diff options
Diffstat (limited to 'gdb/linux-tdep.c')
| -rw-r--r-- | gdb/linux-tdep.c | 73 |
1 files changed, 60 insertions, 13 deletions
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c index 5de985d..c1666d1 100644 --- a/gdb/linux-tdep.c +++ b/gdb/linux-tdep.c @@ -586,8 +586,8 @@ mapping_is_anonymous_p (const char *filename) } /* Return 0 if the memory mapping (which is related to FILTERFLAGS, V, - MAYBE_PRIVATE_P, and MAPPING_ANONYMOUS_P) should not be dumped, or - greater than 0 if it should. + MAYBE_PRIVATE_P, MAPPING_ANONYMOUS_P, ADDR and OFFSET) should not + be dumped, or greater than 0 if it should. In a nutshell, this is the logic that we follow in order to decide if a mapping should be dumped or not. @@ -625,12 +625,17 @@ mapping_is_anonymous_p (const char *filename) see 'p' in the permission flags, then we assume that the mapping is private, even though the presence of the 's' flag there would mean VM_MAYSHARE, which means the mapping could still be private. - This should work OK enough, however. */ + This should work OK enough, however. + + - Even if, at the end, we decided that we should not dump the + mapping, we still have to check if it is something like an ELF + header (of a DSO or an executable, for example). If it is, and + if the user is interested in dump it, then we should dump it. */ static int dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v, int maybe_private_p, int mapping_anon_p, int mapping_file_p, - const char *filename) + const char *filename, ULONGEST addr, ULONGEST offset) { /* Initially, we trust in what we received from our caller. This value may not be very precise (i.e., it was probably gathered @@ -640,6 +645,7 @@ dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v, (assuming that the version of the Linux kernel being used supports it, of course). */ int private_p = maybe_private_p; + int dump_p; /* We always dump vDSO and vsyscall mappings, because it's likely that there'll be no file to read the contents from at core load time. @@ -680,13 +686,13 @@ dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v, /* This is a special situation. It can happen when we see a mapping that is file-backed, but that contains anonymous pages. */ - return ((filterflags & COREFILTER_ANON_PRIVATE) != 0 - || (filterflags & COREFILTER_MAPPED_PRIVATE) != 0); + dump_p = ((filterflags & COREFILTER_ANON_PRIVATE) != 0 + || (filterflags & COREFILTER_MAPPED_PRIVATE) != 0); } else if (mapping_anon_p) - return (filterflags & COREFILTER_ANON_PRIVATE) != 0; + dump_p = (filterflags & COREFILTER_ANON_PRIVATE) != 0; else - return (filterflags & COREFILTER_MAPPED_PRIVATE) != 0; + dump_p = (filterflags & COREFILTER_MAPPED_PRIVATE) != 0; } else { @@ -695,14 +701,55 @@ dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v, /* This is a special situation. It can happen when we see a mapping that is file-backed, but that contains anonymous pages. */ - return ((filterflags & COREFILTER_ANON_SHARED) != 0 - || (filterflags & COREFILTER_MAPPED_SHARED) != 0); + dump_p = ((filterflags & COREFILTER_ANON_SHARED) != 0 + || (filterflags & COREFILTER_MAPPED_SHARED) != 0); } else if (mapping_anon_p) - return (filterflags & COREFILTER_ANON_SHARED) != 0; + dump_p = (filterflags & COREFILTER_ANON_SHARED) != 0; else - return (filterflags & COREFILTER_MAPPED_SHARED) != 0; + dump_p = (filterflags & COREFILTER_MAPPED_SHARED) != 0; } + + /* Even if we decided that we shouldn't dump this mapping, we still + have to check whether (a) the user wants us to dump mappings + containing an ELF header, and (b) the mapping in question + contains an ELF header. If (a) and (b) are true, then we should + dump this mapping. + + A mapping contains an ELF header if it is a private mapping, its + offset is zero, and its first word is ELFMAG. */ + if (!dump_p && private_p && offset == 0 + && (filterflags & COREFILTER_ELF_HEADERS) != 0) + { + /* Let's check if we have an ELF header. */ + gdb::unique_xmalloc_ptr<char> header; + int errcode; + + /* Useful define specifying the size of the ELF magical + header. */ +#ifndef SELFMAG +#define SELFMAG 4 +#endif + + /* Read the first SELFMAG bytes and check if it is ELFMAG. */ + if (target_read_string (addr, &header, SELFMAG, &errcode) == SELFMAG + && errcode == 0) + { + const char *h = header.get (); + + /* The EI_MAG* and ELFMAG* constants come from + <elf/common.h>. */ + if (h[EI_MAG0] == ELFMAG0 && h[EI_MAG1] == ELFMAG1 + && h[EI_MAG2] == ELFMAG2 && h[EI_MAG3] == ELFMAG3) + { + /* This mapping contains an ELF header, so we + should dump it. */ + dump_p = 1; + } + } + } + + return dump_p; } /* Implement the "info proc" command. */ @@ -1306,7 +1353,7 @@ linux_find_memory_regions_full (struct gdbarch *gdbarch, if (has_anonymous) should_dump_p = dump_mapping_p (filterflags, &v, priv, mapping_anon_p, mapping_file_p, - filename); + filename, addr, offset); else { /* Older Linux kernels did not support the "Anonymous:" counter. |