-compat-semi.c | 51 ++++++--------------- semihosting/syscalls.c | 81 ++++++++++++++++++++++++++++++++++ 4 files changed, 102 insertions(+), 38 deletions(-) diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h index 95a8b7b056..b588c306cc 100644 --- a/include/exec/gdbstub.h +++ b/include/exec/gdbstub.h @@ -41,6 +41,11 @@ #define GDB_ENAMETOOLONG 91 #define GDB_EUNKNOWN 9999 +/* For gdb file i/o remote protocol lseek whence. */ +#define GDB_SEEK_SET 0 +#define GDB_SEEK_CUR 1 +#define GDB_SEEK_END 2 + /* For gdb file i/o stat/fstat. */ typedef uint32_t gdb_mode_t; typedef uint32_t gdb_time_t; diff --git a/include/semihosting/syscalls.h b/include/semihosting/syscalls.h index 2464467579..841a93d25b 100644 --- a/include/semihosting/syscalls.h +++ b/include/semihosting/syscalls.h @@ -39,4 +39,7 @@ void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete, void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete, GuestFD *gf, target_ulong buf, target_ulong len); +void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete, + int fd, int64_t off, int gdb_whence); + #endif /* SEMIHOSTING_SYSCALLS_H */ diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c index d591fcd7c2..a117d180bc 100644 --- a/semihosting/arm-compat-semi.c +++ b/semihosting/arm-compat-semi.c @@ -224,16 +224,6 @@ static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err) #else syscall_err = err; #endif - } else { - /* Fixup syscalls that use nonstardard return conventions. */ - target_ulong reg0 = common_semi_arg(cs, 0); - switch (reg0) { - case TARGET_SYS_SEEK: - ret = 0; - break; - default: - break; - } } common_semi_set_ret(cs, ret); } @@ -257,6 +247,18 @@ static void common_semi_rw_cb(CPUState *cs, target_ulong ret, target_ulong err) common_semi_set_ret(cs, arg2 - ret); } +/* + * SYS_SEEK returns 0 on success, not the resulting offset. + */ +static void common_semi_seek_cb(CPUState *cs, target_ulong ret, + target_ulong err) +{ + if (!err) { + ret = 0; + } + common_semi_cb(cs, ret, err); +} + /* * Return an address in target memory of 64 bytes where the remote * gdb should write its stat struct. (The format of this structure @@ -290,7 +292,6 @@ common_semi_flen_cb(CPUState *cs, target_ulong ret, target_ulong err) * via common_semi_cb. */ typedef void sys_isattyfn(CPUState *cs, GuestFD *gf); -typedef void sys_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset); typedef void sys_flenfn(CPUState *cs, GuestFD *gf); static void host_isattyfn(CPUState *cs, GuestFD *gf) @@ -298,12 +299,6 @@ static void host_isattyfn(CPUState *cs, GuestFD *gf) common_semi_cb(cs, isatty(gf->hostfd), 0); } -static void host_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset) -{ - off_t ret = lseek(gf->hostfd, offset, SEEK_SET); - common_semi_cb(cs, ret, ret == -1 ? errno : 0); -} - static void host_flenfn(CPUState *cs, GuestFD *gf) { struct stat buf; @@ -320,11 +315,6 @@ static void gdb_isattyfn(CPUState *cs, GuestFD *gf) gdb_do_syscall(common_semi_cb, "isatty,%x", gf->hostfd); } -static void gdb_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset) -{ - gdb_do_syscall(common_semi_cb, "lseek,%x,%x,0", gf->hostfd, offset); -} - static void gdb_flenfn(CPUState *cs, GuestFD *gf) { gdb_do_syscall(common_semi_flen_cb, "fstat,%x,%x", @@ -353,12 +343,6 @@ static void staticfile_isattyfn(CPUState *cs, GuestFD *gf) common_semi_cb(cs, 0, 0); } -static void staticfile_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset) -{ - gf->staticfile.off = offset; - common_semi_cb(cs, 0, 0); -} - static