| Message ID | 20201001123807.42978-1-eafanasova@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | elfload: use g_new instead of malloc | expand |
On 01/10/2020 14.38, Elena Afanasova wrote: > Signed-off-by: Elena Afanasova <eafanasova@gmail.com> > --- > bsd-user/elfload.c | 92 +++++++++++++++------------------------------- > 1 file changed, 30 insertions(+), 62 deletions(-) > > diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c > index 32378af7b2..e10ca54eb7 100644 > --- a/bsd-user/elfload.c > +++ b/bsd-user/elfload.c > @@ -867,18 +867,14 @@ 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); > + g_free(elf_phdata); > return ~((abi_ulong)0UL); > } > > @@ -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; > } > #ifdef BSWAP_NEEDED > eppnt = elf_phdata; > @@ -940,7 +935,7 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, > if (error == -1) { > /* Real error */ > close(interpreter_fd); > - free(elf_phdata); > + g_free(elf_phdata); > return ~((abi_ulong)0UL); > } > > @@ -983,7 +978,7 @@ 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); > + g_free(elf_phdata); > > *interp_load_addr = load_addr; > return ((abi_ulong) interp_elf_ex->e_entry) + load_addr; > @@ -1064,24 +1059,15 @@ 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_new(symtab.sh_size, 1); > + s->disas_strtab = strings = g_new(strtab.sh_size, 1); > > lseek(fd, symtab.sh_offset, SEEK_SET); > if (read(fd, syms, symtab.sh_size) != symtab.sh_size) { > - free(s); > - free(syms); > - free(strings); > + g_free(s); > + g_free(syms); > + g_free(strings); > return; > } > > @@ -1113,22 +1099,16 @@ 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); > + g_free(s); > + g_free(syms); > + g_free(strings); > return; > } [...] Hi! That clean-up sounds like a very good idea ... but I think this would be a perfect place to use g_autofree in the declaration of the variables, then you can get rid of the free() calls completely! Thomas
Elena Afanasova <eafanasova@gmail.com> writes: > Signed-off-by: Elena Afanasova <eafanasova@gmail.com> > --- > bsd-user/elfload.c | 92 +++++++++++++++------------------------------- > 1 file changed, 30 insertions(+), 62 deletions(-) > > diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c > index 32378af7b2..e10ca54eb7 100644 > --- a/bsd-user/elfload.c > +++ b/bsd-user/elfload.c > @@ -867,18 +867,14 @@ 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); > + g_free(elf_phdata); > return ~((abi_ulong)0UL); > } > > @@ -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. > } > #ifdef BSWAP_NEEDED > eppnt = elf_phdata; > @@ -940,7 +935,7 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, > if (error == -1) { > /* Real error */ > close(interpreter_fd); > - free(elf_phdata); > + g_free(elf_phdata); > return ~((abi_ulong)0UL); > } > > @@ -983,7 +978,7 @@ 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); > + g_free(elf_phdata); > > *interp_load_addr = load_addr; > return ((abi_ulong) interp_elf_ex->e_entry) + load_addr; > @@ -1064,24 +1059,15 @@ 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_new(symtab.sh_size, 1); g_new() takes a struct type argument, symtab.sh_size is an expression. I'm pretty sure this doesn't even compile. I'm looking no further. Nacked-by: Markus Armbruster <armbru@redhat.com> [...]
On 02/10/2020 07.05, Markus Armbruster wrote: > Elena Afanasova <eafanasova@gmail.com> writes: > >> Signed-off-by: Elena Afanasova <eafanasova@gmail.com> >> --- >> bsd-user/elfload.c | 92 +++++++++++++++------------------------------- >> 1 file changed, 30 insertions(+), 62 deletions(-) >> >> diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c >> index 32378af7b2..e10ca54eb7 100644 >> --- a/bsd-user/elfload.c >> +++ b/bsd-user/elfload.c >> @@ -867,18 +867,14 @@ 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); >> + g_free(elf_phdata); >> return ~((abi_ulong)0UL); >> } >> >> @@ -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. Thomas
Thomas Huth <thuth@redhat.com> writes: > On 02/10/2020 07.05, Markus Armbruster wrote: >> Elena Afanasova <eafanasova@gmail.com> writes: >> >>> Signed-off-by: Elena Afanasova <eafanasova@gmail.com> >>> --- >>> bsd-user/elfload.c | 92 +++++++++++++++------------------------------- >>> 1 file changed, 30 insertions(+), 62 deletions(-) >>> >>> diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c >>> index 32378af7b2..e10ca54eb7 100644 >>> --- a/bsd-user/elfload.c >>> +++ b/bsd-user/elfload.c >>> @@ -867,18 +867,14 @@ 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); >>> + g_free(elf_phdata); >>> return ~((abi_ulong)0UL); >>> } >>> >>> @@ -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. 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().
