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Make read_program_header return a gdb::byte_vector

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While reading a recent patch, I found this spot where a gdb::byte_vector
could be used instead of an allocated buffer returned as a plain
pointer.

gdb/ChangeLog:

	* solib-svr4.c (read_program_header): Return
	gdb::optional<gdb::byte_vector>, remove p_sect_size param.
	(find_program_interpreter): Return
	gdb::optional<gdb::byte_vector>.
	(scan_dyntag_auxv): Adjust.
	(enable_break): Adjust.
	(svr4_exec_displacement): Adjust.
This commit is contained in:
Simon Marchi 2018-08-22 14:17:57 -04:00 committed by Simon Marchi
parent 4e2aa47284
commit 17658d46e4
2 changed files with 70 additions and 71 deletions
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10
gdb/ChangeLog
View File

@ -1,3 +1,13 @@
2018-08-22 Simon Marchi <simon.marchi@polymtl.ca>
* solib-svr4.c (read_program_header): Return
gdb::optional<gdb::byte_vector>, remove p_sect_size param.
(find_program_interpreter): Return
gdb::optional<gdb::byte_vector>.
(scan_dyntag_auxv): Adjust.
(enable_break): Adjust.
(svr4_exec_displacement): Adjust.
2018-08-22 Simon Marchi <simon.marchi@polymtl.ca>
* inf-child.h (inf_child_target) <terminal_save_inferior>: New.

