Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree
Signed-off-by: Elena Afanasova <eafanas...@gmail.com>
---
bsd-user/elfload.c | 79 ++++++++--------------------------------------
1 file changed, 14 insertions(+), 65 deletions(-)
diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c
index 32378af7b2..bc4be4c874 100644
--- a/bsd-user/elfload.c
+++ b/bsd-user/elfload.c
@@ -838,7 +838,7 @@ static abi_ulong load_elf_interp(struct elfhdr *
interp_elf_ex,
int interpreter_fd,
abi_ulong *interp_load_addr)
{
- struct elf_phdr *elf_phdata = NULL;
+ g_autofree struct elf_phdr *elf_phdata = NULL;
struct elf_phdr *eppnt;
abi_ulong load_addr = 0;
int load_addr_set = 0;
@@ -867,18 +867,13 @@ static abi_ulong load_elf_interp(struct elfhdr *
interp_elf_ex,
if (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum >
TARGET_PAGE_SIZE)
return ~(abi_ulong)0UL;
- elf_phdata = (struct elf_phdr *)
- malloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);
-
- if (!elf_phdata)
- return ~((abi_ulong)0UL);
+ elf_phdata = g_new(struct elf_phdr, interp_elf_ex->e_phnum);
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr)) {
- free(elf_phdata);
return ~((abi_ulong)0UL);
}
@@ -891,7 +886,6 @@ static abi_ulong load_elf_interp(struct elfhdr *
interp_elf_ex,
if (retval < 0) {
perror("load_elf_interp");
exit(-1);
- free (elf_phdata);
return retval;
}
#ifdef BSWAP_NEEDED
@@ -940,7 +934,6 @@ static abi_ulong load_elf_interp(struct elfhdr *
interp_elf_ex,
if (error == -1) {
/* Real error */
close(interpreter_fd);
- free(elf_phdata);
return ~((abi_ulong)0UL);
}
@@ -983,7 +976,6 @@ static abi_ulong load_elf_interp(struct elfhdr *
interp_elf_ex,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE|MAP_ANON, -1, 0);
}
- free(elf_phdata);
*interp_load_addr = load_addr;
return ((abi_ulong) interp_elf_ex->e_entry) + load_addr;
@@ -1036,9 +1028,10 @@ static void load_symbols(struct elfhdr *hdr, int fd)
{
unsigned int i, nsyms;
struct elf_shdr sechdr, symtab, strtab;
- char *strings;
- struct syminfo *s;
- struct elf_sym *syms, *new_syms;
+ g_autofree char *strings = NULL;
+ g_autofree struct syminfo *s = NULL;
+ g_autofree struct elf_sym *syms = NULL;
+ struct elf_sym *new_syms;
lseek(fd, hdr->e_shoff, SEEK_SET);
for (i = 0; i < hdr->e_shnum; i++) {
@@ -1064,24 +1057,12 @@ static void load_symbols(struct elfhdr *hdr, int fd)
found:
/* Now know where the strtab and symtab are. Snarf them. */
- s = malloc(sizeof(*s));
- syms = malloc(symtab.sh_size);
- if (!syms) {
- free(s);
- return;
- }
- s->disas_strtab = strings = malloc(strtab.sh_size);
- if (!s->disas_strtab) {
- free(s);
- free(syms);
- return;
- }
+ s = g_new(struct syminfo, 1);
+ syms = g_malloc(symtab.sh_size);
+ s->disas_strtab = strings = g_new(char, strtab.sh_size);
lseek(fd, symtab.sh_offset, SEEK_SET);
if (read(fd, syms, symtab.sh_size) != symtab.sh_size) {
- free(s);
- free(syms);
- free(strings);
return;
}
@@ -1113,22 +1094,13 @@ static void load_symbols(struct elfhdr *hdr, int fd)
that we threw away. Whether or not this has any effect on the
memory allocation depends on the malloc implementation and how
many symbols we managed to discard. */
- new_syms = realloc(syms, nsyms * sizeof(*syms));
- if (new_syms == NULL) {
- free(s);
- free(syms);
- free(strings);
- return;
- }
+ new_syms = g_realloc(syms, nsyms * sizeof(*syms));
syms = new_syms;
qsort(syms, nsyms, sizeof(*syms), symcmp);
lseek(fd, strtab.sh_offset, SEEK_SET);
if (read(fd, strings, strtab.sh_size) != strtab.sh_size) {
- free(s);
- free(syms);
- free(strings);
return;
}
s->disas_num_syms = nsyms;
@@ -1156,10 +1128,10 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
unsigned char ibcs2_interpreter;
int i;
struct elf_phdr * elf_ppnt;
- struct elf_phdr *elf_phdata;
+ g_autofree struct elf_phdr *elf_phdata = NULL;
abi_ulong elf_bss, k, elf_brk;