void staticfile_flenfn(CPUState *cs, GuestFD *gf) { common_semi_cb(cs, gf->staticfile.len, 0); @@ -366,24 +350,20 @@ static void staticfile_flenfn(CPUState *cs, GuestFD *gf) typedef struct GuestFDFunctions { sys_isattyfn *isattyfn; - sys_seekfn *seekfn; sys_flenfn *flenfn; } GuestFDFunctions; static const GuestFDFunctions guestfd_fns[] = { [GuestFDHost] = { .isattyfn = host_isattyfn, - .seekfn = host_seekfn, .flenfn = host_flenfn, }, [GuestFDGDB] = { .isattyfn = gdb_isattyfn, - .seekfn = gdb_seekfn, .flenfn = gdb_flenfn, }, [GuestFDStatic] = { .isattyfn = staticfile_isattyfn, - .seekfn = staticfile_seekfn, .flenfn = staticfile_flenfn, }, }; @@ -520,12 +500,7 @@ void do_common_semihosting(CPUState *cs) case TARGET_SYS_SEEK: GET_ARG(0); GET_ARG(1); - - gf = get_guestfd(arg0); - if (!gf) { - goto do_badf; - } - guestfd_fns[gf->type].seekfn(cs, gf, arg1); + semihost_sys_lseek(cs, common_semi_seek_cb, arg0, arg1, GDB_SEEK_SET); break; case TARGET_SYS_FLEN: diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c index eefbae74f1..9e3eb464b5 100644 --- a/semihosting/syscalls.c +++ b/semihosting/syscalls.c @@ -114,6 +114,13 @@ static void gdb_write(CPUState *cs, gdb_syscall_complete_cb complete, (target_ulong)gf->hostfd, buf, len); } +static void gdb_lseek(CPUState *cs, gdb_syscall_complete_cb complete, + GuestFD *gf, int64_t off, int gdb_whence) +{ + gdb_do_syscall(complete, "lseek,%x,%lx,%x", + (target_ulong)gf->hostfd, off, (target_ulong)gdb_whence); +} + /* * Host semihosting syscall implementations. */ @@ -216,6 +223,29 @@ static void host_write(CPUState *cs, gdb_syscall_complete_cb complete, unlock_user(ptr, buf, 0); } +static void host_lseek(CPUState *cs, gdb_syscall_complete_cb complete, + GuestFD *gf, int64_t off, int whence) +{ + /* So far, all hosts use the same values. */ + QEMU_BUILD_BUG_ON(GDB_SEEK_SET != SEEK_SET); + QEMU_BUILD_BUG_ON(GDB_SEEK_CUR != SEEK_CUR); + QEMU_BUILD_BUG_ON(GDB_SEEK_END != SEEK_END); + + off_t ret = off; + int err = 0; + + if (ret == off) { + ret = lseek(gf->hostfd, ret, whence); + if (ret == -1) { + err = errno; + } + } else { + ret = -1; + err = EINVAL; + } + complete(cs, ret, err); +} + /* * Static file semihosting syscall implementations. */ @@ -241,6 +271,33 @@ static void staticfile_read(CPUState *cs, gdb_syscall_complete_cb complete, unlock_user(ptr, buf, len); } +static void staticfile_lseek(CPUState *cs, gdb_syscall_complete_cb complete, + GuestFD *gf, int64_t off, int gdb_whence) +{ + int64_t ret; + + switch (gdb_whence) { + case GDB_SEEK_SET: + ret = off; + break; + case GDB_SEEK_CUR: + ret = gf->staticfile.off + off; + break; + case GDB_SEEK_END: + ret = gf->staticfile.len + off; + break; + default: + ret = -1; + break; + } + if (ret >= 0 && ret <= gf->staticfile.len) { + gf->staticfile.off = ret; + complete(cs, ret, 0); + } else { + complete(cs, -1, EINVAL); + } +} + /* * Syscall entry points. */ @@ -356,3 +413,27 @@ void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete, complete(cs, -1, EBADF); } } + +void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete, + int fd, int64_t off, int gdb_whence) +{ + GuestFD *gf = get_guestfd(fd); + + if (!gf) { + complete(cs, -1, EBADF); + return; + } + switch (gf->type) { + case GuestFDGDB: + gdb_lseek(cs, complete, gf, off, gdb_whence); + return; + case GuestFDHost: + host_lseek(cs, complete, gf, off, gdb_whence); + break; + case GuestFDStatic: + staticfile_lseek(cs, complete, gf, off, gdb_whence); + break; + default: + g_assert_not_reached(); + } +}