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linux-user: Clean up arg_start/arg_end confusion

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We had two sets of variables: arg_start/arg_end, and
arg_strings/env_strings.  In linuxload.c, we set the
first pair to the bounds of the argv strings, but in
elfload.c, we set the first pair to the bounds of the
argv pointers and the second pair to the bounds of
the argv strings.

Remove arg_start/arg_end, replacing them with the standard
argc/argv/envc/envp values.  Retain arg_strings/env_strings
with the meaning we were using in elfload.c.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/714
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220427025129.160184-1-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson 2022-04-26 19:51:29 -07:00 committed by Laurent Vivier
parent 3757b0d08b
commit 60f1c8017a
5 changed files with 28 additions and 14 deletions
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10
linux-user/elfload.c
View File

@ -1516,8 +1516,8 @@ static inline void init_thread(struct target_pt_regs *regs,
regs->iaoq[0] = infop->entry;
regs->iaoq[1] = infop->entry + 4;
regs->gr[23] = 0;
regs->gr[24] = infop->arg_start;
regs->gr[25] = (infop->arg_end - infop->arg_start) / sizeof(abi_ulong);
regs->gr[24] = infop->argv;
regs->gr[25] = infop->argc;
/* The top-of-stack contains a linkage buffer. */
regs->gr[30] = infop->start_stack + 64;
regs->gr[31] = infop->entry;
@ -2120,8 +2120,10 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
u_envp = u_argv + (argc + 1) * n;
u_auxv = u_envp + (envc + 1) * n;
info->saved_auxv = u_auxv;
info->arg_start = u_argv;
info->arg_end = u_argv + argc * n;
info->argc = argc;
info->envc = envc;
info->argv = u_argv;
info->envp = u_envp;
/* This is correct because Linux defines
* elf_addr_t as Elf32_Off / Elf64_Off

12
linux-user/linuxload.c
View File

@ -92,6 +92,11 @@ abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
envp = sp;
sp -= (argc + 1) * n;
argv = sp;
ts->info->envp = envp;
ts->info->envc = envc;
ts->info->argv = argv;
ts->info->argc = argc;
if (push_ptr) {
/* FIXME - handle put_user() failures */
sp -= n;
@ -99,19 +104,22 @@ abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
sp -= n;
put_user_ual(argv, sp);
}
sp -= n;
/* FIXME - handle put_user() failures */
put_user_ual(argc, sp);
ts->info->arg_start = stringp;
ts->info->arg_strings = stringp;
while (argc-- > 0) {
/* FIXME - handle put_user() failures */
put_user_ual(stringp, argv);
argv += n;
stringp += target_strlen(stringp) + 1;
}
ts->info->arg_end = stringp;
/* FIXME - handle put_user() failures */
put_user_ual(0, argv);
ts->info->env_strings = stringp;
while (envc-- > 0) {
/* FIXME - handle put_user() failures */
put_user_ual(stringp, envp);

4
linux-user/main.c
View File

@ -878,9 +878,9 @@ int main(int argc, char **argv, char **envp)
fprintf(f, "entry 0x" TARGET_ABI_FMT_lx "\n",
info->entry);
fprintf(f, "argv_start 0x" TARGET_ABI_FMT_lx "\n",
info->arg_start);
info->argv);
fprintf(f, "env_start 0x" TARGET_ABI_FMT_lx "\n",
info->arg_end + (abi_ulong)sizeof(abi_ulong));
info->envp);
fprintf(f, "auxv_start 0x" TARGET_ABI_FMT_lx "\n",
info->saved_auxv);
qemu_log_unlock(f);

12
linux-user/qemu.h
View File

@ -40,15 +40,19 @@ struct image_info {
abi_ulong data_offset;
abi_ulong saved_auxv;
abi_ulong auxv_len;
abi_ulong arg_start;
abi_ulong arg_end;
abi_ulong arg_strings;
abi_ulong env_strings;
abi_ulong argc;
abi_ulong argv;
abi_ulong envc;
abi_ulong envp;
abi_ulong file_string;
uint32_t elf_flags;
int personality;
abi_ulong alignment;
/* Generic semihosting knows about these pointers. */
abi_ulong arg_strings; /* strings for argv */
abi_ulong env_strings; /* strings for envp; ends arg_strings */
/* The fields below are used in FDPIC mode. */
abi_ulong loadmap_addr;
uint16_t nsegs;

4
semihosting/arm-compat-semi.c
View File

@ -1106,7 +1106,7 @@ target_ulong do_common_semihosting(CPUState *cs)
#else
unsigned int i;
output_size = ts->info->arg_end - ts->info->arg_start;
output_size = ts->info->env_strings - ts->info->arg_strings;
if (!output_size) {
/*
* We special-case the "empty command line" case (argc==0).
@ -1146,7 +1146,7 @@ target_ulong do_common_semihosting(CPUState *cs)
goto out;
}
if (copy_from_user(output_buffer, ts->info->arg_start,
if (copy_from_user(output_buffer, ts->info->arg_strings,
output_size)) {
errno = EFAULT;
status = set_swi_errno(cs, -1);