int retval;
- char * elf_interpreter;
+ g_autofree char *elf_interpreter = NULL;
abi_ulong elf_entry, interp_load_addr = 0;
abi_ulong start_code, end_code, start_data, end_data;
abi_ulong reloc_func_desc = 0;
@@ -1190,10 +1162,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
}
/* Now read in all of the header information */
- elf_phdata = (struct elf_phdr *)malloc(elf_ex.e_phentsize*elf_ex.e_phnum);
- if (elf_phdata == NULL) {
- return -ENOMEM;
- }
+ elf_phdata = g_new(struct elf_phdr, elf_ex.e_phnum);
retval = lseek(bprm->fd, elf_ex.e_phoff, SEEK_SET);
if(retval > 0) {
@@ -1204,7 +1173,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
if (retval < 0) {
perror("load_elf_binary");
exit(-1);
- free (elf_phdata);
return -errno;
}
@@ -1220,7 +1188,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
elf_brk = 0;
- elf_interpreter = NULL;
start_code = ~((abi_ulong)0UL);
end_code = 0;
start_data = 0;
@@ -1231,8 +1198,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
if (elf_ppnt->p_type == PT_INTERP) {
if ( elf_interpreter != NULL )
{
- free (elf_phdata);
- free(elf_interpreter);
close(bprm->fd);
return -EINVAL;
}
@@ -1242,13 +1207,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
* is an a.out format binary
*/
- elf_interpreter = (char *)malloc(elf_ppnt->p_filesz);
-
- if (elf_interpreter == NULL) {
- free (elf_phdata);
- close(bprm->fd);
- return -ENOMEM;
- }
+ elf_interpreter = g_new(char, elf_ppnt->p_filesz);
retval = lseek(bprm->fd, elf_ppnt->p_offset, SEEK_SET);
if(retval >= 0) {
@@ -1298,8 +1257,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
if (retval < 0) {
perror("load_elf_binary3");
exit(-1);
- free (elf_phdata);
- free(elf_interpreter);
close(bprm->fd);
return retval;
}
@@ -1323,8 +1280,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
}
if (!interpreter_type) {
- free(elf_interpreter);
- free(elf_phdata);
close(bprm->fd);
return -ELIBBAD;
}
@@ -1346,8 +1301,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
}
}
if (!bprm->p) {
- free(elf_interpreter);
- free (elf_phdata);
close(bprm->fd);
return -E2BIG;
}
@@ -1486,18 +1439,14 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
reloc_func_desc = interp_load_addr;
close(interpreter_fd);
- free(elf_interpreter);
if (elf_entry == ~((abi_ulong)0UL)) {
printf("Unable to load interpreter\n");
- free(elf_phdata);
exit(-1);
return 0;
}
}
- free(elf_phdata);
-
if (qemu_log_enabled())
load_symbols(&elf_ex, bprm->fd);
--
2.25.1
On Fri, 2020-10-02 at 10:08 -0500, Eric Blake wrote:
> On 10/2/20 3:58 AM, Markus Armbruster wrote:
>
> > > > > @@ -890,9 +886,8 @@ static abi_ulong load_elf_interp(struct
> > > > > elfhdr * interp_elf_ex,
> > > > > }
> > > > > if (retval < 0) {
> > > > > perror("load_elf_interp");
> > > > > + g_free(elf_phdata);
> > > > > exit(-1);
> > > > > - free (elf_phdata);
> > > > > - return retval;
> > > >
> > > > Deleting return looks wrong.
> > >
> > > Why? There is an exit(-1) right in front of it, so this is dead
> > > code...
> > > well, maybe that should be done in a separate patch, or at least
> > > mentioned in the patch description, though.
> >
> > You're right; I missed the exit(-1).
> >
> > Following the unpleasant odour spread by exit(-1)... Aha, the
> > function's behavior on error is inconsistent: sometimes it returns
> > zero,
> > sometimes it exits.
>
> Eradicating exit(-1) (which is indistinguishable from exit(255), and
> generally not what you want, unless your program is designed to
> specifically invoke the immediate-exit semantics of xargs) is also a
> worthwhile cleanup project. But I agree with the advice for separate
> patches for separate bugs.
>
> > Since the problem is bigger than just one dead return, I recommend
> > leaving it to a separate patch, and keeping this one focused on
> > g_new().
> >
> >