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(). > > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree Signed-off-by: Elena Afanasova <eafanasova@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(). > > > >
Please don't post respins as replies, because our tooling will miss them there, and even humans may. Start a new thread instead. Next time :) Elena Afanasova <eafanasova@gmail.com> writes: > Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree > > Signed-off-by: Elena Afanasova <eafanasova@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; Note for later: @strings, @syminfo and @syms are freed on return. > > 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); The smaller change would be s = g_malloc(sizeof(*s)); Matter of taste. > + syms = g_malloc(symtab.sh_size); > + s->disas_strtab = strings = g_new(char, strtab.sh_size); I'd prefer the simpler s->disas_strtab = strings = g_malloc(strtab.sh_size); Yes, it returns void * whereas g_new() returns char *, but the char * is vanishingly unlikely to catch actual bugs. > > 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; #if ELF_CLASS == ELFCLASS32 s->disas_symtab.elf32 = syms; s->lookup_symbol = (lookup_symbol_t)lookup_symbolxx; #else s->disas_symtab.elf64 = syms; s->lookup_symbol = (lookup_symbol_t)lookup_symbolxx; #endif s->next = syminfos; syminfos = s; @strings, @syminfo and @syms are freed here. s->disas_strtab, s->disas_symtab.elf{32,64}, s->next become dangling pointers. I'd expect this to blow up. Have you tested? } > @@ -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); This assumes elf_ex.e_phentsize == sizeof(struct elf_phdr). Why is that true? > > 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); Again, I'd prefer the simpler elf_interpreter = g_malloc(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);
On Sun, 4 Oct 2020 at 13:22, Elena Afanasova <eafanasova@gmail.com> wrote: > > Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree > > Signed-off-by: Elena Afanasova <eafanasova@gmail.com> > --- > bsd-user/elfload.c | 79 ++++++++-------------------------------------- > 1 file changed, 14 insertions(+), 65 deletions(-) Random question -- how are you testing this change? (bsd-user isn't covered by 'make check' I think). thanks -- PMM
Since bsd user space emulation doesn't work for me I can only use 'gmake check'... But some tests don't seem to be supported. On Mon, 2020-10-05 at 10:55 +0100, Peter Maydell wrote: > On Sun, 4 Oct 2020 at 13:22, Elena Afanasova <eafanasova@gmail.com> > wrote: > > Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree > > > > Signed-off-by: Elena Afanasova <eafanasova@gmail.com> > > --- > > bsd-user/elfload.c | 79 ++++++++-------------------------------- > > ------ > > 1 file changed, 14 insertions(+), 65 deletions(-) > > Random question -- how are you testing this change? (bsd-user > isn't covered by 'make check' I think). > > thanks > -- PMM
diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c index 32378af7b2..e10ca54eb7 100644 --- a/bsd-user/elfload.c +++ b/bsd-user/elfload.c @@ -867,18 +867,14 @@ 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); + g_free(elf_phdata); return ~((abi_ulong)0UL); } @@ -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; } #ifdef BSWAP_NEEDED eppnt = elf_phdata; @@ -940,7 +935,7 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, if (error == -1) { /* Real error */ close(interpreter_fd); - free(elf_phdata); + g_free(elf_phdata); return ~((abi_ulong)0UL); } @@ -983,7 +978,7 @@ 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); + g_free(elf_phdata); *interp_load_addr = load_addr; return ((abi_ulong) interp_elf_ex->e_entry) + load_addr; @@ -1064,24 +1059,15 @@ 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_new(symtab.sh_size, 1); + s->disas_strtab = strings = g_new(strtab.sh_size, 1); lseek(fd, symtab.sh_offset, SEEK_SET); if (read(fd, syms, symtab.sh_size) != symtab.sh_size) { - free(s); - free(syms); - free(strings); + g_free(s); + g_free(syms); + g_free(strings); return; } @@ -1113,22 +1099,16 @@ 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); + g_free(s); + g_free(syms); + g_free(strings); return; } s->disas_num_syms = nsyms; @@ -1190,10 +1170,7 @@ 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(elf_ex.e_phentsize, elf_ex.e_phnum); retval = lseek(bprm->fd, elf_ex.e_phoff, SEEK_SET); if(retval > 0) { @@ -1203,9 +1180,8 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, if (retval < 0) { perror("load_elf_binary"); + g_free(elf_phdata); exit(-1); - free (elf_phdata); - return -errno; } #ifdef BSWAP_NEEDED @@ -1231,8 +1207,8 @@ 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); + g_free(elf_phdata); + g_free(elf_interpreter); close(bprm->fd); return -EINVAL; } @@ -1242,13 +1218,7 @@ 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(elf_ppnt->p_filesz, 1); retval = lseek(bprm->fd, elf_ppnt->p_offset, SEEK_SET); if(retval >= 0) { @@ -1297,11 +1267,10 @@ 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); + g_free(elf_phdata); + g_free(elf_interpreter); close(bprm->fd); - return retval; + exit(-1); } } elf_ppnt++; @@ -1323,8 +1292,8 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } if (!interpreter_type) { - free(elf_interpreter); - free(elf_phdata); + g_free(elf_interpreter); + g_free(elf_phdata); close(bprm->fd); return -ELIBBAD; } @@ -1346,8 +1315,8 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } } if (!bprm->p) { - free(elf_interpreter); - free (elf_phdata); + g_free(elf_interpreter); + g_free(elf_phdata); close(bprm->fd); return -E2BIG; } @@ -1486,17 +1455,16 @@ 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); + g_free(elf_interpreter); if (elf_entry == ~((abi_ulong)0UL)) { printf("Unable to load interpreter\n"); - free(elf_phdata); + g_free(elf_phdata); exit(-1); - return 0; } } - free(elf_phdata); + g_free(elf_phdata); if (qemu_log_enabled()) load_symbols(&elf_ex, bprm->fd);
Signed-off-by: Elena Afanasova <eafanasova@gmail.com> --- bsd-user/elfload.c | 92 +++++++++++++++------------------------------- 1 file changed, 30 insertions(+), 62 deletions(-)