131
gdb/solib-svr4.c
View File

@ -409,37 +409,34 @@ get_svr4_info (void)
static int match_main (const char *);
/* Read program header TYPE from inferior memory. The header is found
by scanning the OS auxillary vector.
by scanning the OS auxiliary vector.
If TYPE == -1, return the program headers instead of the contents of
one program header.
Return a pointer to allocated memory holding the program header contents,
or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
size of those contents is returned to P_SECT_SIZE. Likewise, the target
architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE and
the base address of the section is returned in BASE_ADDR. */
Return vector of bytes holding the program header contents, or an empty
optional on failure. If successful and P_ARCH_SIZE is non-NULL, the target
architecture size (32-bit or 64-bit) is returned to *P_ARCH_SIZE. Likewise,
the base address of the section is returned in *BASE_ADDR. */
static gdb_byte *
read_program_header (int type, int *p_sect_size, int *p_arch_size,
CORE_ADDR *base_addr)
static gdb::optional<gdb::byte_vector>
read_program_header (int type, int *p_arch_size, CORE_ADDR *base_addr)
{
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0;
int arch_size, sect_size;
CORE_ADDR sect_addr;
gdb_byte *buf;
int pt_phdr_p = 0;
/* Get required auxv elements from target. */
if (target_auxv_search (current_top_target (), AT_PHDR, &at_phdr) <= 0)
return 0;
return {};
if (target_auxv_search (current_top_target (), AT_PHENT, &at_phent) <= 0)
return 0;
return {};
if (target_auxv_search (current_top_target (), AT_PHNUM, &at_phnum) <= 0)
return 0;
return {};
if (!at_phdr || !at_phnum)
return 0;
return {};
/* Determine ELF architecture type. */
if (at_phent == sizeof (Elf32_External_Phdr))
@ -447,7 +444,7 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
else if (at_phent == sizeof (Elf64_External_Phdr))
arch_size = 64;
else
return 0;
return {};
/* Find the requested segment. */
if (type == -1)
@ -467,7 +464,7 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
if (target_read_memory (at_phdr + i * sizeof (phdr),
(gdb_byte *)&phdr, sizeof (phdr)))
return 0;
return {};
p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
4, byte_order);
@ -484,7 +481,7 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
}
if (i == at_phnum)
return 0;
return {};
/* Retrieve address and size. */
sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
@ -504,7 +501,7 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
if (target_read_memory (at_phdr + i * sizeof (phdr),
(gdb_byte *)&phdr, sizeof (phdr)))
return 0;
return {};
p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
4, byte_order);
@ -521,7 +518,7 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
}
if (i == at_phnum)
return 0;
return {};
/* Retrieve address and size. */
sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
@ -541,17 +538,12 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
}
/* Read in requested program header. */
buf = (gdb_byte *) xmalloc (sect_size);
if (target_read_memory (sect_addr, buf, sect_size))
{
xfree (buf);
return NULL;
}
gdb::byte_vector buf (sect_size);
if (target_read_memory (sect_addr, buf.data (), sect_size))
return {};
if (p_arch_size)
*p_arch_size = arch_size;
if (p_sect_size)
*p_sect_size = sect_size;
if (base_addr)
*base_addr = sect_addr;
@ -560,11 +552,9 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
/* Return program interpreter string. */
static char *
static gdb::optional<gdb::byte_vector>
find_program_interpreter (void)
{
gdb_byte *buf = NULL;
/* If we have an exec_bfd, use its section table. */
if (exec_bfd
&& bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
@ -576,16 +566,15 @@ find_program_interpreter (void)
{
int sect_size = bfd_section_size (exec_bfd, interp_sect);
buf = (gdb_byte *) xmalloc (sect_size);
bfd_get_section_contents (exec_bfd, interp_sect, buf, 0, sect_size);
gdb::byte_vector buf (sect_size);
bfd_get_section_contents (exec_bfd, interp_sect, buf.data (), 0,
sect_size);
return buf;
}
}
/* If we didn't find it, use the target auxillary vector. */
if (!buf)
buf = read_program_header (PT_INTERP, NULL, NULL, NULL);
return (char *) buf;
/* If we didn't find it, use the target auxiliary vector. */
return read_program_header (PT_INTERP, NULL, NULL);
}
@ -700,24 +689,22 @@ scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr,
CORE_ADDR *ptr_addr)
{
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
int sect_size, arch_size, step;
int arch_size, step;
long current_dyntag;
CORE_ADDR dyn_ptr;
CORE_ADDR base_addr;
gdb_byte *bufend, *bufstart, *buf;
/* Read in .dynamic section. */
buf = bufstart = read_program_header (PT_DYNAMIC, &sect_size, &arch_size,
&base_addr);
if (!buf)
gdb::optional<gdb::byte_vector> ph_data
= read_program_header (PT_DYNAMIC, &arch_size, &base_addr);
if (!ph_data)
return 0;
/* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
step = (arch_size == 32) ? sizeof (Elf32_External_Dyn)
: sizeof (Elf64_External_Dyn);
for (bufend = buf + sect_size;
buf < bufend;
buf += step)
for (gdb_byte *buf = ph_data->data (), *bufend = buf + ph_data->size ();
buf < bufend; buf += step)
{
if (arch_size == 32)
{
@ -746,14 +733,12 @@ scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr,
*ptr = dyn_ptr;
if (ptr_addr)
*ptr_addr = base_addr + buf - bufstart;
*ptr_addr = base_addr + buf - ph_data->data ();
xfree (bufstart);
return 1;
}
}
xfree (bufstart);
return 0;
}
@ -2197,7 +2182,6 @@ enable_break (struct svr4_info *info, int from_tty)
struct bound_minimal_symbol msymbol;
const char * const *bkpt_namep;
asection *interp_sect;
char *interp_name;
CORE_ADDR sym_addr;
info->interp_text_sect_low = info->interp_text_sect_high = 0;
@ -2280,9 +2264,11 @@ enable_break (struct svr4_info *info, int from_tty)
/* Find the program interpreter; if not found, warn the user and drop
into the old breakpoint at symbol code. */
interp_name = find_program_interpreter ();
if (interp_name)
gdb::optional<gdb::byte_vector> interp_name_holder
= find_program_interpreter ();
if (interp_name_holder)
{
const char *interp_name = (const char *) interp_name_holder->data ();
CORE_ADDR load_addr = 0;
int load_addr_found = 0;
int loader_found_in_list = 0;
@ -2436,14 +2422,12 @@ enable_break (struct svr4_info *info, int from_tty)
{
svr4_create_solib_event_breakpoints (target_gdbarch (),
load_addr + sym_addr);
xfree (interp_name);
return 1;
}
/* For whatever reason we couldn't set a breakpoint in the dynamic
linker. Warn and drop into the old code. */
bkpt_at_symbol:
xfree (interp_name);
warning (_("Unable to find dynamic linker breakpoint function.\n"
"GDB will be unable to debug shared library initializers\n"
"and track explicitly loaded dynamic code."));
@ -2467,7 +2451,7 @@ enable_break (struct svr4_info *info, int from_tty)
}
}
if (interp_name != NULL && !current_inferior ()->attach_flag)
if (interp_name_holder && !current_inferior ()->attach_flag)
{
for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
{
@ -2604,13 +2588,14 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
{
/* Be optimistic and clear OK only if GDB was able to verify the headers
really do not match. */
int phdrs_size, phdrs2_size, ok = 1;
gdb_byte *buf, *buf2;
int phdrs2_size, ok = 1;
gdb_byte *buf2;
int arch_size;
buf = read_program_header (-1, &phdrs_size, &arch_size, NULL);
gdb::optional<gdb::byte_vector> phdrs_target
= read_program_header (-1, &arch_size, NULL);
buf2 = read_program_headers_from_bfd (exec_bfd, &phdrs2_size);
if (buf != NULL && buf2 != NULL)
if (phdrs_target && buf2 != NULL)
{
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
@ -2627,12 +2612,12 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
content offset for the verification purpose. */
if (phdrs_size != phdrs2_size
if (phdrs_target->size () != phdrs2_size
|| bfd_get_arch_size (exec_bfd) != arch_size)
ok = 0;
else if (arch_size == 32
&& phdrs_size >= sizeof (Elf32_External_Phdr)
&& phdrs_size % sizeof (Elf32_External_Phdr) == 0)
&& phdrs_target->size () >= sizeof (Elf32_External_Phdr)
&& phdrs_target->size () % sizeof (Elf32_External_Phdr) == 0)
{
Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
@ -2653,7 +2638,7 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
CORE_ADDR displacement_vaddr = 0;
CORE_ADDR displacement_paddr = 0;
phdrp = &((Elf32_External_Phdr *) buf)[i];
phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i];
buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
@ -2671,9 +2656,12 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
break;
}
/* Now compare BUF and BUF2 with optional DISPLACEMENT. */
/* Now compare program headers from the target and the binary
with optional DISPLACEMENT. */
for (i = 0; i < phdrs_size / sizeof (Elf32_External_Phdr); i++)
for (i = 0;
i < phdrs_target->size () / sizeof (Elf32_External_Phdr);
i++)
{
Elf32_External_Phdr *phdrp;
Elf32_External_Phdr *phdr2p;
@ -2681,7 +2669,7 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
CORE_ADDR vaddr, paddr;
asection *plt2_asect;
phdrp = &((Elf32_External_Phdr *) buf)[i];
phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i];
buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
phdr2p = &((Elf32_External_Phdr *) buf2)[i];
@ -2764,8 +2752,8 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
}
}
else if (arch_size == 64
&& phdrs_size >= sizeof (Elf64_External_Phdr)
&& phdrs_size % sizeof (Elf64_External_Phdr) == 0)
&& phdrs_target->size () >= sizeof (Elf64_External_Phdr)
&& phdrs_target->size () % sizeof (Elf64_External_Phdr) == 0)
{
Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
@ -2786,7 +2774,7 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
CORE_ADDR displacement_vaddr = 0;
CORE_ADDR displacement_paddr = 0;
phdrp = &((Elf64_External_Phdr *) buf)[i];
phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i];
buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
@ -2806,7 +2794,9 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
/* Now compare BUF and BUF2 with optional DISPLACEMENT. */
for (i = 0; i < phdrs_size / sizeof (Elf64_External_Phdr); i++)
for (i = 0;
i < phdrs_target->size () / sizeof (Elf64_External_Phdr);
i++)
{
Elf64_External_Phdr *phdrp;
Elf64_External_Phdr *phdr2p;
@ -2814,7 +2804,7 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
CORE_ADDR vaddr, paddr;
asection *plt2_asect;
phdrp = &((Elf64_External_Phdr *) buf)[i];
phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i];
buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
phdr2p = &((Elf64_External_Phdr *) buf2)[i];
@ -2900,7 +2890,6 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
ok = 0;
}
xfree (buf);
xfree (buf2);
if (!ok)